|
|||||||
Deposition from United States v. SFWMD, et al., Case No. 88-1886-CIV-HOEVELER |
|||||||
|
|||||||
|
|||||||
|
|||||||
Deposition from United States v. SFWMD, et al., Case No. 88-1886-CIV-HOEVELER |
|||||||
|
|||||||
|
|||||||
1227
1 UNITED STATES DISTRICT COURT
FOR THE
2 SOUTHERN DISTRICT OF FLORIDA
3
****************************
4 UNITED STATES OF AMERICA, *
Plaintiff *
5 * Case Number
VS. * 88-1886-CIV
6 * Hoeveler
SOUTH FLORIDA WATER *
7 MANAGEMENT DISTRICT, ET AL., *
Defendants *
8 *****************************
9
10 Deposition of WILLIAM W. WALKER, JR.,
11 taken on behalf of the defendants South Florida
12 Water Management District and John R. Wodraska
13 pursuant to the applicable rules of the Federal
14 Rules of Civil Procedure, before Linda Marie
15 MacDonald, Registered Professional Reporter and
16 Notary Public within and for the Commonwealth
17 of Massachusetts, at the offices of Skadden,
18 Arps, Slate, Meagher & Flom, One Beacon Street,
19 Boston, Massachusetts, on Thursday,
20 February 14, 1991, commencing at 9:05 a.m.
21
22
23 LINDA MARIE MacDONALD, RPR-CM
REGISTERED PROFESSIONAL REPORTER
24 60 LAWRENCE ROAD, PLYMOUTH, MA 02360
(508) 747-6615
1228
1 A P P E A R A N C E S:
2 UNITED STATES ATTORNEY'S OFFICE
By AUSA Richard Harrison
3 155 South Miami Avenue, Suite 600
Miami, FL 33130
4 for the United States of America.
5 SKADDEN, ARPS, SLATE, MEAGHER & FLOM
By Attorney Laura B. Ahearn
6 1440 New York Ave., N.W.
Washington, D.C. 20005
7 for South Florida Water Management
District and John R. Wodraska.
8
PEEPLES, EARL & BLANK
9 By Attorney Rick J. Burgess
One Biscayne Tower, Suite 3636
10 Miami, FL 33131
for the cities of Belle Glade and
11 Clewiston, defendant intervenors.
12 STATE OF FLORIDA OFFICE OF GENERAL COUNSEL
By Asst. Gen. Counsel David A. Crowley
13 Department of Environmental Regulation
Twin Towers Office Building
14 2600 Blair Stone Road
Tallahassee, FL 332301
15 for the Florida Department of
Environmental Regulation.
16
17
18
19
20
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1229
1 I N D E X
Witnesses Examination
2
WILLIAM W. WALKER, JR.
3 (By Ms. Ahearn) 1230
(By Mr. Crowley) 1284
4 (By Mr. Burgess) 1297
5
E X H I B I T S
6
Number For ID
7
DX 79 Fax Cover Sheet dated 11/22/89 1312
8 to Higer from Walker, with
attachments (S12 Flows retrieved
9 from SWFMD Hydro. Database)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1230
1 P R O C E E D I N G S
2 WILLIAM W. WALKER, JR.,
3 having been previously duly sworn, was deposed
4 and testified as follows:
5 CONTINUED DIRECT EXAMINATION
6 BY MS. AHEARN:
7 Q. Good morning, Dr. Walker.
8 A. Good morning, Ms. Ahearn.
9 Q. By whom is Jim Loftis employed?
10 A. I believe it's Colorado State University.
11 Q. And that's Jim Loftis who performed the
12 analysis of your draft trends analysis report
13 in Exhibit 10?
14 A. Yes.
15 Q. I just wanted to make sure we have the right
16 individual.
17 Dr. Walker, can you, please, identify
18 Exhibit 77?
19 A. Exhibit 77 is a table entitled Wetland P
20 Balance Data, with six figures attached to it.
21 Q. Did you create this document or the documents
22 comprising Exhibit 77?
23 A. Yes, I did.
24 Q. Could you, please, explain to us what appears
DEPOSITION OF WILLIAM W. WALKER, JR.
1231
1 on the first page?
2 A. The first page contains data on phosphorus and
3 nitrogen loadings and removal efficiencies in
4 wetlands as derived from the literature.
5 Q. Am I correct that the first approximately
6 one-third of the first page reflects data
7 derived from Richardson and Nichols, a
8 publication in 1984?
9 A. Approximately. But I believe the correct date
10 would be 1985.
11 (Witness writing on exhibit)
12 Q. What is the source of the information that
13 appears on the lower two-thirds of this page?
14 A. I believe that information was extracted from
15 nutrient balance calculations that are
16 summarized in the Everglades SWIM plan.
17 Q. Do you recall which draft of the SWIM plan?
18 A. No.
19 Q. Do you recall when it is you created this
20 page 1?
21 A. Fall of 1990.
22 Q. Do the labels that appear at the top of the
23 page also apply to the columns on the lower
24 two-thirds of the page?
DEPOSITION OF WILLIAM W. WALKER, JR.
1232
1 A. I'm not sure, but I believe so, with the
2 possible exception of the column labeled YRS.
3 That's short for "years."
4 Q. So the third column from the left on the bottom
5 two-thirds of the page refers to something
6 other than the number of years in the period of
7 record?
8 A. Yes.
9 Q. What does this third column from the left on
10 the bottom two-thirds of the page reflect?
11 A. I believe it identifies the different Water
12 Conservation Areas 1, 2 or 3.
13 Q. Do the columns on the bottom two-thirds of the
14 page reflect simply your organization of data
15 from the draft SWIM plan as opposed to
16 calculations that you then performed on that
17 data?
18 A. There may have been some conversion of units
19 that was necessary in order to take the
20 information from the draft plan and put it into
21 this spreadsheet. I don't recall.
22 Q. But, for example, you didn't take some loading
23 figures and some other figures and from that
24 calculate the numbers that appear in the far
DEPOSITION OF WILLIAM W. WALKER, JR.
1233
1 right-hand column for P removal?
2 MR. HARRISON: Object to form.
3 A. Well, it could very well be that the far
4 right-hand column was a figure that was
5 calculated from the loading figures and the
6 phosphorus removal figures that were contained
7 in the SWIM plan.
8 Q. My basic question is: If I were to go to the
9 draft SWIM plans and look through it for these
10 data, will I find them there, or have you gone
11 beyond those data to calculate new values?
12 A. To the best of my recollection, the figures for
13 phosphorus load in grams per square meter per
14 year and phosphorus removal in percent were
15 derived directly from the SWIM plan, whereas
16 the figure for phosphorus removal in grams per
17 square meter per year appears to have been
18 calculated from those other two values.
19 Q. Could you, please, explain to us what the
20 remaining pages of Exhibit 77 reflect?
21 A. These are graphs of the data that's contained
22 in Table 1.
23 Q. And you created these graphs, as well?
24 A. Yes.
DEPOSITION OF WILLIAM W. WALKER, JR.
1234
1 Q. And what was your purpose in creating
2 Exhibit 77?
3 A. The purpose was to summarize phosphorus balance
4 data from wetlands that had been studied and
5 reported in the literature that were used for
6 wastewater treatment as well as phosphorus
7 balance data from the Water Conservation Areas
8 as described in the SWIM plan and to use that
9 information to examine empirical relationships
10 between phosphorus loading into wetlands and
11 phosphorus outflow from wetlands.
12 Q. How did you plan to employ this information in
13 the work you are doing or anticipate doing in
14 the South Florida litigation?
15 A. Primarily to provide some independent
16 perspective on whether the design criteria that
17 were being proposed by the District for the
18 Water Management Areas were consistent with
19 data from other wetland systems.
20 Q. Were those proposed design criteria consistent?
21 MR. HARRISON: Object to form. The
22 witness has already stated he is not quite sure
23 which SWIM plan draft or what scenario we're
24 discussing here.
DEPOSITION OF WILLIAM W. WALKER, JR.
1235
1 A. I can -- from -- as is shown in the first
2 figure, the design criteria for what is termed
3 the ENR, the Everglades Nutrient Removal
4 project, the pilot project, appear to be
5 consistent with the wetland data that I'm
6 examining here. Whether or not the full-scale
7 design of the nutrient -- or Water Management
8 Areas is consistent, I still have not evaluated
9 that because I frankly don't know what the
10 full-scale design looks like or I haven't seen
11 anything that specifies what those designs
12 would involve in any detail.
13 Q. Other than what's reflected here in Exhibit 77,
14 have you performed any other analysis
15 specifically of the Everglades Nutrient Removal
16 project, also known as the Knight's Farm
17 project?
18 A. Other than reading the report -- one of the
19 draft reports, I believe, on that project, no,
20 I have done no quantitative analysis or
21 modeling.
22 Q. Based on the comparative analysis in reading
23 the ENRP report, can you estimate the maximum
24 rate of phosphorus removal achievable through
DEPOSITION OF WILLIAM W. WALKER, JR.
1236
1 the Everglades Nutrient Removal project?
2 A. Well, I can state that the design criteria for
3 the ENR project are consistent with the
4 regression model that is shown in the first
5 figure of this exhibit, and that would imply
6 some predicted removal efficiency at some given
7 loading rate. But in terms of stating at this
8 point what that removal efficiency would be, I
9 would have to go through the calculations. But
10 it's a fairly straightforward calculation.
11 Q. Do you know what the removal efficiency for the
12 Iron Bridge Orlando wetlands is?
13 A. Well, according to the data summary on the
14 first page of Exhibit 77, the Iron Bridge
15 system had an average removal efficiency of
16 88 percent.
17 Q. That was in one particular year, 1989?
18 A. I don't recall whether that was just for 1989.
19 That reference to 1989 may have been the date
20 of the document that I used to get that
21 information. I don't recall.
22 Q. Could you, please, explain to me the elements
23 of the regression reflected on page 2 of
24 Exhibit 77?
DEPOSITION OF WILLIAM W. WALKER, JR.
1237
1 A. The regression is a bivariate regression
2 involving only two variables, an X variable and
3 a Y variable. The X variable, or the
4 predictor, is the total phosphorus load
5 entering the wetland expressed in terms of
6 grams per square meter per year. The Y
7 variable, or the predicted variable, is the
8 total phosphorus leaving the wetland,
9 discharged from the wetland, also expressed in
10 terms of grams per square meter of wetland
11 surface area per year.
12 The regression equation is shown in
13 Figure -- in the first figure of this exhibit,
14 and it is developed using standard regression
15 techniques and applying it to the data from the
16 wetlands that were summarized by Richardson and
17 Nichols. In other words, only the -- the
18 regression is actually fit to the data from the
19 first 16 wetlands identified on the first page
20 of Exhibit 77.
21 Q. So the diamonds that are plotted on the second
22 page are not among the values --
23 A. They were not among the values that were used
24 to calculate the regression line.
DEPOSITION OF WILLIAM W. WALKER, JR.
1238
1 Q. Okay. Could you turn to the third page? Could
2 you explain the entry "Extrapolation of
3 Regression" on this version of the graph?
4 A. That refers to the fact that, as I just
5 mentioned, the regression equation was
6 developed using only data from the wastewater
7 treatment systems and did not include the Water
8 Conservation Areas.
9 The fact that -- the reference to
10 extrapolation means that when I'm drawing this
11 line beyond the bounds of the wetland
12 wastewater treatment systems, I'm extrapolating
13 that regression equation into the lower loading
14 regimes which are characteristic of the
15 Everglades Water Conservation Areas.
16 Q. In other words, you've drawn regression lines
17 of the same slope among these other lower
18 values?
19 A. Those aren't regression lines on the left side
20 of the second figure. The only regression line
21 on the left side is the line that is on the
22 lower part of that portion of the figure, and
23 that is the extrapolation of the regression
24 line which generally goes through the region
DEPOSITION OF WILLIAM W. WALKER, JR.
1239
1 where the data points for Water Conservation
2 Area 3 are located.
3 Q. What are the lines labeled 1 and 2 with circles
4 around them?
5 A. The other two lines are just handwritten lines
6 that are parallel to the regression line that
7 approximately are -- on the average cover the
8 or reflect the general regions where points
9 from Water Conservation Areas 1 and 2 are
10 located.
11 Q. Did you use a particular program on your
12 computer to generate these graphs and perform
13 the analysis?
14 A. These graphs were generated from within a Lotus
15 1-2-3 work sheet. The regressions were also
16 done within a work sheet. I believe the first
17 graph was also -- was finalized with a -- with
18 the Freelance program.
19 Q. Dr. Walker, have you performed any analysis of
20 the potential effects on hydrology, water
21 quantity and water supply of proposed or
22 potential actions intended to remedy or address
23 alleged water quality threats to the Park?
24 A. Yes.
DEPOSITION OF WILLIAM W. WALKER, JR.
1240
1 Q. Okay. And what analysis is that?
2 A. This analysis was contained in a memo that I
3 submitted to the Justice Department.
4 Q. Is that memo among the deposition exhibits we
5 have identified thus far?
6 A. No, it is not.
7 Q. Does that memo exist on your computer, computer
8 diskettes or hard drive?
9 A. Not to my recollection.
10 Q. Did you provide a copy of this memo to be
11 produced in conjunction with your deposition?
12 A. Yes, I did.
13 Q. Do you recall any recommendations or
14 conclusions you report in this memo?
15 MR. HARRISON: Could I have the memo
16 described again? That was back in your
17 original question, memo regarding modeling or
18 regarding hydrologic impacts?
19 MS. AHEARN: You want me to ask a
20 question for you?
21 MR. HARRISON: No. I'm asking you, to
22 avoid going back on the record, is this one
23 looking at hydrologic impacts?
24 MS. AHEARN: Yes.
DEPOSITION OF WILLIAM W. WALKER, JR.
1241
1 MR. HARRISON: Okay. Go ahead.
2 Q. Let's try to characterize the memo.
3 When did you provide this memo to the
4 Department of Justice?
5 A. Either spring or summer of 1990.
6 Q. And to whom was it addressed?
7 A. I don't recall.
8 Q. Does it have a title or "re" line?
9 A. I don't recall the specific title.
10 Q. Do you recall findings, recommendations or
11 conclusions you report in this memo?
12 A. Generally.
13 Q. Okay. What are those findings, recommendations
14 or conclusions you generally recall?
15 A. The memo outlines some calculations that were
16 designed to put an approximate scale on the
17 magnitude of water losses that might be
18 associated with construction and operation of
19 Water Management Areas being proposed to
20 provide water quality protection for the Water
21 Conservation Areas.
22 Q. Anything else you recall?
23 A. No.
24 Q. Have you made any actual application of these
DEPOSITION OF WILLIAM W. WALKER, JR.
1242
1 calculations?
2 A. No.
3 Q. Can you give me any more detail on what these
4 calculations were that you outlined?
5 (The witness gave no response.)
6 Q. Am I correct that this was -- when you said
7 outline calculations, it was a description of
8 how one might calculate hydrologic water
9 quality or water supply changes from the Water
10 Management Areas -- due to Water Management
11 Areas?
12 A. Yes. There was a description on how one might
13 estimate the magnitude of water losses
14 associated with the Water Management Areas.
15 Q. And can you describe these calculations?
16 A. Yes.
17 Q. Okay. Would you, please?
18 A. Well, these calculations were intended to
19 provide, as I said, a scale or rough estimate
20 of the magnitude of water loss, and essentially
21 the calculations involved assuming first a
22 certain area of the Water Management Areas
23 which I believe was derived from one of the
24 SWIM plans and then applying to that area a
DEPOSITION OF WILLIAM W. WALKER, JR.
1243
1 certain magnitude of water loss in terms of
2 inches per year that would reflect the net
3 increase in evapotranspiration that would be
4 expected when converting acreage of
5 agricultural land or barren land, open land,
6 into a flooded marsh.
7 Q. Do you recall any other elements that are
8 included in the calculation other than expected
9 change in ET?
10 A. That was the extent of the calculations that I
11 performed.
12 Q. Do you know of anyone who has taken the
13 calculations you have outlined and applied them
14 to determine predictions of the magnitude of
15 water losses?
16 A. Yes.
17 Q. Who has done that?
18 A. Myself.
19 Q. Other than yourself?
20 A. I don't know of anyone who has taken the
21 precise methodology that I outlined and done
22 those calculations.
23 Q. Do you know of other persons employed by or
24 working with the federal government who have
DEPOSITION OF WILLIAM W. WALKER, JR.
1244
1 used other methodologies to analyze the
2 potential effects of hydrology, water quantity
3 and water supply of proposed or potential
4 actions to address water quality in South
5 Florida?
6 A. Yes.
7 Q. Who are those persons?
8 A. People from the Corps of Engineers,
9 Jacksonville district.
10 Q. Do you know names of these Corps personnel?
11 A. The work would have been done under the
12 direction of Mike Choate, C-H-O-A-T-E.
13 Q. Was Mr. Choate himself involved in this work?
14 A. All I know is he is -- he was involved, in
15 charge of the work. I don't know the extent to
16 which he performed the work himself.
17 Q. And what do you know about the work that the
18 Corps has done on this issue?
19 A. The Corps has done some simulation, hydrologic
20 simulation of a Water Management Area scenario
21 in order to quantify the water supply impacts.
22 Q. Do you know what the results of these
23 simulations are?
24 A. The results are expressed to my recollection in
DEPOSITION OF WILLIAM W. WALKER, JR.
1245
1 the form of a series of graphs and figures, and
2 I don't recall the quantitative aspects of the
3 results.
4 Q. Are those graphs and figures in your
5 possession?
6 A. Yes, they are.
7 Q. Did you produce copies of those to be provided
8 in conjunction with this deposition?
9 A. Yes, I did.
10 MS. AHEARN: Mr. Harrison, I'm not sure
11 if I can identify these. If they weren't among
12 the box of materials sent to us, I would
13 request that they do be provided.
14 MR. HARRISON: Counsel for the United
15 States is still claiming privilege. I'm going
16 to have to check when I get back to Miami, but
17 I think we're claiming privilege on the nature
18 of that work.
19 MS. AHEARN: The Corps is studying
20 hydrology of its own project and is not willing
21 to give the results of those scientific and
22 technical analyses to its local sponsor?
23 MR. HARRISON: If that characterization
24 were accurate, you may have a different
DEPOSITION OF WILLIAM W. WALKER, JR.
1246
1 situation. That is not what the Corps is
2 doing, and it certainly is not their original
3 work.
4 The Corps is doing work for the
5 Department of Justice analyzing certain
6 strengths and/or weaknesses in the District's
7 proposed SWIM plans. And depending on whether
8 the District chooses to use this information as
9 its defense in this lawsuit, it may or may not
10 be rebuttal evidence. It's certainly nothing
11 that the United States intends to make or has a
12 burden to use as part of its case-in-chief.
13 MS. AHEARN: This is amazing.
14 Q. Dr. Walker, do you remember in what format the
15 Corps has expressed the potential magnitude of
16 water losses associated with the Water
17 Management Areas?
18 A. As I said earlier, they produced a series of
19 graphs.
20 Q. Do you recall, are they in terms of percentage
21 losses, acre-foot losses?
22 A. I don't recall anything expressed in terms of
23 percentage. There may have been some graphs
24 that reflect flow volume in some measure,
DEPOSITION OF WILLIAM W. WALKER, JR.
1247
1 whether it was acre-feet or thousand-acre-feet
2 or whatever.
3 Q. When did you first see these graphs and
4 figures?
5 A. January of 1991.
6 Q. Have you discussed these graphs and figures
7 with anyone?
8 A. Briefly, yes.
9 Q. And with whom did you discuss those?
10 MR. HARRISON: You may give the
11 identities of anyone that was there during the
12 discussions.
13 A. To my recollection, it would have been Bob
14 Johnson, Jim Vearil, Lewis Hornung and Mike
15 Choate, Geoff Garver. There may have been
16 others. I don't recall.
17 Q. And what did you discuss? Can you give me any
18 particulars of what you recall that you
19 discussed?
20 MR. HARRISON: I'm going to object to
21 any response which would disclose reasons why
22 the United States wants the data used or wants
23 the data generated. By Dr. Walker's answer,
24 Geoff Garver was present at the discussions.
DEPOSITION OF WILLIAM W. WALKER, JR.
1248
1 The discussions took place in privileged
2 meetings.
3 I will, however, let Dr. Walker go into
4 any scientific knowledge he has about the
5 results or purely scientific discussions. I
6 think this is an area, Counsel, that before we
7 finally come to the in-camera inspection on the
8 documents, I'm not aware that we've gotten
9 together a meeting yet to discuss privileged
10 documents. I know we were supposed to try to
11 do that by the 8th, and I think Mr. Jackson and
12 I have both been busy on other depositions.
13 But this is an area that we would like
14 to discuss to get some categorical agreements
15 between the District and the United States as
16 to types of things that we are or are not going
17 to claim privilege on for the purposes of
18 either being on equal ground and turning such
19 documents over to each other or going ahead and
20 submitting it to the court for in-camera
21 inspection.
22 This is one of the categories I wanted
23 to discuss with Mr. Jackson. We just have not
24 had the opportunity. But I won't shut
DEPOSITION OF WILLIAM W. WALKER, JR.
1249
1 Dr. Walker down on any scientific knowledge or
2 even the quantitative impacts which he recalls
3 from those documents.
4 Q. This is very important, Dr. Walker.
5 A. I realize. But I would appreciate it since --
6 I would appreciate it if you would repeat the
7 question. And then we'll go on.
8 Q. Can you, please, tell me any of the particulars
9 you recall from your discussion with Johnson,
10 Vearil, Hornung, Choate, at which Mr. Garver
11 was apparently present?
12 A. Well, as I recall from my perspective this was
13 the first time that I had really sat down and
14 looked at the document and tried to understand
15 it. As I stated, the document consists largely
16 of a series of figures and there's very little
17 discussion or description of the results.
18 We had a phone conversation and a
19 conference call in the context of this meeting
20 with Mike Choate and with the technical person
21 who assisted Mike Choate in conducting the
22 analysis, I don't recall his name, in order to
23 better understand what the various figures and
24 graphs were showing. And I don't recall the
DEPOSITION OF WILLIAM W. WALKER, JR.
1250
1 numerical aspects. I don't recall the
2 magnitudes that we were discussing.
3 The only other aspect that I recall in
4 that meeting is discussing what follow-up work
5 might be done, what additional analyses or what
6 additional summaries of the results might be
7 developed in order to permit us to better
8 understand what the results were saying.
9 Q. And what is the follow-up work --
10 MR. HARRISON: I won't permit Dr. Walker
11 to go into that until we have some sort of
12 agreements as to certain categories. This work
13 all was in the nature of privileged work. The
14 memos which are reflected on the privilege list
15 are all to the Department of Justice; and under
16 the rules that Judge Bandstra and we have all
17 operated under this far, they are going to be
18 protected. I'm saying the United States --
19 MS. AHEARN: If I could, please,
20 complete my question, Mr. Harrison?
21 MR. HARRISON: I'm not going to allow
22 you to go into what future work is planned in
23 that area. If you can ask some other question,
24 that's fine.
DEPOSITION OF WILLIAM W. WALKER, JR.
1251
1 MS. AHEARN: I never even asked that
2 question.
3 Q. Dr. Walker, could you describe for me the
4 future follow-up work that was discussed in
5 terms of what would be necessary to better
6 understand the issue?
7 MR. HARRISON: Objection. That work has
8 not been decided upon yet.
9 MS. AHEARN: I didn't ask what's been
10 decided upon. I'm asking what were the
11 analyses that were discussed that would reflect
12 what was needed to better understand the issue.
13 MR. HARRISON: In that case, Counsel,
14 you are asking for confidential discussions
15 between an attorney and a client and
16 confidential representatives, and that is
17 privileged information. And I direct
18 Dr. Walker not to go into it.
19 Q. What were the issues that the technicians, the
20 scientists in the group felt they did not
21 adequately understand based on the work
22 performed to produce these graphs and figures?
23 MR. HARRISON: Objection. Don't answer,
24 Dr. Walker. Same grounds, attorney/client
DEPOSITION OF WILLIAM W. WALKER, JR.
1252
1 privilege.
2 Q. Did Mr. Choate have issues regarding this
3 analysis that he felt he did not at that point
4 adequately understand?
5 MR. HARRISON: Attorney/client
6 privilege. Don't answer. Object.
7 Q. Same question for Messrs. Johnson, Vearil and
8 Hornung. None of those individuals are
9 attorneys, am I correct, Johnson, Vearil and
10 Hornung?
11 A. That's correct.
12 Q. Did any of those three nonattorneys have
13 questions, outstanding issues regarding the
14 analysis that the Corps had performed to
15 produce these graphs and figures?
16 MR. HARRISON: Objection. Attorney/
17 client privilege. If you want to satisfy
18 yourself as to the nature of these discussions,
19 Counsel, you can ask him the predicate
20 questions, which would then satisfy you and the
21 record that it was attorney/client. I will
22 represent that these meetings were called
23 together by the Department of Justice for the
24 purposes of determining which directions to go
DEPOSITION OF WILLIAM W. WALKER, JR.
1253
1 in this lawsuit. And these were confidential
2 discussions with the attorney -- with
3 litigation counsel present.
4 Now, if you want to ask those questions,
5 elicit testimony from the witness as to what
6 his understanding of these meetings were, that
7 is fine. But they are attorney/client
8 communications, and you are not going to be
9 allowed to go into them any further.
10 Q. Does the Corps as the builder, the creator and
11 the entity ultimately in charge of the Central
12 and South Florida Flood Control Project have
13 concern over potential effects on hydrology,
14 water quantity and water supply of proposed or
15 potential actions that may be taken to protect
16 water quality in South Florida?
17 MR. HARRISON: Object to the
18 characterization. Object to the form of the
19 question, the generalities. And also object,
20 calls for speculation as to what Dr. Walker
21 knows about what the Corps' concerns are.
22 A. I don't know.
23 Q. Do you know if the Corps has performed any work
24 on this issue other than that which the
DEPOSITION OF WILLIAM W. WALKER, JR.
1254
1 Department of Justice has requested the Corps
2 to do?
3 MR. HARRISON: You may answer that.
4 A. Not to my knowledge.
5 Q. Do you recall the approximate number of graphs
6 and figures that you saw from the Corps?
7 A. Approximately between five and twenty.
8 Q. Are these on letter-sized paper?
9 A. Yes.
10 Q. When you applied the calculations outlined in
11 your prior memo, do you recall the assumed area
12 of Water Management Areas that you looked at?
13 MR. HARRISON: Object to form. Which
14 prior memos, Counsel? One that's already been
15 introduced that Dr. Walker had just done, 77?
16 MS. AHEARN: Dr. Walker described a memo
17 to the Department of Justice which described a
18 method of calculating the magnitude of water
19 losses associated with WMAs.
20 MR. HARRISON: Oh.
21 MS. AHEARN: And he's also testified
22 that he's applied those calculations.
23 Q. My question is: When you applied the
24 calculation, do you recall the area of Water
DEPOSITION OF WILLIAM W. WALKER, JR.
1255
1 Management Areas that you employed?
2 MR. HARRISON: You can answer that.
3 A. Not precisely. It was somewhere in the range
4 of fifty to seventy thousand acres.
5 Q. Do you recall the magnitude of water loss that
6 your calculations indicated?
7 MR. HARRISON: Objection. Asked and
8 answered. He already stated he didn't.
9 A. I don't recall the numerical results of the
10 calculation.
11 Q. Can you describe them qualitatively?
12 MR. HARRISON: Objection to form.
13 A. I can describe -- they were -- as I stated,
14 they were in the form of a certain number of
15 acre-feet per year. That's all I can describe
16 them in terms of.
17 Q. As an environmental engineer, is there a
18 magnitude of water loss that would be
19 associated with constructing and operating the
20 Water Management Areas that you would find
21 unacceptable?
22 MR. HARRISON: Objection. Calls for a
23 conclusion on the part of this witness that is
24 not his to make.
DEPOSITION OF WILLIAM W. WALKER, JR.
1256
1 Q. As an environmental engineer, are you able to
2 make that decision for yourself to form a
3 judgment about this?
4 A. As an environmental engineer, I am able to
5 consider such issues. But in order to answer
6 that question, that question is really somewhat
7 -- that question should be answered by people
8 who can define the water needs of the Park, and
9 I'm not in that kind of position, the water
10 needs of the other users -- water users in the
11 system.
12 MR. HARRISON: Counsel, you're free to
13 ask him his opinion of -- his own opinion of
14 whether or not the proposed Water Management
15 Areas that have been in the District's various
16 SWIM plans will or will not have adverse
17 impacts on the Park.
18 MS. AHEARN: Thank you, Mr. Harrison.
19 Q. Dr. Walker, have you performed any analysis or
20 collected information concerning the water
21 needs of the users of the Central and South
22 Florida water control project?
23 A. No, I have not.
24 Q. If the Water Management Areas were to be
DEPOSITION OF WILLIAM W. WALKER, JR.
1257
1 constructed and operated resulting in a water
2 loss of 30 percent to the system, would that be
3 acceptable to you as a matter of your own
4 personal opinion?
5 A. I have no way of stating what would be
6 acceptable and what would be unacceptable
7 because that would be a matter of policy.
8 Q. Do you know what as a matter of policy would be
9 acceptable in this regard to the managers of
10 Everglades National Park?
11 MR. HARRISON: Object to form. Also
12 object if that information is derived from
13 confidential meetings between the attorneys and
14 the clients and the representatives.
15 Q. I don't ask you what the attorneys may have
16 told the Park managers. I'm wondering if you
17 know what the Park managers think, Dr. Walker.
18 MR. HARRISON: You can answer that if
19 you know.
20 A. No, I don't know.
21 Q. Do you know what the refuge -- the people in
22 charge of the refuge think in this regard?
23 MR. HARRISON: Think of what? I'm
24 sorry. I didn't hear.
DEPOSITION OF WILLIAM W. WALKER, JR.
1258
1 Q. What magnitude of water loss would not be
2 acceptable?
3 A. No.
4 Q. Do you know what the Corps thinks in this
5 regard?
6 A. No.
7 Q. Dr. Walker, can you, please, identify
8 Exhibit 78?
9 A. Exhibit 78 is a single page of numbers and
10 handwritten notes.
11 Q. Are those notes yours?
12 A. No.
13 Q. I believe that the top left-hand corner as
14 you're looking at this chart, you'll see the
15 entry "Implementing 1-6 in 4/11 memo"? Do you
16 know what that refers to?
17 A. I don't recall.
18 MR. HARRISON: Just for the record,
19 Counsel, I see something with "p." I can't get
20 the word "implementing" out of that upper left,
21 so I'll simply object to your characterization
22 of it. It's not been established that's what
23 it says.
24 Q. Do you recognize whose handwriting this is?
DEPOSITION OF WILLIAM W. WALKER, JR.
1259
1 A. No.
2 Q. Dr. Walker, are you aware that the United
3 States has filed with the court a revised
4 designation of expert witnesses that identifies
5 you as an expert expected to testify at trial
6 in the South Florida litigation?
7 A. I'm unaware of the specific filing, but I am
8 aware of the fact that I have been designated
9 as a potential witness.
10 Q. I'd like to hand you a copy of "United States'
11 Revised Designation of Expert Witnesses" and
12 ask you to read what is here as the substance
13 of expected testimony under the entry for
14 Dr. William W. Walker.
15 (Witness examining document)
16 A. I've read it.
17 Q. Dr. Walker, have you performed work concerning
18 water quality in South Florida outside the
19 scope of that described testimony in the
20 revised designation?
21 A. I view this -- these designations to encompass
22 a wide range of potential tasks, and to my
23 knowledge and to my interpretation of these
24 tasks, I don't believe I have performed
DEPOSITION OF WILLIAM W. WALKER, JR.
1260
1 anything outside of this scope.
2 Q. In the course of the work you've performed
3 concerning South Florida water quality, have
4 you formulated any opinions, including
5 preliminary or tentative opinions, regarding
6 matters within the scope of that description of
7 anticipated testimony which you have not voiced
8 during this deposition so far?
9 MR. HARRISON: Objection, Counsel. You
10 had seven days of this deposition, and I'm not
11 about to let the witness try to pin himself
12 down without sitting here and having a
13 transcript as to what he has or has not.
14 MS. AHEARN: No. But Dr. Walker's been
15 very good about reminding me as to what he's
16 testified to previously, even several days
17 previously, and obviously I wouldn't want to --
18 if there is an opinion he is aware of and he is
19 also aware that he has not voiced it in the
20 course of this deposition, I would just ask
21 that he identify those opinions.
22 MR. HARRISON: Fine. If it's one he is
23 aware of sitting here, fine. I'm not going to
24 let you ask him whether there simply is or is
DEPOSITION OF WILLIAM W. WALKER, JR.
1261
1 not. That's an improper question after seven
2 days. I still note my objection on the record
3 to form.
4 A. I can't recall having formulated any opinions
5 or preliminary opinions that we have not
6 discussed in the previous seven days.
7 Q. Has your work led to any findings or
8 conclusions in this regard that we haven't
9 discussed yet in this deposition?
10 A. Not to my recollection.
11 Q. Are you knowledgeable of any work that
12 Dr. Edward Maltby has performed in conjunction
13 with the South Florida litigation?
14 A. Yes.
15 Q. Can you give me a summary of your understanding
16 of Dr. Maltby's work?
17 A. To my recollection, Dr. Maltby's role has been
18 that of an adviser to the case, to provide some
19 perspective from an international viewpoint.
20 Q. Have you relied or do you anticipate that you
21 will rely on any work by Dr. Maltby?
22 A. It is hard for me to separate out my -- the
23 extent to which I have relied on Dr. Maltby's
24 results as compared with all the other things
DEPOSITION OF WILLIAM W. WALKER, JR.
1262
1 that I have been exposed to and read in this
2 case.
3 MS. AHEARN: Off the record.
4 (Off the record)
5 Q. Dr. Walker, let's try it this way. I would
6 just like to know if you have a general
7 familiarity with the work that the other
8 experts identified by the Government have done
9 and if you either have relied on or anticipate
10 you will rely on the work of those experts in a
11 particular way.
12 I understand how all of the work adds to
13 your general understanding. But if there are
14 particular findings or opinions that you have
15 incorporated or anticipate you will incorporate
16 or rely upon in your own work, if you could
17 just identify those, and then I think we can
18 move through this pretty quickly.
19 MR. HARRISON: Counsel, I just want to
20 note for the record that this is an expert
21 witness deposition, and I have no problem with
22 you asking Dr. Walker matters of science which
23 he has relied upon or anticipates relying upon.
24 However, to let you dissect the case
DEPOSITION OF WILLIAM W. WALKER, JR.
1263
1 with what Dr. Walker knows from every witness
2 when a great deal, if not most, of that
3 information that he knows comes from clearly
4 privileged meetings between all of the
5 Government's witnesses and experts is another
6 matter.
7 I am not saying that I will shut that
8 down. But I am going to note right now that if
9 you believe that that is both ethical and
10 proper in the context of an expert witness
11 deposition, then be forewarned, we intend to do
12 it with your witnesses as well, ask what each
13 one knows.
14 I think at this stage of the case this
15 is the type of information that should be
16 coming out, and I'm not going to stop him from
17 doing it. But if you ask the same type of
18 questions, I also likewise will be asking the
19 same type of questions.
20 Q. I don't care if the research is anointed with
21 the holy water of attorneys or not. I don't
22 care if the information comes from privileged
23 meetings or from your review of primary
24 research or reading their publications. I'll
DEPOSITION OF WILLIAM W. WALKER, JR.
1264
1 just ask you to tell me if you know what these
2 individuals have done in terms of investigating
3 South Florida water quality and if you have or
4 anticipate you will rely on some part of that
5 work on your own.
6 MR. HARRISON: That's fine.
7 MS. AHEARN: Thank you.
8 Q. For Dr. Paul Parks?
9 A. I'm not aware of specifically what he has done
10 for the litigation.
11 Q. Dr. Ronald Raschke?
12 A. I'm generally aware of some of the work that he
13 has performed.
14 Q. And your general awareness encompasses what?
15 A. Encompasses the fact that he has done some
16 field work and collected some samples and
17 investigated periphyton relationships in the
18 Everglades.
19 Q. Dr. Wiley Kitchens?
20 A. I believe that he has performed some research
21 focusing on Water Conservation Area 1.
22 Q. Are you acquainted with the particulars of his
23 research?
24 A. No.
DEPOSITION OF WILLIAM W. WALKER, JR.
1265
1 Q. Dr. John Richardson?
2 A. I believe that Dr. Richardson has also done
3 some work on Water Conservation Area 1. I'm
4 not familiar with the details.
5 Q. Dr. Mark Maffei?
6 A. Mark Maffei is also focused on Loxahatchee
7 National Wildlife Refuge.
8 Q. Are you acquainted with any actual field work
9 or research that Dr. Maffei has performed?
10 A. Dr. Maffei has been involved in the
11 interpretation of data collected by others, and
12 he may have also collected -- done some of his
13 own field work. I'm not certain.
14 Q. Delbert Hicks?
15 A. I believe that Delbert Hicks would have worked
16 with Dr. Ronald Raschke on the topic of
17 periphyton.
18 Q. Robert Doren?
19 A. Robert Doren has performed to my knowledge work
20 defining the spatial distribution of various
21 types of vegetation in the Park and the Water
22 Conservation Areas.
23 Q. All three Water Conservation Areas?
24 A. I don't know the extent to which his work has
DEPOSITION OF WILLIAM W. WALKER, JR.
1266
1 been involved in the Water Conservation Areas.
2 I know that he has done work in the Park.
3 Q. Michael Rose?
4 A. I am unaware of specific research having been
5 conducted by Michael Rose.
6 Q. Dr. John W. Duxbury?
7 A. I'm not familiar with research by Dr. Duxbury.
8 Q. Are you acquainted with Dr. Duxbury?
9 A. I may have met him. I don't recall.
10 Q. Richard Bonner?
11 A. Richard Bonner would be involved in issues
12 relating to hydrology.
13 Q. Are you familiar with any work he's performed
14 for the litigation?
15 A. I believe he was also involved in analysis of
16 the hydrologic impacts that we discussed
17 earlier this morning.
18 Q. For Lewis Hornung, anything other than that
19 hydrologic impact study?
20 A. Lewis Hornung has provided general information
21 on operation of the Central and Southern
22 Florida Flood Control Project and on plans for
23 future modification of that project to achieve
24 alternative deliveries -- delivery schedules
DEPOSITION OF WILLIAM W. WALKER, JR.
1267
1 and so forth.
2 Q. Dr. Dennis Helsel?
3 A. Dr. Dennis Helsel has provided assistance in
4 the form of review of the statistical -- the
5 trend analysis work that I have performed.
6 Q. Are you aware of any other work that Dr. Helsel
7 has done in conjunction with the litigation?
8 A. He has also reviewed the methodology and
9 results of -- the development of the interim
10 standards for Park inflows that we discussed
11 yesterday.
12 Q. John Burt?
13 A. I'm not familiar with any research that he has
14 done.
15 Q. Dr. David Lean?
16 A. Dr. Lean has been involved to my knowledge in a
17 review capacity and also providing information
18 on phosphorus cycling, phosphorus analyses and
19 ecological impacts of phosphorus.
20 Q. But you're aware of no primary research
21 conducted by Dr. Lean?
22 A. In the Everglades, I'm not aware of that, no.
23 Q. Martin Fleming?
24 A. I'm not aware of work -- research conducted by
DEPOSITION OF WILLIAM W. WALKER, JR.
1268
1 Martin Fleming.
2 Q. Ronald Smola?
3 A. I'm not aware of any research conducted by
4 Ronald Smola.
5 Q. Dr. Ian Nisbet?
6 A. Dr. Nisbet to my knowledge has not as yet
7 conducted any research on the Everglades.
8 Q. Are you familiar with any review or other
9 secondary work of that nature he's done?
10 A. I believe that he has or is in the process of
11 -- or he is in the process of reviewing
12 information pertaining to pesticides, mercury
13 in the Everglades.
14 Q. Do you know when he started that work?
15 A. I believe that work is just now getting under
16 way.
17 Q. Dr. Walter Adey?
18 A. I'm not familiar with work by Dr. Adey.
19 Q. Do you know Dr. Adey?
20 A. No.
21 Q. Dr. Guy Lanza?
22 A. I'm not aware of specific research that
23 Dr. Lanza has conducted for the case.
24 Q. Dr. Robert Kadlec?
DEPOSITION OF WILLIAM W. WALKER, JR.
1269
1 A. Dr. Kadlec is conducting research pertaining to
2 phosphorus cycling and phosphorus removal in
3 wetlands.
4 Q. Will Dr. Kadlec be performing field research in
5 the Everglades?
6 A. I do not know.
7 Q. Can you describe the nature of the research by
8 Dr. Kadlec that you are familiar with?
9 A. I believe I just described the topic that he is
10 working on, and that is the area of phosphorus
11 cycling or phosphorus removal in the wetlands.
12 Q. Are you knowledgeable of any of the details
13 about this work?
14 A. No.
15 Q. Dr. Walker, as an environmental engineer, what
16 specific feasible alternatives can you suggest
17 to the District which the District is not
18 already implementing or planning to implement
19 for achieving and maintaining water quality in
20 the Everglades?
21 MR. HARRISON: I object to form. A
22 question like that could call for a great deal
23 of speculation, and I simply caution the
24 witness not to speculate. I am going to permit
DEPOSITION OF WILLIAM W. WALKER, JR.
1270
1 him to answer. Answer the question, however
2 broad it is.
3 I note for the record also, Counsel, we
4 don't know very much about what the District is
5 planning other than what's been in the SWIM
6 plan.
7 A. I have difficulty answering that question
8 because in reading the last draft of the SWIM
9 plan, I have trouble understanding exactly what
10 it is is being proposed by the District. So I
11 can't --
12 Q. Well, what is your understanding of what's
13 being proposed by the District?
14 A. As I stated, it's -- I have -- I have read
15 concepts. I read about concepts and
16 possibilities, but I -- from my reading of the
17 SWIM plan, I don't see specific plans. I don't
18 see specific proposals. I see concepts and
19 possibilities described.
20 Q. Are there any concepts that are missing from
21 the District's SWIM plan that you would
22 recommend?
23 A. There may be.
24 Q. And what would be those concepts?
DEPOSITION OF WILLIAM W. WALKER, JR.
1271
1 A. If we could start from a list of the specific
2 concepts that are in the SWIM plan, maybe I
3 could then amend that list or add to it if I
4 felt it was necessary. But as I stated, I have
5 a hard time understanding from my reading the
6 SWIM plan what exactly is being proposed.
7 Q. In terms of Water Management Areas, what
8 specific feasible alternatives would you
9 suggest?
10 MR. HARRISON: To which Water Management
11 Areas, Counsel? The District has put forth two
12 or three different versions.
13 MS. AHEARN: As proposed in the final
14 draft SWIM plan.
15 A. The final draft of the SWIM plan is not
16 specific enough for me to be able to evaluate
17 or develop an opinion on whether that plan is
18 adequate.
19 Q. So what you need first is more specificity?
20 A. Yes.
21 Q. Can you provide us what specific and feasible
22 measures you think would be best for the
23 District to incorporate in the SWIM plan?
24 MR. HARRISON: Object to form.
DEPOSITION OF WILLIAM W. WALKER, JR.
1272
1 A. The SWIM plan should incorporate specific
2 standards over certain time frames for water
3 quality entering the Water Conservation Areas
4 and for water quality at each of the Park
5 inflow points, and the SWIM plan should be more
6 specific about how that water quality -- what
7 specific technical approaches would be taken to
8 achieve those water quality measures.
9 My interpretation of the Water
10 Management Area concept, I can see the concept
11 in the SWIM plan. But I don't see, for
12 example, which basin is hooked up to which
13 Water Management Area. I don't see the --
14 there's not enough information on how these
15 systems would be operated hydrologically. That
16 information is something that needs to be
17 developed and specified.
18 Q. Such as the Corps is apparently doing at least
19 in part.
20 Let's put the SWIM plan aside. As an
21 environmental engineer --
22 MR. HARRISON: Object to the
23 self-serving characterization.
24 Q. -- what specific feasible alternatives would
DEPOSITION OF WILLIAM W. WALKER, JR.
1273
1 you like to see actually implemented for
2 maintaining water quality and achieving water
3 quality standards in the Everglades?
4 MR. HARRISON: Could I have the question
5 read back, please.
6 (The record was read as requested.)
7 MR. HARRISON: Object to form. The
8 question is too broad. The doctor may answer
9 it if he can.
10 A. I can outline my recommendations in general.
11 They would include four components. The
12 problem we're talking about here has to do with
13 phosphorus and eutrophication, and the general
14 approach to solving such a problem is to reduce
15 as much as possible the source of phosphorus
16 entering a water body.
17 So I would recommend as the first
18 control -- set of controls would involve
19 application of best management practices to try
20 to reduce the source of phosphorus leaving the
21 agricultural areas as well as the urban areas
22 that discharge into the Water Conservation
23 Areas. I believe as another control measure
24 the concept of the Water Management Area is
DEPOSITION OF WILLIAM W. WALKER, JR.
1274
1 important.
2 So those first two items I would lump as
3 one category, as one -- one category of items
4 that is directed at reducing the source of
5 phosphorus to the Water Conservation Areas.
6 The second item would involve setting
7 standards or limits on the loadings or the
8 concentrations at the inflows to the Water
9 Conservation Areas to provide a frame of
10 reference for tracking the success of efforts
11 to limit or reduce phosphorus loadings from the
12 Water Conservation -- from the watersheds
13 discharging into the conservation areas.
14 The third area would be reviewing the
15 operation -- the schedules and the whole
16 operation of the Water Conservation Area system
17 from the point of view of the hydrology to
18 perhaps take a harder look at water quality as
19 one of the additional objectives that one might
20 incorporate into the water -- into the
21 management of these systems -- that is, water
22 quality in addition to water quantity,
23 providing a wildlife habitat, providing
24 vegetative habitat, providing flood control; in
DEPOSITION OF WILLIAM W. WALKER, JR.
1275
1 other words, a harder look at how the system is
2 operated to see if there isn't some way that
3 the water quality objectives could be given
4 somewhat greater weight.
5 And that general approach, I believe, is
6 difficult because these Water Conservation
7 Areas are already being used for several
8 things, and we're also asking these Water
9 Conservation Areas to be used as wastewater
10 treatment systems.
11 And I think some of the effects and some
12 of the trends that I have observed reflect the
13 fact that you're asking too many things of the
14 Water Conservation Areas. And the way to
15 reduce that stress and to alleviate the risk --
16 reduce the risk of water quality problems, that
17 the best way to do that is to reduce the
18 loading of phosphorus to the system.
19 The fourth category that I think is very
20 important is another set of standards that
21 would be designed to protect water quality in
22 the Park, setting standards at the Park at each
23 inflow point to the Park or, as I have
24 described it, for each separate basin to ensure
DEPOSITION OF WILLIAM W. WALKER, JR.
1276
1 that phosphorus concentrations and loadings do
2 not increase over time and that levels that are
3 consistent with the five-year baseline period
4 that we have developed are eventually achieved
5 at those inflow points.
6 Q. Is there any category among your four which the
7 District has not undertaken the work on?
8 MR. HARRISON: Object to form. Basis of
9 Dr. Walker's knowledge.
10 A. I have seen reference to work in these areas in
11 various documents, including drafts of the SWIM
12 plan. But, as I stated, I have a hard time
13 understanding exactly what -- you know, the
14 extent of the -- the extent to which the work
15 has progressed and what has actually been
16 planned and committed to, that's where I'm
17 confused.
18 Q. Do you consider each of your four categories to
19 be specific feasible alternatives and measures?
20 A. Yes.
21 Q. You talked about reducing the source of
22 phosphorus to the Water Conservation Areas. If
23 the source of phosphorus is agricultural
24 activity, would you support reducing
DEPOSITION OF WILLIAM W. WALKER, JR.
1277
1 agricultural activity?
2 A. The methods that I described -- namely, the use
3 of best management practices or essentially
4 refinements in the agricultural operations so
5 that they are conducted with water quality
6 considerations in mind -- would be a preferable
7 approach. But the decision about whether one
8 should eliminate agriculture is really not --
9 that's not a scientific decision. That's a
10 policy decision.
11 Q. How is it that the South Florida Water
12 Management District should refine agricultural
13 practices?
14 MR. HARRISON: Object to form and also
15 to any predicate showing that Dr. Walker would
16 know what capabilities the District has or
17 doesn't. He may testify to whatever he knows,
18 but I think the question calls for speculation.
19 A. Well, there are a range of specific techniques
20 that I have seen discussed with regard to best
21 management practices and ways that may be
22 effective in reducing phosphorus loss from
23 agricultural lands, and the role of the
24 District it would seem to me would be to see
DEPOSITION OF WILLIAM W. WALKER, JR.
1278
1 that those techniques are implemented.
2 Q. Do you have anything in mind as to exactly how
3 the District should do that?
4 A. Well, in general, the approach a regulatory
5 agency would take -- in my experience, I've
6 seen regulatory agencies put standards to apply
7 numeric limits on dischargers as a way of
8 providing an incentive for a given discharger,
9 whether it's an agricultural piece of land or
10 whether it's an industrial discharge, to
11 provide some limit that has to be met in the
12 water coming off a given piece of land or out
13 of a given wastewater treatment plant.
14 Q. Do you know if it's the District or some other
15 regulatory agency that should do that in South
16 Florida?
17 MR. HARRISON: Objection. Calls for a
18 legal conclusion.
19 MS. AHEARN: I asked what Dr. Walker
20 knows.
21 A. I think that gets more into the range of
22 regulatory framework and governmental
23 structure. I'd as soon stay out of that.
24 MS. AHEARN: I'm ready to stop my
DEPOSITION OF WILLIAM W. WALKER, JR.
1279
1 examination of Dr. Walker on behalf of the
2 District at this time. Given that we did
3 receive such a significant volume of documents
4 just a couple days before the deposition
5 commenced in a shorter time period than what is
6 envisioned by the court in terms of preparation
7 for expert depositions, given that the
8 materials included approximately 40 million
9 bytes of computerized information that was
10 provided to other parties participating in this
11 deposition much later and which just simply
12 could not be physically examined in its
13 entirety for use in this deposition, given that
14 many of Dr. Walker's opinions are preliminary
15 or tentative, given that he has much work that
16 is ongoing or just starting or anticipated for
17 the future and given that we have several
18 dozens of questions which I believe are
19 appropriately framed on the record which the
20 deponent was not allowed to answer, the
21 District does reserve all rights to continue
22 this examination when Dr. Walker's deposition
23 resumes in the future.
24 MR. HARRISON: The United States does
DEPOSITION OF WILLIAM W. WALKER, JR.
1280
1 disagree with the District's position,
2 obviously. The documents that you referred to
3 were provided some seven, not a couple, days
4 prior to this deposition. Both you and the
5 court were warned early on that this deposition
6 was scheduled and it was scheduled prior to the
7 court's order and that we would do our best to
8 comply. For the record, we are the only party
9 that has provided expert witness documents in
10 advance of an expert witness deposition to
11 date. Larry Grosser showed up with no
12 documents or even knowing that he was going to
13 be a witness in this case.
14 But, nevertheless, the United States
15 does not believe that the District has any
16 right to secure the second deposition of
17 Dr. Walker. You were informed prior to this
18 deposition that many of his opinions were
19 preliminary, and you chose to depose him at
20 this point in time.
21 MS. AHEARN: Well, the Government
22 apparently thinks this work is advanced enough
23 that there are no material issues of fact as to
24 liability based largely on Dr. Walker's work.
DEPOSITION OF WILLIAM W. WALKER, JR.
1281
1 So --
2 MR. HARRISON: And, Counsel -- if I may
3 finish, Counsel. You have had full rein to
4 depose him, and you had the declaration
5 provided with the summary judgment motion and
6 you have your own experts who have been working
7 on many of these same issues for 20 years. You
8 are certainly not hampered by that.
9 Nevertheless, that will be a question reserved
10 for the court as to whether the United States
11 will or by agreement of the parties as to
12 whether we will produce Dr. Walker to the
13 District for a second set of questioning.
14 MS. AHEARN: Thank you.
15 (Off the record)
16 (Short recess)
17
18 MR. HARRISON: Before Mr. Crowley begins
19 examination of Dr. Walker, I would like to just
20 note for the record that throughout the week I
21 have been checking on the availability of
22 Colonel Malson with the Corps of Engineers as
23 the District has been trying to get his
24 deposition scheduled and has sent notices, and
DEPOSITION OF WILLIAM W. WALKER, JR.
1282
1 he has for one reason or another been
2 unavailable.
3 Colonel Malson will be available for
4 deposition, and I'm requesting that the
5 District notice him while that calendar is
6 open. And I have directed the Corps to keep
7 that calendar open, but he will be available
8 March 7th and 8th for deposition. And should
9 the need arise to continue that deposition, the
10 Government will also do its best to make him
11 available and he is currently available on
12 April 22nd through the 24th.
13 The only conflicts that I'm aware of in
14 that scheduling, not to say that there aren't
15 others, was the United States currently has
16 Gary Goforth noticed I believe for the March
17 time frame. I also believe that we have
18 availability to switch and depose Gary Goforth
19 during the first week of May, which I think was
20 one of the time frames that was going to be
21 slotted for Colonel Malson. We're trying to
22 provide Colonel Malson earlier than that. So
23 if we can shift Goforth back to that time, that
24 would be one possibility.
DEPOSITION OF WILLIAM W. WALKER, JR.
1283
1 Even if Goforth can't be shifted, the
2 United States will see whether we can get other
3 counsel to do Mr. Goforth during the originally
4 scheduled time frame. And the only other
5 conflict is that should the District or the
6 Cities feel or DER feel that they have to go
7 into the April 22nd to 24th time frame with
8 Colonel Malson, that would conflict with a
9 deposition planned for Dick Slyfield, and that
10 deposition I think can be slid to the week of
11 April 29th to May 3. And I'm offering these
12 and we will attempt to confirm these in a
13 letter and await the District's response as to
14 when you would desire to notice Colonel Malson.
15 And if -- I am telling you that he will not be
16 available prior to March 7th and 8th, and I
17 believe we have communicated that information.
18 I do not see the need to go for
19 protective order. If the District intends to
20 pursue the February time frame, I would request
21 that they let me know so that I can file such a
22 motion for protective order. I don't see the
23 need for the pleadings. The scheduling is
24 complicated enough. But we will do whatever we
DEPOSITION OF WILLIAM W. WALKER, JR.
1284
1 have to do.
2 CROSS-EXAMINATION
3 BY MR. CROWLEY:
4 Q. Dr. Walker, I'm David Crowley. I'm
5 representing the Florida Department of
6 Environmental Regulation and Carol Browner, the
7 Secretary of the Department. I have just a
8 couple questions here, and I'll try to be as
9 brief as possible.
10 At the end of your testimony just a few
11 minutes ago, you went over recommendations in
12 the four areas that you mentioned, I believe,
13 that you thought attention should be given to
14 in solving some of these problems, and I just
15 wanted to pursue in a little more detail some
16 of your recommendations along the lines of the
17 third category you mentioned, which I believe
18 was reviewing the operation and schedules of
19 the water management system to see if water
20 quality objectives could be given greater
21 weight.
22 Have you done any work yourself in that
23 regard?
24 A. No, I haven't.
DEPOSITION OF WILLIAM W. WALKER, JR.
1285
1 Q. Do you know of any other scientists who have or
2 who are currently doing such work?
3 A. I believe that the concept of revising the
4 operation schedules for delivery to the Park
5 has been discussed both by the Park and by the
6 District. The extent to which water quality
7 considerations would factor into those -- would
8 factor into the discussions that have already
9 taken place, I'm uncertain.
10 Q. Okay. Just so I'm clear on your earlier
11 opinions, would those recommendations deal only
12 with the delivery schedules to the Park and
13 possible modifications thereto, or might they
14 also deal in a broader sense with the overall
15 water delivery within the whole system?
16 A. Well, the overall way that water is distributed
17 and moved in the system. There may be some
18 modifications in that. Essentially the concept
19 is trying as much as possible to promote sheet
20 flow as compared with canal flow.
21 Q. To your knowledge, is anyone doing any work in
22 terms of the whole system -- in other words,
23 outside of just simply delivery schedules to
24 the Park?
DEPOSITION OF WILLIAM W. WALKER, JR.
1286
1 A. No.
2 Q. Might such work involve review of the schedules
3 of how water is moved around in some of the
4 adjacent watersheds to the Water Conservation
5 Areas in the Park?
6 MR. HARRISON: Object to form.
7 A. Are you referring to a specific watershed or a
8 specific Water Conservation Area?
9 Q. I was referring generally to adjacent
10 watersheds, but we can limit it to specific
11 ones piece by piece if you prefer. I'm just
12 kind of asking as a general concept.
13 A. Well, as a general concept, as I stated, I
14 think that the objective would be to provide as
15 even a distribution of flow across the marshes
16 as possible as one additional way of sort of
17 promoting phosphorus removal within the Water
18 Conservation Areas. As something that would
19 not necessarily solve the problem but something
20 that would help to achieve better water quality
21 downstream, I believe that the source control
22 reduction in phosphorus going into the Water
23 Conservation Areas would be necessary in
24 combination with these measures.
DEPOSITION OF WILLIAM W. WALKER, JR.
1287
1 Q. So this might influence the way water is pumped
2 or moved through particular structures?
3 A. Inflow points to the water quality areas in the
4 Park?
5 MR. HARRISON: Object to form.
6 A. I'm not so much talking about the way in which
7 water is released into the Park as I am the way
8 in which water is released into the water
9 quality areas. The path that water takes as it
10 moves through the Water Conservation Areas down
11 to the Park inflow points.
12 Q. How about the way that water enters the
13 conservation areas? Is that also important?
14 A. I believe that's what I just stated. The way
15 that water enters the Water Conservation Areas,
16 whether it enters through a -- in a
17 concentrated form at a structure and flows down
18 a canal, which is something that promotes
19 transport of flow and nutrients downstream, as
20 compared with say a situation where you had
21 multiple inflow points and tried to introduce
22 it more as sheet flow as compared with canal
23 flow.
24 Q. What about the way that water moves from or is
DEPOSITION OF WILLIAM W. WALKER, JR.
1288
1 moved from one Water Conservation Area to
2 another? Should that also be included in such
3 an analysis?
4 A. Well, from the point of view of the water
5 quality entering the Park, I wouldn't view that
6 as being as important as the way that water
7 enters the Park from the external watersheds.
8 And that's primarily because the nutrient
9 budget of Water Conservation Area 3A is
10 dominated largely by inflows from the external
11 watersheds as compared with inflows from the
12 other Water Conservation Areas.
13 Q. So are you saying, then, that Water
14 Conservation Area -- it's more important to
15 look at Water Conservation Area No. 3 with
16 regard to reviewing the operations and
17 schedules of the water management system than
18 it is No. 2 and No. 1?
19 A. Well, I would think I would want to look at the
20 entire system. But I'm just saying that in
21 terms of the operation of or the way the water
22 moves through Water Conservation Area 3A has a
23 greater direct impact on the Park because 3A is
24 the direct source of water to the releases into
DEPOSITION OF WILLIAM W. WALKER, JR.
1289
1 Shark slough at the Park.
2 Q. Would you also want to look at the way that
3 water is moved, for example, within the
4 Everglades Agricultural Area before it enters
5 any of the Water Conservation Areas?
6 MR. HARRISON: Object to form only for
7 the reason that the purpose for the inquiry as
8 to what Dr. Walker would or would not want to
9 look for may be misleading. And I have no
10 issue with counsel going into broad discovery
11 issues with the understanding that many of the
12 questions you are asking now are not the areas
13 to which the United States has purported to
14 proffer Dr. Walker as a witness for the United
15 States.
16 MR. CROWLEY: Okay. I understand.
17 Q. But I'm merely trying to follow up on your
18 third recommendation, your third component of
19 your general recommendations regarding
20 reviewing the operations and schedules of the
21 water management system as you have testified
22 earlier, and I'm trying to get a little more
23 specific information on what we're talking
24 about when we refer to the water management
DEPOSITION OF WILLIAM W. WALKER, JR.
1290
1 system and how we would look at this review of
2 the operation and schedules of that system.
3 A. Well, the concept of alternative distributions
4 of flow from the Everglades Agricultural Area I
5 believe has been discussed either in the SWIM
6 plan or discussed by the District elsewhere
7 regarding using different canals to divert load
8 in various directions, and that I believe was
9 also discussed in relation to the Water
10 Management Areas, essentially replumbing the
11 system to provide a way for the runoff from
12 various basins to reach the Water Management
13 Areas, and then designing the Water Management
14 Areas in such a way that -- and here's where we
15 get into this third area -- in such a way that
16 instead of releasing the flow and the
17 phosphorus load all at one point, that it
18 releases it at several points along say the
19 northern boundary of the Water Conservation
20 Area 3A, for example, so that the flow as it
21 enters the Water Conservation Area has a
22 greater tendency to start off as sheet flow in
23 addition to being -- having a much reduced
24 phosphorus concentration as a result of the
DEPOSITION OF WILLIAM W. WALKER, JR.
1291
1 phosphorus uptake in the Water Management Areas
2 and whatever best management practices would
3 have been applied the agricultural areas.
4 Q. So would enhancing and promoting sheet flow,
5 then, in your opinion be the major thing that a
6 review of the operation and schedules of the
7 water management system would be concerned
8 with?
9 MR. HARRISON: Object to form.
10 A. That would be one of the factors. Another
11 factor would be to provide not only even
12 distribution of flow but to try to maintain as
13 high a stage as possible in operating the Water
14 Conservation Areas.
15 In other words, the correlations that I
16 have identified in the process of looking at
17 water quality at the S12s in relation to
18 hydrologic factors shows that there is a
19 negative correlation between concentration and
20 flow; that is, water that is delivered to the
21 Park at low stage tends to have a higher
22 concentration. So that if we are -- if we are
23 to try to modify the way in which the system is
24 operated to provide lower phosphorus
DEPOSITION OF WILLIAM W. WALKER, JR.
1292
1 concentrations to the Park, then another
2 objective aside from promoting sheet flow would
3 be to try to keep the stage levels in -- the
4 storage of water in the Water Conservation
5 Areas as high as possible.
6 This is where you get into juggling the
7 various other objectives for operating the
8 Water Conservation Areas. And the objectives
9 for flood control and water supply aren't
10 always consistent with the objectives for
11 providing high stage and lower -- and thereby
12 lower phosphorus concentrations.
13 And that's why I believe that it's going
14 to be difficult to answer or to solve this
15 problem exclusively by changing operations
16 within the system and some control on the
17 external load is going to be required.
18 Q. Do you have an opinion as to why high stage
19 produces lower phosphorus concentrations in
20 inflows?
21 A. I believe some ideas along those lines are
22 discussed in Exhibit 17 in the report that I
23 prepared to the Justice Department.
24 Essentially -- on pages 16 and 17 of Exhibit 17
DEPOSITION OF WILLIAM W. WALKER, JR.
1293
1 there are three reasons that are discussed, one
2 having to do with at higher stage, there's just
3 more volume stored in the Water Conservation
4 Areas and water -- the time it takes for water
5 to pass through the system or the hydraulic
6 residence time is longer, and this promotes
7 phosphorus uptake.
8 The second reason that I discuss has to
9 do with when the water level is drawn down just
10 because of the topographic situation and
11 location of the canals and the marshes, a
12 higher proportion of the total flow that
13 reaches the Park in the S12s is from the
14 perimeter canals -- namely, L67 -- as compared
15 with marsh sheet flow; so that when water is
16 released at low elevation, it tends to be more
17 canal water as compared with sheet flow.
18 In that type of situation it would be
19 desirable to avoid that or to give -- the
20 alternative to -- again, to having problems
21 that are related to discharge of high-
22 concentration water at low stage is to improve
23 the quality of the water entering the Water
24 Conservation Areas to begin with so this kind
DEPOSITION OF WILLIAM W. WALKER, JR.
1294
1 of relation would not be as sensitive.
2 The third reason why nutrient
3 concentrations or phosphorus concentrations in
4 particular may be higher during periods of low
5 stage, that it's a characteristic that may be a
6 general -- that generally is found in the marsh
7 stations themselves. As the water level is
8 drawn down, there's more mineralization of the
9 peat, greater contact between the water and the
10 peat and a tendency for higher concentrations
11 to be present.
12 Q. So if you're talking about holding the water at
13 a higher stage, then you're also talking about
14 modifying the hydroperiod of the water body; is
15 that correct?
16 A. That would be part of it, correct.
17 Q. Would that also mean that you're talking about
18 minimizing the variations in that hydroperiod?
19 A. I don't know if I could get into that level of
20 detail. But I'm just saying that the general
21 concept of a higher water level would be --
22 would generally promote lower phosphorus
23 concentrations. It's tricky because of the --
24 you know, the interactions in the multiple
DEPOSITION OF WILLIAM W. WALKER, JR.
1295
1 objectives that you have in operating these
2 Water Conservation Areas.
3 Q. Might it also, for example, have potential
4 adverse effects that should be investigated on
5 wildlife if you hold the water at a higher
6 stage?
7 MR. HARRISON: Object to form.
8 A. That's a possibility.
9 Q. In your opinion, should a review of the
10 operation and schedules of the water management
11 system also include a review of flood control
12 measures in the adjacent agricultural lands?
13 MR. HARRISON: Object to form. There's
14 been no foundation laid to show that Dr. Walker
15 is familiar with the flood control measures in
16 the EAA.
17 A. Well, if one -- in general I can say that if
18 one were to propose changes in the operation of
19 the Water Conservation Areas to provide some
20 increased level of water quality protection,
21 one would have to review the impacts of that
22 change on the entire operation of the system to
23 meet the other objectives, including flood
24 control.
DEPOSITION OF WILLIAM W. WALKER, JR.
1296
1 Q. Would that answer also hold true for the
2 agricultural areas down around Homestead, which
3 I believe you testified earlier might influence
4 the discharge through S332?
5 MR. HARRISON: Same objection to
6 foundation.
7 A. I wonder if you could rephrase your question.
8 Q. Well, I guess it's a very general question. In
9 essence, I'm asking you if we're going to be
10 looking at flood control measures in the EAA
11 and that's part of the watershed for some of
12 the Water Conservation Areas, is it logical
13 that we would be doing the same thing in some
14 of the agricultural watershed for inflows
15 through the S332 structure?
16 A. Yes. It is logical that you would do that
17 there, as well.
18 Q. If changes were to be implemented, do you have
19 any opinions as to how this would be
20 accomplished between or among the various
21 regulatory agencies involved?
22 MR. HARRISON: Objection. Calls for
23 speculation and for legal conclusions.
24 A. That's well beyond the scope of my involvement.
DEPOSITION OF WILLIAM W. WALKER, JR.
1297
1 MR. CROWLEY: Okay. I think that's all
2 the questions I have. Thank you, Dr. Walker.
3 CROSS-EXAMINATION
4 BY MR. BURGESS:
5 Q. Good morning, Dr. Walker.
6 A. Good morning, Mr. Burgess.
7 Q. As you know, I represent the cities of Belle
8 Glade and Clewiston, and I appreciate your
9 attendance and patience and time during the
10 past week. And while Ms. Ahearn did cover a
11 lot of the issues that I would have covered and
12 documents also if it was my turn to go first,
13 she hasn't covered all of it.
14 It's now almost 11:30 a.m. on Thursday,
15 February 14th, and I'm about to begin my
16 examination on behalf of my client.
17 I understand from Mr. Harrison that you
18 are not available to attend this deposition
19 tomorrow or next week. Is that correct?
20 A. That's correct.
21 Q. Do you know when you might next be available
22 for a period of perhaps two or three
23 consecutive days after next week to appear for
24 the continuation of this deposition?
DEPOSITION OF WILLIAM W. WALKER, JR.
1298
1 A. Well, I have obligations to complete other work
2 on different projects under contract by the
3 beginning of April, so the entire month of
4 March is going to be infeasible for me to
5 continue with this deposition. I would say
6 that the second week in April would be the
7 earliest date that I would be willing to commit
8 myself for that purpose.
9 Q. That would be the week beginning Monday,
10 April 8th?
11 A. Yes.
12 Q. Are there specific days that you know you would
13 be available during that week?
14 A. I don't have my calendar with me.
15 MR. BURGESS: Rick, on behalf of the
16 United States, would you work with Dr. Walker
17 and see if you can confirm in writing to the
18 Cities a date that we could resume his
19 deposition?
20 MR. HARRISON: You bet. And I would
21 appreciate it if you and I could sort of also
22 work together on our scheduling. I'm not sure
23 -- I mean, there's obviously some way that we
24 can provide him in April; we'll just find a way
DEPOSITION OF WILLIAM W. WALKER, JR.
1299
1 and we'll work it out.
2 MR. BURGESS: Thank you.
3 Q. That being the case, I'm going to try in the
4 limited amount of time I have available to
5 cover as much ground as possible.
6 Dr. Walker, could you turn to Exhibit
7 No. 17? And specifically, it is the second
8 page, but it has the word "abstract" on the top
9 in the middle.
10 The second paragraph on that page, if
11 you would, Doctor, read to yourself so you can
12 familiar yourself for purposes of my questions
13 the first two sentences of that paragraph.
14 (Witness examining exhibit)
15 Q. Dr. Walker, did you expect when you adjusted
16 the data to account for variations in
17 antecedent rainfall and water surface elevation
18 that you would in fact have seen more trends
19 and not less trends as you in fact found?
20 A. I don't recall having an expectation one way or
21 the other.
22 Q. Would another way of saying that you adjusted
23 to account for variations in antecedent
24 rainfall and water surface elevation be to say
DEPOSITION OF WILLIAM W. WALKER, JR.
1300
1 that when you removed the deterministic effects
2 of antecedent rainfall and water surface
3 elevation?
4 MR. HARRISON: Object to form. I'm not
5 sure that was -- I didn't understand it to be a
6 completed question.
7 MR. BURGESS: Okay. Let me clear it up.
8 Q. The second sentence of that paragraph says:
9 When the data are adjusted to
10 account for variations in antecedent
11 rainfall and water surface elevation...
12 And my question to Dr. Walker would be:
13 Would it have been proper if you would have
14 begun that sentence, When the data were
15 adjusted such that the deterministic effects of
16 antecedent rainfall and water surface
17 elevation?
18 MR. HARRISON: Object to form.
19 A. Well, as is stated in the report, the objective
20 of the hydrologic adjustment or Series C is to
21 remove those variations that were correlated
22 with antecedent rainfall and/or antecedent
23 water surface elevation.
24 Q. And when you remove those effects, are you in
DEPOSITION OF WILLIAM W. WALKER, JR.
1301
1 effect removing what you scientists term
2 sometimes background noise?
3 A. I don't know that we have to give it any other
4 term. All I'm saying is that I'm removing the
5 variations that are correlated with rainfall
6 and water surface elevation.
7 Q. Are you removing those variations in order to
8 make your trends clearer?
9 MR. HARRISON: Asked and answered.
10 A. I wouldn't use the word "clearer." I would
11 state that I'm removing the variations in order
12 to provide a test that is not influenced by
13 variations that are correlated with antecedent
14 rainfall and water surface elevation.
15 Q. And the fact that once you removed them, you in
16 fact saw less trends than you saw when they
17 were not removed, did that lead you to question
18 whether you really captured the effects of
19 antecedent rainfall and water surface
20 elevation?
21 MR. HARRISON: Objection to the
22 predicate characterization.
23 A. The Series C calculations removed the
24 variations that were correlated with antecedent
DEPOSITION OF WILLIAM W. WALKER, JR.
1302
1 rainfall and water surface elevation. I had no
2 reason to suspect that I did not capture those
3 effects. The time series that I tested were
4 independent of antecedent rainfall and water
5 elevation. There was no reason to suspect
6 regardless of the outcome on the trend test
7 that I did not remove the variations that were
8 correlated with those hydrologic factors.
9 Q. And your testimony is that you had no
10 expectation one way or the other as to whether
11 or not your trends -- likelihood of trends
12 would have increased or decreased after you
13 removed antecedent rainfall and water surface
14 elevation?
15 MR. HARRISON: Asked and answered.
16 A. That's correct. When I conducted these tests,
17 I designed a methodology and I implemented the
18 methodology. I was not anticipating results in
19 one way or another for any of the stations or
20 any elements.
21 Q. Would you turn to page 3, please.
22 The last sentence of the first full
23 paragraph reads:
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1303
1 The ongoing SFWMD monitoring
2 program provides a consistent water
3 quality data base which is not subject
4 to difficulties which can be encountered
5 in interpreting data derived from
6 multiple agencies, multiple
7 laboratories, and/or variable sampling
8 intervals.
9 Dr. Walker, what was your basis for
10 making that statement?
11 MR. HARRISON: Asked and answered
12 extensively the first couple of days.
13 A. The basis of that statement was in my
14 experience and in my review of the literature
15 on the topic of data analysis, water quality
16 data analysis and trend analysis in particular,
17 it is inappropriate to mix data from different
18 laboratories and different agencies and in some
19 cases highly variable sampling intervals;
20 mixing data from two different sources is
21 inappropriate and can lead to false
22 impressions.
23 Q. What was your basis for making the portion of
24 the statement that reads "The ongoing SFWMD
DEPOSITION OF WILLIAM W. WALKER, JR.
1304
1 monitoring program provides a consistent water
2 quality database..."?
3 A. The term "consistent" I used in reference to
4 the fact that this was a program that was
5 collected by one agency, that it was collected
6 with a specified sampling interval and it was
7 -- the analyses were done within the same
8 laboratory. That was my definition of
9 "consistent."
10 Q. Were you aware that for the period of record
11 the South Florida Water Management District had
12 changed methods, instruments and labs as well
13 as sampling personnel and location of sampling
14 sites?
15 MR. HARRISON: Object to form. Also
16 assumes a fact not in evidence.
17 A. I do not know any of those statements to be
18 facts.
19 Q. Were you aware prior to making the sentence
20 which we have just read into the record and
21 appears on page 3 that the South Florida Water
22 Management District lab had employed labs with
23 new pieces of analytical equipment during the
24 period of record and during the sampling series
DEPOSITION OF WILLIAM W. WALKER, JR.
1305
1 and that the analytical methods employed by
2 those labs had been subject to change,
3 inaccuracy and precision of detection limits
4 during the period of record?
5 MR. HARRISON: Object to counsel's
6 characterization. It's asking the witness
7 about a fact that's not in evidence in this
8 deposition, if in fact it is a fact.
9 A. Of the statements which you have just made, the
10 only statement that I am aware of as being a
11 fact and something that we have already
12 discussed in this deposition is that there was
13 a change in the detection limit for total
14 phosphorus during this time period and, as I
15 described, effects of that change in detection
16 limit were considered in the trend analysis.
17 Q. Let's turn to page 6 of the report where I
18 think that is addressed. About the middle of
19 the second full paragraph on that page there is
20 a sentence which reads:
21 The detection limit for total and
22 ortho phosphorus increased from .002 to
23 .004 milligrams per liter in 1981.
24 Dr. Walker, does that mean that up until
DEPOSITION OF WILLIAM W. WALKER, JR.
1306
1 1981, a figure of .002 milligrams per liter was
2 detectable; but that after 1981 for the
3 remainder of the period of record, the
4 analytical equipment could not detect less than
5 .004 milligrams per liter?
6 MR. HARRISON: Object to form in that
7 Dr. Walker has not testified to the analytical
8 equipment. It's been clear from his testimony
9 he's been testifying from what was presented in
10 the data. So I object to that as a fact not in
11 evidence. Other than that, Dr. Walker may
12 answer.
13 A. That statement on page 6 refers to the fact
14 that in the data set that was provided to me by
15 the District, the lowest recorded value
16 increased from .002 to .004 in approximately
17 1981.
18 Q. So that in approximately 1981 is it your
19 understanding, Dr. Walker, that up until that
20 time a reading of .002 milligrams per liter
21 total and ortho phosphorus could be detected;
22 and that after 1981, the lowest reading that
23 could be detected was .004 milligrams per
24 liter?
DEPOSITION OF WILLIAM W. WALKER, JR.
1307
1 MR. HARRISON: Same objection.
2 A. The values which appear in the database as
3 created by the District to my knowledge reflect
4 the values that were entered and analyzed by
5 the District laboratory. And the detectability
6 of a specific concentration depends not only on
7 the equipment involved; it depends upon the
8 procedures and upon the confidence of the
9 analyst, the laboratory person in charge, in
10 recording values down to a certain level.
11 Q. Well, the fact that the detection limit
12 changed, was that fact only made known to you
13 by a review of the raw data when after 1981 you
14 all of a sudden did not see any readings for
15 total or ortho phosphorus less than .004?
16 A. I believe I testified earlier that that -- that
17 the change in detection limit to my
18 recollection was also mentioned in our
19 discussions with District staff when we were
20 beginning the ONRW process and beginning to
21 work with these data for the purpose of setting
22 standards for Park inflows.
23 Q. The next sentence in that paragraph reads:
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1308
1 Phosphorus time series have been
2 adjusted to a uniform detection limit of
3 .004 milligrams per liter by setting
4 each value equal to the --
5 and I believe, Dr. Walker, you changed
6 the word "minimum" which appears there to
7 "maximum" --
8 (Witness writing on exhibit)
9 -- of the reported value and .004
10 milligrams per liter.
11 My question is: Did you create two
12 separate values in making the adjustment to a
13 uniform detection limit, or did you take the
14 maximum of the one value between the reported
15 value or .004 milligrams per liter?
16 (The witness gave no response.)
17 Q. I'm not trying to make it difficult. When you
18 changed the word to "maximum" the other day
19 during the deposition in that sentence, it was
20 not clear whether in fact that meant you had
21 two values or you took the higher of the two.
22 It may just be my inability to understand.
23 A. I ended up with one value, which was the
24 maximum of the reported value in .004.
DEPOSITION OF WILLIAM W. WALKER, JR.
1309
1 Q. What I'm trying to understand there is if you
2 adjust it to a uniform detection limit of .004,
3 then what if the reported value was in excess
4 of .004?
5 A. It did not change.
6 Q. It stayed at .004?
7 A. Correct.
8 Q. Okay. And if the reported value was .039 --
9 I'm sorry -- .0039?
10 A. The value .0039, as I testified earlier, was
11 used to distinguish between values that were
12 reported as less than the detection limit or
13 less than .004 from values that were
14 distinguished -- that were identified as being
15 equal to .004 milligrams per liter. So any
16 numeric value in the data set that was reported
17 to be less than .004 or was given a quantified
18 number, such as .003 or .002 or even less than
19 .002, all of the numbers in those four
20 categories were assigned the numeric value
21 .0039 in the process -- for the purpose of
22 conducting the trend analysis.
23 Q. With respect to that second sentence that we're
24 talking about, would you agree with me that as
DEPOSITION OF WILLIAM W. WALKER, JR.
1310
1 written before you changed the word "minimum"
2 to "maximum," it was possible to have a value
3 reported which was either .004 milligrams per
4 liter or a specific numeric value less than
5 .004 milligrams per liter?
6 MR. HARRISON: Object to form.
7 A. I believe I just explained what these two
8 sentences mean. If you think -- if you want
9 further explanation, I guess if you could
10 repeat your question or rephrase it.
11 Q. Well, let's try it this way: With the change
12 that you have made from the word "minimum" to
13 "maximum" in looking at that sentence, would
14 it be possible for you to have instead of
15 changing the word "minimum" to "maximum"
16 written the sentence this way: "Phosphorus
17 time series have been adjusted to a uniform
18 detection limit of .004 milligrams per liter by
19 setting each value to .004 milligrams per
20 liter"?
21 A. No.
22 Q. Would this sentence be correct: "Phosphorus
23 time series have been adjusted to a uniform
24 detection limit of .004 milligrams per liter by
DEPOSITION OF WILLIAM W. WALKER, JR.
1311
1 setting each value, notwithstanding the maximum
2 of the reported value, to .004 milligrams per
3 liter"?
4 A. I'm sorry. I can't follow your logic or your
5 question.
6 Q. Okay. Let's try the next sentence: Values
7 reported to be less than .004 milligrams per
8 liter are set to .0039 milligrams per liter.
9 Dr. Walker, does this mean that if you
10 got a value of .002 milligrams per liter, you
11 set it to .0039 milligrams per liter?
12 A. That's correct.
13 Q. If we could go back to page 3.
14 Dr. Walker, the second paragraph on that
15 page, I believe, the third sentence reads:
16 A complete daily flow record has
17 been compiled for each station.
18 By the word "compiled," did you mean to
19 express that you combined data from different
20 agencies?
21 MR. HARRISON: Objection. It's been
22 asked and answered.
23 A. I believe I testified that the flow data for
24 the S12 structures are provided by the USGS.
DEPOSITION OF WILLIAM W. WALKER, JR.
1312
1 Flow data for the other structures were derived
2 from the District's hydrologic database.
3 (Exhibit No. 79 marked for
4 identification)
5 Q. Let me show you what has been marked as
6 Exhibit 79 and ask you if you can identify that
7 document.
8 A. The first page of Exhibit 79 is a fax cover
9 sheet from my office to Aaron Higer of the USGS
10 in Miami. The remainder of Exhibit 79 contains
11 a series of tables that contain daily flow
12 values for the S12 structures.
13 Q. Did you compile those tables?
14 A. Yes, I did.
15 Q. For what purpose?
16 A. To provide a basis for the work that I was
17 doing for the Justice Department, it was
18 necessary to have a flow record for each of the
19 inflow points to the Park.
20 Q. And if you turn to the first page after your
21 fax cover sheet of that exhibit, could you tell
22 us what the different categories are that
23 appear under the S12, S12A, et cetera, numbers
24 at the top?
DEPOSITION OF WILLIAM W. WALKER, JR.
1313
1 A. I believe these are data retrieved from the
2 District's computer. The first column
3 identifies the date, year, month -- or month,
4 year, day. The second column would be the
5 entry that is reported as the total flow
6 through the S12s.
7 The third column would be the flow
8 through S12A; the fourth column, through S12B;
9 the fifth column, the flow through S12C; then
10 the flow through S12D. And the last column,
11 which is titled Error, would be something that
12 I calculated the total flow for S12 minus the
13 sum of the daily flows reported for each of the
14 individual S12 Structures A, B, C and D.
15 Q. And what does the word "error" mean?
16 A. The value reported for the total flow through
17 the S12s if the values are accurate should
18 reflect approximately the sum of the flows
19 through the individual structures. So the
20 error would denote any deviation from that
21 equation.
22 Q. Did you utilize the data on this exhibit for
23 purposes of your trend analysis?
24 MR. HARRISON: Asked and answered.
DEPOSITION OF WILLIAM W. WALKER, JR.
1314
1 A. This exhibit reflects early work involving
2 setting up the databases required for trend
3 analysis. I did not use this exhibit -- the
4 data in this exhibit directly in the trend
5 analysis.
6 Q. What would the reason or reasons be that there
7 exists a difference between what's reported as
8 daily flow for S12 and what's reported as daily
9 flow for A, B, C and D?
10 MR. HARRISON: Object to form.
11 A. I do not know the specific reasons why those
12 errors occur.
13 Q. Did you put the -- is that your handwriting,
14 the question mark and the arrows on the first
15 page?
16 A. Yes.
17 Q. And did you ever ask anybody to answer your
18 question mark?
19 A. I asked the USGS to provide a version of this
20 database that was corrected. I didn't ask the
21 USGS to give me reasons why the errors were
22 present on a particular date.
23 Q. And did they provide you that database?
24 A. Yes.
DEPOSITION OF WILLIAM W. WALKER, JR.
1315
1 Q. Has that been entered as an exhibit?
2 A. I believe it's in the computer files that I
3 supplied to the Justice Department and to you.
4 Q. Meaning on the diskettes themselves?
5 A. Yes.
6 Q. You haven't seen that data, then, in
7 typewritten form entered as an exhibit here?
8 A. Not to my recollection.
9 Q. Is this data that's contained on this exhibit,
10 is this in fact District data or USGS data?
11 A. It is my understanding that these measurements
12 were made by the USGS and entered into the
13 District's computer by District staff or they
14 could have been transferred directly from the
15 USGS to the District computer. But the
16 measurements themselves were at USGS stations.
17 Q. Do you know what the difference is, if any,
18 between values that are reported as zero and
19 values which are not reported -- in other
20 words, a blank space appears on the page?
21 A. According to conventions used by the USGS in
22 reporting their data, a zero means that the
23 flow was zero, and a space would mean a missing
24 value, no reported measurement for some reason
DEPOSITION OF WILLIAM W. WALKER, JR.
1316
1 or another.
2 Q. Dr. Walker, in earlier testimony I believe you
3 identified the directory of G:\FLOPPIES\DISK9
4 on Exhibit 18 as containing surface water
5 quality data supplied by the USGS.
6 Would that be the disk which contains
7 the corrected data which you have just
8 testified you did receive from the USGS with
9 respect to the S12 structures?
10 A. No.
11 Q. Where would the corrected data for Exhibit 79
12 be among your diskettes?
13 A. I believe that the corrected data as received
14 from the USGS would be contained in the
15 directory entitled G:\FLOPPIES\DISK1 on
16 pages 2 and 3.
17 Q. What specific files in that directory?
18 A. I believe all of those files are -- contain
19 flow data from the S12s.
20 Q. Received from USGS?
21 A. Some of those files in that directory may have
22 been received from the Park from David Sikkema
23 at the Park.
24 Q. Am I correct in assuming that, for instance,
DEPOSITION OF WILLIAM W. WALKER, JR.
1317
1 with respect to the first file there that
2 appears under DISK1 is S12.78, that contains
3 S12 data for the year 1978?
4 A. I did not assign the file names. I don't
5 recall specifically, but that appears to be the
6 case. I'm not sure.
7 Q. Okay. How about S12ABCDQ.DAT? Would that be a
8 combination of the four preceding files?
9 A. It may be. It wouldn't necessarily contain the
10 same data that are in the four preceding files.
11 Q. Over onto the next page, page 3, do you know
12 whether the letter Q as it is used at the top
13 of that page is meant to denote flow?
14 A. I believe that is the case.
15 Q. Are these all data files?
16 A. I believe so.
17 Q. Okay. What programs can utilize these files as
18 they're set up?
19 A. I believe that some of these are what are
20 called ASCII files that would be accessible
21 from a word processor or from any spreadsheet
22 that would have the capability of importing
23 ASCII or text files, and some of them are work
24 sheets that were created, I believe, with the
DEPOSITION OF WILLIAM W. WALKER, JR.
1318
1 Symphony program.
2 Q. Can you tell us what programs exist on
3 Exhibit 18 which can utilize these files as
4 they're set up?
5 A. Exhibit 18 contains data files and programs
6 that I have created or obtained in the process
7 of my work. It does not contain software such
8 as a word processor or a spreadsheet that would
9 provide access to those files. You would
10 require commercially available software to
11 access these files.
12 Q. Well, can you tell us what programs are
13 contained on Exhibit 18 that you have either
14 created or received which can access these
15 files?
16 (The witness gave no response.)
17 Q. Is that a -- do you understand my question?
18 For instance, under DISK2 I think we have a
19 program titled COMPARE.EXE. Do you know
20 whether or not that program can access the data
21 files under DISK1?
22 A. I don't believe that there are any files on
23 Exhibit 18 that can access directly the files
24 in DISK1.
DEPOSITION OF WILLIAM W. WALKER, JR.
1319
1 Q. Okay. What files or programs did you use,
2 whether or not they're on Exhibit 18, which
3 allowed you to access directly the files on
4 DISK1?
5 A. I believe I would have used Lotus 1-2-3 work
6 sheet.
7 Q. And did you utilize any of the data contained
8 on DISK1 performing your trend analysis shown
9 on Exhibit 17?
10 A. Yes.
11 Q. Dr. Walker, with respect to Exhibit 79 and the
12 data we were discussing that you received from
13 Dave Sikkema containing flows from S12s, do you
14 have a recollection as to whether, after you
15 received the corrected data, you did or did not
16 continue to have missing valuations for any of
17 the A, B, C, D structures on that data?
18 A. I don't recall any missing values in the final
19 version of the data set.
20 Q. And was that data set set up similar to this in
21 that there was a value for S12 and then
22 individual values for A, B, C and D?
23 A. Which -- which --
24 Q. The corrected data.
DEPOSITION OF WILLIAM W. WALKER, JR.
1320
1 A. -- data?
2 Q. Would it appear off the disk if you were to
3 print off the disk similarly columned to what
4 appears on Exhibit 79?
5 A. In the data as provided by David Sikkema?
6 Q. Yes.
7 A. I don't recall.
8 Q. So you don't know whether you just received in
9 that data set a value for S12 without
10 individual values for A, B, C and D?
11 A. I believe that I received from David Sikkema
12 the individual values for A, B, C and D on a
13 daily basis, and there may have also been in
14 those spreadsheets or data files that he
15 supplied monthly values that would compare the
16 sum of the individual flows for A, B, C and D
17 with the report of total monthly flow for the
18 S12s.
19 Q. And did you do a similar error calculation as
20 shown on Exhibit 79?
21 A. In the database as I have used it, the sum of
22 the individual flows through the structures is
23 equated to the sum -- is equated to the S12
24 total discharge.
DEPOSITION OF WILLIAM W. WALKER, JR.
1321
1 Q. So with that corrected data set, then, you
2 didn't have the situation which is presented in
3 Exhibit 79?
4 A. That's correct. That's correct.
5 Q. Did you ever have any conversation with anyone
6 at the District or the Park or USGS concerning
7 why this preliminary data set from Exhibit 79
8 contains missing values for certain days?
9 A. To my recollection in conversations with
10 Carolyn Price of the USGS, there were certain
11 times when data were entered -- preliminary
12 data reported by the USGS were entered into the
13 District computer before the data were
14 finalized.
15 The USGS goes through a two-step process
16 apparently in entering the data and then
17 revising it and issuing a final version. Some
18 of the numbers in the District's database were
19 preliminary and not final, and that could be
20 some of the reason for some of the
21 discrepancies reported here. But to my
22 knowledge, based upon the information that was
23 provided to me by the USGS, the database that
24 was ultimately supplied to me reflected the
DEPOSITION OF WILLIAM W. WALKER, JR.
1322
1 USGS measurements at the S12 structures over
2 this time frame and it reflected their official
3 version.
4 Q. Would you turn to Exhibit 51, please? Does the
5 second page of Exhibit 51 reference the
6 response from Carolyn Price which you just
7 testified to?
8 MR. HARRISON: The second page of
9 Exhibit --
10 MR. BURGESS: Exhibit 51.
11 THE WITNESS: Excuse me. How many pages
12 are total in that exhibit?
13 MR. BURGESS: Five.
14 (Exhibit stapled by witness)
15 A. This is one of the letters that I received from
16 Carolyn Price. I may have received others. I
17 don't recall.
18 Q. Okay. And how about the next page of that
19 exhibit -- I'm sorry. I'm going to apologize.
20 Was it your testimony yesterday that you
21 didn't recall ever seeing that letter before?
22 I'm speaking to the December 6, 1989, letter
23 which is addressed to Carolyn Price from what
24 purports to be yourself but it's not signed.
DEPOSITION OF WILLIAM W. WALKER, JR.
1323
1 A. This is a letter from myself to Carolyn Price.
2 Q. Do you recollect sending that letter to Carolyn
3 Price?
4 A. I don't recollect typing the letter and mailing
5 it to her, but it appears to be a letter from
6 me and I suspect that it was a letter from me.
7 Q. The letter refers to certain periods of time
8 where you state balances continued to deviate
9 beyond reasonable round-off errors.
10 Is that your recollection, that after
11 having received at least one set of further
12 data from the USGS, you still had periods of
13 time which deviated beyond reasonable round-off
14 errors?
15 A. That's correct.
16 Q. Did you subsequently receive further data which
17 allowed you to conclude that these errors no
18 longer existed in the data set?
19 A. I received at least one or two additional
20 corrected data sets from Carolyn Price and/or
21 David Sikkema.
22 Q. And would it be your recollection that in fact
23 the data sets which you previously testified to
24 today as appearing on DISK1 contain completed
DEPOSITION OF WILLIAM W. WALKER, JR.
1324
1 data sets which include corrections for those
2 periods of time referenced in your December 6th
3 letter?
4 A. I believe so.
5 Q. If you could turn to page 5 of Exhibit 17. In
6 the paragraph at the beginning of the page
7 starting, "Station S12T reflects total
8 discharge..." The third sentence of that
9 paragraph begins:
10 On sampling dates when no discharge
11 occurred through any structure, simple
12 arithmetic averages have been used.
13 What arithmetic averages did you use?
14 MR. HARRISON: Object to form. I don't
15 think it's clear whether you're getting numbers
16 or the concept behind the arithmetic averages,
17 and also this was asked and answered, I
18 believe.
19 A. I believe I did answer this question before.
20 Essentially, on dates when there was no flow
21 through any of the S12s, to calculate a
22 composite concentration for the S12s, I just
23 took the simple average of the concentrations
24 reported for A, B, C and D.
DEPOSITION OF WILLIAM W. WALKER, JR.
1325
1 Q. Okay. I'm sorry. I know that we did address
2 this yesterday, and I didn't make myself clear.
3 By this sentence, are you referring to
4 sampling dates when there was no discharge
5 reported; in other words, there was a blank in
6 the data set to mean you calculated an
7 arithmetic average?
8 A. No. I believe that I testified earlier that
9 there were no blanks remaining in the final
10 data set. The data set had measured values of
11 either zero or positive or in a few cases a
12 negative value for flows for each day in each
13 structure. So there were no missing flow data
14 for S12s.
15 Q. Would dates when no discharge occurred then be
16 reflected with a zero?
17 A. Yes.
18 Q. And did you then average some numbers to come
19 up with a flow value on those dates where a
20 zero was reported for one or more of the
21 structures?
22 A. I was not trying to come up with a flow value.
23 The flow value -- the total flow was still
24 zero. I'm referring to averaging the
DEPOSITION OF WILLIAM W. WALKER, JR.
1326
1 concentrations to calculate a composite average
2 concentration for the S12s.
3 Q. Do you need a flow value in order to make that
4 calculation?
5 A. Not as I've defined it. I've defined it as a
6 simple arithmetic average. A flow value is not
7 needed for that purpose.
8 Q. So in essence a simple arithmetic average
9 refers to a P concentration?
10 A. Yes.
11 Q. Okay.
12 A. Or concentration of what -- any of the other 20
13 water quality components.
14 (Off the record)
15 (Luncheon recess)
16
17
18
19
20
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1327
1 A F T E R N O O N S E S S I O N
2 BY MR. BURGESS:
3 Q. Dr. Walker, if we could go back to Exhibit 17
4 and to page 5 and the sentence that I think we
5 left off on, which is in that first full
6 paragraph and reads:
7 On sampling dates when no discharge
8 occurred through any structure, simple
9 arithmetic averages have been used.
10 By the term "any structure," did you
11 mean sampling dates when there was no discharge
12 through any of the four 12 structures -- in
13 other words, A, B, C and D?
14 A. When I was calculating the composite
15 concentration for the discharge through the
16 S12s, that would be what I identify as station
17 S12T. If the flows for each of individual
18 structures A, B, C and D all equaled zero, then
19 I used the simple arithmetic average.
20 Q. Okay. If we turn to page 14, the first
21 sentence of the bottom paragraph reads:
22 The test data set includes 281
23 observations collected between December
24 1977 and September 1989; 257 of the
DEPOSITION OF WILLIAM W. WALKER, JR.
1328
1 samples were collected on days with
2 positive flow.
3 Does this mean that the difference of
4 some 24 sampling events then would be the
5 totality of sampling dates when no discharge
6 occurred through any structure?
7 A. For the S12s, yes.
8 Q. Do you have any recollection as to on how many
9 of those 24 dates you utilized an arithmetic
10 average?
11 A. According to the methods that I have described,
12 I would have used an arithmetic average on each
13 of those 24 days.
14 Q. Where either in Exhibit -- well, let's start
15 with is there anyplace in Exhibit 17 where that
16 arithmetic average would be shown?
17 A. Exhibit 17 does not contain a listing of the
18 raw data, so it would not be contained in the
19 exhibit.
20 Q. Where would we find it?
21 A. That would be in the data files that I
22 transferred through the Justice Department and
23 to you.
24 Q. When we talking about data files, we're talking
DEPOSITION OF WILLIAM W. WALKER, JR.
1329
1 about the diskettes, or the floppies?
2 A. Correct.
3 Q. If we could turn to Exhibit 18, could you show
4 us on Exhibit 18 where the data files
5 containing those arithmetic averages would be
6 located?
7 A. They would be contained in the directory
8 labeled DBASE starting on page 24.
9 Q. Do you know in which specific data file those
10 averages would be located?
11 A. In the case of the S12 composite -- that is,
12 Station S12T -- the values would be contained
13 in the file that's on page 26 that's called
14 S12T.DAT.
15 Q. Dr. Walker, I'd like to optimize the time I
16 have left this afternoon in attempting to work
17 with this Exhibit 18 and find out similar to
18 the exercise we just went through as much in
19 the underlying data that is contained in your
20 diskettes that support the opinions and
21 conclusions that are in your affidavit filed in
22 support of the motion for summary judgment and
23 also the data that supports Exhibit 17. I
24 don't mean to be repetitive.
DEPOSITION OF WILLIAM W. WALKER, JR.
1330
1 I have reviewed in earnest my notes from
2 your previous testimony on this subject. I'm
3 sure Mr. Harrison will remind me through "asked
4 and answered" objections if I'm getting into
5 that territory. But I think that optimally if
6 I review this exhibit with you, I can maximize
7 my time in locating the data that supports your
8 testimony.
9 All that having been said, I want to
10 give my question concerning DISK1 one more
11 try. I know that you have said that there are
12 no programs located within this exhibit which
13 could utilize those data files.
14 Have those data files been reformatted
15 into other data files which exist in
16 Exhibit 18?
17 A. Yes.
18 Q. And then are there in fact programs contained
19 in Exhibit 18 which can access those
20 reformatted files?
21 A. Correct.
22 Q. Would you be able to review the exhibit and
23 tell us where those reformatted files are
24 located?
DEPOSITION OF WILLIAM W. WALKER, JR.
1331
1 (The witness gave no response.)
2 Q. Let me ask you this: What I just asked, is
3 that a simple or a difficult exercise? Is that
4 something that would take an inordinate amount
5 of time?
6 A. You're referring to the --
7 Q. USGS data.
8 A. -- USGS flow data for the S12s, where would
9 that be located?
10 Q. Yes.
11 A. That could be done fairly quickly.
12 Q. Okay. Could you tell us that?
13 A. The flow data files that are accessed by the
14 trend analysis software that was utilized to
15 support Exhibit 17 would be contained in the
16 directory called DBASE on page 24.
17 The flow data files are identified by
18 structure with the last name or with the
19 extension FLO. For example, the daily flows
20 for Structure S12A would be contained in the
21 file S12A.FLO and so forth for the other
22 structures.
23 Q. I know that in earlier testimony during the
24 deposition you did in response to Ms. Ahearn's
DEPOSITION OF WILLIAM W. WALKER, JR.
1332
1 questions tell us that G:\DBASE and G:\ANAL
2 were two directories which you relied on in
3 performing the trend analysis; is that correct?
4 A. To my recollection, the data files that are
5 read by the trend analysis software would be
6 contained in those two directories.
7 Q. Are all of the data files which you needed to
8 access to perform the trend analysis contained
9 in those two files, those two directories,
10 G:\DBASE and G:\ANAL?
11 A. In describing the method of executing these
12 various programs that were used for trend
13 analysis previously, I believe that I mentioned
14 that for each program there would be one data
15 file that would be located in the same
16 directory as the program is located and that
17 would contain instructions as to the particular
18 stations and water quality components and time
19 periods that would be analyzed.
20 So that would be like an instruction
21 set, and that type of a data file would be
22 contained in the same directories as the
23 respective programs. But in terms of the data,
24 the actual measurements, the flow measurements
DEPOSITION OF WILLIAM W. WALKER, JR.
1333
1 and the water quality measurements, stage
2 measurements, rainfall and so forth that are
3 accessed by these programs that I used for the
4 analysis of inflow trends to the Park, the
5 preliminary analysis of marsh stations within
6 the Park and the preliminary analysis of Water
7 Conservation Area input and output stations,
8 those data files to my knowledge are contained
9 exclusively in directories DBASE and ANAL.
10 Q. Have you identified the one program within each
11 the G:\DBASE and the G:\ANAL which contains the
12 instructions, I think you labeled them?
13 A. No. As I stated, the data file that contains
14 the instructions or the -- identifies the
15 stations and the parameters and so forth would
16 be contained in the directories where the
17 programs -- the actual trend analysis programs
18 are located.
19 Q. Let's start with the G:\DBASE on page 12.
20 (Off the record)
21 Q. I'm sorry. Page 24. It has a typewritten "12"
22 on the bottom of page 24.
23 Can you identify for me amongst the
24 files that exist on pages 24 through 27 what
DEPOSITION OF WILLIAM W. WALKER, JR.
1334
1 file or program we would need to access to
2 learn what specific data files you used to
3 execute that program?
4 A. The DBASE directory only contains data files.
5 It does not contain programs.
6 Q. What purpose does the G:\TOOLS\MULTI directory
7 found on page 21 serve, if any, in connection
8 with the G:\DBASE directory?
9 A. To my recollection, the programs in the
10 directory TOOLS\MULTI do not access the DBASE
11 directory.
12 Q. Do they access the ANAL directory?
13 A. I believe so.
14 Q. What file accesses the G:\DBASE directory?
15 A. Well, the G:\DBASE directory is the source of
16 -- contains all the flow and water quality
17 data. It's accessed by several different
18 programs. It would take me a long time to go
19 through and explain each program that accesses
20 the DBASE directory, and I'm not even sure I
21 can remember all that.
22 Q. Instead of explaining them, can you list them?
23 A. Are you interested in a particular kind of
24 analysis or -- I mean --
DEPOSITION OF WILLIAM W. WALKER, JR.
1335
1 MR. HARRISON: I don't know -- this is
2 confusing to me, too, and I'm just hoping that
3 we're all going to have to rely on our own
4 experts to some degree. But a great deal of
5 this was covered. If there's any way you can
6 be more specific, it might speed things up.
7 I'm trying to stay out of the middle of your
8 deposition with "asked and answered" because it
9 has been six days and you don't have a
10 transcript, obviously.
11 But just to ask Dr. Walker to go back
12 through and just identify a whole bunch of
13 things, unless there's some point to it, I
14 think it makes more sense for you to rely on
15 John Davis' understanding of what went on last
16 week, et cetera, et cetera, and have some more
17 specific questions the next time we do the
18 deposition. I understand you need to have a
19 good enough understanding of this so you can
20 work with his data. So --
21 MR. BURGESS: That's really what I'm
22 trying to get at. Let me -- and I realize that
23 it may take some time to review Exhibit 18 to
24 answer these questions, but I'm trying to make
DEPOSITION OF WILLIAM W. WALKER, JR.
1336
1 them as specific as possible to allow us to
2 work with the diskettes. We have not had very
3 much success to date in working with those
4 diskettes.
5 Q. Dr. Walker, can you tell me what data files in
6 the entirety of Exhibit 18 that are contained
7 or set up in any directories, whether they be
8 G:\DBASE or G:\ANAL included, were utilized by
9 you to generate Exhibit 17?
10 A. You're asking about the entirety of the
11 exhibit, all analyses contained in the exhibit?
12 Q. Well, let's -- that's a fair response.
13 The KTEST file referenced on page 32
14 through page 36, is that in essence the trend
15 analysis that's contained in Exhibit 17?
16 A. Yes.
17 Q. Well, then, can we answer my question by
18 telling me what data files in the entirety of
19 Exhibit 18 were set up in any other directories
20 you utilized to generate the KTEST?
21 A. The data files would be contained in the
22 directory G:\DBASE starting on page 24. These
23 are the source data files that would contain
24 information on either water quality or
DEPOSITION OF WILLIAM W. WALKER, JR.
1337
1 hydrology that was used in the trend analysis.
2 Data files to my recollection would
3 include a file called S12.FLO; S12_334.FLO;
4 S12A.FLO; S12B.FLO; S12C.FLO; S12D.FLO;
5 S18C.FLO; S332.FLO; S333.FLO; and then on
6 page 25, the data files S12B.DAT; S12.STG;
7 S12C.DAT; S12A.DAT; then on page 26, S12D.DAT;
8 S332.DAT; S333.DAT; S12_334.DAT; S12T.DAT;
9 3A-MN2.PCP; TAMIAMI.PCP; S18C-U.PCP;
10 S332-U.PCP; 3A-MN3.PCP; S18C.DAT; 3A-MN.PCP.
11 I believe that's all.
12 Q. Those were all from the G:\DBASE file?
13 A. All from that directory.
14 Q. From that directory?
15 A. Yes.
16 Q. Okay. So there are no files in the G:\ANAL
17 directory that were used to generate the trend
18 analysis contained in Exhibit 17?
19 MR. HARRISON: Is that a question,
20 Mr. Burgess?
21 MR. BURGESS: Let me turn it into one.
22 MR. HARRISON: I think it would be safer
23 if you did.
24 A. That's correct.
DEPOSITION OF WILLIAM W. WALKER, JR.
1338
1 MR. HARRISON: Okay.
2 Q. Let's take a look at the appendix to Exhibit 17
3 so I'm positive that I asked the question in
4 the correct manner.
5 The files which you just listed for us,
6 are those the entirety of the data files which
7 you utilized to generate the trend numbers
8 contained in Appendix A to Exhibit 17?
9 A. Those were the source data files that were used
10 in the trend analysis calculations.
11 Q. Are there other data files within Exhibit 17
12 that you utilized to generate the trends shown
13 in Exhibit A?
14 A. I listed the data files that were read by the
15 software and analyzed in the course of doing
16 the trend analysis. I don't know -- if you're
17 asking a different question, I don't understand
18 it.
19 Q. Are the data files which you just listed the
20 only files which this KTEST program works on to
21 generate output?
22 A. Other than the instruction file that I
23 mentioned earlier that is contained within the
24 KTEST directory, that's correct.
DEPOSITION OF WILLIAM W. WALKER, JR.
1339
1 Q. And which instruction file is that?
2 A. That would be in the case of running the
3 program for one series of tests, it would be
4 contained in the file KTEST.DAT contained in
5 the directory KTEST.
6 Q. The KTEST directory has, amongst other files,
7 the programs labeled KTEST.MAP, KTEST1.FOR;
8 KTEST2.FOR, KTEST3.FOR and KTEST.EXE. What are
9 the differences among those programs?
10 A. Well, those are different files -- the files
11 with the extension FOR would be the FORTRAN
12 source code; in other words, that's the actual
13 programming language that I created to conduct
14 the analysis.
15 The MAP file is a file that's created by
16 the -- what is called the Linker; that is, that
17 is the program that's part of the operating
18 system that converts the FORTRAN files into an
19 executable program. And the executable program
20 is the file with the extension EXE.
21 Q. Going over to page 33, there's a file
22 KTEST2.OBJ. What is that file?
23 A. That is what is called an object file. That's
24 another intermediate file that's computed by
DEPOSITION OF WILLIAM W. WALKER, JR.
1340
1 the FORTRAN compiler. It's generated by the
2 FORTRAN compiler in the process of converting
3 the FORTRAN code -- that is, the .FOR-type file
4 into an executable program.
5 Q. Can you tell us what source data files existing
6 in the entirety of Exhibit 18 you have utilized
7 in connection with the ENP marsh stations work
8 that you've conducted to date?
9 A. I believe that the preliminary trend analysis
10 of ENP marsh data access the file called
11 MARSH.WK1 in directory G:\ANAL.
12 Q. What page is that on?
13 A. Oh, I'm sorry. That would be on page 29.
14 Q. So all of the source data utilized to run the
15 preliminary trend analysis is in that one file
16 MARSH.WK1?
17 A. For the marsh stations, yes.
18 Q. What is the MARSH.D.WK1 file?
19 A. I believe you're referring to the MARSH_D?
20 Q. Oh, I'm sorry. MARSH_D. There's a line
21 underneath.
22 A. I don't recall exactly what that file is for.
23 It may contain some supplementary calculations
24 having to do with the marsh data, although I
DEPOSITION OF WILLIAM W. WALKER, JR.
1341
1 don't believe that that file was accessed by
2 the trend analysis software.
3 Q. Is there trend analysis software in connection
4 with your analyzing the inflows and outflows of
5 the Water Conservation Areas?
6 A. Yes.
7 Q. Similar to what you have done for the KTEST and
8 the marsh stations, can you tell us where in
9 Exhibit 18 the source data is for any
10 preliminary analysis you have conducted of the
11 inflows and outflows of the Water Conservation
12 Areas?
13 A. The file is contained in the directory G:\DBASE
14 on page 26. Its name is CAMBNPS.WK1. That's
15 the source file that is read by the software
16 that does the preliminary analysis of trends
17 for the Water Conservation Area inflows and
18 outflows.
19 Q. And what software reads that source data file
20 for the purpose of conducting a preliminary
21 analysis of trends in the Water Conservation
22 Areas?
23 A. That software would be contained in the
24 directory G:\TOOLS\RMED on pages 23 and 24.
DEPOSITION OF WILLIAM W. WALKER, JR.
1342
1 Q. What files within that directory contain the
2 software?
3 A. Well, the executable program is called
4 RMED.EXE.
5 Q. Okay. Does Exhibit 18 contain a source data
6 file or files which you have utilized to
7 evaluate the effects of nutrient loading
8 reductions proposed in the SWIM plan on
9 nutrient balances for the Water Conservation
10 Areas, or Water Management Areas actually?
11 A. Which?
12 Q. Let me ask first Water Conservation Area.
13 A. Yes.
14 Q. Is that the file that you just -- what file is
15 that?
16 A. Files on that topic would be contained on
17 page 27 in the directory G:\123. They would
18 include files -- these are all with the
19 extension WK1 PHASE1B, PHASE1, possibly
20 PBAL_WCA, possibly WCABAL.
21 Q. Those would be source data files?
22 A. Those are spreadsheets that contain both data
23 and programs, if you will, instructions for
24 calculating nutrient balances.
DEPOSITION OF WILLIAM W. WALKER, JR.
1343
1 MR. HARRISON: Just to clear up
2 something, your question -- the predicate in
3 your question, Mr. Burgess, indicated that both
4 had been done with the SWIM plan. I'm not sure
5 you got -- in conjunction with analyzing the
6 SWIM plan. That may be true, but I don't think
7 the record is clear. I know that Water
8 Management Area was. I'm just not sure that
9 this was, if you want to try to clear that up.
10 Q. Did you respond to my question on the basis of
11 the Water Conservation Areas?
12 A. Yes.
13 Q. Okay. And was it also on the basis of
14 calculations which you have performed to
15 evaluate the effects of nutrient loading
16 reductions proposed in the SWIM plan on
17 nutrient balances for Water Conservation Areas?
18 A. Yes.
19 Q. Okay. Thank you.
20 Dr. Walker, you described in your
21 testimony over the past several days a project
22 that you are working on concerning the modeling
23 or a project which includes modeling the
24 performance of wetlands for nutrient removal.
DEPOSITION OF WILLIAM W. WALKER, JR.
1344
1 Did I describe that accurately?
2 A. That's generally one of the tasks that I have
3 been involved with, yes.
4 Q. Does Exhibit 18 contain any source data file or
5 files that you have utilized in connection with
6 that modeling effort?
7 A. Yes.
8 Q. Where are those located?
9 A. Well, work on that topic to my recollection
10 would be contained in the directory G:\123 on
11 page 27 in the files NICHOLS.WK1, possibly in
12 the file DECISION.WK1.
13 Q. Have you performed a preliminary set of
14 calculations to evaluate the effects of
15 nutrient loading reductions proposed in the
16 SWIM plan for the Water Management Areas?
17 MR. HARRISON: Object to form.
18 MR. BURGESS: Strike that.
19 Q. Dr. Walker, in addition to the six files that
20 you have identified in the G:\123 file as
21 containing source data in connection with your
22 review of nutrient loading reductions proposed
23 in the SWIM plan on nutrient balances for the
24 Water Conservation Areas and also the modeling
DEPOSITION OF WILLIAM W. WALKER, JR.
1345
1 effort for wetland nutrient removal, are there
2 other source data files contained in Exhibit 18
3 that have reference to the Water Management
4 Areas proposed in the SWIM plan?
5 A. Not to my recollection.
6 Q. Okay. Sticking with this G:\123 file for a
7 moment, could you tell us what the ST12_TP.WK1
8 work sheet is utilized for?
9 A. I believe that that work sheet was used to
10 prepare graphs and, I believe, perform
11 regression analyses of S12 total phosphorus
12 data that are described in Exhibit 17. I'm not
13 sure about that.
14 Q. How about the 5YR_TNTP.WK1 file? And
15 Dr., Walker, I don't want you to speculate. If
16 looking at these you don't know what the work
17 sheets are for, just tell me. I realize you're
18 not going to know everything on something like
19 this.
20 A. I don't recall what's in that file.
21 Q. How about the TERMS.WK1?
22 A. I believe that that file would contain data
23 extracted from the SWIM plan on the various
24 water balance and mass balance terms of the
DEPOSITION OF WILLIAM W. WALKER, JR.
1346
1 Water Conservation Areas for various years.
2 Q. How about the 5YR_TP.WK1?
3 A. I don't recall what that file is about.
4 Q. How about the OUTLIER.WK1?
5 A. I believe that file was a -- is a listing of
6 the outliers that were identified under the
7 ONRW process and are the values that are also
8 listed in one of the exhibits -- okay, it would
9 have been Exhibit 30.
10 Q. And the SFWMD.WK1 file?
11 A. I don't recall what's in that file.
12 Q. The FRQCMP.WK1 file?
13 A. I don't recall.
14 Q. POWER.WK1?
15 A. I believe POWER would also contain some of the
16 statistical calculations that were used to
17 relate sampling frequency to probability of
18 detecting trends as part of the sensitivity
19 analysis that I did for ONRW.
20 Q. And finally the FRQMETH.WK1 file?
21 A. I don't recall what's in that file.
22 Q. Okay. Dr. Walker, with respect to the NICHOLS
23 and the DECISION files which you just testified
24 recently here this afternoon contain the source
DEPOSITION OF WILLIAM W. WALKER, JR.
1347
1 data for modeling of the wetland nutrient
2 removal project, does Exhibit 18 contain the
3 software that you would need to access those
4 two files?
5 MR. HARRISON: I'm going to object only
6 because I'm not sure that your characterization
7 of the prior testimony was accurate.
8 A. Those two files are, as far as I recall,
9 independent of any other software files
10 contained on the disk or listed in Exhibit 18.
11 Q. If you would turn to page 3 of Exhibit 18, I
12 would just like to try and run through some of
13 these directories, some preliminary questions.
14 With respect to DISK2, the program
15 COMPARE.EXE, do you recall what that program is
16 set up to do?
17 A. I believe it was set up to compare water
18 quality data files supplied by the District in
19 approximately April of 1990 with the data files
20 that I was working with.
21 Q. With respect to DISK3, the COMPQ.EXE program,
22 what was that set up to do?
23 A. I believe that was designed to compare daily
24 flow files supplied to me by the District in
DEPOSITION OF WILLIAM W. WALKER, JR.
1348
1 April of 1990 with the flow files that I was
2 working with.
3 Q. You previously testified with respect to
4 DISK4\STDS, that that directory contained
5 surface water quality data supplied by the
6 District and also some files which you
7 created. Do you know which are which or can
8 you tell which are which?
9 A. I believe the files INFXVAR0, LMKVAR, LMONRW,
10 E2FTN.FOR, INFK.FOR, were supplied by the
11 District, and the remaining were mine, to the
12 best of my recollection.
13 Q. The programs shown there on page 4, RPACK.EXE,
14 RREAD.EXE and STDS.EXE, do those three programs
15 need to be executed in any particular order?
16 A. I don't recall whether those three programs
17 even perform related tasks.
18 Q. Do you recall what they were set up to do? I
19 guess not if you don't recall whether the tasks
20 are related.
21 Turning to page 6 to file
22 G:\FLOPPIES\DISK5, do you recall what the
23 SIM.EXE file was set up to do?
24 A. That program is designed to perform sensitivity
DEPOSITION OF WILLIAM W. WALKER, JR.
1349
1 analysis for the effects of different baseline
2 period lengths, one year, three years, five
3 years, for example, on the effectiveness of the
4 procedures that we were using for setting ONRW
5 standards.
6 Q. Would you ascribe the same definitions to the
7 CLEAN and MESSY files which appear on DISK5 as
8 you gave us the other day in your testimony?
9 A. I -- I --
10 Q. Let me strike that. And at the risk of an
11 "asked and answered" objection, how do you
12 define clean data and how do you define messy
13 data?
14 A. Well, for the purposes of these simulations, I
15 believe I discussed that clean data was
16 essentially lognormally distributed random
17 variations and messy data would be nonrandom,
18 would happen to have some serial correlation
19 associated with it.
20 Q. I know that we spoke about those terms in the
21 context of another exhibit, and I do recall
22 your definitions. And I just didn't know
23 whether or not the definitions held to the
24 naming, if you will, of those data files.
DEPOSITION OF WILLIAM W. WALKER, JR.
1350
1 DISK6 appears to contain all data files;
2 is that correct?
3 A. No.
4 Q. What is the EXTRACT.BAS? Is that a program
5 file?
6 A. Yes. I believe that's a program written in
7 BASIC.
8 Q. Do you recall what the purpose of the creation
9 of this file was?
10 A. No, not specifically.
11 Q. DISK7 begins on page 6, over to the top of page
12 7 contains two, I believe, data files; the
13 first, 788RAIN.DAT. Is that rainfall data, do
14 you know?
15 A. I believe so.
16 Q. And is the next file stage data?
17 A. I believe so.
18 Q. Do you know what those were set up for?
19 A. These were not my files.
20 Q. Okay. And, therefore, you don't know what
21 they're set up for?
22 A. Well, I believe they -- they contain data on
23 rainfall and stage I believe on the Park that
24 were supplied by David Sikkema of the Park
DEPOSITION OF WILLIAM W. WALKER, JR.
1351
1 Research Center.
2 Q. The next disk, DISK8, contains a program
3 FMISS.FOR. Is that a FORTRAN program?
4 A. Yes.
5 Q. Do you recall what that was set up to do?
6 A. I believe that program was designed to estimate
7 missing values in the stage record for marsh
8 stations.
9 Q. The next disk, DISK9, you've testified
10 contained surface water quality data supplied
11 by USGS. What is the WALKER.TAB file set up to
12 work with?
13 (The witness gave no response.)
14 Q. Let me ask first, what does the file contain,
15 if you know?
16 A. I believe it contains a listing of the data as
17 supplied by the USGS.
18 Q. And is that file set up to work with one or
19 more of the programs in Exhibit 18?
20 A. No.
21 Q. Does it exist only as a source data file?
22 A. Yes.
23 Q. Have you extracted data from that file and put
24 it into other files?
DEPOSITION OF WILLIAM W. WALKER, JR.
1352
1 A. No.
2 Q. With respect to DISK10, the files on the top of
3 page 8, WALKER1 and WALKER2, do you know what
4 is in those files?
5 A. I believe those files also contain a listing of
6 water quality data supplied by the US
7 Geological Survey.
8 Q. DISK11, do you know what is in the DCFS.DAT
9 file?
10 A. I believe that file contains daily flow data
11 for the inflow structures to the Park as
12 supplied by the District for the purpose of the
13 ONRW process.
14 Q. And the remainder of the four files of that
15 disk all start with ENPDMP. Do you know what
16 is contained in those files?
17 A. I believe they contain water quality data from
18 ENP inflow points as supplied by the District
19 for the ONRW process.
20 Q. With respect to DISK12, do you know what are in
21 the three files that begin CAMBDP?
22 A. I believe those files contain water quality
23 data supplied by the District to Everglades
24 National Park describing results from their
DEPOSITION OF WILLIAM W. WALKER, JR.
1353
1 Project CAMB, which is the monitoring program
2 for Water Conservation Area inflow and outflow
3 points.
4 Q. With respect to DISK15 on page 9, which you
5 described as a disk that could contain surface
6 water quality data files or hydrology files and
7 you were not sure of the source, when we placed
8 that disk in the computer, the header had a
9 title AURAS Raw Data Report For WQ. Do you
10 know what "AURAS" means?
11 A. No, I'm sorry, I don't.
12 Q. Could you go to page 14? Does the file
13 G:\LIB\FOR contain the source codes for all of
14 your FORTRAN programs?
15 A. No.
16 Q. What does that file contain?
17 A. It contains the source code for some of my
18 FORTRAN programs.
19 Q. Anything else?
20 A. I don't believe so.
21 Q. Okay. Turn to page 20. The G:\TOOLS\FLUX, is
22 that program the program that was designed at
23 the Army Corps station in Vicksburg?
24 A. That was the program that was developed for the
DEPOSITION OF WILLIAM W. WALKER, JR.
1354
1 Army Corps stationed -- water quality -- it was
2 a program that was developed for the waterways
3 experiment station in Vicksburg.
4 Q. Did you modify it?
5 A. I developed the program and I have been
6 modifying it as I have been working with it,
7 yes.
8 Q. On page 21 the G:\TOOLS\FLOWCON, you testified
9 earlier in the deposition that this was a
10 program for converting flow data. Can you tell
11 us what files it converts?
12 A. It's designed to convert flow data that's
13 stored in a work sheet, in a Lotus 1-2-3 work
14 sheet into a file that is stored in ASCII
15 format.
16 Q. Can you look through -- or by looking at
17 Exhibit 18, could you show us an example of
18 what source file that program has been used on
19 and what converted file was the result?
20 A. Okay. If you turn to page 25, for example,
21 that program that we were just discussing, the
22 FLOWCON program, might be used to convert daily
23 flow data that would be stored in the work
24 sheet called S12_US.WK1. So that would be the
DEPOSITION OF WILLIAM W. WALKER, JR.
1355
1 source file.
2 And an output file might be on page 24,
3 the file, for example, S12D.FLO. I don't know
4 specifically whether that particular run of the
5 program was what is actually executed, but
6 that's an example of how that FLOWCON program
7 might be used.
8 Q. Thank you.
9 MR. HARRISON: Would this be a good time
10 for about ten?
11 MR. BURGESS: Yes. Sure.
12 (Short recess)
13
14 BY MR. BURGESS:
15 Q. Dr. Walker, Exhibit 17 contains on pages 10,
16 13, 14, 20 and 28 certain regression equations.
17 Would it be possible for you to tell us what
18 data sets and what programs in Exhibit 18 you
19 used to perform those regressions?
20 A. I believe that all of those regressions were
21 performed using the KTEST program which we
22 discussed earlier which accesses the data files
23 contained in the DBASE directory.
24 Q. And those would have been the data sets you
DEPOSITION OF WILLIAM W. WALKER, JR.
1356
1 testified about earlier this afternoon in
2 response to my question about what source data
3 sets the KTEST program utilizes?
4 A. Yes.
5 Q. A regression analysis is a parametric
6 procedure; is that a correct statement?
7 A. Regression analyses can be performed in a
8 parametric or in a nonparametric way.
9 Q. Is a regression analysis a statistical
10 technique which is sensitive to outliers?
11 A. It can be.
12 Q. When is a regression analysis sensitive to
13 outliers and when is it not sensitive to
14 outliers?
15 MR. HARRISON: Object to form. You may
16 answer.
17 A. If the particular data set that you're working
18 with contains one or more outliers or
19 unrepresentative data points that, because of
20 their magnitude and because of the type of
21 regression model that you're fitting, have a
22 large influence on the computed coefficients or
23 the slopes or the terms of the regression
24 equation, then in that situation one might
DEPOSITION OF WILLIAM W. WALKER, JR.
1357
1 characterize the regression analysis as being
2 sensitive to outliers.
3 Q. And is the situation that you just described
4 the situation that you faced with this data
5 set?
6 A. The procedure that I used for the trend
7 analysis as we discussed is the Seasonal
8 Kendall test, and that is because it is based
9 upon ranks and is nonparametric, tends to be
10 insensitive to outliers.
11 The regression analyses that I performed
12 prior to doing the Seasonal Kendall test in
13 Series C may have been sensitive to certain
14 data points in the data file. The purpose --
15 one of the purposes for the sensitivity
16 analyses that I conducted and that are
17 described in Exhibit 17 was to examine in fact
18 whether the results of the trend tests,
19 including the various ways of making the
20 hydrologic adjustment, influenced the overall
21 results of the study with respect to the
22 likelihood of trends.
23 Q. Could you have performed your Seasonal Kendall
24 test without first performing a regression
DEPOSITION OF WILLIAM W. WALKER, JR.
1358
1 analysis?
2 A. That's precisely what I did do in the case of
3 Series A and Series B.
4 Q. Okay. Could you have done that with respect to
5 Series C?
6 A. I would have had to have some other way aside
7 from regression analysis to remove the
8 variations that were related to the hydrologic
9 factors.
10 Q. And those are some of the other statistical
11 procedures we discussed the other day, the
12 Spearman's Rho test or --
13 A. I don't know if -- I don't believe that the
14 Spearman's Rho test could have been used for
15 that purpose.
16 Q. What else could have been used?
17 A. The regression analysis procedure, as I stated
18 earlier, essentially follows the procedure that
19 was used by the USGS in their nationwide study
20 of trends in US rivers with respect to
21 phosphorus. There are other curve fitting
22 techniques or regression analyses techniques, I
23 guess you could classify them, that could be
24 applied that might be less sensitive to
DEPOSITION OF WILLIAM W. WALKER, JR.
1359
1 outliers in this situation.
2 Q. Would one of those be smoothing splines?
3 A. That's not one that really pops into my head,
4 no.
5 Q. Did you attempt any other methodology to
6 account for those hydrological factors other
7 than the regression analysis?
8 A. Only insofar as they are represented in the
9 sensitivity analysis section of my report.
10 Q. In response to my first question, I think you
11 said that regression analysis was not
12 necessarily a parametric procedure. Is that
13 your testimony?
14 A. That's right.
15 Q. Is it within the field of statistics
16 classically described more often as a
17 parametric procedure than a nonparametric
18 procedure?
19 MR. HARRISON: Object to form.
20 MR. BURGESS: What's your objection?
21 MR. HARRISON: I'm not sure that the
22 terms "classically described" would be terms of
23 art. Dr. Walker may well understand them.
24 Q. Within your field of statistics, is a
DEPOSITION OF WILLIAM W. WALKER, JR.
1360
1 regression analysis more commonly described as
2 a parametric procedure or a nonparametric
3 procedure?
4 A. As it is most typically used, a regression
5 analysis would be characterized as a parametric
6 procedure.
7 Q. And as it is most typically known, is it known
8 as a technique that is sensitive to outliers or
9 insensitive to outliers?
10 A. I believe that I answered that question
11 previously in that sensitivity to outliers
12 would depend upon the particular data set and
13 model that you were dealing with.
14 Q. In response to one of Ms. Ahearn's questions
15 over the last several days, you stated that I
16 believe more or less, quote, unquote, for
17 examining trends I would not use a technique
18 sensitive to outliers.
19 Do you believe that the regression
20 analysis you employed with respect to the
21 Series C data was the employment of a technique
22 sensitive to outliers?
23 A. As I stated previously, the primary test that I
24 have applied here is the nonparametric Seasonal
DEPOSITION OF WILLIAM W. WALKER, JR.
1361
1 Kendall test for trend. The regression
2 analyses used for hydrologic adjustment may
3 have been sensitive to outliers in certain
4 examples or in certain situations. And that
5 was the reason for my performing the
6 sensitivity analyses contained in Exhibit 17.
7 Q. Could you turn to Table 1 on page 7? The
8 median concentrations in milligrams per liter
9 for total phosphorus and ortho phosphorus that
10 are shown on this page, are those
11 concentrations below the flow-weighted mean for
12 total phosphorus in rainfall for South Florida
13 using either your figure for phosphorus content
14 in rainfall or the District's figure?
15 MR. HARRISON: Could I trouble you to
16 read the question back?
17 (The record was read as requested.)
18 MR. HARRISON: Thank you.
19 A. Are you referring to a particular station?
20 Q. Any of them.
21 MR. HARRISON: Counsel, just to make
22 sure the record is clear, by use of the term
23 "rainfall," do you include both the wet and
24 the dry?
DEPOSITION OF WILLIAM W. WALKER, JR.
1362
1 MR. BURGESS: Yes, approximate bulk.
2 A. The concentration at each of the stations is
3 below the bulk concentration calculated by the
4 District of .05. It's less than or equal to
5 what I calculate to be the bulk concentration
6 over the ENP Research Center of .015.
7 But the concentration in each case is
8 greater than the concentration in wetfall in
9 the actual rainfall over the -- at the Park
10 Research Center, which was .005 milligrams per
11 liter.
12 Q. Are you aware of what the typical tap water
13 phosphorus content is in the cities of Belle
14 Glade or Clewiston?
15 A. No.
16 Q. Would it surprise you if the total P and
17 ortho P readings contained here on your Table 1
18 were both within a very close range of the
19 typical phosphorus tap water readings for Belle
20 Glade and Clewiston?
21 MR. HARRISON: Objection.
22 A. Would it surprise me?
23 Q. Yes.
24 A. No, it wouldn't surprise me.
DEPOSITION OF WILLIAM W. WALKER, JR.
1363
1 Q. Dr. Walker, could you turn to page 9 of
2 Exhibit 17? The first sentence on the first
3 full paragraph speaks in terms of serial
4 correlation.
5 Dr. Walker, have you during the course
6 of this deposition described how you conducted
7 your analysis to remove the effects of serial
8 and auto-correlation?
9 (The witness gave no response.)
10 Q. I don't recall that you did and the record will
11 obviously be the final arbiter. If you recall
12 that you did, then I'll wait the transcript.
13 If you didn't, then I'm going to ask you to do
14 it.
15 MR. HARRISON: Counsel, you mentioned a
16 word other than serial correlation. Maybe if
17 you're going to rely on the doctor's
18 recollection, it would be better for you and
19 for the record to break that down to make sure
20 that you don't get a no or a yes to a compound
21 question.
22 MR. BURGESS: Okay.
23 Q. Is serial correlation the same as
24 auto-correlation?
DEPOSITION OF WILLIAM W. WALKER, JR.
1364
1 A. Generally, yes.
2 Q. Did you conduct your analysis to remove the
3 effects of serial and auto-correlation?
4 A. The second version of the Seasonal Kendall test
5 which I used in the analysis accounts for
6 effects of serial correlation in the data
7 within certain ranges of the serial correlation
8 coefficient.
9 And as we discussed previously in the
10 record, in the situation in the case of S12, I
11 believe it was in Series A and B in the case of
12 total phosphorus, there was a further
13 adjustment in the results of that Seasonal
14 Kendall test and the results of the outcome
15 probabilities to account for a serial
16 correlation using the methods that are
17 described in the Exhibit 17.
18 Q. Were your serial correlation coefficients
19 calculated on the basis of residuals after
20 seasonality was removed?
21 A. I don't believe so, no.
22 Q. If you could turn to page 11? The fifth line
23 down, the paragraph beginning "Because of
24 intentional shifts," a sentence begins:
DEPOSITION OF WILLIAM W. WALKER, JR.
1365
1 Sensitivity analyses indicate that
2 little additional concentration variance
3 is explained by including flow terms,
4 once rainfall and elevation terms have
5 been considered.
6 Does this mean that you ran your
7 sensitivity analysis with the flow included and
8 that it didn't make much of a difference?
9 A. Essentially, yes.
10 Q. And where is that reflected within Exhibit 17?
11 A. On page 27, Table 3.
12 Q. Dr. Walker, could you point out where on that
13 table we see that analysis showing not much of
14 a difference? And I'm going to retract the
15 "not much of a difference" and ask you to show
16 us where that chart shows little additional
17 concentration variance.
18 A. Okay. If you -- essentially, there are two
19 lines that I'm going to ask you to compare.
20 For example, the first line would be the 8th
21 line down from the top of the page which under
22 the column Hydrologic Variables there's an
23 entry "Elev, Rainfall." In that situation I
24 used elevation and rainfall as hydrologic
DEPOSITION OF WILLIAM W. WALKER, JR.
1366
1 variables and regressed them against
2 concentration.
3 And if you move across to the right in
4 that row under the column R2, that's the
5 variance explained, you will note that the R2
6 value is .468, which means that regressing
7 total phosphorus against elevation and rainfall
8 only explained 46.8 percent of the variance.
9 And then if you move down from that row
10 four rows to the row that has -- that's
11 identified as Flow, Elevation and Rainfall, and
12 here I have used flow in addition to elevation
13 and rainfall in doing the hydrologic
14 regression. And then if you move across to the
15 right under the column R2, you will see that
16 the R2 value is .478.
17 So that adding flow to the regression
18 once elevation and rainfall are accounted for
19 increases the R2 value from .468 to .478, which
20 is a small increase.
21 And over on the far right-hand column
22 when you compare the PROB2 values, those are
23 the overall significance levels, you will see
24 that the PROB2 level changes from .011 to
DEPOSITION OF WILLIAM W. WALKER, JR.
1367
1 .021, which generally indicates more than a
2 98 percent likelihood of increasing trend in
3 either case.
4 Q. Thank you. Would you turn to page 12, six
5 lines down in the bottom paragraph, the
6 sentence begins:
7 When multiple observations are
8 available in a given season and year,
9 the median value is used in the trend
10 test.
11 I know that we discussed earlier in your
12 deposition the difference between taking the
13 median or the mean. Let me ask you whether it
14 would have been scientifically acceptable to
15 you if, instead of selecting the median with
16 respect to months with more than one
17 observation and months with one observation,
18 assuming sampling occurs more than one time a
19 month, to have chosen the value closest in time
20 to the observation in the month that you only
21 had one observation.
22 A. I don't understand your question.
23 Q. You have elected to pursue a procedure where,
24 given multiple observations, you have chosen a
DEPOSITION OF WILLIAM W. WALKER, JR.
1368
1 median value, correct?
2 A. That's correct.
3 Q. Okay. Was that with respect to multiple
4 observations available in a given month or, as
5 referenced in your paper, a given season and
6 year?
7 A. Well, more precisely with reference to values
8 within a given season and year. I'm using --
9 seasons here are defined in most of the
10 analysis that I have done here to roughly equal
11 a month.
12 Q. I may not understand the sentence, and that may
13 clear up my need to ask you the question. So
14 let me ask whether the sentence that I read
15 from your text has reference to a situation
16 where you have a series of observations
17 available during one month and no observations
18 available during another month?
19 (The witness gave no response.)
20 Q. That's not very clear. Let me retract the
21 question and ask it this way: Why would you
22 need to select a median value?
23 A. Because in order to perform the Seasonal
24 Kendall test as described by Hirsch et al., we
DEPOSITION OF WILLIAM W. WALKER, JR.
1369
1 need to have a maximum of one value for every
2 season and year. There can be missing values,
3 but you can have no more than one value in a
4 given season and year.
5 Q. So you're not referring in this sentence to a
6 process of selecting a value for a missing --
7 for a month which has a missing value?
8 A. No.
9 Q. Okay. I now understand. Turn to page 16, the
10 paragraph beginning "Figure 4 shows..."
11 The three mechanisms that you say may be
12 involved and then go on to describe in that
13 paragraph, have you listed those mechanisms in
14 the order of which in your opinion has had the
15 more probable effect?
16 A. I don't -- no. They're listed in no particular
17 order.
18 Q. Do you have an opinion as to which one may have
19 the primary effect upon the three of them on
20 the results which you found?
21 A. No.
22 Q. Further down on page 17 there is a sentence
23 seven lines down in the paragraph beginning
24 "Application of..." and that sentence reads:
DEPOSITION OF WILLIAM W. WALKER, JR.
1370
1 For any season, the Kendall slope
2 is the median of slope estimates
3 calculated from each pair of years.
4 Is that a correct statement?
5 A. To my knowledge, yes.
6 Q. If I were to say "for any season, the Kendall
7 slope is the median of slope estimates
8 calculated from all possible pairs of years,"
9 would I be incorrect?
10 A. I fail to see the distinction between your
11 statement and the one that's in the text.
12 Q. So you believe my statement is also correct?
13 A. Yes.
14 Q. Turn to the next page, 18. The column furthest
15 over to the right, PROB, P-R-O-B, is described
16 at the bottom of the page as a two-tailed
17 significance level.
18 Do you believe that these probabilities
19 for each individual month have any statistical
20 meaning?
21 MR. HARRISON: Object to form. I think
22 "statistical meaning" is vague without some
23 definition of statistical meaning for what,
24 such as, for example, for the purpose of
DEPOSITION OF WILLIAM W. WALKER, JR.
1371
1 finding trends.
2 A. The PROBs calculated for each month were
3 calculated from the Mann-Kendall S statistic
4 and the variance of the S statistic as
5 calculated for each month. The emphasis of the
6 Seasonal Kendall test and of the analysis that
7 I have conducted in general is not on the PROB
8 values calculated for the individual seasons
9 but on the PROB values calculated over all
10 seasons. That is the values that would be
11 associated with the rows marked Year and Year*
12 in Table 2 on page 18.
13 Q. Do those two rows, the Year and the Year*, have
14 equal meaning?
15 A. No.
16 Q. What is the meaning of the row Year?
17 A. Year essentially contains the results of what I
18 refer to as the first version of the Seasonal
19 Kendall test. That is the version that does
20 not account for serial correlation, and that's
21 the version of the test as described in the
22 paper by Hirsch et al. in 1982.
23 The row marked Year* reflects the
24 results of the second version of the Seasonal
DEPOSITION OF WILLIAM W. WALKER, JR.
1372
1 Kendall test that was developed by Hirsch and
2 Slack in 1984. This second version accounts
3 for correlation between months -- serial
4 correlation between months.
5 Q. Can you explain why the PROB value for the year
6 in the Series A data on page 18 is .0000?
7 A. That value is calculated from the S and the
8 VAR(S) statistics that was listed in that table
9 and essentially reflect the outcome of the test
10 when the test does not account for serial
11 correlation. Essentially, it means that
12 there's less than one chance in 10,000 that the
13 underlying distribution of concentrations was
14 stable, that there was no trend.
15 Q. And then is the year with the asterisk or the
16 star what you have termed your second version
17 of the Seasonal Kendall test?
18 A. Yes.
19 Q. Is there in your opinion a statistically
20 significant difference between the PROB value
21 for the year and the PROB value for the Year*
22 in the Series A table?
23 MR. HARRISON: Object to form.
24 A. The numbers are as they are stated. The
DEPOSITION OF WILLIAM W. WALKER, JR.
1373
1 probabilities are .000 and .0437. They are
2 probabilities themselves. I don't know what
3 you mean by "significant difference."
4 Q. If I asked you the difference, are you going to
5 tell me .0437?
6 A. That would be a close approximation.
7 (Laughter)
8 Q. Let me ask you this, Dr. Walker: Would the
9 ultimate outcome of your Series A Seasonal
10 Kendall test as applied to S12T total
11 phosphorus data reflected on page 18 -- strike
12 that.
13 Move on to page 21. Could you explain
14 for us the four graphs which appear under the
15 Series A, All Data, on that page? And by
16 "explain," I mean, What is happening in those
17 graphs?
18 A. Well, I can explain what's plotted in these
19 graphs.
20 Q. Thank you.
21 A. Series A is contained on the left-hand side.
22 Again, we're looking at all the data without
23 regard to flow. And the top graph shows the
24 individual data points for each sampling date,
DEPOSITION OF WILLIAM W. WALKER, JR.
1374
1 and the horizontal line in that top graph I
2 believe is the log mean where all these data
3 are being plotted on a logarithmic scale. The
4 horizontal line is just an average number
5 that's shown in relation to the individual data
6 points.
7 The next graph down shows the -- the
8 solid line is the monthly median values that
9 were used in the Seasonal Kendall test -- in
10 other words, starting from the raw data and
11 taking the monthly medians for each month and
12 year and plotting them against time. And the
13 dashed line in that figure shows the trend line
14 as estimated using the Seasonal Kendall slope,
15 and that's defined in the text.
16 The next two graphs under Series A are
17 the same general idea except -- well, in the
18 case of the third graph, the solid line
19 reflects the monthly median measured
20 concentration rather than -- excuse me. The
21 third graph reflects the yearly median
22 concentration as distinct from the monthly
23 median in the graph above that. And the yearly
24 median is shown in relation again to the
DEPOSITION OF WILLIAM W. WALKER, JR.
1375
1 Seasonal Kendall trend line estimated from the
2 trend analysis procedure.
3 And the bottom graph shows the five-year
4 running median concentration in relation to the
5 Seasonal Kendall trend line, the dotted line.
6 Q. Does the SIG or S-I-G figure above the graphs
7 mean probability?
8 A. It's very blurred in my copy, but I believe,
9 yes, that's what it refers to. It refers to
10 the probability levels that are estimated by
11 the first and the second versions of the
12 Seasonal Kendall test.
13 Q. On my copy I'll represent to you that I can see
14 the SIG line on the second, third and fourth
15 graphs under Series A and they all read .000
16 and then .039.
17 My question is: Why don't the
18 probability values change in those Runs 2, 3
19 and 4?
20 A. It's because the Seasonal Kendall test is not
21 repeated in those second, third and fourth
22 graphs. These are just graphs of the data in
23 relation to the outcome of the same -- the same
24 Seasonal Kendall test that's reflected in the
DEPOSITION OF WILLIAM W. WALKER, JR.
1376
1 dotted line.
2 Q. My second graph has one-month medians in the
3 description section, and the next one has one
4 year medians and the next one has five-year
5 medians. Am I reading that correctly?
6 A. That's correct.
7 Q. Okay. Are the amount of data points that are
8 reflected in each of those three graphs, do
9 those change as you go from one-month medians
10 to one-year medians to five-year medians?
11 A. They're all derived from the same original data
12 set.
13 Q. Okay. I see. So the answer is, then, that the
14 data points would remain the same from graph to
15 graph?
16 MR. HARRISON: Object to form. I think
17 there's some semantical problems.
18 Q. As I looked at this graph, Dr. Walker, it just
19 seemed to me that the same analysis was
20 reflected and that the data was being plotted
21 differently, and it appeared that the
22 significance as you went from one-month medians
23 to one-year medians to five-year medians would
24 necessarily change because of the number of
DEPOSITION OF WILLIAM W. WALKER, JR.
1377
1 data points.
2 But did I misunderstand and we're
3 talking about the data points that appear in
4 the first graph on that row of or column of
5 four are the same data points in each graph?
6 MR. BURGESS: It's getting late.
7 A. The data points that are shown plotted in the
8 top row are used to perform the Seasonal
9 Kendall test, and I only performed the Seasonal
10 Kendall test once for each series for each
11 water quality component in each station. All
12 that's happening here as we move down the rows
13 is that we are summarizing the data points, we
14 are smoothing the data points over different
15 time intervals and showing those smooth values
16 in relation to the Seasonal Kendall trend line,
17 and we're using smoothing intervals of one
18 month, one year and five years as described in
19 the text.
20 Q. So then it is of no surprise to you that the
21 significance level remains the same from graph
22 to graph?
23 A. No, because I never repeated the test.
24 Q. Okay. If you would turn to page 23, does that
DEPOSITION OF WILLIAM W. WALKER, JR.
1378
1 chart or, I'm sorry, graph that appears on
2 page 23 have as its basis one of the smaller
3 graphs that we just looked at on page 21?
4 A. Essentially some of the same information is
5 portrayed, that's correct.
6 Q. Are you in this chart taking the slope that you
7 generated on page 21 and fitting that slope
8 onto this five-year running median? Is this in
9 essence -- strike that.
10 Is this in essence the same slope that
11 appears at the bottom of the column under
12 Series A on page 21?
13 A. No.
14 Q. Okay. What does this five-year running median
15 attempt to show?
16 A. Figure 6 contains three lines, if you will.
17 The dashed line is identified as the Seasonal
18 Kendall trend line. It's derived from the
19 results of Series C and is shown essentially
20 the same dotted line as shown in Figure 5 in
21 the lower right-hand corner; the second line
22 shown in Figure 6 which we will describe as
23 containing dashes and dots essentially. It's
24 represented by dashes and dots and it has --
DEPOSITION OF WILLIAM W. WALKER, JR.
1379
1 and is identified by the caption entitled
2 Adjusted for Elevation and Rainfall Variations;
3 that is the five-year running median
4 concentration of the data adjusted as is
5 indicated for the hydrologic factors, and that
6 is essentially the same graph aside from the
7 scale as shown in Figure 5 in the lower
8 right-hand corner with the solid line.
9 The third line in Figure 6 is the solid
10 line, and that is identified by the caption Raw
11 Data with Flow Greater than Zero, and that is
12 the same line as is shown in Figure 5 in the
13 bottom center for Series B. That is the
14 five-year running median concentration without
15 adjustment for hydrologic factors as derived
16 from the data.
17 Q. Was the slope that you generated on page 21
18 generated using log data?
19 A. As is indicated in the text, all of the
20 Seasonal Kendall tests were performed on a log
21 scale, so the slopes were calculated in a log
22 scale.
23 Q. Does this chart on Figure 6 utilize absolute
24 data?
DEPOSITION OF WILLIAM W. WALKER, JR.
1380
1 A. That's right. In Figure 6 they're graphed on
2 an arithmetic scale so that there is a
3 transformation of the data and the trend line.
4 Q. How do you do that, take the log data or take
5 the slope from the log data and apply it here
6 to a chart which shows absolute data?
7 A. Well, it's just algebra. It's just --
8 MR. HARRISON: Off the record.
9 (Off the record)
10 Q. Are those algebraic calculations contained on
11 any of the diskettes referenced on Exhibit 18?
12 A. I believe that Exhibit 18 contains a work sheet
13 that shows how Figure 6 was generated and --
14 Q. Would you be able to look at Exhibit 18 and
15 tell us where that is?
16 A. I believe so.
17 Q. Could you do that?
18 A. I believe that the algebra required to
19 calculate the trend line shown in Figure 6 is
20 given in the file on page 27 of Exhibit 18
21 under the directory 123 -- I believe it's in
22 the file S12_TP.WK1.
23 Q. Thank you. Could you turn to page 24 of
24 Exhibit 17? I believe in response to questions
DEPOSITION OF WILLIAM W. WALKER, JR.
1381
1 over the last several days you stated with
2 respect to the total phosphorus .03 milligrams
3 per liter part of this figure, that it does not
4 necessarily reflect a step change in the data
5 since we're looking here at five-year
6 frequencies in the data, not the raw data.
7 Did you look at the raw data to see
8 whether or not a step change was reflected?
9 A. I certainly looked at the raw data, and that's
10 what we have been discussing at various times.
11 For example, Figure 5 contains the raw data.
12 Also, Figure -- I believe it would be best to
13 look at Figure 4 on page 15; on the top is the
14 individual measurements at S12 for total P, and
15 that's the raw information. Whether one can by
16 looking at that graph discern or differentiate
17 a step change from a gradual trend, it would be
18 a rather subjective matter. I'm not able to
19 make that distinction.
20 Q. What type of statistical procedures could one
21 employ with respect to the raw data to
22 determine whether or not a step change versus a
23 -- I'm sorry, what did you call it? Gradual
24 change -- gradual change occurred?
DEPOSITION OF WILLIAM W. WALKER, JR.
1382
1 A. It's difficult statistically in the presence of
2 this kind of variability to distinguish between
3 those two types of trends. The most reliable
4 method in my view of distinguishing between
5 those two types of trends is to continue
6 monitoring. The longer the period of record
7 you have, the greater the possibility that you
8 may have of distinguishing between those two
9 types of two trend shapes.
10 Q. So there's nothing that you can -- no
11 statistical procedure you can tell me could be
12 employed on that data to determine whether step
13 change or gradual change is not determined --
14 let me strike that and say make it more likely
15 than not that one versus the other occurred,
16 step change or gradual change?
17 A. I don't know that one could distinguish --
18 could use a statistical technique to
19 distinguish between those two types of trends.
20 There are methods that could be applied.
21 Q. Such as?
22 A. Such as a regression. There are ways of
23 formulating a regression equation, for example,
24 to reflect a step change at a certain date.
DEPOSITION OF WILLIAM W. WALKER, JR.
1383
1 But again, in order to apply that type of
2 technique, we would be into a parametric
3 procedure and we would have to assume a certain
4 date for that step change. We would have to
5 make other assumptions.
6 Q. And then that step change would -- I'm sorry.
7 That regression would give you a probability as
8 to whether or not the step change did in fact
9 occur?
10 A. Well, one could fit -- if you go -- well, one
11 could fit a regression model that would include
12 a step change at a certain date, and the
13 regression results would tell you something
14 about the probability -- the significance level
15 of that step change.
16 But the difficulty is that as -- because
17 of factors such as serial correlation in the
18 data, it would be hard to get an accurate
19 estimate of that probability, and it would also
20 be difficult because you would -- you would
21 have to assume a certain date for that step
22 change to have occurred. So there's lots of
23 degrees of freedom that would be involved in
24 testing that kind of model.
DEPOSITION OF WILLIAM W. WALKER, JR.
1384
1 Q. Would you turn to page 32? In Table 5 under
2 the S12T variable, how do you explain your
3 analysis having only detected a positive trend
4 for phosphorus and every other parameter, I
5 believe, being negative?
6 MR. HARRISON: Objection. Are you
7 talking about any one of the particular series,
8 Counsel, or all three series?
9 MR. BURGESS: I believe that my
10 statement is true for all three other than
11 temperature in Series A and Series B.
12 MR. HARRISON: I still must object to
13 the breadth. Are you asking Dr. Walker to
14 compare the total phosphorus with all the
15 others combined or with each individual
16 constituent?
17 MR. BURGESS: I'm asking him to explain,
18 if he has an explanation, for why his analysis
19 detects only a positive trend for phosphorus
20 compared to all of the other parameters which
21 appear as negative, as I said, other than
22 temperature under Series A and Series B. And
23 to avoid having asked the same question for
24 Series A, B and C, if you permit me, I'll ask
DEPOSITION OF WILLIAM W. WALKER, JR.
1385
1 it for all three series. And if he wants to
2 divide up his reasons between the series, I'll
3 let him do that.
4 MR. HARRISON: That's fine.
5 A. Well, first let me clarify one additional point
6 here just to correct the statement. The other
7 positive trend that was identified in the case
8 of Series A at S12T was a positive trend in
9 ortho phosphorus aside from total phosphorus
10 and temperature.
11 Q. And that positive trend was greater than 0.0?
12 A. Right.
13 Q. Okay.
14 A. It was -- the magnitude of the trend was not --
15 we were not able to determine that because a
16 high percentage of the values were below the
17 detection limit.
18 As to why we got negative values for the
19 other constituents as compared with positive
20 trends for phosphorus, the precise reason for
21 that pattern is something that I can't explain
22 except to say that each of these constituents
23 is different and has a different source and
24 different dynamics. Phosphorus has its own --
DEPOSITION OF WILLIAM W. WALKER, JR.
1386
1 its own dynamics just as chlorides, and the
2 sources of those substances are not necessarily
3 identical. There would be no reason beforehand
4 to expect that they would behave in a similar
5 way.
6 (Pause)
7 Q. Are you done?
8 A. Yes.
9 Q. Do you have any opinion as to what
10 substantively could be occurring in the
11 watershed to the Park to account for the
12 results that you found?
13 MR. HARRISON: Object to form. I think
14 it's too broad. Dr. Walker is welcome to try
15 to answer it.
16 A. Is this question with reference to my results
17 in general?
18 Q. No. I'm sorry. The S12T positive versus all
19 negative results.
20 A. Well, I've given some explanations previously
21 as to changes in nutrient concentrations and
22 trends in nutrient concentrations that I've
23 detected. With respect to the inorganic
24 species, as I stated earlier, I don't have any
DEPOSITION OF WILLIAM W. WALKER, JR.
1387
1 particular explanation why the inorganic
2 species behaved as they do at the S12s.
3 Q. Those being what parameter?
4 A. The inorganic species I would generally include
5 as the ones that are in the lower part of the
6 table -- conductivity, alkalinity, chloride,
7 calcium, magnesium, potassium and sodium.
8 Q. You have no explanation as to why those values
9 were negative?
10 A. At the S12s -- no, I really haven't looked into
11 mechanisms for that. But as is stated in the
12 text, the total discharge to Shark slough
13 S12_334, that discharge reflects all the
14 releases into the Park in Shark slough. And
15 the only trend other than nutrients in that
16 case for Series B and C is in situations where
17 the flow was actually moving into the Park.
18 The only trend was identified there in
19 the case of sodium, and there is a discussion
20 of that in the text as being an observation
21 that does not occur at a frequency that would
22 be higher than we would expect based on chance
23 for the number of tests involved here.
24 Q. Do you know whether prior to the time of trial
DEPOSITION OF WILLIAM W. WALKER, JR.
1388
1 you will be examining the trends here with
2 respect to the inorganics to develop an
3 explanation or opinion as to why those
4 inorganics have behaved the way they have?
5 A. I don't have any plans at this time to conduct
6 such an analysis.
7 Q. Do you know whether any of the other Government
8 listed expert witnesses are looking into that
9 question?
10 A. Not to my knowledge.
11 MR. BURGESS: Off the record.
12 (Off the record)
13 MR. BURGESS: At this time as a result
14 of the deponent's schedule, which was a
15 schedule made known to the Cities' benefit to
16 the District and the DER at the commencement of
17 the deposition, the cities of Belle Glade and
18 Clewiston adjourn their examination,, to begin
19 again on a date agreed to by the parties and
20 convenient to the deponent which was
21 represented today as possibly the week of
22 April 8th. Certainly if it is at all possible,
23 the Cities would prefer to recommence the
24 deposition in Miami. But as soon as the United
DEPOSITION OF WILLIAM W. WALKER, JR.
1389
1 States can make the deponent available again,
2 the Cities would like to resume their inquiry.
3 (Off the record)
4 (Deposition adjourned at 5:12 p.m.)
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1390
1 Excerpt from Rule 30(e): Submission to Witness;
Changes; Signing.
2
When the testimony is fully transcribed,
3 the deposition shall be submitted to the
witness for examination and shall be read to or
4 by him, unless such examination and reading are
waived by the witness and by the parties. Any
5 changes in form or substance which the witness
desires to make shall be entered upon the
6 deposition by the officer with a statement of
the reasons given by the witness for making
7 them.
8 *****************************************************
9 I, WILLIAM W. WALKER, JR., have examined
the above transcript of my testimony and it is
10 true and correct to the best of my knowledge,
information and belief. Any corrections are
11 noted on the errata sheet.
12 Signed under the pains and penalties of
perjury this day of ,
13 1990.
14
_____________________________
15 Deponent's Signature
16
Subscribed and sworn to before me this
17 day of , 1991.
18
______________________________
19 Notary Public
20
My Commission Expires:
21
22 ____________________________
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
1391
1 COMMONWEALTH OF MASSACHUSETTS)
) ss.
2 COUNTY OF PLYMOUTH )
3
I, Linda Marie MacDonald, a Notary
4 Public within and for the Commonwealth of
Massachusetts, duly commissioned, qualified and
5 authorized to administer oaths and to take and
certify depositions, do hereby certify that
6 heretofore, on the date cited above, the
witness personally appeared before me at the
7 above location and testified in the
above-captioned case; that the said witness was
8 by me duly sworn to testify to the truth, the
whole truth and nothing but the truth; that
9 thereupon and while said witness was under
oath, the deposition was taken down by me in
10 machine shorthand at the time and place therein
named and was reduced to typewriting
11 thereafter.
12
I further certify that the said
13 deposition constitutes a true record of the
testimony given by the said witness.
14
15 I further certify that I am not
interested in the event of this action.
16
17 IN WITNESS WHEREOF, I have hereunto
subscribed my hand this 25th day of February,
18 1991.
19
___________________________________
20 Notary Public in and for the
Commonwealth of Massachusetts
21
My Commission expires
22 November 29, 1996.
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
