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Deposition from United States v. SFWMD, et al., Case No. 88-1886-CIV-HOEVELER |
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Deposition from United States v. SFWMD, et al., Case No. 88-1886-CIV-HOEVELER |
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658
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 Nancy L.
15 Eaton, 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 Monday, February 11,
20 1991, commencing at 10:00 a.m.
21
22
23 LINDA MARIE MacDONALD, RPR-CM
REGISTERED PROFESSIONAL REPORTER
24 60 LAWRENCE ROAD, PLYMOUTH, MA 02360
(508) 747-6615
659
1 A P P E A R A N C E S:
2 UNITED STATES ATTORNEY'S OFFICE
By A.U.S.A. 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.
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 A L S O P R E S E N T:
18 Douglas Robson, Consultant, SFWMD
John Davis, Consultant, Belle Glade
19 and Clewiston
Peter Ghavami, Legal Assistant,
20 Skadden Arps
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
660
1
I N D E X
2 Witnesses Examination
WILLIAM W. WALKER, JR.
3 (By Ms. Ahearn) 661
4
5 E X H I B I T S
6 Number
For ID
7
DX 33 Confidential Memo 705
8 DX 34 Water Quality Trends,
Executive Summary 722
9 DX 35 Declaration of 9-1990 723
DX 36 Article - Techniques of
10 Trend Analysis 750
DX 37 Article - Nonparametric
11 Trend Test for Seasonal
Data with Serial Dependence 750
12
13
14
15
16
17
18
19
20
21
22
23
24
DEPOSITION OF WILLIAM W. WALKER, JR.
661
1 DIRECT EXAMINATION - CONTINUED - BY MS. AHEARN
2 Q. Good morning, Doctor Walker.
3 A. Good morning.
4 Q. Just to let you know, you are still under oath
5 from last week throughout this deposition.
6 Did you review any materials
7 regarding South Florida water quality over the
8 weekend?
9 A. No.
10 Q. Took it off. Last week before we commenced
11 your deposition, it is my understanding that
12 you met with counsel for the government on
13 Monday and Tuesday, is that correct?
14 A. Yes, I believe that's correct.
15 Q. Over that Monday and Tuesday, did you look at
16 materials regarding water quality in South
17 Florida?
18 MR. HARRISON: You may answer yes
19 or no.
20 A. Yes.
21 Q. Did you look at materials other than those that
22 you provided to be produced in conjunction with
23 your deposition?
24 A. No.
DEPOSITION OF WILLIAM W. WALKER, JR.
662
1 Q. Can you describe for me the general nature of
2 the documents and materials you looked at prior
3 to the commencement of this deposition last
4 week?
5 MR. HARRISON: Objection,
6 counsel. You're going into my two-day
7 preparation session with Dr. Walker. He
8 already testified the materials we used that we
9 went over over the weekend were materials that
10 he has provided for this deposition. I think
11 it is inappropriate for you to ask further as
12 to what Dr. Walker and I went into. It is
13 clearly attorney client.
14 MS. AHEARN: I didn't ask him what
15 nature. I asked him the nature of the
16 materials that he did look at. That would
17 clearly go to the deponent's recollection, his
18 ability to seize on certain facts that might
19 relate to one type of the science you have been
20 looking at versus the other, so I think my
21 question was appropriate.
22 MR. HARRISON: Counsel, it goes
23 into whatever my mental impressions are, what
24 we were going to work for in this deposition.
DEPOSITION OF WILLIAM W. WALKER, JR.
663
1 It is entirely beyond the scope of anything you
2 have a right to go into and wish you would go
3 into the science, but not asking what him and I
4 did at our preparation session. I am not going
5 to let him answer those questions.
6 Q. Dr. Walker, I'd like to get a complete overview
7 of the opinions that you have formulated that
8 you would be prepared to give at trial in this
9 case. Now, let me make clear, I'm not asking
10 you to tell me what the United States attorneys
11 have or haven't told you they'll want you to
12 testify to. I am simply trying to identify the
13 opinions in your mind which you have formulated
14 to such a degree that you as a scientist would
15 be prepared to testify as to those opinions at
16 trial.
17 MR. HARRISON: Counsel, just to
18 clarify any misinterpretation of your
19 characterization, the United States has never
20 told Dr. Walker what they want him to testify
21 to nor would we ever -- or at least I certainly
22 as an attorney would not.
23 MS. AHEARN: I was simply trying
24 to fend off your objection.
DEPOSITION OF WILLIAM W. WALKER, JR.
664
1 MR. HARRISON: We have discussed
2 areas which are necessary, or we as lawyers
3 believe are necessary, for proof in this case,
4 but Doctor Walker's opinions are his own. The
5 United States has certainly never put opinions
6 in Doctor Walker's head and I just want to
7 clear up that.
8 Q. Have you formulated such opinions that you
9 would be prepared to give at trial regarding
10 the current existence of water quality problems
11 within Everglades National Park?
12 MR. HARRISON: Objection to form.
13 Counsel, just to make sure we have
14 a clear record, are you asking about stuff that
15 Doctor Walker has opinions he has formulated
16 based on his own work or opinions that he would
17 be comfortable in giving based on work of other
18 and reliance thereon?
19 MS. AHEARN: What I'd prefer to
20 do, Mr. Harrison, is identify those opinions
21 and then I will give Dr. Walker the opportunity
22 to explain his bases, identify what he relies
23 on for each opinion.
24 MR. HARRISON: Okay.
DEPOSITION OF WILLIAM W. WALKER, JR.
665
1 A. I believe that I testified last week that one
2 of the tasks in which I am currently involved
3 is a study of trends at monitoring stations
4 within the Park. I have not completed that
5 task and I have not at this time formulated
6 definite opinions regarding that analysis.
7 Q. Have you formulated tentative opinions at this
8 time?
9 A. The analysis that I've completed thus far
10 indicates that increasing trends in phosphorus
11 concentrations are likely at some of the
12 stations monitored within the Park.
13 Q. Are these increasing trends in total
14 phosphorus?
15 A. That's correct.
16 Q. Any other constituents?
17 A. The preliminary analysis also indicates a
18 decreasing trend in dissolved oxygen
19 concentration at one station.
20 Q. What station is that?
21 A. I believe it was station P33.
22 Q. When you say that trends are likely based on
23 your preliminary analyses, can you quantify
24 this likelihood?
DEPOSITION OF WILLIAM W. WALKER, JR.
666
1 A. The likelihood is defined in the same way that
2 I define the likelihood in the trend analysis
3 that I conducted on the inflows to the Park as
4 described in the report that I submitted to the
5 Justice Department and as described in the
6 declaration that I signed for the Justice
7 Department regarding trends in water quality at
8 inflow points to the Park.
9 Q. Are you using the identical statistical
10 procedures in your Park marsh station analysis
11 that you used in the analysis reflected in
12 Exhibit 17, your final report?
13 A. The fundamental statistical procedure that is
14 used to examine or to estimate the likelihood
15 of trend is the same, that is, the Seasonal
16 Kendall test.
17 Q. Does the work differ in some other respects,
18 for example, maybe in how you have to adjust
19 the database?
20 A. What do you mean by adjust?
21 Q. Well, I asked you if you were using the same
22 procedures and in answering you told me that
23 you are using the Seasonal Kendall test. I am
24 trying to confirm whether or not other
DEPOSITION OF WILLIAM W. WALKER, JR.
667
1 procedures used in Exhibit 17 are also being
2 employed in the marsh station analysis or not.
3 A. At this point in my research, I have not
4 completed the investigation of hydrologic
5 factors as they may contribute to variations in
6 the water quality at marsh stations.
7 Q. So is it too early to tell whether you will use
8 the same procedures?
9 A. That's correct.
10 Q. And then you told me that in terms of
11 quantifying this likelihood, you're doing it in
12 the same manner as Exhibit 17. Have you
13 quantified for the marsh stations the
14 likelihood of increasing trends in total
15 phosphorus?
16 A. The statistical procedure that I'm using tests
17 the hypothesis that is called the null
18 hypothesis of no increasing trend or no change
19 in the data.
20 The likelihood is expressed in
21 terms of the probability that that hypothesis
22 is true, and when the likelihood -- when that
23 probability is less than .1, as described in my
24 report on the inflow trends, I'm using that as
DEPOSITION OF WILLIAM W. WALKER, JR.
668
1 a working definition of differentiating between
2 stations with trends and stations without
3 trends.
4 Q. Have you also done analyses of the marsh
5 stations using a probability factor of less
6 than .05?
7 A. Well, the Kendall test estimates that
8 probability. The interpretation of the
9 importance of that probability in terms of
10 whether or not a trend exists is really not a
11 statistical question. The procedure estimates
12 the probability and I am just using .1 as a
13 convenient way of summarizing the results and
14 tabulating the results. I'm also reporting the
15 exact probability levels as they are derived
16 from the Seasonal Kendall test.
17 Q. At the probability level of less than .10, how
18 many of how many total marsh stations show some
19 trend?
20 A. I don't recall those details.
21 Q. How many total marsh stations have you analyzed
22 so far?
23 A. I believe there are nine stations.
24 Q. Do you recall whether using a probability level
DEPOSITION OF WILLIAM W. WALKER, JR.
669
1 of less than .05 you get a certain number of
2 these nine stations showing a likely trend?
3 A. I don't recall.
4 Q. How many total water quality constituents are
5 you looking at at these marsh stations?
6 A. I don't recall the exact number.
7 Q. Is it more than twenty?
8 A. I don't recall the exact number.
9 Q. Do you recall if it is more than ten?
10 MR. HARRISON: Objection. Asked
11 and answered.
12 A. I don't recall the exact number.
13 Q. Are there documents among those you produced
14 for the deposition that would reflect the
15 number of constituents being analyzed as well
16 as those that show likely trends at given
17 probability levels?
18 A. Yes, there are.
19 Q. Would these be computer printouts?
20 A. I guess you could define them as computer
21 printouts, yes.
22 Q. What would you define them as?
23 A. Tables.
24 Q. Can you give me identifying features of these
DEPOSITION OF WILLIAM W. WALKER, JR.
670
1 tables so that I could find them in your
2 documents?
3 A. I recall a series of tables that are
4 collections that are in a similar format to
5 those that are included in Appendix A of
6 Exhibit 17, that is, my report on the inflow
7 trends. And I recall some one or more tables
8 that summarize results of the Seasonal Kendall
9 test for different stations and water quality
10 components.
11 Q. Great, thanks. That will give me some
12 guidance. Do you recall approximately when
13 these tables were generated?
14 A. They would have been generated in -- within the
15 last two months.
16 Q. Is it your opinion as an environmental engineer
17 specializing in water quality that this
18 likelihood of an increasing trend in total
19 phosphorus at certain Park stations constitutes
20 an existing water quality problem in the Park?
21 MR. HARRISON: Object to form.
22 Inflow stations or marsh stations or both?
23 Q. The marsh stations that we just discussed.
24 A. As I stated earlier, I have not completed my
DEPOSITION OF WILLIAM W. WALKER, JR.
671
1 analysis of these data. I have not completed
2 my analysis of the hydrologic factors as they
3 may influence these measurements, and so I
4 cannot at this point state one way or another
5 whether I believe these trends from the
6 analysis that I have completed thus far
7 constitute water quality problems.
8 Q. Is that answer also applicable if we consider
9 other work that you've done regarding water
10 quality in South Florida in addition to the
11 marsh trend analysis?
12 A. No.
13 Q. Based on that entirety of work that you've
14 done, do you have an opinion whether there are
15 existing water quality problems within the
16 Park?
17 A. The work that I've completed on the inflows to
18 the Park indicates that most of the stations
19 that are monitored at those inflow points show
20 increasing trends in phosphorus, decreasing
21 trends in nitrogen to phosphorus ratio during
22 the period of monitoring that I examined.
23 Inasmuch as the Park ecosystems
24 are downstream of those inflow points, I
DEPOSITION OF WILLIAM W. WALKER, JR.
672
1 believe that those trends at the inflow points
2 constitute water quality problems for the Park.
3 Q. Is it your opinion as an environmental engineer
4 specializing in water quality that this
5 likelihood of trend which your work shows of
6 increasing phosphorus concentrations in Park
7 inflows constitutes a current as opposed to
8 threatened problem for the Park?
9 MR. HARRISON: Objection,
10 counsel. Asked and answered.
11 A. I don't understand your question.
12 Q. I asked you if you were of the opinion whether
13 a water quality problem existed within the Park
14 and your answer suggested to me that the trend
15 you see at the perimeter of the Park is
16 upstream of marsh stations and in that respect
17 constitutes a problem. From the perspective of
18 the interior marsh stations, is this an
19 existing problem or a threatened problem?
20 A. My opinion is based upon analysis of data that
21 was collected between December of 1977 and
22 September of 1989. The fact that phosphorus
23 concentrations increased at Park inflow points
24 during that period indicates to me that during
DEPOSITION OF WILLIAM W. WALKER, JR.
673
1 that period the Park -- the downstream
2 locations in the Park -- were subjected to
3 those higher phosphorus concentrations and that
4 would constitute water quality problems.
5 Q. Have you an opinion whether the trends of
6 increasing phosphorus concentrations and
7 inflows which you report has caused any
8 imbalance in natural populations of aquatic
9 flora or fauna within the Park?
10 MR. HARRISON: Objection. Lack of
11 foundation to show that he's done that type of
12 work.
13 Also objection to the definition
14 of the term balance.
15 A. My work has focused on water quality measures
16 at Park inflows and within the Park and not on
17 direct measurements of flora and fauna and the
18 imbalance thereof.
19 Q. Consulting the work of others on flora and
20 fauna, have you any opinion?
21 A. No.
22 Q. Have you any opinion whether natural
23 populations of aquatic flora or fauna within
24 the Park are imbalanced?
DEPOSITION OF WILLIAM W. WALKER, JR.
674
1 MR. HARRISON: Objection,
2 counsel. I don't see where it differs from
3 your last question.
4 MS. AHEARN: I think my last
5 question had a causation element in it which
6 this question does not.
7 MR. HARRISON: Object to form.
8 Imbalanced from what?
9 A. Would you rephrase the question?
10 Q. Have you any opinion whether there exists an
11 imbalance in natural populations of aquatic
12 flora or fauna within the Park?
13 MR. HARRISON: Object to form.
14 A. My work is focused on the analysis of water
15 quality data and has not been -- I have not
16 analyzed data on that topic.
17 Q. Have you any opinion as to the cause of the
18 increasing trend in total phosphorus which you
19 report in Park inflows?
20 A. I have identified categories of causes that
21 could be factors but I have not quantitatively
22 evaluated them.
23 Q. What are the categories of factors which you've
24 identified?
DEPOSITION OF WILLIAM W. WALKER, JR.
675
1 A. The first category would be that the increasing
2 trends in phosphorus at Park inflows reflect
3 increases in the concentrations or loadings of
4 phosphorus discharged to the water conservation
5 areas from the adjacent watersheds.
6 The second category is related to
7 a loss in the retention capacity or the
8 assimilative capacity of the water conservation
9 areas to absorb or remove the phosphorus
10 loadings discharged from -- discharged to the
11 water conservation areas from adjacent
12 watersheds.
13 The third category has to do --
14 pertains to changes in the distribution of flow
15 or changes in water management, the
16 distribution of flow into the Park which may
17 have influenced phosphorus concentrations at
18 certain stations during this time period; and
19 the fourth category of cause has to do with
20 climatologic variations which I believe could
21 be related or -- could be related to the
22 apparent trends.
23 Q. Before you -- strike that.
24 You said you hadn't quantified
DEPOSITION OF WILLIAM W. WALKER, JR.
676
1 these categories of factors. Do you presently
2 have any preliminary opinions as to which if
3 any or all of these factors are causally
4 related to the increasing trends in total
5 phosphorus that you report?
6 MR. HARRISON: Object to
7 characterization. I think he's already said
8 that he's identified all four as being causally
9 related. That was my understanding. Feel free
10 to clear it up.
11 A. I'm sorry. I lost your question. Would you
12 repeat your question or rephrase it?
13 Q. At this point are you ready to give an opinion
14 whether or not each of these categories of
15 factors is causally related to the trends that
16 you report?
17 A. As described in Exhibit 17, Series C of the
18 analysis adjusted for effects of hydrologic
19 factors including antecedent rainfall, water
20 elevation and in the case of the analysis of
21 trends in nutrient transport, the work also
22 considered variations in flow.
23 Based upon that, I believe that
24 the fourth category that I've identified
DEPOSITION OF WILLIAM W. WALKER, JR.
677
1 earlier, that is, the category relating to
2 climatologic or hydrologic variations, is a
3 relatively unimportant factor.
4 With respect to the other three
5 factors, my current opinion is based upon the
6 analysis of the inflow data; and the
7 preliminary analysis of the inflow data to the
8 water conservation areas, that is, analysis of
9 the inflows to the Park and the analysis of the
10 inflows to the water conservation areas which
11 generally showed similar patterns, and I
12 therefore believe, based upon the work that
13 I've completed thus far, that it is likely that
14 increasing loads to the water conservation
15 areas and increasing concentration at inflow
16 points to the water conservation areas are
17 causative factors contributing to the trends at
18 the Park inflow points.
19 With respect to the other factors
20 and with respect to overall quantifying each of
21 these factors and putting numbers on each of
22 them, I have not as yet completed my work so
23 that I would be able to do that.
24 Q. Now, with one, your category one, where you say
DEPOSITION OF WILLIAM W. WALKER, JR.
678
1 that it is likely that it is a causative factor
2 and your category four, climatologic
3 variations, where you say it is probably
4 relatively unimportant, are you relying there
5 on the work you've done to investigate
6 statistical correlation with those factors and
7 total phosphorus concentration and loadings?
8 A. I have, to the best of my ability, attempted to
9 remove, using the statistical techniques that
10 are described in Exhibit 17, those portions of
11 the variations in phosphorus concentrations
12 that are related to hydrologic factors and I
13 have found trends remaining in the data.
14 Q. And those trends you believe are likely to have
15 some causal relationship with increased
16 concentrations or loadings of phosphorus
17 discharged to the water conservation areas,
18 that was your category one?
19 A. I believe that category one is likely to be a
20 factor contributing to those trends.
21 Q. And am I correct, your work is still too
22 preliminary to reach that type of tentative
23 opinion regarding your categories two and
24 three? Can you tell us now whether categories
DEPOSITION OF WILLIAM W. WALKER, JR.
679
1 two and/or three have likely causal
2 relationships with total phosphorus?
3 MR. HARRISON: Counsel, if you're
4 asking for a preliminary opinion, I have no
5 objection. He's already stated that the work
6 has not progressed to the point that he has
7 firm opinions on that.
8 A. My work has not completed to the point of being
9 able to quantitatively rank these various
10 potential causes.
11 Q. Let me just try and ask it one more way. It
12 seems to me you told us that in the final
13 category of causative factors, it is likely
14 that your category one is in and your category
15 four is relatively unimportant. I am not
16 clear, where do you stand currently on
17 categories two and three?
18 A. I am still in the process of evaluating all of
19 these categories. All of these are preliminary
20 conclusions that we're discussing regarding
21 causation and preliminary opinions.
22 Q. I recognize that. If you've told it to me, I
23 apologize, I missed it. Do you have a
24 preliminary opinion on the causal relationships
DEPOSITION OF WILLIAM W. WALKER, JR.
680
1 of your categories two and three to the
2 phosphorus inputs to the Park?
3 A. I have preliminary opinions regarding category
4 three.
5 Q. And what is that opinion?
6 A. As I stated earlier, it is possible that trends
7 at some of these stations may be related to
8 changes in the distribution of flow entering
9 the Park. The one -- one example of that, if I
10 could refer to Exhibit 17?
11 (Witness looked at document.)
12 Figure 2 on page 4 shows the
13 monthly flows that were released at the various
14 inflow points to Shark slough including S12A,
15 S12B, S12C, S12D and S333; and as is described
16 in the report, there have been various changes
17 in the relative magnitudes of those release
18 points, in particular, the latter years as --
19 in an effort to provide increased flow to the
20 northeast portion of Shark River slough, there
21 was an increased flow through the structure
22 S333.
23 The S333 structure is located
24 right adjacent to the L67A canal and it is
DEPOSITION OF WILLIAM W. WALKER, JR.
681
1 possible that some of the -- some portion of
2 the overall trend which I identified for the
3 combined discharge to Shark slough, that is,
4 the station S12_334, is related to that
5 increased discharge of canal water directly
6 into the Park in the later portion of the
7 record.
8 The overall magnitude of that
9 effect, if I could refer to Figure 10 on page
10 37, there is a trend line shown for what I call
11 station S12T which is the composite discharge
12 through the S12s, A, B, C and D, and that, as
13 indicated, there is a significant increasing
14 trend. There is also a trend line shown for
15 the station S12_334 which is the total
16 discharge to Shark slough.
17 And my preliminary opinion
18 regarding an effect of water management is that
19 the difference in the trend between that
20 measured at or for S12, for the S12 composite,
21 and the trend reported for the Shark River
22 slough composite could be related to the
23 increase inflow through S333.
24 Now, it is possible that trends
DEPOSITION OF WILLIAM W. WALKER, JR.
682
1 also exist at S333, so we don't know whether
2 the difference between S12T and S12_334 is just
3 an effect of water management or whether there
4 are also effects of the other causal factors
5 involved here as well; but that is one example
6 of water management -- of a case where water
7 management may influence trend at a particular
8 station.
9 Q. And this preliminary opinion regarding this
10 water management change as reflected in S12T
11 and S12_334 is based on correlative analyses
12 that are described in Exhibit 17; is that
13 correct?
14 A. No, it is based upon common sense and mass
15 balance.
16 Q. Are you relying on any particular body of
17 scientific literature in deriving this opinion?
18 A. I am relying on the fundamental principle of
19 mass balance.
20 Q. What experimental work have you done concerning
21 potential causative factors for the increasing
22 trends that you report for Park inflows?
23 A. I've done no experimental work. That is not
24 part of the scope of work and is not part of
DEPOSITION OF WILLIAM W. WALKER, JR.
683
1 what I normally do in the course of analyzing
2 data from a system such as this.
3 Q. Have you reviewed any experimental work on this
4 topic performed by others?
5 A. We are discussing a very large and very complex
6 system that is operated for many purposes, and
7 the feasibility of doing experimental work to
8 evaluate causes of trends, the feasibility of
9 experimenting with this whole system to
10 evaluate causes is nonexistent.
11 Q. Would you agree that it is hazardous as a
12 matter of science to accept correlation as
13 sufficient proof of causation?
14 MR. HARRISON: Object to form.
15 Are you speaking in particular context of this
16 particular study Doctor Walker has done or are
17 you just asking any field of science?
18 Q. I'm asking if he would agree with that
19 statement.
20 A. Correlation can be used as a basis for forming
21 opinions regarding causation. It is not
22 necessarily hazardous to do so. It is on a
23 case specific basis. Correlation is sufficient
24 -- is a factor that can be used in assisting
DEPOSITION OF WILLIAM W. WALKER, JR.
684
1 one in formulating opinions regarding
2 causation.
3 Q. Is correlation alone a sufficient basis on
4 which to form an opinion constituting proof in
5 court?
6 MR. HARRISON: Objection, counsel.
7 Q. Let me rephrase the question. Dr. Walker, in
8 your opinion is correlation alone sufficient on
9 which to base an opinion concerning causation
10 of a water quality trend?
11 MR. HARRISON: Object to form.
12 Question is too broad.
13 A. It is valid to consider correlation as a factor
14 in formulating one's opinions regarding
15 causation.
16 Q. Would you base an opinion on this matter on
17 correlative statistics alone?
18 MR. HARRISON: Objection. Asked
19 and answered.
20 A. The correlative statistics or the trends that
21 have been reported in the work that I've done
22 so far describe the development of a problem at
23 Park inflow points over the period of record
24 that was monitored.
DEPOSITION OF WILLIAM W. WALKER, JR.
685
1 The interpretation of causation
2 can be based partially upon those observed
3 trends and upon interpretation of other factors
4 and other observation and other work that have
5 been made that has occurred in the water
6 conservation areas.
7 Q. Developing your opinions concerning the water
8 quality in the Park, have you relied on
9 specific work performed in the water
10 conservation areas other than your own?
11 A. I have relied on the description of the work
12 that has been done that is documented in the
13 SWIM plan regarding the development of
14 eutrophication in certain of the -- certain
15 areas of the water conservation areas.
16 Q. Any other documents or reports concerning work
17 in the water conservation areas on which you've
18 relied?
19 A. The list of or the documents which I turned
20 over to the Justice Department contain a number
21 of references that are related to this topic
22 that are outside of the SWIM plan, so those
23 would also be included in the list of documents
24 that I have read and relied upon.
DEPOSITION OF WILLIAM W. WALKER, JR.
686
1 Q. Do you have any opinion as to whether water
2 quality problems currently exist within the
3 Loxahatchee Refuge?
4 MR. HARRISON: Object to form.
5 A. I believe that the trend analysis of water
6 conservation area inflow and outflow points
7 that I described last week as one of the tasks
8 with which I am currently involved indicated a
9 likely trend or trends at one or more of the
10 outflow points from the water conservation
11 areas and those trends were increasing
12 phosphorus concentration.
13 Q. So you found those trends specifically at
14 points leading into the Refuge?
15 A. I believe they were trends at points coming out
16 of the Refuge.
17 Q. Would those be the S10 structures?
18 A. I believe that's correct.
19 Q. Any other structures or points leading out of
20 the Refuge at which you found these trends?
21 A. I don't recall.
22 Q. Have you any opinion as to whether there exists
23 an imbalance in natural populations of aquatic
24 flora or fauna in the Refuge?
DEPOSITION OF WILLIAM W. WALKER, JR.
687
1 MR. HARRISON: Objection,
2 counsel. No foundation.
3 A. I have not studied the imbalance of natural
4 flora or fauna in the Refuge and I have no
5 opinion on that.
6 Q. Have you any opinion as to what factors have
7 caused the water quality problem at the Refuge
8 as you've defined it, your likely trends in
9 increasing total phosphorus at outflow points?
10 A. My work in Water Conservation Area 1 or the
11 Loxahatchee National Wildlife Refuge has been
12 very preliminary and I have not formulated any
13 such opinions in that area.
14 Q. That would include tentative opinions.
15 A. I really haven't thought about it as much as
16 the other -- the Park inflow points. I have
17 not completed my analysis of Loxahatchee.
18 Q. Doctor Walker, do you have an opinion as to
19 what numeric level as a total phosphorus
20 standard for inflows to Everglades National
21 Park should be adopted?
22 MR. HARRISON: Object to form.
23 Adopted for what purpose? And also the term
24 standards is not defined.
DEPOSITION OF WILLIAM W. WALKER, JR.
688
1 Q. I'll rephrase the question.
2 MR. HARRISON: I am going to allow
3 him to answer anything that he believes
4 standards for inflows. I just want to make
5 sure that the question is couched right as to
6 what purpose and what type of standard you're
7 talking about, counsel. These questions can be
8 misinterpreted.
9 Q. Dr. Walker, in the context of ONRW standards,
10 have you an opinion as to what number should be
11 used as the limitation for acceptable mean
12 annual total phosphorus concentrations for
13 inflows to Everglades National Park?
14 MR. HARRISON: Object to form.
15 A. The ONRW methodology as we developed it in a
16 number of working sessions with the District
17 staff did not involve setting standards on a
18 mean annual timeframe, so your question makes
19 no sense to me.
20 I can't answer it.
21 Q. Do you have an opinion as to whether numeric
22 limitations for phosphorus -- total phosphorus
23 inputs to Everglades National Park should be
24 implemented?
DEPOSITION OF WILLIAM W. WALKER, JR.
689
1 A. Yes.
2 Q. What is the nature of the limitations which you
3 believe should be implemented?
4 MR. HARRISON: Object to form.
5 You may answer.
6 A. My recommendations concerning phosphorus,
7 interim phosphorus standards for inflows to
8 Everglades National Park, are described in what
9 was introduced as Exhibit No. 28 last week.
10 Essentially these are limits that are based
11 upon the first five years of monitoring data in
12 each Park basin, that is, Shark River slough,
13 Taylor slough and the coastal basin, and these
14 are standards that would apply to five-year
15 running flow-weighted mean concentrations for
16 each basin. The specific values for these
17 basins are derived directly from the monitoring
18 data and are identified in Exhibit 28.
19 Q. Could you please direct me in Exhibit 28 to the
20 specific numbers which you recommend be
21 employed as these limitations?
22 A. Well, with respect to the flow-weighted mean
23 concentrations, these values are identified for
24 each basin in Table 1 of Exhibit 28, and in the
DEPOSITION OF WILLIAM W. WALKER, JR.
690
1 case of Shark slough, the standard would be
2 designed to preserve a long term flow-weighted
3 mean concentration not greater than .0083
4 milligrams per liter. For any five-year period
5 the flow-weighted mean concentration would not
6 exceed .009 milligrams per liter.
7 In the case of Taylor slough as
8 shown in Table 1, the standards are designed to
9 preserve a long term flow-weighted mean of
10 .0078 milligrams per liter and the five-year
11 running flow-weighted mean concentration for
12 any five-year period would not exceed .0091
13 milligrams per liter.
14 And in the case of the coastal
15 basin, the standards would preserve a long term
16 flow-weighted mean of .0084 milligrams per
17 liter. The value for any five-year period
18 would not exceed .0096 milligrams per liter.
19 These numbers are derived directly from the
20 monitoring data for the first five years of
21 record in each basin using the statistical
22 methods that we agreed upon and developed with
23 the District staff under the ONRW discussions.
24 Q. Have you any opinion as to whether these
DEPOSITION OF WILLIAM W. WALKER, JR.
691
1 numeric limitations that you've just pointed
2 out to us on Table 1 should be implemented
3 through the South Florida litigation?
4 MR. HARRISON: Objection. You may
5 answer.
6 A. These limits would insure that the inflow
7 concentrations to the Park in each basin would
8 not exceed the values that I've listed.
9 Exactly how the limits are implemented would
10 not matter.
11 Q. Have you any opinion as to whether these
12 limitations are achievable?
13 MR. HARRISON: Object. Lack of
14 foundation.
15 A. As I mentioned, these limits are based upon the
16 first five years of monitoring data for each
17 basin. They therefore reflect a condition that
18 once existed at the inflows to the Park.
19 Therefore, I believe they are achievable.
20 Q. Have you any opinion as to what reasonable and
21 reliable measures, if any, should be
22 implemented upstream of the Park to achieve
23 these standards?
24 MR. HARRISON: Objection.
DEPOSITION OF WILLIAM W. WALKER, JR.
692
1 Foundation.
2 You may answer.
3 A. Yes.
4 Q. What is your opinion in that regard?
5 A. I believe that measures should be taken to
6 control or reduce the loading of phosphorus
7 entering the water conservation areas from the
8 various sources.
9 Q. What reasonable and reliable methods should be
10 implemented to control phosphorus loading to
11 the water conservation areas?
12 MR. HARRISON: Object to the form
13 of the question and to the foundation or lack
14 of.
15 A. I would generally categorize those methods as
16 methods that are directed at reducing the
17 loading and concentration of phosphorus in the
18 watersheds, in runoff from the watersheds that
19 drain into the water conservation areas using
20 any of a variety of best management practices
21 or other techniques for doing so.
22 Another category of control would
23 be use of what has been termed by the district
24 as water management areas or buffer areas for
DEPOSITION OF WILLIAM W. WALKER, JR.
693
1 -- to provide interception of phosphorus
2 loadings from the adjacent land uses and
3 removal of phosphorus prior to discharge into
4 the water conservation areas.
5 Q. Is it necessary to reduce existing phosphorus
6 loads to the water conservation areas in order
7 to comply with your interim standards in Table
8 1?
9 MR. HARRISON: Object to form. I
10 think that the question requires more
11 specificity. His analysis includes several
12 combinations of structures. Are you asking
13 about everything or a particular basin?
14 A. Would you repeat the question, please?
15 Q. Is it necessary to reduce your existing
16 phosphorus loads to water conservation areas in
17 order to comply with the interim standards in
18 your Table 1 of Exhibit 28?
19 A. Well, in the case of Taylor slough and the
20 coastal basin, these systems are not directly
21 -- these systems are not directly linked to
22 the water conservation areas. There is some
23 linkage, but they are also influenced by other
24 watersheds, so it is very difficult to answer
DEPOSITION OF WILLIAM W. WALKER, JR.
694
1 your question with -- as to whether reducing
2 phosphorus loads to the water conservation
3 areas is necessary to achieve these limits for
4 Taylor slough and the coastal basin.
5 With respect to Shark slough, I
6 believe that some reduction in the loads to the
7 water conservation areas would be needed in
8 order to comply with these limits.
9 Q. Do you know how much in terms of metric tons
10 per year?
11 A. My work has not progressed to the point of
12 being able to predict that or to quantitatively
13 specify that.
14 Q. Can you predict how much loading in terms of
15 metric tons per year could be reduced by the
16 variety of BMPs which you say are available?
17 A. No, I cannot. There are a range of techniques
18 and the particular performance of those
19 techniques and the amount of phosphorus that
20 would be controllable using those techniques
21 would depend upon the specific techniques and
22 the specific conditions that are present in the
23 watersheds and how effectively these are
24 applied and enforced.
DEPOSITION OF WILLIAM W. WALKER, JR.
695
1 Q. Have you done any investigation of those
2 techniques, the conditions that exist in the
3 watersheds and how they can be enforced?
4 A. Not personally, no.
5 Q. Have you reviewed the work of others in this
6 regard?
7 A. I believe that my review has been limited to
8 whatever discussion is contained in the SWIM
9 plan.
10 Q. Are there any specific BMPs or similar methods
11 which, in your opinion, are more likely to lead
12 to a reduction of phosphorus loading?
13 MR. HARRISON: Object to form.
14 A. That's a very general question. If you could
15 be more specific, maybe I could answer that.
16 Q. Are there specific BMPs and similar measures
17 which, in your opinion, should be implemented
18 in order to reduce phosphorus loadings to the
19 water conservation areas?
20 A. I have not analyzed in any detail the various
21 options that are available, and one category of
22 control that seems to me to make some sense for
23 -- at least for the point of view of further
24 investigation -- would be more careful control
DEPOSITION OF WILLIAM W. WALKER, JR.
696
1 of water level in the agricultural fields.
2 Q. Without further field investigation, would you
3 be able to determine what reduction in
4 phosphorus loading could be achieved through
5 more careful control of water level?
6 A. I have not done any field investigation.
7 Q. Let me put it this way. Does the data exist,
8 the information exist such that you could
9 determine the potential phosphorus reduction
10 from more careful control of water level or is
11 more field work still necessary to create that
12 basic raw data?
13 A. Well, my research has not focused on the
14 quantitative aspects of that. I believe that
15 that is a category of management option that
16 should be implemented. There may be other
17 experts and a body of research that would be
18 available to make quantitative predictions in
19 that regard but that is not my field.
20 Q. And you corrected me in that the Taylor slough
21 basin and coastal basin aren't so directly
22 impacted by the loadings to the water
23 conservation areas. What are the methods that
24 should be implemented to ensure that your
DEPOSITION OF WILLIAM W. WALKER, JR.
697
1 interim standards from Table 1 in Exhibit 28
2 are met in those two basins?
3 MR. HARRISON: Object to the
4 characterization of his prior testimony.
5 A. I have not investigated in any way the control
6 possibilities for these watersheds, but I will
7 state that the numeric limits that are
8 specified in Table 1 are very close to the
9 values that were measured in the last five
10 years of data that I looked at. In other
11 words, under -- at least looking at the last
12 five years of data -- the system would already
13 be very close to being in compliance with these
14 limits.
15 Q. So that additional control methods might not be
16 necessary?
17 A. I wouldn't go so far as to say that because the
18 -- the analysis the trend analysis indicated
19 significant increasing trend especially in the
20 Taylor slough basin, so some form of control
21 may be necessary to arrest that trend in order
22 to ensure compliance with these limits.
23 Q. For purposes of establishing these interim
24 standards for phosphorus concentrations into
DEPOSITION OF WILLIAM W. WALKER, JR.
698
1 the Park, is there any important difference
2 between a level of .0083 milligrams per liter
3 and .01 milligrams per liter?
4 MR. HARRISON: Objection to form.
5 A. I am not in a position to state whether or not
6 such differences are important. These are the
7 numbers that came out of the statistical
8 analysis. If someone wants to round them off
9 in one direction or another, that would be up
10 to them. That would be a policy decision. But
11 from the point of view of having a set of
12 numbers that come directly out of the baseline
13 data, these are the numbers that come out and I
14 feel uncomfortable with rounding them off and
15 using those rounded off values as standards.
16 Q. Have you any opinion as to whether a standard
17 of .01 milligrams per liter as opposed to .0083
18 milligrams per liter would have any impact on
19 the biota within the Park?
20 MR. HARRISON: Counsel, object,
21 lack of foundation.
22 A. I have seen no indication that .01, that a
23 standard of .010 milligrams as compared to the
24 .0083 milligrams per liter would not result in
DEPOSITION OF WILLIAM W. WALKER, JR.
699
1 some impact.
2 Q. Have you seen any information which suggests
3 the limit of .01 milligram per liter would
4 adequately protect the Park from adverse
5 impacts?
6 A. These numbers in Table 1 of Exhibit 28 are
7 based upon the first five years of record for
8 each station. And the numeric values assume a
9 five-year averaging period. Now, a level of
10 .01 milligrams per liter applied to a shorter
11 timeframe, shorter than five years, might be
12 statistically the equivalent of this standard
13 of .0083 and provide the same level of
14 protection, but the important distinction here
15 is that .01 would apply to a shorter timeframe
16 than five years.
17 Q. So .01 would be acceptable if it applied to the
18 five-year averaging period but nothing shorter?
19 A. No, the .0083 which works, as I stated earlier,
20 in the case of Shark River slough for any five-
21 year period, the standard would be .009 for any
22 five-year period .009 should not be exceeded
23 and that would apply to a five-year period. If
24 one wanted to adopt a standard of .01
DEPOSITION OF WILLIAM W. WALKER, JR.
700
1 milligrams per liter and provide the same level
2 of protection, then one would have to use an
3 averaging period that is shorter than five
4 years.
5 Q. I get you. Thank you.
6 (Recess.)
7 Q. Doctor Walker, would a flow-weighted mean total
8 phosphorus concentration of .01 milligrams per
9 liter be consistent with historic inflow and
10 marsh data for the Park?
11 A. Again, you would have to specify what timeframe
12 you're talking about and which inflows and
13 which marsh stations you're talking about.
14 Q. You would be uncomfortable making such a
15 general statement as the one framed in my
16 question?
17 A. You would have to specify the timeframe and the
18 stations that you are referring to.
19 Q. What is the scientific rationale for the first
20 five year of sampling period of record for each
21 basin adopted in your Exhibit 28?
22 A. The concept of a five year running average was
23 something that was developed in the discussions
24 that we had with the District staff regarding
DEPOSITION OF WILLIAM W. WALKER, JR.
701
1 ONRW standards. I believe it was originally
2 suggested by the District staff.
3 Q. So you just rely on the District for purposes
4 of establishing this parameter?
5 A. Well, I have analyzed the data and I'm familiar
6 with the variations that have occurred in
7 phosphorus over this timeframe and I believe
8 that a five-year basis for the standard is a
9 reasonable one.
10 Q. Have you looked at other periods of record to
11 see what kind of standards they would generate?
12 A. Yes.
13 Q. How many other periods of record have you
14 looked at?
15 A. Well, the original period of record that was
16 investigated under the ONRW was the period that
17 was specified, I believe, by some legislative
18 or regulatory body in Florida for the ONRW
19 standards. It was specified that we would use
20 data for the period from -- excuse me, data
21 through March of 1981, so the first period of
22 record that we examined used all the data that
23 we had up through that timeframe, and so that
24 would be roughly a three-year period of record
DEPOSITION OF WILLIAM W. WALKER, JR.
702
1 from 1978 through 1981.
2 Q. Any other periods of record that you examined?
3 A. I believe some calculation were done early
4 using shorter time periods, one year, for
5 example, and the District had originally
6 proposed using a ten-year or using the entire
7 period of record for their monitoring program
8 as a basis for setting the standard.
9 Q. What would be the scientific rationale for
10 using the entire period of record?
11 A. Well, it wasn't our suggestion. That was the
12 suggestion by the -- made by the District.
13 Q. Do you recognize any scientific rationale for
14 using the entire period of record?
15 A. I believe their rationale was that was all the
16 data they had. It was the longest period of
17 record that was available with a consistent set
18 of laboratory techniques and procedures and so
19 forth.
20 Q. You accept the District's position on this
21 point in terms of establishing the standards?
22 A. Not in terms of using the ten-year or the
23 entire period of record for setting the
24 standards, no, I do not.
DEPOSITION OF WILLIAM W. WALKER, JR.
703
1 Q. When you looked at the ONRW period, how did the
2 numbers derived from that period of record
3 compare to those in Table 1 of Exhibit 28?
4 A. They were similar with the exception of, excuse
5 me, with the exception of Taylor slough and
6 coastal basin because the monitoring periods
7 for Taylor slough and coastal basin did not
8 begin until 1983. We had no data for the ONRW
9 timeframe prior to March of 1981 for those
10 basins, so we only had data for Shark slough
11 prior to 1981.
12 Q. How did the values for Shark slough for the
13 ONRW time period compare to those reflected in
14 Exhibit 28?
15 A. Very similar.
16 Q. Were they higher or lower?
17 A. I think they were in terms of the upper 95
18 percent confidence limit for the flow-weighted
19 mean which is the value not to be exceeded in a
20 five-year period. They were essentially
21 identical. I don't recall. It was within .001
22 milligrams per liter.
23 Q. That number not to exceed that you just
24 referred to, what value is that in Exhibit 28?
DEPOSITION OF WILLIAM W. WALKER, JR.
704
1 A. .0090.
2 Q. Could you please take this line in Table 1 for
3 Shark slough in Exhibit 28 and explain the
4 meaning of each entry in the categories across
5 that line?
6 A. You want me to explain each of the columns in
7 Table 1?
8 Q. Please.
9 A. The first column identifies the basin, Shark
10 slough, Taylor slough or coastal basin. The
11 second column identifies the number of samples
12 that were available during the baseline periods
13 for the first five years of monitoring for each
14 of those basins.
15 The next column identifies the
16 flow-weighted mean concentration that was
17 calculated for each of those basins during the
18 first five years of record.
19 The next column that's in
20 parentheses identifies the upper 95 percent
21 confidence limit for the flow-weighted mean
22 that was calculated for each of the basins
23 during the first five years of record.
24 Q. And that's the number you would employ as the
DEPOSITION OF WILLIAM W. WALKER, JR.
705
1 standards for purposes of computing the five
2 years?
3 A. That number would be the number that would be
4 compared with the five year flow-weighted mean
5 concentration for any period in the future for
6 the purposes of determining compliance with
7 this standard.
8 Q. Please proceed.
9 A. The rest of this table has apparently been
10 obscured by someone's handwritten notes that
11 are not mine and I can't continue explaining
12 this table.
13 (Off the record discussion.)
14 (Confidential Memorandum was
15 marked Exhibit 33.)
16 Q. Doctor Walker, could you please identify the
17 document which has been marked as Exhibit 33?
18 A. This appears to be a partial copy of a
19 confidential memorandum that I prepared for the
20 Justice Department in February of 1990
21 regarding phosphorus standards for inflows to
22 Everglades National Park.
23 Q. And when you say it is partial, are you
24 referring to pages 8, 9 and 10 which are
DEPOSITION OF WILLIAM W. WALKER, JR.
706
1 captioned for figures which do not appear here?
2 A. Upon reviewing this document, that's all that I
3 note at this moment as being missing. There
4 may be other things missing, but I don't see
5 anything at this moment.
6 Q. Did you author Exhibit 33 in its entirety?
7 A. Yes.
8 Q. And to whom did you direct this document?
9 A. This was directed to the US Department of
10 Justice, what was then the Land and Natural
11 Resources Division.
12 Q. Anyone else to whom you sent this document?
13 A. I don't recall whether I sent copies directly
14 to anyone else or not.
15 Q. Do you recall, did you receive comments back on
16 this document?
17 A. No, I don't recall receiving any comments.
18 Q. Do any more recent versions of this document
19 exist?
20 A. Not of this particular document, no.
21 Q. May I turn your attention to page 3 of Exhibit
22 33, the next to last paragraph and the first
23 sentence of the last paragraph read:
24 "Total phosphorus should not
DEPOSITION OF WILLIAM W. WALKER, JR.
707
1 exceed .03 mg/liter in more than 2.8% (or 2.1%)
2 of the samples collected in each basin.
3 "This is just justified based on
4 inflow data for the ONRW time frame (regardless
5 of water management)."
6 Do you still agree with that
7 statement in Exhibit 33?
8 MR. HARRISON: Object to
9 characterization and foundation. Statement
10 without being read in contact with the whole
11 paragraph may be out of context. I am not
12 saying that it is, but there has been no
13 predicate laid that he agrees with that
14 statement as read into the record.
15 Q. If there is a context, the document will
16 further provide it.
17 A. This statement was offered as an alternative
18 expression of the standards as is identified in
19 Paragraph 7 on page 3 of Exhibit 33. This way
20 of expressing these standards targeted the .03
21 milligram per liter level and was a statistical
22 way of using that, expressing the standards
23 with respect to that frame of reference.
24 As is stated at the end of
DEPOSITION OF WILLIAM W. WALKER, JR.
708
1 Paragraph 7, because of the underlying
2 lognormal frequency distribution of the data,
3 the alternative frequency standard, that is,
4 the frequency greater than .02 milligrams less
5 than 10 percent of the time would provide
6 essentially the same level of protection.
7 So this is just, this alternative
8 frame of reference of .03 milligrams per liter
9 is another way of expressing the standards that
10 I derived from the historic data and just
11 included in the report for consideration by the
12 Justice Department and by the Park staff.
13 Q. Was this standard as expressed in the
14 highlighted paragraph on page 3, was that
15 proposed to the District?
16 A. Not to my knowledge.
17 Q. Why not?
18 MR. HARRISON: Objection, counsel.
19 Proposed by whom? If you're talking about by
20 the Unified Federal Response to SWIM, that was
21 a Department of Justice mental processes that
22 you cannot go into even if the doctor does
23 know. Don't answer if --
24 A. I can't answer that.
DEPOSITION OF WILLIAM W. WALKER, JR.
709
1 Q. Because of Mr. Harrison's instruction?
2 MR. HARRISON: If it was expressed
3 to the District during the course of Doctor
4 Walker's ONRW meetings, which are not
5 privileged meetings that he held with the
6 District, I have no problem, counsel, but you
7 have not asked; and if in fact it was
8 expressed, whether or not it was expressed in
9 the Unified Federal Response which came from
10 the Department of Justice, that is clearly
11 attorney-client and I am not going to let him
12 go into why or why not the Department of
13 Justice chose which response to put in SWIM.
14 A. I don't recall having discussed this particular
15 way of expressing the standards with the
16 District in the context of the ONRW meetings.
17 Q. Is there any reason why this was not discussed
18 with the District in any context?
19 MR. HARRISON: Same objection,
20 counsel.
21 A. Well, from a statistical point of view, as I
22 pointed out earlier, it is because it partially
23 it is consistent and is partially redundant
24 with the frequency base standard that was
DEPOSITION OF WILLIAM W. WALKER, JR.
710
1 already being discussed with the District.
2 Q. I'm just trying to find out, do you know of any
3 reason why this statement of the standard was
4 not put forth to the District?
5 MR. HARRISON: Objection, counsel.
6 Q. Do you know of any reason?
7 MR. HARRISON: Objection, counsel.
8 Q. Simply a yes-or-no question.
9 MR. HARRISON: You may answer
10 that.
11 A. No.
12 Q. I am going to address your attention up in the
13 paragraph numbered 6 starting at the end of the
14 7th line there is the sentence:
15 "The precise concentration level
16 at which biological damage occurs is unknown."
17 As you sit here today, do you believe that
18 statement to be true?
19 A. I believe that increasing phosphorus
20 concentration above an existing condition in
21 the Park or elsewhere has a potential of doing
22 biological damage. I do not know the precise
23 concentration level in terms of milligrams per
24 liter at which biological damage starts or
DEPOSITION OF WILLIAM W. WALKER, JR.
711
1 stops.
2 Q. The next line reads: "Estimates range from .01
3 to .03 milligrams per liter," then referencing
4 Doctor Ron Jones, .01-.03 milligrams per
5 liter. What is the source of that information
6 concerning Doctor Jones?
7 A. That was a range that I recall Doctor Jones
8 having discussed in early meetings with Doctor
9 Jones and Park staff and the attorneys as being
10 a possible level at which impacts could be
11 quantified based upon his preliminary work.
12 Q. That was at more than one meeting?
13 A. Yes.
14 Q. Was this discussed at your February 8, 1990
15 meeting which is referenced on the first page
16 of Exhibit 33?
17 MR. HARRISON: Object to form and
18 I am going to object to going into specifics
19 about the February meeting, other than what is
20 reflected in this document. This document
21 obviously constitutes what the United States
22 could have claimed attorney-client and work
23 product privileges on. It has been turned
24 over. I will not say that the privilege is
DEPOSITION OF WILLIAM W. WALKER, JR.
712
1 waived. I do not intend at this time to seek a
2 return of this document.
3 You may go into the scientific
4 bases that he knows for anything stated in this
5 document, his scientific opinion on anything in
6 this document, but I will not allow you to go
7 into the source of any discussions he may have
8 had with respect to why information was in here
9 other than his own scientific bases.
10 Strategy decision which may have
11 come up at the February 1989 meeting are
12 clearly privileged and are improper inquiry
13 even regarding this document.
14 Q. Doctor Walker, were Doctor Jones' estimates for
15 level at which biological damage occurred
16 discussed at the February 8 meeting?
17 A. I don't recall whether he addressed that topic
18 specifically at that meeting or not.
19 Q. Do you recall any discussions of this issue
20 subsequent to the time you prepared Exhibit 33?
21 A. Yes.
22 Q. What was said during those discussions?
23 MR. HARRISON: Objection,
24 counsel. I will let you go into what Doctor
DEPOSITION OF WILLIAM W. WALKER, JR.
713
1 Walker knows or does not know that is in the
2 heads of the scientists. I would appreciate it
3 if you wouldn't characterize it as coming out
4 of that meeting.
5 If you want to ask Doctor Walker
6 what he knows about Ron Jones' current opinion
7 on those numbers or what he does not know, Ron
8 Jones is undergoing a deposition. I am sure
9 you already have that information.
10 MS. AHEARN: I think there has
11 clearly been a subject matter waiver as to
12 everything that's raised in this document and
13 the other documents which you've divulged.
14 MR. HARRISON: Counsel --
15 MS. AHEARN: I am moving on. I
16 think our record is clear. Doctor Walker
17 received information from other scientists and
18 he reports it in his drafts; and when they talk
19 about it subsequently, you won't let me find
20 out what's being developed here.
21 MR. HARRISON: Counsel, I want to
22 clarify the record. You may go into the
23 scientific basis that is in Doctor Walker's
24 head, or if he knows the scientific bases in
DEPOSITION OF WILLIAM W. WALKER, JR.
714
1 any of the other government experts' heads,
2 regarding what is in this document. But as
3 long as your questions do not go to why
4 something was presented, why it wasn't, why it
5 was transmitted to the District, what I
6 characterize are strategy decisions, I don't
7 think we'll have a problem and I don't think
8 you need to go into those.
9 Q. Doctor Walker, do you know if Doctor Jones
10 still estimates this precise concentration at
11 which biological damage occurs as .01 to .03
12 milligrams per liter?
13 A. To my knowledge Doctor Ron Jones has not
14 precisely quantified a value or a range at
15 which biological damage occurs.
16 Q. Do you know if Doctor Jones still estimates
17 that this range may be as high as .03
18 milligrams per liter?
19 A. To my knowledge Doctor Jones has not identified
20 a particular concentration level at which
21 biological damage begins to occur.
22 Q. Could you please turn to page 11 of Exhibit 33.
23 MR. HARRISON: Eleven, counsel?
24 Q. Eleven. Did you compute the values that appear
DEPOSITION OF WILLIAM W. WALKER, JR.
715
1 on page 11?
2 A. Yes.
3 Q. The entries for S12+S333, do those entries
4 reflect the same structures that are included
5 for the basin Shark slough on Table 1 of
6 Exhibit 28?
7 A. I don't recall if they reflect precisely the
8 same structures. There is an adjustment for
9 the flow through S334 that is subtracted
10 through S333 and I don't recall whether the
11 values in Exhibit 33 are adjusted for that.
12 Okay. Upon further review on page
13 6, it is indicated that the flows to S333 are
14 adjusted for the flows to S334, so as far as I
15 can tell or I recollect, the values for
16 S12+S333 referred to on page 11 of Exhibit 33
17 are the same structures as the values referred
18 to as Shark slough in Table 1 of Exhibit 28.
19 Q. Did you use the same computational methods to
20 derive the flow-weighted means in each exhibit?
21 A. I did.
22 Q. Do the numbers in Table 1 of Exhibit 28 include
23 outliers?
24 A. The numbers in Table 1 on Exhibit 28 were
DEPOSITION OF WILLIAM W. WALKER, JR.
716
1 computed using the methodology that we had
2 agreed upon with the district which -- and that
3 methodology included a systematic procedure for
4 screening for outliers, so Table 1, the numbers
5 in Table 1, do not include the effects of
6 outliers.
7 Q. How did the District express its agreement to
8 this procedure for excluding outliers?
9 A. In the course of one or more of the meetings
10 that we had with the District, there was a
11 verbal agreement and there was also a written
12 agreement, I recall, in the form of a letter
13 from Paul Trimble or excuse me, I don't recall
14 Paul's last name, but there was a letter from
15 District staff that indicated that we had
16 reached agreement regarding methodology for
17 handling outliers.
18 Q. Is that among the documents you produced, that
19 letter?
20 A. I believe so.
21 Q. Do you recall by name any other person from the
22 District who expressed agreement?
23 A. There was general agreement in the meeting, in
24 more than one meeting that we had with the
DEPOSITION OF WILLIAM W. WALKER, JR.
717
1 District regarding ONRW on the methodology.
2 Q. Did anyone holding an executive office or
3 position with the District agree to this
4 methodology for outliers?
5 MR. HARRISON: Objection,
6 foundation. Not shown that Doctor Walker would
7 know what that title is and who would hold it.
8 A. Based upon my limited knowledge of the
9 District's organizational framework, I believe
10 that the highest ranking person who was present
11 at the meeting at which we agreed upon a method
12 and the concept of screening the data for
13 outliers was Thomas McVicar.
14 Q. And it is your testimony Mr. McVicar agreed
15 with this methodology?
16 A. To my recollection there was a general
17 agreement in the meeting.
18 Q. Did Mr. McVicar specifically agree?
19 A. He was present at the meeting and I don't
20 recall his voicing any objection to the
21 agreement.
22 Q. Let me make sure I understand this. With
23 reference to page 11 in Exhibit 33, do these
24 values, does this table reflect that if you
DEPOSITION OF WILLIAM W. WALKER, JR.
718
1 employ the period of record for discharges to
2 Shark River slough before 1985 and include
3 outliers, the flow-weighted mean is 17.9
4 milligrams per liter -- excuse me, parts per
5 billion -- total phosphorus?
6 A. No.
7 Q. Utilizing the second period of record that is
8 reflected in this table on page 11 and
9 including outliers, what is the flow-weighted
10 mean for the S12s plus S333 structures?
11 A. The second period of record reflects the
12 measurements that were collected after 1985.
13 The flow-weighted mean concentration excluding
14 outliers was 16.9 parts per billion. The
15 flow-weighted mean concentration including
16 outliers was 17.9 parts per billion.
17 Q. Thank you for correcting me. Then when you use
18 "all" for period of recording, what period of
19 record is that?
20 A. That would be the entire period of record from
21 the District's database: December of 1977
22 through September of 1989.
23 Q. And using that period of record, what is the
24 flow-weighted mean for discharges to Shark
DEPOSITION OF WILLIAM W. WALKER, JR.
719
1 River slough including outliers?
2 A. The flow-weighted mean including outliers is
3 13.1 parts per billion.
4 Q. Could I turn your attention back to the bottom
5 of page 3, Exhibit 33.
6 Did you test for lognormality of
7 the historic pre-1981 distribution of
8 flow-weighted mean total phosphorus
9 concentrations?
10 A. Yes.
11 Q. What test procedure did you employ?
12 A. I believe the test involved comparing the
13 observed and the predicted frequencies of total
14 phosphorus concentrations exceeding .01, .02
15 and .03 milligrams per liter where the observed
16 frequencies would be calculated directly from
17 -- by counting the number of measurements that
18 were above those values and the predicted
19 frequencies would be calculated from the log
20 mean and log standard deviation of the
21 measurements calculated during that same time
22 period and applying the lognormal frequency
23 distribution equations.
24 Q. Did you do that type of analysis for each of
DEPOSITION OF WILLIAM W. WALKER, JR.
720
1 the structures?
2 A. I believe I applied that only to the Shark
3 River slough discharge.
4 Q. The total value or for each structure?
5 A. I don't recall whether -- I may have done
6 testing involving the individual structures as
7 well. I don't recall.
8 Q. Did you record the results of this testing
9 procedure in any way?
10 A. I recall doing it on a spreadsheet. I don't
11 recall whether I saved those results or not.
12 Q. When did you do this testing?
13 A. It would have been in January probably or early
14 winter of 1990.
15 Q. And you did this on your personal computer?
16 A. Correct.
17 Q. Let me make sure I've made this clear. Is it
18 that you can't remember if you did the testing
19 to each of the structures discharging to Shark
20 River slough?
21 MR. HARRISON: Objection. Asked
22 and answered.
23 A. I may have done it to each of the structures.
24 I don't recall.
DEPOSITION OF WILLIAM W. WALKER, JR.
721
1 Q. Do you recall if you did the test to the
2 combined?
3 A. I did perform it for the combined discharge to
4 Shark slough.
5 Q. This was all done on the same occasion, the
6 same session at your computer?
7 A. Not necessarily.
8 Q. Is a flow-weighted mean of lognormal
9 concentrations distributed lognormally?
10 A. Not necessarily.
11 Q. When would the flow-weighted mean of lognormal
12 concentrations be distributed lognormally?
13 MR. HARRISON: Object to form.
14 You mean with respect to Shark
15 River slough, the same topic we're on or
16 generally?
17 A. I can't answer your question because I don't
18 know what the question refers to. You'd have
19 to be more specific.
20 Q. This isn't a statistical issue question
21 addressed on a conceptual level?
22 A. Not unless you define what you mean by the
23 distribution of the flow-weighted mean.
24 Q. The frequency distribution?
DEPOSITION OF WILLIAM W. WALKER, JR.
722
1 A. I'm sorry, I still can't answer your question.
2 It is not specific enough.
3 (Water Quality Trends, Executive
4 Summary, was marked Exhibit 34.)
5 Q. Doctor Walker, can you please identify Exhibit
6 34?
7 A. This is entitled Water Quality Trends at
8 Inflows to Everglades National Park, Executive
9 Summary.
10 Q. Did you prepare this document?
11 A. No.
12 Q. Do you know who did?
13 A. I believe that Doctor Robert Harris prepared
14 this.
15 Q. Have you seen this document before today?
16 A. I believe I have seen it, yes.
17 Q. Do you know why Doctor Harris prepared this?
18 MR. HARRISON: Objection, if it
19 calls for a direction or instruction from the
20 Department of Justice. If you happen to know a
21 scientific basis on which Doctor Harris
22 provided it, you may answer.
23 A. I can't answer.
24 Q. Based on your counsel's instruction?
DEPOSITION OF WILLIAM W. WALKER, JR.
723
1 A. Yes.
2 Q. Did Doctor Harris write any of what appears in
3 Exhibit 7?
4 A. Are you asking me if Doctor Harris coauthored
5 Exhibit 7?
6 Q. Did Doctor Harris coauthor Exhibit 7?
7 A. No.
8 Q. What do you mean by coauthor?
9 A. I mean whether Doctor Harris wrote any of
10 Exhibit 7.
11 Q. So Doctor Harris did not write any of Exhibit
12 7?
13 A. That's correct.
14 MR. HARRISON: Counsel, I do
15 suggest before you go into the next exhibit we
16 have lunch.
17 MS. AHEARN: Why don't we do a
18 simple identification, Mr. Harrison.
19 (Declaration of September 1990 was
20 marked Exhibit 35.)
21 Q. Doctor Walker, can you please identify Exhibit
22 35?
23 A. This is a declaration that I prepared in
24 September of 1990 that describes my research
DEPOSITION OF WILLIAM W. WALKER, JR.
724
1 results regarding the South Florida problem.
2 Q. Did Doctor Harris write any of this?
3 MR. HARRISON: Object to form,
4 counsel. I think "any" in this situation has
5 to be very tightly defined.
6 A. Doctor Harris prepared an early draft of this.
7 Q. Did you prepare Exhibit 35 in its entirety?
8 MR. HARRISON: Object to form.
9 A. The words and opinions expressed in Exhibit 35
10 are my own.
11 Q. Who actually wrote Exhibit 35?
12 A. I wrote Exhibit 35.
13 Q. How many prior draft declarations were there?
14 MR. HARRISON: Objection,
15 counsel.
16 A. I don't recall.
17 MR. HARRISON: This document was
18 written specifically for a legal purpose and
19 you've already established it was for the
20 summary judgment I think last week. I am not
21 going to go into the preparation of the
22 document.
23 MS. AHEARN: Mr. Harrison, the
24 government has made multiple entries on
DEPOSITION OF WILLIAM W. WALKER, JR.
725
1 privileged lists attributing this document and
2 draft to different authors. I am simply trying
3 to sort out how many documents the government
4 has here.
5 MR. HARRISON: I object to your
6 characterization. I think that you're probably
7 misinterpreting something.
8 MS. AHEARN: If I am, this is my
9 chance to straighten it out.
10 MR. HARRISON: You can ask him how
11 many. I won't let you go into the substance or
12 who had what input to any of the drafts. You
13 have this declaration before you and you have
14 had Doctor Walker's testimony that it
15 represents his words and his opinions. You can
16 ask him how many drafts that he personally
17 wrote.
18 Q. How many drafts authored by persons other than
19 yourself of your declaration are you aware of?
20 MR. HARRISON: Objection,
21 counsel. I will not permit him to go into what
22 other assistance or technical consultants may
23 have had, whether they have had input or not
24 into this. You're looking at the final
DEPOSITION OF WILLIAM W. WALKER, JR.
726
1 product. Doctor Walker already testified it
2 was his own, and if you want to go into how
3 many prior drafts Doctor Walker prepared, feel
4 free to do so.
5 MS. AHEARN: You won't permit me
6 to determine what other documents Doctor Walker
7 was able to consult incorporating this final
8 product?
9 MR. HARRISON: As far as I am
10 concerned, counsel, go ahead. I don't want to
11 fight over this particular area. I'll let you
12 ask. I won't let you go into the substance,
13 but you can go over how many drafts he has
14 seen.
15 A. I will have to ask for the question again,
16 please.
17 Q. How many drafts of the declaration of Doctor
18 William Walker, other than those drafted by
19 yourself, are you aware of?
20 A. I recall one.
21 Q. And who was the author of that one draft?
22 MR. HARRISON: Object to form. I
23 think draft also needs to be defined, counsel.
24 Talking about an entire document or an outline
DEPOSITION OF WILLIAM W. WALKER, JR.
727
1 or whatever? I think it needs to be defined.
2 A. There was one document that was prepared by
3 Doctor Robert Harris that essentially
4 summarized important points in my report on
5 trend analysis and presented those points,
6 extracted those points from my report and
7 provided an example of the format and the
8 presentation that would be appropriate for a
9 declaration.
10 Q. Did you utilize this draft by Doctor Harris in
11 preparing the final declaration?
12 A. The final declaration is my own words and my
13 own opinions.
14 Q. Did you utilize Doctor Harris' draft?
15 A. I read Doctor Harris' draft to provide some
16 frame of reference, but I subsequently prepared
17 my own version that expresses my own words and
18 my own opinions.
19 MS. AHEARN: Thank you. Let's
20 have lunch.
21 (Luncheon recess.)
22 AFTERNOON SESSION
23 MR. HARRISON: Counsel, prior to
24 lunch I told you I'd try to get ahold of Lloyd
DEPOSITION OF WILLIAM W. WALKER, JR.
728
1 Pike, the attorney for the Corps of Engineers
2 in Jacksonville, that I had heard that Col.
3 Malson was not going to be made available on
4 February 19th and the District does have a
5 notice for the 19th and the 20th, as I
6 understand, for his deposition based on dates
7 that he was available; but Senator Graham has
8 requested his presence and the Chief of
9 Engineers, and I believe the Division
10 Commander, General Hatch and General Sabke, I
11 think, to be in Washington,DC and it is my
12 understanding that that is for the 20th.
13 I do not know whether or not that
14 was precipitated because of the case or the new
15 governor or what precipitated it, but Colonel
16 Malson is being requested to come to Washington
17 for Senator Graham.
18 MS. AHEARN: You don't know if it
19 precipitated by the proceeding involving South
20 Florida?
21 MR. HARRISON: It would be pure
22 speculation, but I would be surprised if the
23 discussions with the Senator do not center on
24 the issues in the Everglades lawsuit. If we
DEPOSITION OF WILLIAM W. WALKER, JR.
729
1 find out that has been communicated to Colonel
2 Malson or to anybody with the government as to
3 what the reason for that briefing was, I'll let
4 you know, but I am going to have to ask you to
5 withdraw that notice, or obviously I'd have to
6 file a motion for protective order. There is
7 nothing I can do about it.
8 I did get Mr. Pike to reaffirm the
9 dates that are on Colonel Malson's calendar now
10 that he has blocked off for Lloyd Pike for
11 deposition, and that's April 22nd through April
12 24th or the entire week of April 29th through
13 May third, and let me know if you want me to
14 file a motion for protective order on the 19th
15 or how we should proceed.
16 I am hoping that I won't have to
17 do that since I don't think that there is
18 anything any of us can do about this particular
19 meeting. I would like -- I think it would be
20 most judicious for the District to notice him
21 right now before his calendar fills up for one
22 of those two timeframes in April, but that's
23 simply my suggestion.
24 MS. AHEARN: I know, Rick. I
DEPOSITION OF WILLIAM W. WALKER, JR.
730
1 thank you. Unfortunately, I followed the
2 advice once before and it didn't work for you,
3 and I think I thank you and I will convey the
4 information to those who need to know.
5 MR. HARRISON: Will you let me
6 know whether or not you're going to continue to
7 seek him for February 19th so I might file a
8 protective order? I've held back because the
9 reasons for that briefing are totally beyond
10 our control, and I think if you delve back into
11 your side, you may well find that some of the
12 reasons were precipitated by certain elements
13 of the state.
14 I certainly don't object to him
15 going up there, but I can't be torn between
16 Senator Graham and this case and we simply
17 can't produce him.
18 MS. AHEARN: I have just learned
19 about this new conflict for Colonel Malson and
20 I will convey the information to the people who
21 will decide what action to take and I am sure
22 they'll let you know.
23 MR. HARRISON: Thanks.
24 (Off the record discussion.)
DEPOSITION OF WILLIAM W. WALKER, JR.
731
1 DIRECT EXAMINATION - CONTINUED - BY MS. AHEARN
2 Q. I'd like the record to reflect that we have
3 provided an unmarked version of Table 1, the
4 second page to Exhibit 28, and I've asked
5 Doctor Walker to insert that unmarked page into
6 the deposition copy of Exhibit 28.
7 Doctor Walker, does this Table 1
8 now reflect the table as you prepared it?
9 A. I believe so.
10 Q. I'd like to turn your attention to Exhibit 17.
11 Now, Doctor Walker, we've
12 discussed this report briefly on Friday and the
13 application of the Seasonal Kendall test to the
14 District's surface water quality data for
15 inflows to the Park for 1977 through 1989.
16 Have you applied the Seasonal
17 Kendall test to surface water quality data for
18 Park inflows that are collected by any agency
19 other than the District?
20 A. No, I have not.
21 Q. In the second paragraph of the abstract, you
22 report that trend magnitudes range from four
23 percent a year at S12D to 21 percent per year
24 at S332. Does this mean that in water year
DEPOSITION OF WILLIAM W. WALKER, JR.
732
1 1990 total phosphorus levels at S12D would be
2 four percent higher than levels from water year
3 1989?
4 A. No, not necessarily.
5 Q. Does the trend analysis reflected in Exhibit 17
6 make any prediction of water quality for years
7 subsequent to the period of record actually
8 employed in the test?
9 A. No. As is stated in the conclusions of the
10 report, on what I believe is page 44, although
11 I can't tell because the page numbers have been
12 somehow missed in the copying process, but on
13 the last page of the text in my report in the
14 middle of the paragraph it states the trends
15 detected for the 1977 to 1989 period cannot be
16 extrapolated into the past or into the future.
17 Q. I believe you told us that you -- correct me if
18 I'm wrong -- that you've acquired the water
19 quality data for the year following the year of
20 record employed in Exhibit 17; is that correct?
21 A. I do not have the data in a raw form.
22 The only information which I have,
23 which I believe was entered into an exhibit
24 already, was a flow-weighted mean concentration
DEPOSITION OF WILLIAM W. WALKER, JR.
733
1 calculated by the District for, I believe, it
2 was CS12's and S333 for water year 1990.
3 Q. Is that summary data adequate for you to test
4 whether any trend is evident for water year
5 1990?
6 A. No.
7 Q. Do you have any plans to perform analyses to
8 determine if trends exist subsequent to the
9 period of record analyzed in Exhibit 17?
10 A. I do not have any definite plans to do that.
11 Q. Now, you explained how the Kendall test was
12 applied to three time series. One is all
13 concentration data, the second concentration
14 data collected on days with appreciable
15 discharge; and thirdly, concentrations
16 suggested for hydrologic factors including an
17 antecedent rainfall and water surface
18 elevation.
19 Did you perform analyses for all
20 twenty water quality components for each of
21 these three series?
22 A. Yes.
23 Q. How?
24 A. Yes.
DEPOSITION OF WILLIAM W. WALKER, JR.
734
1 Q. How did you select the twenty water components
2 to analyze?
3 A. These water quality components reflect those
4 that were consistently sampled by the District
5 during this period and which were provided to
6 the Park staff for the purpose of setting ONRW
7 baseline standards.
8 Q. So was it largely data availability that
9 directed the selection of components?
10 MR. HARRISON: Object to form.
11 A. It was availability of consistently collected
12 data.
13 Q. And by consistently collected, you mean in
14 terms of the field methodology employed?
15 A. I mean in terms of sampling frequency and
16 period of record.
17 Q. You also looked at nutrient transport rates.
18 Is that what is also commonly referred to as
19 loading?
20 A. Yes.
21 Q. And in your abstract you report that an
22 increasing trend in phosphorus transport rate
23 is indicated for Taylor slough. Was any trend
24 indicated for the other structures or basins?
DEPOSITION OF WILLIAM W. WALKER, JR.
735
1 A. Yes.
2 Q. Were the other trends detected decreasing
3 trends?
4 A. There were no decreasing trends in total
5 phosphorus that exceeded or that had
6 probabilities less than .1.
7 Q. And by total phosphorus you mean the total
8 phosphorus transport rate?
9 A. Total phosphorus transport rate, correct.
10 Q. Any trends with probabilities using a standard
11 of .05?
12 MR. HARRISON: Of decreasing
13 trends, counsel?
14 Q. Yes.
15 A. Would you fully repeat your question? I'm
16 sorry. We started talking about trends and now
17 we're talking about decreasing trends. Would
18 you please repeat your question fully?
19 Q. I asked you, you're reporting the increasing
20 trend at Taylor slough, and I asked you if
21 there were trends at the other basins and
22 stations, and you said yes, so I'm trying to
23 clarify that those were decreasing trends,
24 inferring from reporting an increasing trend
DEPOSITION OF WILLIAM W. WALKER, JR.
736
1 for Taylor slough that those other trends were
2 decreasing.
3 A. Well, that inference is incorrect. That's your
4 assumption. Those are not my results.
5 Q. Then what I am asking for is your results, if
6 you can point me to, if there were trends at
7 the other structures for phosphorus transport
8 rate, what were they?
9 A. In the case of Shark River slough, when I
10 examined all of the data including the days on
11 which the structure was sampled when there was
12 no flow, and during those days the calculation
13 of loading would be completely insensitive to
14 the concentration, that first series of tests
15 indicated there was no trend at Shark slough.
16 Q. Doctor Walker -- I'm sorry.
17 A. When I examined the data collected on days when
18 there was flow passing through the structure,
19 there was an increasing trend indicated in
20 Shark slough, and that trend magnitude was 9.9
21 percent per year.
22 Q. And Doctor Walker, you're answering in
23 reference to a table in Exhibit 17. Could you
24 please point me to the page where I'll find
DEPOSITION OF WILLIAM W. WALKER, JR.
737
1 this?
2 A. The table I am referring to is Table 6 and I
3 believe, although I can't -- just from looking
4 at the adjacent pages -- because the page
5 number has been omitted from the copy and it
6 looks like it is on page 41.
7 Q. Doctor Walker, during our next break I will see
8 if I can find a copy that wasn't cropped at the
9 top if that will make it easier to see the
10 pages for you.
11 On the first page of the text of
12 Exhibit 17 in the first paragraph, 8th line,
13 you report that in retaining some 94% of the
14 total phosphorus load discharged from the
15 sources you discuss above, between 1979 and
16 1988, the WCAs had been utilized as water
17 quality buffers.
18 Could you characterize the
19 phosphorus uptake efficiency reflected by that
20 94 percent figure?
21 MR. BURGESS: Sorry, counsel,
22 which page are you on?
23 MS. AHEARN: First on
24 introduction.
DEPOSITION OF WILLIAM W. WALKER, JR.
738
1 MR. HARRISON: I'm sorry. The
2 page labeled introduction, counselor?
3 MS. AHEARN: Yes. It doesn't have
4 a page number on it.
5 MR. HARRISON: When you said first
6 page of the text, I was looking at the
7 abstract. The very next page after the cover
8 sheet.
9 A. That sentence refers to the fact that based
10 upon the District's calculation of nutrient
11 loads into and out of the water conservation
12 areas, 94 percent of the total phosphorus load
13 that is discharged into the water conservation
14 areas is retained within the water conservation
15 areas.
16 Q. Have you performed any verification of those
17 calculations?
18 A. I have not recalculated the total phosphorus
19 budgets for each structure leading into and
20 leading out of the water conservation areas as
21 performed by the District.
22 Q. Do you have any information to suggest that
23 this 94 percent uptake figure is wrong?
24 A. Assuming that the District's calculation of
DEPOSITION OF WILLIAM W. WALKER, JR.
739
1 total phosphorus loads from the various
2 structures is correct, and assuming that the
3 District's assumptions regarding the loading of
4 phosphorus in rainfall and atmospheric load is
5 correct, one would calculate the removal
6 efficiency of 94 percent for this entire period
7 of record, but I have not verified or tested
8 those specific assumptions myself.
9 Q. Those are assumptions which you have employed
10 in any work you've performed on the South
11 Florida matter?
12 MR. HARRISON: Objection.
13 Employed -- he obviously employed them here.
14 You mean in his reports, counsel?
15 A. Yes.
16 Q. Can you characterize a 94 percent phosphorus
17 uptake rate relative to uptake rates that have
18 been studied throughout North America?
19 MR. HARRISON: Objection,
20 foundation.
21 A. I can characterize it generally in relation to
22 uptake rates that were present in the
23 particular water resource systems that I've
24 studied.
DEPOSITION OF WILLIAM W. WALKER, JR.
740
1 Q. Okay. How would you characterize it relative
2 to the systems you've studied?
3 A. It is relatively high, unusually high for -- in
4 relation to the systems that I've studied.
5 Q. And when we talk about the systems that you've
6 studied, are those the ones reflected in your
7 project summaries, for example, Exhibit 2?
8 A. That's correct.
9 Q. A little bit far farther down in the
10 introduction with respect to WC and nutrient
11 trap efficiency, you state the longevity of
12 this is unknown.
13 Do you believe that to be true
14 today, that the longevity of WC and nutrient
15 trap efficiency is unknown?
16 A. Generally, yes.
17 Q. Could it be indefinite?
18 A. Could what be indefinite?
19 Q. The nutrient trap efficiency longevity?
20 MR. HARRISON: Objection, counsel,
21 based on what assumptions, based on the
22 assumption that the nutrients continue as they
23 are now? There is a million assumptions that
24 go into that assumption.
DEPOSITION OF WILLIAM W. WALKER, JR.
741
1 MS. AHEARN: I don't think I want
2 to ask him the question a million different
3 ways.
4 MR. HARRISON: No, but I think in
5 all fairness you should characterize what
6 you're asking in assumptions.
7 A. The question of whether a trap efficiency of
8 this magnitude could be maintained indefinitely
9 must be considered in relation to the
10 literature studies that the study reported in
11 the literature on wetlands where people have
12 quantified inputs and outputs over periods of
13 time and people have documented declines in
14 phosphorus trapping efficiency over time.
15 Q. Would you be able to apply that information
16 from the literature to the water conservation
17 areas of the Everglades?
18 A. One would have to consider that information in
19 evaluating the longevity of the phosphorus
20 trapping efficiency in the Everglades.
21 Q. The areas under consideration in the
22 literature, are they comparable to the water
23 conservation areas?
24 A. Comparable in what way?
DEPOSITION OF WILLIAM W. WALKER, JR.
742
1 Q. In size and configuration, in climate, in
2 macrophyte, soil composition?
3 A. Each system has its own unique characteristics.
4 Q. Are you aware of any studies of the longevity
5 of nutrient uptake efficiency in any wetland
6 comparable to Water Conservation Area 3?
7 MR. HARRISON: Object to form.
8 A. Studies would be located perhaps in different
9 regions and of different sizes, but there are
10 studies that show that wetlands used for waste
11 water treatment such as these water
12 conservation areas have been used, in other
13 words, being used as water quality buffers have
14 a tendency to lose that buffer capacity over
15 time.
16 Q. Could you identify one wetland that's been
17 studied in the literature that you would point
18 to as most comparable to the Water Conservation
19 Area 3A for these purposes?
20 MR. HARRISON: Object to form.
21 Q. The best example that we could employ?
22 MR. HARRISON: My objection,
23 counsel, is just over the definition of the
24 words comparable and best.
DEPOSITION OF WILLIAM W. WALKER, JR.
743
1 A. I've stated that there were probably no systems
2 to my knowledge that are comparable in terms of
3 size or location. All that I stated is that
4 there have been waste water treatment system
5 wetlands that are used for waste water
6 treatment that have been documented to lose
7 their phosphorus trap efficiency over time.
8 Such studies are referenced in an article that
9 was prepared by -- I believe it was Nichols
10 published in 1983 in the Journal of Water
11 Pollution Control Federation and in a
12 subsequent article by Richard Nichols that was
13 in a book published by Van Nostrand in 1984 or
14 1985. I don't recall the particular names of
15 the wetlands.
16 Q. A bit farther down in the introduction you make
17 reference to Belanger, et al, 1989. What was
18 that study about?
19 A. That study was a review of eutrophication
20 problems in the water conservation areas and
21 the Everglades as prepared by Belanger, Scheidt
22 and Platko which appeared in Lake and Reservoir
23 Management in 1989.
24 Q. This a review paper as opposed to original
DEPOSITION OF WILLIAM W. WALKER, JR.
744
1 research?
2 A. I believe it was a mixture of both. I don't
3 recall exactly.
4 Q. Have you relied on any original data reported
5 by Belanger at all?
6 A. I reviewed that particular paper by Belanger,
7 et al.
8 Q. Do you know if there is any primary data or
9 original research in the next reference Lake
10 Okeechobee Technical Advisory Council, 1990?
11 A. I am not certain whether that contains any
12 original research.
13 Q. Do you know of any original research which
14 supports the statement: "Increases in
15 phosphorus concentration have been associated
16 with changes in plant communities and with
17 declining water quality in portions of the
18 WCAs"?
19 A. The research cited in Belanger, et al and the
20 research cited in the Lake Okeechobee Advisory
21 Council report.
22 Q. Have you reviewed that research that is cited
23 in these two sources?
24 A. I have reviewed these two sources of
DEPOSITION OF WILLIAM W. WALKER, JR.
745
1 information, these two publications.
2 Q. The next to last sentence on this page reads:
3 "Tests for trends in nutrient transport rate
4 (kg/day) and ENP basin are also conducted."
5 When did you conduct those tests?
6 A. Late summer, early fall of 1990.
7 Q. Had you conducted them prior to preparing the
8 first draft of your water quality trends
9 report?
10 A. No.
11 Q. Why wasn't this included in the first set of
12 analyses you did before preparing the draft
13 report?
14 A. The first report focused on trends in
15 concentration and identified such trends, and
16 with the additional timeframe permitted between
17 the draft and the final, and I believe there
18 was also some feedback from one or more of the
19 reviewers of that first draft, that information
20 on nutrient transport rates would be useful, so
21 it was partly a matter of additional time at
22 the suggestion of the reviewer that the
23 analysis of nutrient transport was undertaken.
24 Q. Did you have a deadline for that first draft?
DEPOSITION OF WILLIAM W. WALKER, JR.
746
1 MR. HARRISON: I am going to
2 object to your question, counsel. If there is
3 some sort of a deadline, if it is his own
4 deadline, fine. If it is some deadline that
5 the
