Science & Technical Advisory Committee
January 10, 2007
Ms. Susan Pastor
Re: Proposed Changes to Fox River Remediation Plan
Dear Ms. Pastor:
The Science & Technical Advisory Committee (STAC) of the Lower Fox River and Green Bay Remedial Action Plan (RAP) has reviewed the EPA and WDNR (the “Agencies”) proposed changes to the remedy described in the Record of Decision (ROD). We have also reviewed the Basis of Design Report (BODR) which provides the supporting detail. However, the BODR represents a very complex body of work, and we have not had the resources to evaluate the report to the extent that we would like. Therefore, our comments submitted in this document will address primarily the proposed changes to the original ROD plan as described in the Technical Memorandum which the agencies released in November of 2006.
The Lower Fox River and Green Bay Remedial Action Plan process has been heavily involved in the Fox River contaminated sediments issue for two decades. From the very beginning of this effort, the goal of the STAC has been to identify, evaluate and incorporate the best science and policy into the remediation process as is possible. The Wisconsin Department of Natural Resources (WDNR) no longer supports structured RAP committees. However, our group has worked together since 1986, and will continue to provide comments and input to all parties working towards environmental improvements for the Fox River and Green Bay ecosystems.
Any written comments provided by our committee normally represent a consensus opinion. In this case our comments are being submitted specifically on the merit of the plan developed by the EPA and WDNR, referred to as the Optimized Remedy. It should be noted that the views expressed by the STAC do not reflect the official position of the parent organizations of its members and that our WDNR and U.S. Fish & Wildlife members have chosen not to contribute directly to the statements presented below.
The STAC submitted formal comments to the Proposed Remedial Action Plan
(PRAP) in January of 2002. The following comments will build on our 2002
comments and will specifically address the agencies proposed changes to
the original PRAP cleanup plan.
Comments Regarding the Philosophical Shift to Increased Capping and Less Dredging
The Optimized Remedy would result in substantially less dredging as compared to the current plan; i.e. 3.6 million cubic yards as compared to 7.6 million cubic yards. In order to maintain a similar level of remediation, the proposal calls for a significant increase in capping. The primary benefits of the proposed changes have been reported as: less time to complete; quicker positive response by the fish community (i.e. reductions in PCB body burdens); and lower cost.
However, we continue to be concerned about the tradeoffs which will accompany these benefits. The capping issue was prominent in our 2002 PRAP comments. In that document, we stated:
The process for selecting a final alternative must weigh: capping - the benefits of short term risk reduction coupled with long term risks due to possible cap failure against; dredging - the benefits of long term risk reduction associated with mass removal coupled with the short term risk of PCB release from resuspended sediments during dredging and some amount of risk posed by residual PCBs which remain in the sediment.
The STAC has previously recommended permanent removal of PCBs from the lower Fox River and Green Bay wherever technologically and economically feasible. The intent of the overall cleanup strategy should be to minimize the potential for both short-term and long-term risks, to humans and wildlife populations.
But we also noted that that the concept of mixing dredging and capping was sound, and should be explored during detailed design. Essentially, our opinion in this regard has not changed.
The agencies have highlighted new information that has come to light since the PRAP was published. We wish to comment on four areas included under the heading of “new information” as contained in the EPA document titled, “EPA Proposes Changes to Current Cleanup Plan”, dated November 2006.
First, it appears that a main element of this new information reflects the observation that the concentrations and locations of PCBs in the river are somewhat different than earlier believed. However, we are not at all surprised at this finding. Sediment surveys conducted over the past 20 years have verified that the PCBs are not static, but rather are regularly redistributed by effects of current and other physical disturbance. Concentrations have been shown to be highly variable, and will no doubt continue to show even more variability as more sampling is performed, given the nature of sedimentation characteristics and PCB chemistry. Even when the PRAP was released, it was expected that the estimates of total volumes of sediment to be remediated would be revised as more detailed sediment coring was performed. So, we fail to see how the new analytical data in any way supports the need for a dramatic shift to more capping.
Second, there is discussion in the proposed plan that there are a number of limitations to dredging in several areas of the river, such as along some riverbanks and near structures. Again, this was noted in the original PRAP as a “fine tuning” need to be elucidated during final design. However, we note that the discussion suggests that considerable portions of nearshore areas may not be conducive to dredging. This will no doubt be true in some cases, but as long as the shoreline is stable, there should be no reason to preclude dredging in most nearshore areas, particularly in OU 4.
The third element listed under the “new information” heading relates to limited landfill space. This topic surely represents a critical component to any remediation plan, and has been the subject of considerable discussion ever since the RAP work began. As we review the proposed changes, we have concerns that this element, in fact, may be the primary driver behind the philosophical shift towards capping. Though landfill space has always been a key issue, until now the agencies have not indicated that this element would be a limiting factor in the ultimate remediation strategy. We now have concerns that this may no longer be the case. We have seen serious difficulties with landfill issues every step of the way; first with the Deposits N and 56/57 Demonstrations Projects, then the Little Lake Butte des Mortes project, and most recently with Georgia Pacific’s proposal to accept TSCA sediments at their Green Bay landfill. It should be no surprise to the agencies that securing landfill space was paramount to the successful implementation of any remediation scenario. Our PRAP comments included a recommendation which stated:
Off-site landfilling has been selected as the long-term disposal alternative for all dredged sediments. We have gone on record that landfilling provides the only reasonable and certain means at hand to secure contaminated sediments in a safe and cost effective way, and prevent further contamination of Green Bay. However, the most cost effective means for landfilling dredged sediments may involve the siting and construction of a new landfill. Many institutional and regulatory hurdles would have to be addressed for this option to be viable. We are concerned that this key issue could significantly delay the remediation plan. Therefore, we recommend that the Department present specific details of this issue as soon as possible
However, we can only assume at this point that the agencies have been unsuccessful in this effort. We say “assume” because the agencies have been especially quiet on this aspect since the PRAP was issued. For example, the WDNR reported that it had met with Brown County on several occasions to discuss possible options for utilization of a proposed landfill site near Wrightstown. However, no final decision on the use of that site was ever publicized.
In summary, we feel that the Optimized Remedy represents a significant shift of opinion of the agencies towards a significantly greater proportion of capping versus dredging. Based on our review of the issues, such a shift offers the following advantages and disadvantages.
Advantages – quicker establishment of desired sediment surface concentrations (leading to lower fish body burdens); less use of scarce landfill space; reduced cost.
Disadvantages – significant increase in monitoring costs related to cap integrity; risk of failure to meet fish consumption advisory goals if cap integrity is compromised at any time in the future; risk of liability for ultimate responsibility for cap integrity falling back to the citizens of Wisconsin; potential increased costs related to future in-river construction by area communities.
One final point here concerns ultimate liability for monitoring and
care of any caps. There has been much said that the Responsible Parties
will carry the ultimate responsibility for long term monitoring, maintenance
and repair of any caps, essentially forever. However, our review of the
actual language contained in the documents leaves us less certain on this
issue. Therefore, we strongly recommend that the final Record of Decision
should outline, in detail, the exact liability determination. The final
decision to allow caps should not be made without such documentation.
Comments Addressing Specific Technical Components of the Optimized Remedy
Again, the Basis of Design Report represents a significant body of work, and our committee did not have the resources to pursue a full scientific evaluation. However, we do wish to make a limited number of comments on specific elements of the plan which stand out even at a cursory level of review.
Final Estimates of “Dredged” versus “Dredged and Capped” versus “Capped” Sediments
Regarding the indicated volume of sediments proposed to be capped or dredged and capped, it clearly seems that these numbers will not be known with any degree of accuracy until the final engineering design phase. At our most recent committee meeting on December 12, 2006, Greg Hill of the WDNR provided us with a very useful presentation of the Optimized Remedy. One of our questions concerned the designated areas of possible capping, as indicated in Figure 5 – 6 in the BODR report. If taken literally, the mosaic image would suggest that numerous “plateaus” of undredged, capped sediment would remain, surrounded by large tracts of dredged river bottom. Logistically this would seem terribly inefficient. Greg’s responded that the figure represents areas that meet the capping criteria, but that actual designations would not be done until final engineering design. His response made good sense, but it alludes to a future stage of the project where the final delineations of dredge versus dredge-and-cap versus cap will need to be completed. These delineations must be made based on good engineering as well as ecological considerations, without any previously determined maximum landfill space consideration.
Leaving Highly Contaminated Sediments In Place
One important feature of the 2002 PRAP, and of the ROD itself, specified that PCB concentrations of over 50 parts per million (referred to as TSCA sediments) would all be dredged. The Optimized Remedy indicates that this will no longer be the case, and that some of the TSCA sediments, if deep enough in the sediment column, could be capped.
We strongly recommend against this change. The increased risk of leaving “hot spots” in the river, in our opinion, far outweighs the marginal cost savings. Throughout the earlier planning efforts, it was acknowledged that riverine sediments with higher PCB concentrations posed the greatest risk to long term contamination of the Bay. At the same time, it was shown that dredging high concentration areas provided a cost effective means of removing PCB mass from the ecosystem. Therefore, we see no reason to modify the original ROD guidance on this issue.
Cap Design Criteria
The design flow of 24,200 cfs that was utilized in the BODR for determining the design and applicability of capping is inappropriately low, particularly for the portion of the Fox River below the DePere dam. We recommend a daily design flow in the range of 40,000 to 50,000 cfs, and if needed, an even higher 1 hour design flow, based on the following information:
1) The impact of stream contributions from the East River, Dutchman Creek, Ashwaubenon Creek and other tributaries or urban outfalls below the DePere dam were not adequately considered in the BODR hydrodynamic study. River flow between the dam and the outlet to Green Bay is unregulated. Therefore, discharge records at upstream locations should not be strictly utilized to determine design flows below the DePere dam. It appears that the revised hydrodynamic model discussed in Appendix D of the BODR accounts for contributions from the East River by adding 10% to the discharge at the DePere dam. However, a linear relationship between flow at the DePere dam and the Fox River mouth cannot be assumed for all conditions.
This concern can be demonstrated by reviewing the highest known recorded daily average flow below the DePere dam of 33,800 cfs, which occurred on June 23, 1990 at the USGS Oil Tank Depot station near the Fox River mouth (Station # 040851385). But the highest daily flow at DePere during this same storm event was only 14,500 cfs. The BODR report states that, “Reversing currents associated with seiche effects have resulted in instantaneous peak discharges at the river mouth as high as 957 m3/sec (33,800 cfs).” In fact, the peak one hour mean flow during this event was 47,400 cfs at the Oil Tank Depot station (see Figure below). While the seiche may have had some effect on discharge, the hydrological response at the Fox River outlet is consistent with heavy rainfall occurring over the entire Lower Fox River sub-basin, which has a significant amount of impervious surface with quick drainage to the Fox. A total of 4.9" of rain was recorded by the Green Bay National Weather Service on June 22, 1990. Similar amounts fell over the entire Lower Fox River sub-basin (4.2" at Appleton; 5.0" at Seymour and 4.78" at Brillion, which are just outside of the sub-basin).
2) The importance of localized precipitation events on Fox River flow at the mouth, such as the June 22, 1990 rain event, will no doubt become greater in the future as the area continues to urbanize. Flow contributions to the Fox River below Lake Winnebago are increasingly influenced by urban areas with relatively high proportions of impervious surfaces and associated flashy flows. Urban areas within the Lower Fox River sub-basin increased steadily at a 2.6% annual rate between 1954 and 2000 (Baumgart, 2005). There is little reason to expect that this trend will not continue, so urban areas could occupy over 50% of the entire sub-basin land area by 2025, and nearly 100% by 2050 if current urbanization rates are maintained. Obviously, this level of increased urbanization would serve to increase the Fox River flows even beyond events such as was experienced in June of 1990. In addition, some climate change models predict an increase in the frequency and/or magnitude of intense precipitation events in the future due to the effect of increased greenhouse gas levels. The BODR indicates that elements of cap design are based on conservative climatic conditions. Based on the discussion presented above, we cannot agree with that assertion.
Baseline Water Elevation as it affects shear stress and capping
We recommend that the final design of any remediation efforts, particularly capping, account for the potential effects of climate change on Lake Michigan and Green Bay water levels. Lofgren et al. (2000) reported the results of 12 climate models on the effects on Great Lake water levels. They found 10 of the 12 models showed a decrease in Lake Michigan-Huron water levels ranging from 1.3' to a maximum of 8.13'. The remaining two models predicted a slight increase of 0.16' over varying time frames, a result of their predictions of precipitation increases of 7 to 20%.
We do not see that the Optimized Remedy considers any change in long-term lake levels related to climate change. Based on the assessment by Lofgren et al. (2000), it would not be unreasonable to expect lake level reductions of two to four feet to occur well within the duration of the predicted cap life. Such a decrease would clearly have serious adverse effects on the capping alternative as presented. Shear stresses as estimated by the hydrodynamic model would significantly increase, shipping channel depths would no longer be adequate in areas of the channel that were capped, and overlying water depths for much of the proposed capped areas would no longer meet the existing cap criteria. Even if lake levels stay relatively constant, observed shear stresses could still increase because of increased frequency or intensity of large storms in conjunction with increased level of urbanization.
The 2002 PRAP indicated that alternative technologies could be considered as additional information became available. Comments provided to the agencies at many of the previously held public informational meetings and public hearings have urged that technologies that offer complete disposal, rather than landfilling, be considered. Yet, the current plan has completely dismissed the option of vitrification, even though an extensive amount of information about this technology has been included in the review process. The final assessment by the agencies states that the technology does not offer any significant benefit, primarily due to cost.
However, we recommend that the agencies reconsider this (and any other appropriate) technology in the planning process. The remediation of the Lower Fox River will be an unprecedented event, both in scope, time and cost. It would seem to us a missed opportunity not to consider evaluation of alternative technologies, even if at a pilot scale, within the overall work plan for this project.
Reduced cost has been highlighted as a significant benefit of the Optimized Remedy. Table 5 in the Technical Memorandum includes a comparison of the summary costs for the Current Plan versus the Optimized Remedy. Though the cost savings as listed are indeed significant, we are not confident that these savings may ultimately be realized. We understand that a great deal of detailed cost estimates went into the summaries, but from our review of Table 5 we have two concerns. First, the summary indicates a 72% reduction in costs related to dredging ($37,530,000 versus $132,570,000), yet the volume of sediment to be dredged only reduces by 54% (3.5 million yards compared to 7.6 million yards). This estimate of cost savings, then, would appear to be somewhat optimistic.
Second, the average O & M costs for the Optimized Remedy option, again based on the summary data presented in Table 5, would appear to be understated. Our comments in the Monitoring Plan section below will address this issue further.
The topic of long term monitoring was not addressed to any extent in the agencies Technical Memorandum which compared the Current Plan to the Optimized Remedy. The STAC has previously communicated its strong support for comprehensive, long term monitoring for the Lower Fox River and Green Bay, regardless of the final remediation plan that is developed. We have therefore reviewed Section 7 of the BODR and offer the following comments.
The BODR section on monitoring includes two separate programs for long term monitoring – Cap Performance Monitoring and Maintenance (Section 7.5.2) and long term ambient monitoring (Section 7.6). The monitoring plan scope for assessment of cap integrity, for the most part, appears adequate. However, the long period between surveys (5 years) is unacceptable. We would strongly recommend that some kind of short term, less intensive monitoring, such as an acoustic survey, be conducted every spring. Should a significant portion of any area of cap be damaged, the release of PCB mass could drastically affect the long term reduction of PCB body burdens in fish. Also, we recommend that a full monitoring effort be conducted whenever the Fox River flow rate exceeds the design criteria.
Regarding the long term ecological monitoring plan for Green Bay, our initial response is that it would not be adequate to assess the impacts of the Fox River sediment remediation, whether the Current Plan or the Optimized Remedy is chosen. In our view, it is of the utmost importance that a comprehensive monitoring plan be developed for this project that can provide answers to the wide variety of questions that will surely be asked during and after the implementation phase. Remediation of the Lower Fox River will require significant expenditures, regardless of which option is chosen. It will only be through review and interpretation of detailed monitoring data that our successors will be able to judge the ultimate success or failure of the project.
Section 22.214.171.124 of the BODR report states that one of the main goals of the monitoring plan should be:
Verify that sediment remedial actions in the Lower Fox River result in substantive reductions of PCB loadings to Green Bay. Decreased loadings from the Lower Fox River will help facilitate natural recovery processes in Green Bay.
Our review of the monitoring plan, as described in Section 7.6 of the BODR report, will not generate sufficient information to assess compliance with this goal. The plan emphasizes monitoring only of water and fish. But considering the limited number of sites and sampling events, this effort is not likely to provide sufficient data. Water concentrations, especially in the Bay, will show short term, relatively dramatic changes in PCB concentrations, but are not likely to be useful for identification of longer term, subtle variations. Fish concentrations can be used to judge whether the ultimate goal of elimination of fish consumption advisories is achieved, but may not be helpful in analyzing slow or otherwise unexpected responses along the way.
At a minimum, therefore, we recommend that the monitoring plan include a component designed to assess short to medium term changes in PCB concentrations, such as sediment traps or tissue analysis from young of the year fish.
Overall, we find that the long term monitoring plan, as contained in
Section 7.6 of the BODR, is unacceptable and should be revisited. Our committee
is ready and able to assist the agencies in this endeavor.
Summary and Future Concerns
The critical issue with the Optimized Remedy involves a balance of risk – the possibility of a quicker, cheaper remedy against the possibility of buried PCB mass eventually being released into Green Bay. (The following data is contained in Table ES-1 in the BODR.) The Current Plan would leave 11 - 17% of the estimated total mass of PCBs in the Fox River. Even with this significant amount of PCB removal, modeling estimates for removal of walleye fish consumption advisories suggest several decades. Under the Optimized Remedy, 34 – 38% of the estimated total mass of PCBs will remain in the river, more than twice as much as compared to the Current Plan. The computer models which simulate the response of fish tissue PCB levels to reduction in delivery to Green Bay are driven by surface sediment concentrations. Thus, the Optimized Remedy results in faster reduction of fish tissue PCB level, due to the faster time frame. But what happens if all of the optimistic assumptions about cap integrity fail to occur, and portions of the remaining mass of PCBs are ultimately released to the Bay? There are an unlimited number of possibilities associated with this scenario; none of them good. The big question to be answered is; is the long term risk of leaving these additional PCBs in the river worth the short term cost savings?
Our 2002 PRAP comments concluded with two points: first, that we should move forward with expediency toward cleanup. Second, that as we move ahead we should incorporate the principles of adaptive management to the entire process. We find that these issues are equally pertinent today.
In summary, we are grateful for the extensive work that the agencies have conducted since release of the 2002 PRAP. The proposed changes (summarily identified as a significant shift to much less dredging and much more capping) are not without merit. However, we have serious misgivings about the details of the plan as presented thus far. We would, however, be supportive of the proposal if it can be demonstrated that the agencies will address the following issues:
Please send any correspondence concerning these comments to:
John Kennedy, Chair
Greg Hill, WDNRReferences
Baumgart, P. 2005. Source Allocation of Suspended Sediment and
Lofgren, B.M., F.H. Quinn, A.H. Clites, R.A. Assel, and A.J. Eberhardt (2000). Section 4, Water Resources - Focus: Climate Change and Great Lakes Shipping/boating. In: Preparing for a Changing Climate: The Potential Consequences of Climate Variability and Change Great Lakes. U.S. Global Change Research Program. A Summary by the Great Lakes Regional Assessment Group. Great Lakes. Edited by Peter J. Sousounis and Jeanne M. Bisanz. October 2000