CWF's comments re Chatfield storage expansion project FEIS

September 4, 2013

CWF submitted comments to the US Army Corps of Engineers on August 30 re the Chatfield storage expansion project's Final Environmental Impact Statement.  At the Colorado Parks and Wildlife Commission meeting on Friday, September 13  in Montrose, Colorado Parks and Wildlife staff will present what they believe are the major impacts of the project. Subsequently, we will post the content of their presentation.  At the November Commission meeting in Lamar, the project sponsors will present their proposed mitigation plan and we will provide a link to it if possible.  Then at the December Commission meeting in Pueblo, the Commission will accept public comment and perhaps ask CPW staff to look further into particular aspects of the mitigation.  At the January Commission meeting in Denver, the Commission might accept further public comment and then vote whether to approve the mitigation plan or to request additional mitigation.  Under statute, the Commission may only vote on the mitigation plan, not whether the project may move forward.

CWF's comment letter:

August 30, 2013                       

 District Commander

U.S. Army Corps of Engineers

Omaha District


1616 Capitol Avenue

Omaha, NE 68102 – 4901


Attn:  Chatfield Storage Integrated Final Report and Environmental Impact Statement

 The Colorado Wildlife Federation is the oldest conservation organization in Colorado.  We have reviewed dozens of water projects through the years and have expertise in fish and wildlife management and mitigation issues. This is one of the largest, most complicated and confusing environmental documents we have reviewed.  More importantly, it conflicts with currently recognized proper approaches to mitigation planning.

 In our opinion, the subject document continues to have some serious problems including the following: (a) the selected alternative is the most damaging of the considered alternatives to the environment and recreation and appears to be neither consistent with the National Environmental Policy Act nor the Clean Water Act Section 404(b)(1) Guidelines; (b) the proposed mitigation for losses of cottonwood and riparian forest and wetlands is seriously deficient; and (c) the offsite mitigation model continues to use weighting factors that significantly and perhaps intentionally reduce projected mitigation requirements. 

As a result we believe the mitigation for destruction of federally designated critical habitat important for recovery of the threatened Preble’s meadow jumping mouse will not rise to the level needed to be consistent with the intent of the Endangered Species Act (ESA).  Therefore, we cannot support the project as presently proposed. 

 Furthermore, we remain very concerned that the majority of the mitigation is tied to adaptive management and unidentified parcels of land.  It is much less expensive to do mitigation up front rather than depend on adaptive management.  What if  there are not enough willing sellers available or the project proponents decide that available parcels are too expensive?  More specifics need to be developed in the Adaptive Management Plan on details and contingencies.

The U.S. Army Corps of Engineers responded to the many comments received on the draft Environmental Impact Statement (DEIS) in Appendix DD.  Some responses reflected important changes in the final EIS.  For example, the Adaptive Management Plan in Appendix GG was included because of the many concerns expressed about the significant reliance on adaptive management to achieve needed mitigation, “particularly where impacts are readily identifiable.”[1]   

 However, some of the major concerns were not responded to at all such as the lack of full mitigation for the destroyed cottonwood bird habitat.  Other responses were incomplete.  For example, with regard to the many concerns stated about the inappropriate use of weighting factors in the mitigation model, the response was that they were revised in coordination with the U.S. Fish and Wildlife Service (USFWS) and included in the Compensatory Mitigation Plan (CMP) and the USFWS’ Biological Opinion under ESA.  Appendix DD should have at least summarized the changes that were made, why they were made, what outcomes would change, and where the changes could be found in the several hundred pages comprising the CMP and its appendices.  After searching, we found out the information in the main CMP document, but changes were not made in Appendix C to that document that describes the Ecological Functions Approach. 

Copies of some of the letters of comment the Corps received on the DEIS were included in Appendix DD, e.g., letters from elected officials, applicable state and federal agencies, and supporters of the project.  However, we did not see any letters from the public and conservation organizations like ours who have serious concerns with the project.   That was a biased presentation.  Furthermore, the commenters were listed by number in the first column of the table, but there was no index that identified whom the numbers represented.  Therefore, it was impossible to discern who made most of the comments.  The public should have been able to identify the commenters because some inputs may be more credible than others.

 Unacceptable Preferred Alternative

Our biggest concern is the preferred alternative, which does not meet the intent of NEPA in our opinion nor current federal water development guidelines.  The Corps needs to do a better job of selecting a preferred alternative.  Despite detailed appeals from dozens of affected parties, the Corps continues to prefer Alternative 3, which the EIS confirms is the most environmentally damaging alternative.  This was chosen as the preferred alternative despite the fact the Corps described several alternative actions in their EIS that are very cost effective, less damaging, and more dependable as a source of water. 

The USFWS Biological Assessment, prepared as per the ESA, documented that 454 acres of habitat (155 of which are designated critical) for the federally threatened Preble’s meadow jumping mouse will be destroyed by inundation; thus, leading to the conclusion that the project is likely to adversely affect the mouse and adversely affect its critical habitat.  Hundreds of acres of forested, riparian, and wetland habitats that have proven high value for the many species of plants and wildlife they support will be lost, and they will not be replaced on an acre for acre basis.  Also, much of the mitigation credit is established by protecting existing habitat, which does not replace losses of habitat currently used by wildlife.  The wildlife does not just move into the protected habitats, which are already occupied to carrying capacity in most cases.

 From a socio-economic standpoint, the preferred alternative will have significant lasting adverse impacts on the most heavily visited state park in Colorado and on the park system as a whole.  “One of the most significant impacts of the Reallocation on visitors to Chatfield is the loss of approximately 587 acres of recreational land and wildlife habitat.  This area is considered “lost” because it will be intermittently inundated with water stored in the Reallocated Space and is anticipated to be a large mudflat the remainder of the time.”[2]  Chatfield Park provides invaluable opportunities for thousands of families to enjoy the outdoors in a location close to the largest urban area in the state. 

 It is our understanding that Corps and EPA policy for several years has been to first select a least damaging practicable alternative, and then prescribe measures to mitigate unavoidable impacts.  Furthermore, the EIS claims that only the dredging associated with relocation of recreational facilities and wetlands enhancement onsite are applicable to the Clean Water Act Section 404(b)(1) Guidelines, which vigorously require choosing the least damaging alternative that meets the project purpose.  Mitigation sequencing under the Guidelines requires project proponents to first avoid adverse impacts, then minimize to the degree possible, before looking toward compensation.[3] 

 It is important that the Corps acknowledge that the recreation aspects are integral to the overall project.  Thus, the entire project should be planned in accordance with the Section 404(b)(1) Guidelines.  In addition, the riffle/pool complexes that will be affected on the South Platte River are “special aquatic sites” under the guidelines and must be given strict adherence to the mitigation sequencing, and impacted habitats should be replaced in kind to the degree possible.[4]

 Battelle Memorial Institute was hired by the Corps to conduct an Independent External Peer Review.[5]  Battelle is a 501(c) (3) non-profit science and technology organization, independent, and free from conflicts of interest.  In the summary of their report they state “…more detail could have been presented in the FR/EIS to allow comparisons of water supply yields and reliability among the various alternatives.”  The FEIS still does not identify any dependable yield of water for the project proponents in normal years much less during periods of extended drought.

The Battelle summary also includes the following statements:  “The economic analysis overlooks less costly water supply alternatives and has some inconsistencies with U.S. Water Resources Council (WRC) Economic and Environmental Principles and Guidelines for Water and Related Land Resources Implementation Studies (U.S. WRC, 1983). It is not clear why less costly water rights transfer alternatives were not brought forward as distinct alternatives considered in detail when such water rights transfers were included in three of the four alternatives considered in detail. This seems to undermine the selection of Alternative 3 as the National Economic Development (NED) plan when there are more reliable water sources available for what appears to be half the per acre-foot (AF) costs of Alternative 3. Furthermore, the recreation economic analysis is not consistent with U.S. Water Resources Council Principles and Guidelines . . .”

 Regarding the environment, the report stated, “There was a high level of collaboration with various agency and non-agency stakeholders on the project-specific environmental issues. However, it seems that many environmental impacts that should have been considered were overlooked or not fully addressed. The selection of the preferred alternative also does not seem to consider minimization and avoidance of environmental impacts in keeping with the National Environmental Policy Act (NEPA).”  In our opinion, the environmental impacts still are not fully addressed in the final EIS.

Bird Habitat

We remain seriously concerned that the proposed mitigation for the loss of cottonwood forest remains inadequate, and this concern was not adequately addressed in the Corps’ response to comments in Appendix DD.  We believe full mitigation must be funded by the providers. 

 The Corps’ response to this concern, which was expressed by over 100 commenters, was as follows:  “The cottonwoods lost will be mitigated by a combination of providing new stands of cottonwoods that will mature over time and protecting existing stands of mature cottonwoods near Chatfield State Park. The draft Compensatory Mitigation Plan (CMP, Appendix K of the draft FR/EIS) calls for the following to compensate for the estimated loss of up to 42.5 acres of mature cottonwoods: (1) protect up to 22.5 acres of mature cottonwood woodlands within the defined off-site bird habitat complex near Chatfield State Park and (2) create up to 13 acres of specifically designated cottonwood recruitment areas on-site and up to 10 acres off-site that will contribute toward the total compensatory mitigation goal of providing up to 796 EFUs (Section 5.0 of the draft CMP). In total, the compensatory mitigation for mature cottonwoods involves the creation and protection of about 45 acres of cottonwoods.” 

However, this proposed mitigation only addresses the loss of the unique huge very old cottonwoods on the South Platte River, and the mitigation plans remained unchanged from the draft EIS despite all the public comment.  The Tree Management Plan (Appendix Z) states that at least 243.5 acres of cottonwood trees and 52.8 acres of willows will have to be removed below 5439’.  The functional values of all the cottonwoods and willows that will be lost must be replaced.   The Corps erroneously only refers to the aforementioned huge very old trees as being “mature” when in fact most of the forest that will be affected is mature biologically.  Over 200 acres of “mature” cottonwoods will be removed, not just the 42.5 acres of very old cottonwoods.

Furthermore, it is biologically unsound and disingenuous to claim protection of existing cottonwoods somewhere else will offset losses of the huge old cottonwoods that have existed onsite since before the current dam was constructed.  The birds and many other species of wildlife that depend on this habitat are already using the existing trees.  Protecting them through easements or purchase of property does not replace the lost habitat or provide more habitat for the displaced wildlife, thus affecting local and migratory populations.   

The proximity weighting factor in the EFU model for offsite habitats for birds must be eliminated as it has no ecological value and only serves to reduce the amount of habitat replacement.  Instead, there should be acre for acre replacement of bird habitat.  Of the 586 acres of bird habitat that will be adversely affected, only 165 acres will be mitigated onsite.  Once again, a large percentage of the mitigation depends on an unknown acreage of off-site habitat.    

We were glad to see that the mitigation areas will get planted trees in addition to seedlings.  Variable growth stages are important for ecological richness.  However, we request that plantings include saplings of at least 2 inches in diameter, and the seedlings and plantings should be protected from browsing animals.  Even then, it will be several years before they fully provide replacement values. 

Accordingly, we also support the following comments of CWP on the DEIS: “Riparian type habitats (areas associated with the stream) are known to harbor the highest diversity of wildlife species of any habitat type. The loss of multi-aged cottonwood galleries, including mature large trees, will negatively impact a large number of bird species especially cavity nester and migratory birds. When these multi-aged cottonwood areas are replaced or redeveloped it should be with similar diversity of both the trees and the understory. The need to redevelop this type of habitat on Chatfield State Park would provide immediate habitat for displaced bird and other wildlife and potentially lessen the loss of recreation in the area. Replacement habitat that is located offsite will need to provide similar age structure of tree and associated habitat diversity.” [Emphasis added] It is also important for the operations to minimize the length of time water levels are maintained at the upper reservoir levels because cottonwoods and willows can tolerate temporary flooding, and less trees and shrubs would be lost.


Table 6 of the CMP indicates that 158 acres of wetlands will be impacted.  Only 47 acres will be mitigated onsite and an unknown amount of acreage will be replaced offsite.   If practicable, we request more acreage developed onsite so they can be managed better and replacement of wetland values should be in-kind.   Furthermore, the total amount of mitigation acreage must at least match the acreage that will be lost.  Enhancement of existing wetlands should only receive the amount of EFU credits that is documented as having been produced by the enhancement process (i.e., those values above the measured baseline).  

Among the Success Criteria listed on page 66 of the CMP is one requiring “at least 50% of the [wetland] species be facultative or wetter.”  We support that, but we remain concerned that upland habitat may be credited for loss of wetlands.  Therefore, we request the criterion be expanded to read “…and at least 90% of the plants in the designed wetlands will be facultative upland or wetter.”  To reach this level of success, adequate hydrology will need to be maintained for the new/enhanced wetlands.

 Last but not least, since the EIS continues to assert that this project does not require a Section 404 permit under the Clean Water Act.  Therefore, we remain concerned that the lost and damaged wetland values may not be fully replaced. 

 Preble’s Meadow Jumping Mouse

 Our comments on the DEIS expressed in detail why we were very concerned about the inappropriate use of weighting factors in the Ecological Functional Unit (EFU) model.  We request they be dropped from the model.  We understand the underlying concepts and can accept use of the EFU model for assessing mitigation needs of overlapping priority resources.  However, we remain concerned about the use of weighting factors that give EFU credits to potential Preble’s mouse habitat acquisition parcels for proximity to Chatfield Reservoir, habitat connectivity, and vegetative buffers.

 Such factors have an important role when prioritizing land purchases and easements and for assessing enhancement opportunities, which should be part of the management plan for each acquired parcel.  However, the credits should only be given after the enhancement measures are proven to be workingThese weighting factors should not be applied as credit for a potential acquisition site unless they are also applied to the habitat acreage that will be lost or degraded onsite so it is a fair comparison

Our expressed concerns on the draft EIS were consistent with the following comments made by the Department of the Interior:  “In the opinion of the USFWS, weighting factors employed to encourage selection of best mitigation properties (favoring those properties in proximity to Chatfield Reservoir, those that include upland buffers, and those that would increase connectivity of protected habitat) “inappropriately inflate EFU mitigation credits.”  [Emphasis added]  

Page 20 of the Compensatory Mitigation Plan (CMP), has the following statement:  “Subsequent to release of the draft FR/EIS and draft BA, the Corps and Service held discussions regarding crediting of off-site mitigation measures. Based on these discussions, the CMP was revised as to how weighting factors are applied to EFU calculations for the long-term protection, enhancement, and management of Preble’s habitat. While the EFUs are calculated solely on the basis of target habitat within a particular area, weighting factors form the basis of benefit that comes from the ecological effects of the landscape context in which the off-site mitigation habitats are situated. Weighting factors increase the credited EFUs for protected habitats when buffers from potential development and connections to other protected lands are established [emphasis added)."

It was not clear to us what the term “established” means.  We would prefer that it means after establishment of enhancements not establishment that the factors do exist on a potential acquisition site.  The use of the weights in the model has improved somewhat in that they are now added instead of being multiplied times each other.  However, the resultant effect has not changed much.  The average credit of EUSs/acre only reduced from 0.89 to 0.83 (Section 6.2.2.).   Furthermore, we do not have a problem with the estimate that only about 15% of existing habitat acreage will be available for acquisition.  However, we object to the rationale that therefore a credit of 15% additional EFUs should be given to each parcel identified for acquisition.  There is no biological or ecological basis for doing that.

Therefore, regardless of whether it is intentional, the EFU model continues to significantly inflate the credits given to potential land acquisitions and easements.  The result is less acreage required for mitigation.  That is beneficial to the project proponents that will have to pay for mitigation, but it will result in reduced wildlife habitat values and populations. 

 Thus our concerns have not been resolved. Lost habitat will not be replaced on an acre for acre basis as it should, and the Biological Opinion notes that there will be a net loss in population of the mice.  How is this consistent with recovery actions under the ESA?

 We agree with the following statement made by CPW on the DEIS.  It seems that lost [Preble’s] habitat is being replaced with existing critical habitat. If Chatfield State Park loses habitat, such habitat should be replaced with newly created or suitable unoccupied habitat that is not within the already designated critical habitat. If existing critical habitat is enhanced an agreed upon ratio of enhanced acres versus lost acres will need be developed.”  These concerns have not been fully addressed either.

 We do support the following statements on pages 71 and 72 of the CMP.  “There are uncertainties in implementing the off-site mitigation. Not all private property owners targeted for land protection may be willing to enter into agreements to protect their property or portions of their property at a fair market price. The lands that are protected may not on average provide the needed connectivity, buffers, and habitat enhancement potential that would increase the EFUs beyond the baseline protection credit. As further discussed in Section 7.5 Adaptive Management, these circumstances would require the protection of additional private lands, which might require expanding the geographic scope of private lands considered for protection (Figure 25) and could add to the estimated off-site mitigation costs because additional properties would need to be protected.” 


We believe it is very important for the valuable fisheries and other resources that the Project Coordination Team and the Chatfield Mitigation Company explore ways in close coordination with CPW on how to adjust management and operation of relocated storage to further minimize impacts on the target environmental resources considering system constraints.  One of the main reasons that the park has such high wildlife and recreational values is that Denver Water has worked closely with CPW to minimize rapid water level fluctuations during the growing/recreation season.  The new project proponents must work with the CPW in the same manner.

 This type of coordination must also be applied toward the important goal of protecting spawning walleye in March and April.  Chatfield Reservoir provides about 1/3 of the walleye eggs used for stocking throughout the state and for trading with other states for fish species that help maintain diversity in Colorado’s sport fishing.  At this time of the year, the walleye hang close to the rip rap at the dam.  If several hundred cfs are released during this time period, spawning would be significantly adversely affected.  Furthermore, many of the adult walleye would be flushed out with the water releases, and it would take several years and a lot of expensive stocking to replace the lost walleye fishery.  It is our understanding that this scenario occurred in 2007 so it is a realistic concern. 

The adaptive management plan and compensatory mitigation plan are based upon the assumption that only junior water rights will be used.  What if some providers and/or Denver Water decide to use some senior water rights?  In that case, mitigation must be renegotiated with CPW.  Using senior water rights would change the whole dynamic of how water would be stored, and downstream flows and hatchery operations would be affected. 

 Submission of Mitigation Plan to CPW Commission

 The Fish and Wildlife Coordination Act Report (Appendix X) provided by the U.S. Fish and Wildlife Service states their opinion regarding the Compensatory Mitigation Plan (CMP) that “The plan continues to evolve, and while the Service has not fully evaluated specific details, we are supportive of the concepts underlying the CMP.”  The fact that the CMP continues to evolve makes it very difficult for the reader to completely understand what measures will be implemented.   

For example, in response to several questions regarding mitigation, the EIS in Appendix DD has several statements such as “Mitigation for downstream effects are part of an ongoing negotiation between the project participants and the state of Colorado …” “The negotiations are not yet finalized and will become final when the Colorado Parks and Wildlife Commission approves the complete package of state mitigations. These efforts include proposed activities over and above the Federally Recommended Plan.” 

This coordination effort should have good results, and we are confident the CPW is doing its best to negotiate a plan that will conserve our fish and wildlife resources.  However, at this point there is no way a reader can comprehensively understand whether fish and wildlife impacts will be adequately mitigated. For example, just one of the many key issues remaining to be resolved is the proposed “Coordinated Reservoir Operations Plan”, which will be important for protecting the highly valuable sport fishery. The mitigation measures in the Federal plan obviously are not sufficient, or CPW

would not have had to spend so much time in their ongoing concerted effort to improve the mitigation plans.  Therefore, the EIS should not be given final approval until the Commission’s approval process is completed and the public has a chance to read the plan.  Furthermore, we request the Corps include any approved plan in the Record of Decision.

 We also agree with the USFWS recommendations that it is important that “mitigation occurs in advance of impacts to the extent possible” and that “wetland mitigation should be consistent with the Corps and USEPA 2008 final rule regarding compensatory mitigation for losses of aquatic resources”.  We were pleased to note the EIS does describe staging of the project construction, which should help develop some advance mitigation, although replacing habitat values such as that provided by mature cottonwood forest is not something that can be done quickly.  This needs to be a key focus of monitoring and adaptive management along with the wetland and riparian habitat mitigation.

Positive Features    

Several pieces of important information were added to the draft EIS, including the appended Corps’ Biological Assessment for T/E species and the Adaptive Management Plan.  However, the Adaptive Management Plan remains too general.  We support several of the actions identified in the Adaptive Management Plan and shown in Table 4-1, including reseeding, reshaping, etc. when needed to meet mitigation goals. 

One proposed action in the Plan that we do not support is reconsidering use of approved wetland mitigation banks.  We have observed several mitigation banks that were created in the last 10+ years under approval of the Corps.  Once monitoring reports are no longer required by the Corps (i.e., 5 years), the vegetation in these banks often is taken over by cattails resulting in a monotypic vegetation community with limited wildlife value. 

Therefore, we recommend as much wetland mitigation as possible take place onsite.  There are several existing wetlands onsite that would benefit from rehabilitation (e.g., improved hydrology and weed control).  Accordingly, we also support the hydrological, soils, and other studies being conducted to help assure success with the created wetlands.  We request the management plans for all created wetlands include detail on how a diverse set of native plants will be installed and maintained throughout the life of the project in addition to the needed hydrology.  Invasive and noxious plant species can be a problem and also must be managed as identified in the success criteria. 

Other important commitments in the FEIS include the followings:  “The Corps will retain oversight authority and final approval over project implementation, including final say on which mitigation measures will be undertaken (e.g., recommendations of Technical Advisory Committee). The Chatfield Water Providers will establish an environmental mitigation escrow fund that will be at least equal to the estimated cost of fully implementing and completing the CMP including a reasonable contingency. The draft CMP (Appendix K of the draft FR/EIS) establishes success criteria for mitigation. The required annual monitoring will determine if the success criteria are met. Section 7.2 of the CMP presents a schedule that includes both implementation as well as the EFUs gained (i.e., success criteria met).” The final plan calls for development of management plans for each mitigation parcel, mitigation milestones, and short – mid and long term monitoring.  All of the above management actions are crucial for successful implementation of the mitigation measures that have been selected.


While there were a number of improvements from the draft, the final report and EIS remain unacceptably damaging, particularly for a project that has no firm water yield.  Chatfield State Park is the most heavily used park in the State of Colorado.  It provides over 1.5 million recreation days per year and has unique ecological and biological values for many species of wildlife and plants.  The proposed project does not come close to fully mitigating impacts, and the EIS acknowledges that it will cause the loss of several hundred acres of federally designated critical habitat for the threatened Preble’s meadow jumping mouse, which will not be replaced with new habitat.  Therefore, we strongly urge that the Corps and the providers go back to the drawing board and develop a new alternative that takes advantage of existing realistic options that were identified as such in the EIS, including but not limited to use of gravel pits and the Reuter Hess Reservoir for storage.

Thank you for the opportunity to comment.  Questions may be directed to my email address or (303) 506-4588.


Dennis Buechler

Director Emeritus


cc:  Representatives Perlmutter, Coffman, and DeGette

       Senators Udall and Bennett

       Colorado Parks and Wildlife

       Department of Natural Resources


1410 Grant Street, Suite C-313, Denver CO 80203 (303) 987-0400x1 Fax (303) 987-0200      

[1] Colorado Parks and Wildlife (CPW) comments included in the Colorado Department of Natural Resources (DNR) review of the DEIS.

[2] DNR’s comments on DEIS.

[3] 1990 Memorandum of Agreement (MOA) between the Environmental Protection Agency and the Department of Army

[4] 40CFRPart230 Section404(b)(1)Guidelines

[5] Final Independent External Peer Review Report Chatfield Storage Reallocation Study and Environmental Impact Statement, Battelle Memorial Institute, October 25, 2011


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