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| COOKE SCIENTIFIC SERVICES INC. | ||
| 919 NE 71st Street | Phone: (206) 525-5105 | |
| Seattle, WA 98115 | Fax: (206) 525-5351 | |
| E-Mail: cookess@aol.com | ||
December 13, 1999
Tom Luster
Washington State Department of Ecology
Permit and Coordination Unit
PO Box 47600
Olympia WA 98504-7001
RE: Seatac Third Runway Impact Analysis and Mitigation Design Review for the Airport Communities Coalition
Dear Mr. Luster:
I have been asked by the Airport Communities Coalition (ACC) to review the wetland delineation, impact analysis, and mitigation plan for the proposed Third Runway at the Seattle-Tacoma International Airport. This report represents the summary of my review of this material. This report is in support of ACC’s review of the Section 404 and Section 401 permit applications under consideration by the US Army Corps of Engineers and Washington State Department of Ecology. I have attached a copy of my professional credentials (Curriculum vitae) to this document as is required of any person offering review comments.
I have not been involved with the third runway project until this request by the ACC. I am very familiar with the existing properties and the area that is proposed to be annexed for the third runway because I have visited these areas while preparing the Maintenance and Integrated Pest Management Plan (IPMP) for the Airport (Cooke Scientific Services Inc. January 1997), and have performed a delineation of the area south of the existing runways in 1998. (Northwest Wetlands Alliance, October 1998). I have personally visited many (20 out of 94) of these wetlands as a result of these two previous projects. I have reviewed the following documents for this report:
Adolfson Associates. November 1999. Seatac Third Runway Mitigation Review. Report to: Airport Communities Coalition.
Adolfson Associates. November 1999. Third Runway Wetland Analysis and Mitigation Plan. Report to: Airport Communities Coalition.
BioAnalysts. 1999. Assessment of Spawning and Habitat in Three Puget Sound Streams, Washington. Report to: Airport Communities Coalition.
COE. September 1999. Public Notice of Application for Permit. U.S. Army Corps of Engineers. Regulatory branch, P.O. Box 3755, Seattle Reference Number 1996-4-02325.
Parametrix. August 1999. Natural Resource Mitigation Plan (Revised Draft) Master Plan Update Improvements Seattle-Tacoma International Airport.
Parametrix .August 1999. Wetland Functional Assessment and Impact Analysis. Master Plan Updatre Improvements Seattle-Tacoma International Airport.
Paramterix. August 1999. Revised Draft Wetland Delineation Report. Master Plan Update Improvements Seattle-Tacoma International Airport.
Parametrix. November 1999. Supplemental Airport Site Wetland and Stream Analysis.
Port of Seattle, August 1999. Draft Wetlands Re-evaluation Document. Seattle-Tacoma International Airport Master Plan Update Improvements.
SEATAC and US Department of Agriculture, Animal and Plant Health Inspection Service Wildlife Service, November 1999. Wildlife Hazard Management Plan Seattle-Tacoma International Airport.
I was asked to review this material in light of my experience with the Master Plan Development for the Snohomish County Airport at Paine Field. I was the ecologist who delineated the wetlands, developed the mitigation proposal for impacts resulting from the Master Plan Development, and developed the design for the on-site mitigation. I have been intimately associated with the Paine Field Mitigation Bank project since 1992. I have completed the first season post-installation monitoring for the on-site mitigation at Paine Field, and based on the results I have found, I am convinced that on-site mitigation is absolutely appropriate for airports, even within very close proximity of a runway. While there have been some short-term problems at Paine Field which are attributable to the installation implementation of the mitigation plan, it has been possible to replace impacted functions (except avian habitat) in-basin. I see no reason why similar in-basin mitigation cannot occur at SeaTac for the proposed third runway project. It is possible to provide in-basin mitigation provided the mitigation is correctly designed. Hydrologic modeling and a detailed quantitative functional assessment of the basin are of utmost importance to the design process.
There are three streams that will be impacted as a result of the proposed third runway project. A total of 18.28 acres of wetland is slated for permanent impact and 2.17 acres are to be temporarily impacted. This 20.45 acres represents approximately 50 percent of the existing wetland resources in the area of interest. Obviously, this is a large amount of wetland, from both acreage and a percentage perspective to allow for impact in a particular drainage, especially given the high level of urbanization the basin has already received.
Further, impacts to wildlife and fish have not been adequately addressed. The extent of salmonid resources has been underestimated (Adolfson, November 1999). Wildlife habitat has already been compromised in this urbanized basin. Loss of half of the remaining habitat is being proposed. It is obvious that this will severely impact the remaining wildlife in the basin.
The permanent loss of 18.28 acres is proposed to be replaced both within the same drainage basin (20 acres) and outside the drainage basin (36 acres). The Revised Mitigation Report (Parametrix, August 1999) is not correct when it states "most mitigation for impacts to wetland function are located on-site and in-kind". The majority of the mitigation is proposed out-of-basin. My assessment of the acreage calculations is that only 34 percent of the mitigation will be performed in-basin (19.67 acres) and 66 percent of the mitigation will be performed out-of-basin (38.2 acres). The majority of the in-basin mitigation will be enhancement of existing wetlands.
The in-basin mitigation plan confuses the terms when discussing the details of the mitigation plan. The term restoration means converting existing upland habitat back to wetland in areas that were historically wet. Enhancement is, however, improving the functions of existing wetlands. There will, therefore, be a net loss of wetland acreage because 18.28 acres of wetland will be lost and only 6.09 acres will be enhanced. This yields a ratio of 0.3:1, for in-basin mitigation, not the 1.1:1 stated in the report.
Farmland that has a Prior Converted Wetland status means that the farmer has altered the hydrology (usually through drainage). The soils are almost always left intact although they are tilled. The proposal to restore ten acres of the Vacca farmland from prior converted wetland is therefore more of an enhancement throught replacement of hydrology and replanting plants than a restoration, and the mitigation ratio would be lower than that offered. The total mitigation credit for enhancing the Vacca farm should be only 33 percent of the total acreage proposed. Additionally the plan presented is lacking in sufficient detail to determine if the proposal is viable. If only 5.2 acres is going to be graded then how will ten acres be restored to wetland? There is little to no discussion of hydrology, yet the hydrology is what was destroyed when the land was previously converted to upland. Conversion of ten acres of prior-converted wetland to viable wetland is highly unlikely unless a thorough understanding of the existing hydrology and what it would take to restore the original hydrology to make the area wet is obtained. There is no detail provided in the report that indicates this understanding is present on the design team. Therefore, only 5.2 acres maximum is actually present in the Vacca farm portion of the proposal, and that would be enhancement, not restoration and so should only get the equivalent of 1.73 credits for this particular mitigation.
The Tyee Valley Golf Course mitigation and the Miller Creek riparian corridor enhancement are both misidentified as restorations. These areas are predominantly already wetlands and therefore the proposed mitigations would both be enhancements. Again, both proposals are lacking in sufficient detail to determine if they are viable. At a minimum, hydrologic modeling must be done in order to insure that sufficient hydrology for the wetland plant communities planned will continue to be provided after development of the surrounding area has been completed. Additionally, many claims about the design components and water quality improvement are not supported by current knowledge of toxicant removal by wetland vegetation. Woody vegetation never out-performs emergent vegetation in either sediment removal or toxicant uptake (unpublished data, Puget Sound Wetland and Stormwater Management Research Program 1987-1996). You cannot have a wetland that is composed of woody vegetation (and so therefore is not an attractant to birds), and which also performs water quality improvement functions to a maximum. The two functions (lack of bird habitat and water quality improvement) are almost mutually exclusive in what helps them to perform the function. The total amount of mitigation provided in the Tyee area is 1.5 acres (of enhancement). The total area provided by the Miller Creek mitigation is 1.39 acres.
The out-of-basin plan comprises the majority of the mitigation proposed for the impacts to 50 percent of the wetland in the area to be developed. The details of the out-of-basin mitigation are almost moot because wetland functions that are being lost are in-basin while compensation is out-of basin. It does no good for the drainage functions to be replaced elsewhere. They are needed locally. "There is no ecological relationship with the impacted areas or the adjoining natural environment. Any reduction in wetland area, function, and value in the vicinity of the airport cannot be mitigated in Auburn, irrespective of how much wetland is being enhanced or restored in a disconnected wetland, especially given the magnitude of the proposed impacts" (Adolfson, November 1999). I agree with the Adofson comment that it is wholly inappropriate to set a precedent (of allowing out-of-basin mitigation) with such a large-scale project. I would add that I have examined the Miller and DesMoines Creek basins and feel there is ample opportunity in-basin to enhance, create, and possible restore wetlands within the same basin.
The functional evaluation performed for the existing wetlands to be impacted was the Wetland Evaluation Technique (WET, Adamus et al. 1987, 1992). Two theoretical methods, one for classifying wetlands, and one for identifying (but not quantifying) functions were examined which do not yield in-the-field information. These include the Hydrogeomorphic Classification for Wetlands (Brinson, 1993), and Wetland Values: Concepts and Methods for Wetland Evaluation (Reppert et al. 1979). The WET method therefore was the only method used that actually yielded functional performance data. WET has been shown to be a poor choice for evaluation of Pacific Northwest wetland functions because of the poor reproducibility of the results (Washington State Department of Ecology Technical Memo Comparison of Wetland Functional Evaluation Techniques 1998). Therefore, the functional performance data presented for the project is of questionable use and the results are most likely not useful for assisting an assessment of existing conditions and developing replacement mitigation. The results have been presented more as a best professional judgement of functions and not a quantitative evaluation of functions. This level f accuracy and detail is entirely inappropriate for a project of this scope. The understanding necessary to replace lost functions resulting from the impacts proposed is not present in any of the materials I have reviewed. The mitigation proposed therefore is not truly replacing functions.
Of prime importance are the hydrologic and water quality functions. The existing basin is very developed with a large amount of impervious surface. This project would increase the area of development and decrease the wetland acreage by half. Coho salmon are in the upper reaches of Miller, Walker, and Des Moines Creeks (Adolfson report November 1999). The hydrologic regime (depth, duration, and frequency of inundation) in these Creeks, and the water quality will without a doubt be impacted as a result of filling half of the remaining wetland area. There are already impacts to salmonid habitat in these creeks from the existing development (Adolfson report November 1999). It seems highly likely that the additional impacts proposed could tip the scales and prove fatal to salmon populations in these steams. The loss of 18 plus acres of wetland and the associated water quality improvement afforded by these 18 plus acres cannot be replaced by enhancing the existing emergent wetland areas with woody-dominated communities. This mitigation design makes no scientific or even logical sense.
Instead it would have proven much more useful to use the new Washington State Department of Ecology Functional Assessment Methodology (DOE, 1999), or the modified Reppert Method developed for Pacific Northwest wetlands — Assessment Methodology (SAM, Cooke 1996).
I appreciate the opportunity to review the materials provided for the SEATAC Third Runway project. Please call me at 206-525-5105 or send me an e-mail at cookess@aol.com if you have any questions or comments on my review.
Sincerely,
Sarah Spear Cooke, Ph.D., Senior Plant Ecologist
Cooke Scientific Services, Inc.