29 November 1999
Airport Communities Coalition
c/o Peter J. Eglick
Helsell Fetterman
P.O. Box 21846
Seattle, Washington 98111-3846
RE: Third Runway Wetland Analysis and Mitigation Plan
Dear Mr. Eglick:
Pursuant to your request on behalf of the Airport Communities Coalition (ACC), Adolfson Associates, Inc. is pleased to present the following summary of my review of the wetlands assessment, impact analysis, and mitigation plan for the proposed Third Runway project at Seattle-Tacoma International Airport. We are providing my review in support of the ACC’s review of the Section 404 and Section 401 permit applications under consideration by the Army Corps of Engineers and Washington Department of Ecology, respectively. Below please find a summary of my professional credentials, followed by my analysis of this proposed project.
Credentials. I am the Natural Sciences Director of Adolfson Associates, Inc., and am a certified Professional Wetland Scientist and Certified Professional Soil Scientist. I am also certified (by the National Wetlands Science Training Cooperative) to delineate wetlands. Since 1994, I have been on the national ARCPACS Soils Certification Board and was that Board’s representative to the Certification Advisory Council from 1998 - 1999. Earlier this year, I was appointed to the Board of Directors of the Pacific Northwest Chapter of the Society of Wetland Scientists. I have also been an instructor in the University of Washington’s Wetland Science and Management Certificate Program since its inception in 1994. I am widely published in the scientific and gray literature; for example, I have written or co-authored papers in the Journal of Geophysical Research, Journal of Environmental Quality, Soil Science Society of America Journal, and Northwest Environmental Journal. I also co-authored five wetlands publications printed by the Washington Department of Ecology. I have also been a volunteer and invited speaker at numerous national, regional, and local conferences. For example, in 1997 I was an Invited Speaker at a conference concerning urban stream protection sponsored by Fisheries and Oceans Canada. In 1998 I was an Invited Speaker at the Salmon in the City conference in Mount Vernon, and this year I was invited to speak at the Wetlands in Washington 1999 conference (by Law Seminars International). I have a BS in biochemistry, an MS in environmental sciences, and a Ph.C. in forest soils. I have attached a copy of my curriculum vitae to this letter.
Background. As you are aware, I first became involved in the ACC’s review of Third Runway wetland issues in 1998 at the time of the Port of Seattle’s (Port) initial submittal of the permit applications. At that time, permanent wetland impacts were estimated to be about 12.33 acres, with virtually all of the compensatory wetland mitigation proposed in an off-site location near the Green River in Auburn. Since that time, the Port’s team has identified many new wetlands that will be affected by the proposed project. The current estimate of permanent wetland loss is 18.28 acres (with additional temporary impacts to 2.17 acres of wetland). This represents an increase in permanent wetland area loss of nearly 50%.
For my analysis of current wetland issues facing the Third Runway project, I have reviewed the following documents.
Summary of Key Points. The major premise of the wetland mitigation plan is that most of the compensatory wetland mitigation is being accomplished "on-site," which in the context of this project means "in-basin." However, the mitigation plan calls for less than 20 acres of mitigation credit within the basin and more than 36 acres of mitigation credit outside of the basin. Further, it appears that the mitigation plan, even if successfully implemented, would result in less wetland replacement within the basin than the proposed 20 acres. This is because a great deal of the in-basin mitigation is to be accomplished via wetland enhancement. Wetland enhancement occurs when an existing wetland is altered to increase its functions and values. The proposed mitigation plan seems to confuse enhancement with restoration, which occurs when former wetlands are returned to wetland conditions. Further, a large portion of the in-basin mitigation is to occur at the Vacca Farm. About 10 acres of prior converted cropland (areas that were historically wetland but had their wetland hydrology permanently removed by agricultural practices) is supposed to be restored. However, only about five acres of grading is to occur on the Vacca Farm, and no further mention is made of how wetland hydrology would be returned to this area.
Therefore, it is my finding that the great majority of the compensatory mitigation would occur outside of the basin, in an area with no ecological connection to the impact area or adjoining natural environment.
Discussion. To evaluate wetland functional loss, the Port utilized three functional assessment methods:
Of these, the Wetland Evaluation Technique (or WET) is inappropriate for small wetlands; note that the majority of the wetlands that would be affected by this project are small wetlands. However, I see no evidence that WET was actually used for functional analysis: WET evaluates functions and values in terms of social significance, effectiveness, and opportunity, and assigns qualitative probability ratings of high, moderate, or low to each function and value in terms of social significance, effectiveness, and opportunity. No such terms appear in the application materials I reviewed.
Further, the Brinson (1993) report does not present a wetland functional assessment technique: "This manuscript is not an assessment tool…" (Brinson, 1993, page 62). Wetland functional evaluation techniques based on the hydrogeomorphic (or HGM) classification system have been and continue to be developed. For example, the Washington Department of Ecology has been preparing an HGM-based wetland functional evaluation approach for several years. The wetland functional evaluation conducted on behalf of the Third Runway is at best very loosely based on the HGM system. I did note that the existing wetlands that would be adversely impacted by the project are categorized according to the HGM system of Brinson (1993); I did not note, however, that the proposed mitigated wetlands had been categorized in this manner.
As a result, the wetland functional evaluations were conducted using a hybrid of several systems, but appear to be mainly based on best professional judgment. However, since the introduction of the HGM approach, it has become the cutting edge of wetland functional analysis. Since the functional evaluations were done in part using HGM, the mitigation plan would have benefited from that approach as well. I have additional concerns regarding the mitigation plan; they are as follows.
The Port’s Natural Resource Mitigation Plan (Revised Draft, August 1999) lists four compensatory mitigation options in order of preference:
The August 1999 Draft Plan goes on to state that "most mitigation for impacts to wetland function are located on-site and in-kind." I disagree.
First, compensatory mitigation for wetland loss includes 19.67 acres within the basin (which, for the purpose of this discussion, will be considered equivalent to being on-site) and 36.56 acres out of basin. The in-basin portion of the mitigation therefore represents only about 35% of the total mitigation. Thirty-five percent is not "most" of the mitigation.
Further, from my review of the application materials, it appears that the in-basin mitigation credit has been overestimated. For example, Table 4.1-2 of the August 1999 Draft Plan states that 11 acres of prior converted wetland and farmed wetland at the Vacca Farm will be "restored" to a native peatland by planting trees and shrubs. The most important difference between prior converted wetlands and farmed wetlands is that prior converted wetlands have had their hydrology altered so significantly for so long that they are no longer wetlands, and do not exhibit wetland hydrology. Farmed wetlands maintain wetland hydrology, but are used for agricultural purposes. Therefore, transforming farmed wetlands to native vegetated wetlands is actually a wetland enhancement, for which less credit is typically received. The Port clearly recognizes the lower value of wetland enhancement: at their off-site mitigation area, for a six-acre wetland enhancement (also from emergent to woody species), the Port is taking credit for only two acres of mitigation. Therefore, the enhancement of farmed wetlands at the Vacca Farm should be treated similarly, or mitigation credit should be given for only about one-third of the total area of farmed wetland. The nine farmed wetlands on the Vacca Farm total about 1.03 acres; therefore, the appropriate mitigation credit for this enhancement should be about 0.34 acre, or 0.69 acre less than currently proposed.
My greater concern at the Vacca Farm is the 10 acres of prior converted wetland. Remember that prior converted wetlands do not have wetland hydrology, and no matter how they might be planted, they are not technical or jurisdictional wetlands until wetland hydrology is permanently re-established. Converting 10 acres of prior converted wetland back to wetland is an admirable objective. However, the August 1999 Draft Plan only calls for grading of 5.2 acres. Even if all of this grading is in the prior converted area (and I cannot determine that from the materials provided), at best there could be a restoration of 5.2 acres of wetland. Therefore, under the best-case scenario, the in-basin mitigation credit is another 4.8 acres lower than in the application materials.
At the other large restoration site, the Tyee Valley Golf Course, about 4.5 acres of turf grasses would be "restored" to a native peat wetland. However, according to the August 1999 Draft Plan, this 4.5-acre area is already an emergent wetland, so this restoration is also actually an enhancement, and should receive less mitigation credit than proposed. For example, applying the Port’s off-site mitigation enhancement formula, the 4.5-acre enhancement should only receive 1.5 acres of credit, thus reducing the total mitigation by another 3.0 acres.
Further, while geotechnical studies have confirmed that peat exists at or near the surface, I see no analysis regarding how the altered hydrologic regime would affect this valuable peat resource. Installing the plants specified in the August 1999 Draft Plan would result in structural changes to this area. However, the August 1999 Draft Plan states that the purpose of installing these plants is to improve the wetland’s ability to remove chemicals from runoff, remove and recycle excess nutrients, and decrease certain wildlife use. I cannot find references to support the assertion that woody vegetation would outperform emergent vegetation with respect to chemical and nutrient removal. In fact, in many agricultural areas (and turf grassed areas are similar in many ways to agricultural areas), grassy filter strips are the recommended means of protecting aquatic resources from potential chemical harm. Clearly the only reason to transform this wetland is to discourage waterfowl and flocking bird species from using areas near the airport. Note that I am not opposed to such transformations, however, the value in changing habitat types to favor one assemblage of urban-adapted wildlife species versus another assemblage of urban-adapted species is not necessary very high. Generally, however, the greater the habitat complexity, the more valuable it is considered. With this in mind, however, and with the understanding that the Port would not implement wetland mitigation plans that are likely to attract certain birds, there are many other sites within the affected basins that are suitable for wetland mitigation. Any of these would be preferable to the off-site mitigation area in Auburn. This is because the Auburn site has virtually 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 enhanced or restored in a disconnected location. This is especially so given the magnitude of the wetland impact.
The final in-basin wetland mitigation element is 4.17 acres of wetlands in the Miller Creek riparian corridor that will be enhanced with native plantings. Again, enhancement credit for this should only be about 1.39 acres, further reducing the proposed total in-basin mitigation by 2.78 acres.
Summing up the mitigation credit corrections, it appears that this project has 11.27 acres less in-basin mitigation than presented in the application materials, leaving the in-basin mitigation at about 8.4 acres. Since the amount of wetland lost within these basins is 18.28 acres, the in-basin mitigation ratio is 0.46:1, not the 1.1:1 presented in the permit application materials.
As a result, the project, which was already relying primarily on off-site mitigation in Auburn, is even more dependent upon that compensatory mitigation element than would appear from the permit application materials. Unfortunately, I have no context from which to evaluate this type of off-site mitigation. I am unaware of any other wetland mitigation project in our region that has implemented a compensation project - at any scale - in an area that had a similarly non-existent relationship with the impact site. Without proper debate in scientific and policy circles (especially in light of the State’s developing wetland mitigation banking rules, which would not likely allow out-of-basin mitigation), it is wholly inappropriate to set precedence with such a large-scale project. This is particularly so in this instance, knowing that there are ample sites within the Miller and Des Moines Creeks basins to achieve the necessary wetland mitigation credit, and to do so without attracting bird species that could endanger current or future airport operations. It is further imprudent to set this type of out-of-basin precedent given the potential cumulative impacts of future proposals in the project vicinity. For example, anticipated work on State Route 509, State Route 518, and the LINK light rail system, as well as on innumerable smaller, less visible projects, could impact many more acres of wetlands in the Des Moines, Miller, and Walker Creek basins. Using the Third Runway mitigation example, one can foresee that each of these project proponents would similarly want to implement compensatory wetland mitigation plans at distant, out-of-basin sites, thus further contributing to the permanent loss of wetland resources from this area.
We very much appreciate the opportunity to review the materials you have provided, and to present this analysis to you. If you have any questions, please contact me at 789-9658 or at acastelle@adolfson.com. Thank you.
Sincerely,
ADOLFSON ASSOCIATES, INC.
Andrew J. Castelle, PWS, CPSSc
Director of Natural Sciences