The Wetland Delineation and Mitigation Report by B&A Inc.

This report delineates two wetlands on the property, and considers the rest as non-wetlands. It recommends planting trees in the remaining buffer to mitigate the proposed encroachment into the wetlands and stream buffers, and concludes that "after home construction and during occupancy, the threat to the wetland is minimal" (p.5).

Specifically, it states that "Roof  runoff threats are minimal as roof runoff is considered to be non-polluting. It is best discharged directly into the wetland to maintain wetland hydrology," contrary to what a Washington State Dept. of Ecology senior wetlands specialist says in his letter.

This report also states "Roof runoff can be discharged directly into the wetland, or outside the wetland and allowed to sheet flow into the wetland", "The use of lawn chemicals and fertilizers may pose a hazard to the wetlands, but maintenance of appropriate buffer and vegetated area around the wetlands should intercept pollutants prior to reaching the wetland." (p.5). This needs to be considered in light of the fact that the proposed development sites cuts down the buffers significantly, and nearly touches the wetlands (lot 1), or a stream (lot 4), as shown in the proposed land use plan.

The proposed mitigation plan consists of planting trees in the remaining portion of the existing buffers around the proposed houses and on the West side of the pond opposite while the proposed development site is on the East side of the pond (p.6). Would doing so offset the significant loss of buffer, as well as the removal of trees and vegetation in the house sites (which will be replaced by roof and driveway), and the likely use of the remainder of the land as lawn, which will require removing the existing vegetation? The report concludes that "The proposed mitigation plan should enhance the existing habitat." (p.9).

Studies have found that mitigation often is not successful. For example, a survey of 30 King County's mitigation sites (Mockler, 1998)* that have existed for more than three years found only 7 of the 30 sites were successful. Elsewhere, the author writes that those deemed successful were successful only in the sense that they were built as designed. Many designs, however, do not function property to make up for the loss of wetlands, and she estimates that of the mitigations that passed inspection, "perhaps 1/4, or 4.25 percent of the total, really replace lost wetlands."

A Seattle Times article** on November 1, 1999 about the Snoqualmie Ridge development reports that "Muddy storm-water runoff has reduced fish populations by 50 percent and 90 percent in two streams" and "studies indicate there has been a 25 to 66 percent drop in the number of plant species found in the wetlands." This is particularly noteworthy because it is happening despite the fact that "the company has spent almost $16 million on water-quality consultants, studies and erosion-control measures". The general manager of the development was quoted as saying "when you're early on, starting with the project, I think you make some mistakes ... Quite frankly, we had a lot of good people up here, but everybody was sort of learning."

Similarly, Redmond (1992) found that fewer than 50% of the permitted projects could be considered ecologically successful (Redmond 1992***). It found that only 12% of freshwater sites were successfully restored. Another study of 40 mitigation projects reported the failure or incomplete creation of 24 projects (60%), causing a 50% loss of wetlands area (Erwin 1991****).

Note also that the report also states that "B and A Inc. assumes liability only to the extent of the amount received for preparing this report." (p.9)

For the original pages of the report, click on the page numbers below:

Pages  1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16

*: Mockler, A. 1998. Results of Monitoring Wetland Mitigation Success in King County, WA. Paper for the Society of Wetland Scientists PNW meeting.

To download a word 97 copy of the study (Mockler, A., Casey, L., Bowles, M., Gillen, N. & Hansen, J. (1998). Results of Monitoring King County Wetland and Stream Mitigations. King County Department of Development and Environmental Services) from the Audubon Society web site, please click here => download Mockler et al. 1998.

**: Kelly, B. 1999. Snoqualmie Ridge has hurt water quality, reports say. Seattle Times, November 1, 1999.

***: Redmond, A. 1992. How Successful is Mitigation? Natl. Wetlands Newsl. Jan-Feb 92, Vol. 14(1):5-6. 

****: Erwin, K.L. 1991. An Evaluation of Wetland Mitigation in the South Florida Waster Management District. Vol. I. Final Report to South Florida Water Management District, West Palm Beach, Fl. 124 p. as cited in Mitsch, W.J. and J.G. Gosselink. 1993. Wetlands. Van Nostrand Reinhold: NY, NY.

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