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Wetlands of Island County, Washington : Profile of Characteristics, Functions, and Health Public Deposited

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  • This document partially addresses the Wetlands component of Island County’s Critical Areas Ordinance (CAO). It presents the results of a year-long collaborative project to compile, analyze, and summarize existing data pertinent to Island County wetlands. Similar in concept to the “report card” issued periodically for Puget Sound, this compilation attempts to describe the health and probable functions of Island County wetlands, as one basis for determining what, if any, modifications are needed to the CAO’s wetlands regulations. This project described in this document compiled and statistically correlated data for over 1000 characteristics of Island County’s 958 known wetlands. Spatial data (maps) from many existing sources were overlaid and analyzed using computerized tools at four scales: wetland, contributing area, surrounding area, and watershed (basin). An especially important component of this project is that new data were collected from 103 wetlands that were visited over a 6-month period in 2005 and which represent about one-third of the County’s wetland area. The collected field data are considered generally representative of Island County wetlands because the assessed wetlands were chosen according to a rigorous statistical design implemented by a professional statistician. The assessed wetlands are a spatially balanced, statistically random sample of the County’s approximately 13,429 acres of known wetlands. Data were collected on plant species composition, water regime, alterations, and many other items. These data are intended to serve as part of a baseline or benchmark against which future changes in the County’s wetlands may be compared. The Washington Department of Ecology’s Western Washington Wetlands Rating System also was applied to all the surveyed wetlands, and results were compared with those from wetlands assessed non-randomly by WDOE elsewhere in the region. In addition, information from over 720 of the County’s permit files and on-site evaluation records were reviewed, as was information from historical accounts. Aerial photographs and satellite imagery covering multiple time periods were interpreted to identify alterations of wetlands, and results were compared with data from the field visits and permit files.
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  • Adamus, P.R., J. Burcar, K. Harma, C. Luerkens, A. Boscolo, J. Coleman, and M. Kershner. 2006. Wetlands of Island County, Washington: Profile of Characteristics, Functions, and Health. Report to Island County Dept. of Planning & Community Development, Coupeville, WA.
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