Graduate Project
 

Evaluating design and verifying compliance of wetlands created under section 404 of the Clean Water Act in Oregon

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https://ir.library.oregonstate.edu/concern/graduate_projects/pk02cf81x

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  • Permit specifications, construction plans, and field measurements were used to examine the correlation between design and conditions "as-built" in a population of 11 palustrine emergent marshes created in the metropolitan area of Portland, Oregon, between 1980-1986. The projects ranged from six months to almost seven years in age. Data on planned and existing hydrology, wetland area, wetland shape, slopes of banks, and vegetation were collected for each site. Information on the plans for each site was gathered from the Section 404 permit files of the Portland District Office of the U.S. Army Corps of Engineers and the permit files of the Oregon Division of State Lands. Results indicate that none of the wetlands studied were designed or constructed as permitted. Hydrology could not be evaluated since the information in the permit files was inadequate. There was a cumulative loss of 1.48 ha (3.6 acres), or 29% from the 5.10 ha (12.6 acres) that was to be created. Seven of the created wetlands had very regular shorelines; four had irregular shapes. The predominant slope as-built was gentler then what was to be built as determined from the construction plans and permit specifications for nine of the eleven projects (82%). For 45% of the sites (5/11) the predominant slopes to be built and as-built were steeper than the 5:1 maximum recommended in the literature. Vegetation to be planted did not occur on the sites. The proportion of species found on the created wetlands that were to be planted ranged from 0% to 7%. The differences between the plans and specifications in the project file and the as-built conditions point to the need for verification of projects in both the planning and construction phases of the permitting process. The planning phase should focus on the development of a realistic approach using information from the scientific literature and past projects. The construction phase should culminate in the production of an as-built plan. This would allow immediate checks to ensure that critical features have been included as intended, e.g., wetland area, vegetation type. It would also document any corrective measures that were taken due to unanticipated events during construction. As-built plans of the project would ensure that the details of the actual wetland created were available for future reference in addition to the conceptual design.
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  • United States Environmental Protection Agency (EPA)
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  • Master files scanned at 600 ppi (256 Black and White) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 ppi (256 Black and White) using Capture Perfect 3.0 and OmniPage Professional 15.0 for textual OCR on a Canon DR-9080C.
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