Northern Prairie Wildlife Research Center
Effects of a Legal Drain Clean-Out on Wetlands and
Waterbirds: A Recent Case History
Public and private land developers have converted an estimated 53% of the original wetland area of the contiguous 48 states of the United States to other uses (Dahl 1990). Drainage has been particularly extensive in portions of the prairie pothole region where millions of hectares of wetlands have been converted to cropland (Tiner 1984) through extensive networks of legal drains built mostly with public funds. Once built, these drains must be cleaned intermittently in order to function properly. When clean-outs occur, adjacent wetlands become vulnerable to loss of functions and values if drain dimensions are changed. Therefore, Congress included within Section 404 of the Clean Water Act (33 U.S.C. 1344) a provision to regulate drain repairs (Want 1989). Rules under Section 404 (f)(1)(C) allow landowners to repair or maintain existing drainage ditches to the "as built" original configuration but prohibit the construction of new ditches or modification of existing ditches without first obtaining a permit from the U.S. Army Corps of Engineers (COE). Section 404 (f)(2) recaptures for regulatory purposes those repair or maintenance projects that could significantly impact wetlands or convert wetland habitat to other uses.
Legal drain maintenance or "clean-out" projects generally have received limited attention from natural resource managers, and few studies have evaluated whether drain repairs significantly change functions and values of adjacent wetlands. The present study was undertaken to evaluate whether the clean-out of Drain No. 11 altered adjacent wetlands and adversely affected associated waterbird populations. The work was done in conjunction with litigation initiated by the U.S. Government because sponsors of the Drain No. 11 clean-out had not sought or obtained a Section 404 permit before beginning work on the drain in 1984. In this paper, I (1) address Section 404 issues pertaining to the clean-out of Drain No. 11 and associated federal court rulings, (2) compare water regimes, emergent cover to open areas, waterfowl and other waterbird use and production, and waterfowl hunting activity on BBM before and after the clean-out of Drain No. 11, and compare to Kraft Slough, and (3) describe the relationship of wetland habitat conditions in Sargent County after the clean-out to disease-related waterfowl mortality.
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