EVALUATION OF ARTIFICIAL WETLANDS IN NORTH DAKOTA: RECOMMENDATIONS FOR FUTURE DESIGN AND CONSTRUCTION

Eighteen artificial wetlands were evaluated in North Dakota in 1979 and 1980. Several recommendations are presented for artificial-wetland design and construction based on both the results of the 2-year study and the habitat requirements of breeding waterfowl. It is recommended that (a) a series of wetlands of varying sizes be built rather than one large wetland; (b) multisided, variable-depth wetlands be excavated instead of rectangular, uniformly deep borrow pits; (c) bank gradients not exceed a 10:1 to 20:1 slope; (d) nesting islands be constructed in the center of the wetland when possible; (e) adjacent upland areas be seeded with dense cover to support nesting and reduce erosion and runoff; (f) if necessary, wetlands be sealed with a clay layer to retain water; and (g) topsoil be set aside and respread to provide an adequate substrate for the growth of aquatic plants. Some suggestions for future research on artificial wetlands are also presented. (Author)