Wetland Enhancement and Creation on Reclaimed Abandoned Mined Lands in Northeast Wyoming

Abstract

Abstract. Over l ,200 wetlands have been created in northeast Wyoming as a byproduct of bentonite mining activities. Most of these wetlands were created or enhanced as a result of the reclamation of abandoned bentonite surface mines by the Abandoned Mine Land Division of the Wyoming Department of Environmental Quality (WAML). Beginning in 1985, and eventually using over $40.6 million from fees collected for abandoned mine reclamation under the federal Surface Mining Control and Reclamation Act of l 977 (SMCRA), W AML reclaimed over 3,320 hectares of terrestrial habitat and l 80 ha of wetland habitat at 236 AML sites. These reclamation activities included enhancing existing wetlands and creating new wetlands to mitigate for the destruction of jurisdictional (Section 404c of the Clean Water Act) wetlands that were deemed hazardous. Enhancement and creation activities produced small ( X = l .2 ha) and shallow ( < 2 m deep) wetlands, designed to provide maximum habitat benefits for migrating and breeding waterfowl. We subsequently examined 92 wetlands that had been enhanced or created under WAML. Our objectives were to identify physical variables that were important to waterfowl and could be manipulated during the construction process. In general, waterfowl use wetlands that are > l.O ha in size, have abundant emergent and submersed vegetation, and are located within complexes of> 5 wetlands within a l km radius. Soil qualities on abandoned bentonite sites are generally heavy clay in texture with high Exchangeable Sodium Percentages and require physical and chemical amendments to facilitate vegetative growth. Wetland plants have been slow to establish at these created wetlands because of the poor soils and a lack of suitable propagules; natural wetlands within this region are almost nonexistent and are mostly limited to seasonal playas and small creeks. Ongoing research, including both greenhouse experiments and field trials, has been focused on improving aquatic plant establishment and growth. Techniques to improve bentonite wetlands will be useful not only in future WAML activities, but to bentonite mining companies. Additional

Salvaged-Wetland Soil as a Technique to Improve Aquatic Vegetation at Created Wetlands in Wyoming, USA

“…Previous research (McKinstry et al 2001;Anderson 2002, 2004, in review) has shown that aquatic vegetation establishes slowly at these created wetlands for several reasons including: (1) isolation from other wetlands, (2) high turbidity due to suspension of bentonite in the water column, and (3) high salinity and alkalinity due to sodium bentonite substrates. Diverse stands of submersed and emergent vegetation are critical to many invertebrates and vertebrates, but few species of aquatic macrophytes can germinate Table 2.…”

“…Aquatic plants have not established in many of these wetlands and creation and restoration activities have never included plant propagation techniques. Furthermore, plant growth at these sites is further hampered by poor substrates (clay with high sodium concentrations) and water quality conditions (extreme turbidity) that limit the species pool to those plants that can tolerate high salinity, alkalinity, turbidity, and unconsolidated bottoms (McKinstry and Anderson 1994;McKinstry et al 2001;McKinstry and Anderson 2004 Larson (1993).…”