A New Vision for Federal Policy to Facilitate Restoration and Development of Wetlands as Off-Field Nitrogen Sinks for Cropped Landscapes.
Dean W. Lemke1, Randy L. Cooney1, Shawn L. Richmond1, William G. Crumpton2, and Matthew J. Helmers2. (1) Iowa Dept of Agriculture and Land Stewardship, Wallace Bldg, Des Moines, IA 50319, (2) Iowa State Univ, Dept of Ecology, Evolution, and Organismal Biology, Ames, IA 50011
Wetlands as off-field nitrogen sinks are a critical technology to meet water quality goals while maintaining economic crop production and minimizing nutrient and soil organic matter mining in cropped lands. Wetlands strategically restored and developed through the Iowa Conservation Reserve Enhancement Program (CREP) are sited to intercept subsurface drainage from cropped landscapes with 500-3500 acre drainage areas and will remove 40-90% of nitrate and 90+% of herbicide. The initial 20 wetland sites developed under the program total 185 acres of wetland pool intercepting a contributing watershed drainage area of 27,717 acres of cropped lands and are projected to remove 13,886 tons of nitrate over their design life. A new vision for federal policy is needed to accelerate adoption of this practice. The 45-60% nitrate reduction of the current science re-assessment to meet the 2015 goal of the Gulf of Mexico Hypoxia Action Plan would require an estimated 9000-20,000 targeted nitrate-removal wetland sites in Iowa alone, requiring a major scale-up from the 25 sites/year of the current Iowa CREP program. Protection of drinking water supplies necessitates scale-up as well. Iowa CREP wetlands were initially developed under Clean Water Act (CWA) Section 404 Nationwide Permit #27 (NWP27), with NEPA protections assured under USDA procedures. The later determination that NWP27 is not applicable requires an individual permit for each site, extremely complicating the program yet only duplicating USDA’s NEPA assessments. Revision of NWP27, development of a nationwide permit dedicated to this practice across the corn belt, and improved federal agency collaboration are options for regulatory streamlining. Implementation of nitrate-removal wetlands through existing watershed management authorities, drainage districts, has the potential to facilitate widespread adoption through market-based approaches as part of drainage system rehabilitation. Cost-sharing under the CREP format with drainage districts and re-evaluation of farmed wetland regulatory policy are options for accelerating adoption.