Choptank River Conservation Effects Assessment Project NRCS Special Emphasis Watershed Research Findings and Recommendations 2004—2008 Conservation Effects Assessment Project USDA - Agricultural Research Service Choptank River Watershed Project Final Report Contact Information: Project PIs NRCS Special Emphasis Watershed Gregory W. McCarty As part of the USDA-Natural Resources Conser- The Choptank River Watershed project has now USDA-ARS Beltsville, Maryland vation Service (NRCS) Special Emphasis Water- been converted to a USDA-ARS Benchmark [email protected] shed Program, the Choptank River Watershed Watershed for long-term study. This document 301-504-7401 project was initiated in 2004 and was continued serves as the final report to NRCS for the spe- Laura L. McConnell through 2008. cial emphasis watershed project. USDA-ARS Beltsville, Maryland [email protected] 301-504-6298 Watershed Description Project Co-PIs Thomas R. Fisher The Choptank River is a major tributary of University of Maryland the Chesapeake Bay and is located on the Del- Center for Environmental marva Peninsula. The 1756 square km (675 Science, Horn Point Laboratory square mi) Choptank River Watershed is 58% Cambridge, Maryland agricultural (cropland and extensive poultry pro- [email protected] duction), 33% forested, and only 9% urban. Cathleen J. Hapeman Portions of the Choptank River have been identi- USDA-ARS Beltsville, Maryland fied as “impaired waters” under Section 303(d) Cathleen. [email protected] of the Federal Clean Water Act due to high levels W. Dean Hively of nutrients and sediments. USDA-ARS Beltsville, Maryland The Choptank River Watershed Project pro- [email protected] vides several unique aspects to the national Thomas E. Jordan Smithsonian Environmental Research CEAP effort. The river itself is tidal for much of Center its length and includes an ecologically delicate Edgewater, Maryland estuarine ecosystem. The soils in the region are [email protected] poorly drained and the topography is especially Megan W. Lang USDA-ARS flat; therefore, farmers have historically utilized Beltsville, Maryland a network of drainage ditches to facilitate the [email protected] movement of water into streams. Urban influ- Clifford P. Rice Choptank River Watershed ences are growing rapidly. USDA-ARS Beltsville, Maryland [email protected] Ali M. Sadeghi Project Goals USDA-ARS Beltsville, Maryland • Improve estimates of nutrient reduction [email protected] Table of Contents efficiency values for the widely accepted David Whitall NOAA-NOS-NCCOS agricultural Best Management Practices (BMPs) Executive Summary 2 within the Choptank. Silver Spring, Maryland Background 3 [email protected] Collaborators • Develop innovative remote sensing tools for Watershed Characteristics & Mustafa Altinikar estimate cover crop biomass/nutrient uptake Water Quality Sampling 4 University of Mississippi and to examine wetland hydroperiod and University, Mississippi Linking Land Use with Nutrient [email protected] connectivity on a watershed scale. & Pesticide Loads 5 Marilyn Fogel • Examine land use and hydrology effects on Carnegie Institution of Washington Forested Wetland Function Revealed 6 Washington, DC pesticide and nutrient loads to streams. [email protected] Improving Cover Crop Programs 8 • Utilize watershed water quality models to exam- Kenneth Staver Controlled Drainage for Nutrient Reduction 10 Wye Research and Education Center ine conservation practice implementation sce- Queenstown, Maryland narios to achieve water quality improvements. Modeling the Future of the Choptank 12 [email protected] Outreach to the Agricultural Community 14 John Rhoderick • Foster positive relationships with farmers, stake- Maryland Department of Agriculture holders, and customers to preserve the natural References 15 Annapolis, Maryland [email protected] resources of the Chesapeake Bay Watershed. Executive Summary Page 2 ` Project Outcomes Recommendations Linking Land use with Improving Cover Crops. Modeling the Future of to Achieve Nutrient and Pesticide Remote sensing technologies the Choptank. One sub- Water Quality Concentrations. Nutrient were combined with agronomic watershed of the Choptank, the practice data to determine bio- Improvement concentrations were negatively German Branch, was used to mass and nutrient uptake by Goals correlated with percent forest test two different watershed - winter cover crops. Critical fac- water quality models: An- content. NO3 concentrations tors governing uptake were varied little over time which is nAGNPs and SWAT. The Ger- planting date, crop species, and consistent with the more steady man Branch covers nearly planting method. A threshold delivery groundwater flow. 12,000 acres and is primarily Increase implementa- cover crop biomass of about 1 Phosphorus, however, was deliv- dominated by corn and soybean tion of early planted ton per acre was observed to ered primarily via overland flow. production receiving poultry winter cover crops of control root zone nitrate. Re- Both atrazine and metolachlor manure and fertilizer applica- barley and rye. sults of this work have been showed spikes in concentration tions. This approach significantly used to improve the ef- during early spring when those increases nutrient uptake fectiveness of the Mary- herbicides are typically applied. when compared with late land Cover Crop Program, Pesticide concentrations did not planted cover crops. The and improved nutrient follow the same land use corre- recommended target efficiency values have lations as nutrients indicating cover crop biomass for been developed with the that pesticide transport is more control of root zone Chesapeake Program complicated. Delivery can occur nitrate is about 1 ton per Office Nutrient subcom- via leaching, overland flow, and acre. mittee for use in the atmospheric delivery to riparian Chesapeake Bay water corridors via drift, volatilization, quality model. and/or deposition. Strategically place controlled drainage structures to reduce Forested Wetland Controlled Drainage for Among the nutrients, nitrate nutrient flows into Function Revealed. Nutrient Reduction. losses are of particular concern, ditches. These struc- A combination of RADAR and Drainage ditches are extensively much of which escapes through tures enhance the process LiDAR remotely sensed data was used in the Choptank and pro- leaching from the crop land via of denitrification in soils. used to develop fine resolution vide a rapid pathway for nutri- subsurface flow from this domi- Storm events, however, maps of forested wetlands within ents to move into streams. nantly flat landscapes that per- can still result in nutrient the Choptank Watershed and to Studies have shown that an sist throughout the watershed. flushing into waterways. monitor their hydrology (i.e., average of 6% of nitrate applied In one assessment, the SWAT Further optimization of inundation and soil moisture). to agricultural fields can be model was used for analyses of this practice is required. This work provides a powerful transported in drainage water to alternative management prac- new approach to examine wet- receiving surface waters. Water tice and/or cropping system land connectivity and to monitor control structures installed at scenarios. Evaluation of cover Protect existing wetland function on a landscape the drainage outlet were evalu- crop effects on nitrogen reduc- wetlands within the scale. These tools also can be ated as a potential conservation tion from the watershed was Choptank watershed used to assess ecological ser- practice. Proper management of the primary objective of this utilizing newly- vices provided by wetlands. For these structures not only re- model evaluation. Simulation developed tools. example, information gained on duces water flow, but also nutri- results demonstrated that cover These tools can show the biogeochemical status and ents, mainly N, due to enhanced crops could potentially reduce connectivity with adjacent landscape connection of wet- denitrification. Drainage control large amounts of nitrate in agricultural areas and lands provides an important structures are often managed to streams. Specifically, 5 to 30% monitor wetland function. indication of the role of wetlands increase water levels to just of nitrate could be reduced in Targeted expansion of in retention or removal of agri- below the root zone during the streams if cover crops are im- existing wetland areas cultural nutrients or pesticides growing season and to near the plemented on up to 50% of the and restoration of historic from agricultural production bottom of the drainage ditch conventional croplands in the wetlands could be used as areas. Furthermore, these tools during planting and harvesting. watershed. Furthermore, the an effective management can be used to monitor the ef- Proper management of these model simulations showed that strategy to reduce nutri- fectiveness of broad scale wet- structures can potentially reduce nitrogen loss reductions could ent and pesticide loads land hydrologic restoration. nitrate losses in drainage water also be more effective if cover prior to entering streams. from 15% to 30%. These re- crop implementation followed a sults have led to the addition of targeted watershed manage- controlled drainage to the Mary- ment approach. land cost share program. Background Page 3 Land use, Conservation Programs, and Conservation Concerns Land Use. The Choptank vation practices implemented by lar