Blanchard Watershed Modeling Laura Weintraub, Amanda Flynn, Joe DePinto Great Lakes Tributary Modeling Program 516(e) Meeting May 18, 2011 2 Western Basin Lake Erie Concerns Sedimentation Increasing SRP loads Algae blooms Maumee Basin Largest tributary sediment source to Lake Erie Highly agricultural watershed (~80%) Focus of WLEB Partnership Maumee Bay / Toledo Harbor dredging Annual volume: ~640,000 yd 3 ( ) Annual cost: ~$5 million Sources to Western Basin of Lake Erie (2005) Blanchard River Watershed: Project Overview 4 Fine-scale Watershed Models of the Maumee Basin Objectives Continue effort to apply fine-scale models to Maumee watersheds (build upon Upper Auglaize) Quantify sediment and nutrient loading Evaluate land management alternatives to estimate potential benefit from reduced loading Support broader sediment and nutrient modeling efforts of the lower Maumee River and Maumee Bay Funding Under 516(e) Timeline: Jul 2009 to Oct 2010 Integrated Project Team 5 USACE- Buffalo District Byron Rupp Funding, Technical Review, Project Oversight USACE- ERDC Billy Johnson Contracting, Technical Review LimnoTech Joe DePinto, Greg Peterson Laura Weintraub Amanda Flynn, Pranesh Selvendiran Technical Lead, Project Management, Reporting USDA-NRCS Jim Stafford, Steve Davis Soils, Crop Management USDA-ARS Ron Bingner, Fred Theurer AnnAGNPS Model Support Univ. of Toledo Kevin Czajkowski, David Dean GIS Data (Topography, Land Cover, Soils) Heidelberg Univ. Pete Richards Historical WQ Data USGS Greg Koltun Hydraulic Geometry, Climate Additional Technical Support Nutrients (OSU Libby Dayton) Point Sources (OEPA) Project Team Blanchard River Watershed 6 Population : 91,266 Area : 771 miles 2 6 major subbasins within 6 counties Low slope (typically < 2%) Poorly drained soils (42% hydric) Cropland > 80% ( Beans, Corn, Wheat) Drains into the Auglaize River AnnAGNPS Background Developed by USDA-ARS Continuous simulation of surface runoff and pollutant loading Incorporates revised universal soil loss equation (RUSLE) Provides most utility at monthly or annual scales Models flow, suspended solids, and nutrients Simulates direct surface runoff and tile drain flow based on SCS curve number Distinguishes between sheet and rill, ephemeral gully erosion 7 AnnAGNPS Sediment Erosion Sheet and Rill Erosion Overland flow or small concentrated flow paths Calculated based on RUSLE AnnAGNPS algorithms thoroughly tested Ephemeral Gully Erosion Erosion in deep, narrow channels Calculated based on TI-EGEM Limited testing of AnnAGNPS algorithms 8 Sheet and Rill Erosion Ephemeral Gully Erosion AnnAGNPS Data Requirements 9 Input Data Type Data Sources Topography/DEMUSGS Stream network/NHD USGS MeteorologyNCDC SoilsSSURGO LULC/TillageLANDSTAT, USGS, USDA Reach GeometryUSGS Point SourcesEPA PCS Feedlots EPA PCS, Watershed Rapid Assessment, TMDL Report Fertilizer / Manure Application Blanchard Watershed Rapid Assessment Streamflow Data USGS, Heidelberg University, OEPA Water Quality Data Heidelberg University, OEPA Spatial Input Data Soil NameSoil Type% Area Blountsilt loam 39.77% Pewamosilty clay loam 18.67% Pauldingclay 6.45% Toledosilty clay loam 3.31% Lenaweesilty clay loam 3.29% All Other Soils 28.52% 3,830 cells Average cell size = 52 ha Model Cell Delineation with Dominant Soils Approximately 1500 PEG sites Function of: CTIndex (1000) Watershed topography Potential Ephemeral Gully Locations Crop and Tillage Rotation 11 Data from remote sensing - compared with NRCS transect data Developed a detailed four (4) year crop rotation and tillage operation sequence for each cropland cell Removed unrealistic combinations (Example: WNCTCMSN) Year Crop WheatCorn Soybean Tillage No TillTraditional TillMulch TillNo Till Model Calibration/Confirmation Datasets and Time Periods Hydrology USGS ( ) at Findlay 1923 to Current (daily) USGS ( ) at Cuba 2005 to 2007 (daily) Water Quality (solids, nitrogen, phosphorus) Heidelberg at Findlay 2007 to Current (daily) OEPA seven sentinel stations 2005 to 2006 (~ 2x per month) OEPA ~100 stations 1991 to 2008 (variable and infrequent) Calibration 2002 2009 Confirmation 1995 2001 Hydrology Calibration Calibration resulted in a good to very good prediction of runoff Runoff slightly over-predicted at Cuba and slightly under- predicted at Findlay Annual performance better than monthly or daily Cuba NSE R2R2 TimeHYSEPPARTHYSEPPART Annual Monthly Daily Hydrology Calibration (continued) Runoff under-predicted late winter/early spring and over- predicted summer/early fall time periods Water Quality Calibration (Sediment) Annual performance very good Monthly and daily performance less robust ranging from fair to good Ephemeral gully erosion was 85% of the total landscape erosion 15 TimeNSER2R2 Annual Monthly Daily Water Quality Calibration (Total Phosphorus and Total Nitrogen) Poor to fair performance Sensitive to initial soil concentrations Limitations in model capabilities for nutrient cycling Fertilizer application timing in model may not reflect on the ground practices 16 Total P Total N AnnAGNPS Model Application Goal: Test the impact of land management alternatives on watershed loadings Process: Coordinate with stakeholders to develop a set of reasonable BMPs/land management alternatives NRCS, Blanchard River Watershed Partnership, Environmental Defense Fund, Putnam Soil and Water Conservation District, Ohio DNR, Northwest Ohio Flood Mitigation Partnership Translate BMPs into model, direct or indirect representations Run scenarios and interpret results 17 Selected Management Alternatives Tile Drain Management Conservation Tillage Cover Crops Cropland Conversion to Grassland random cropland (~10%) to grassland targeted cropland (~10%) to grassland Improved Nutrient Management All Natural Watershed Combined Management conservation tillage + cropland to grassland + nutrient management Example BMP Scenario Convert dominant highly erodible cells to improved rotation and tillage 19 Continuous Corn with Traditional Till (CTCTCTCT or CTCTBNCT) Continuous Corn with Traditional Till (CTCTCTCT or CTCTBNCT) Rotating Corn and Beans with Conservation Tillage (CMBNCMBN) Rotating Corn and Beans with Conservation Tillage (CMBNCMBN) Moldboard plow Mulch till continuous corn with traditional till corn/bean rotation with conservation till Converted 7,683 acres 2.5 % of total crop area 56 watershed cells Sediment Alternative Scenario Results Base versus Combined Management Random cropland conversion = -2% Targeted cropland conversion = -54% Combined management = -60% Sediment Maps 21 Base CaseCombined Management Scenario Example: Sediment load reduction in Lye Creek Watershed due to improved land management practices Phosphorus Alternative Scenario Results Cover crops across all conventional tilled land = -25% Reduce fertilizer by 60% = -21% Combined management = -24% Base versus Combined Management Nitrogen Alternative Scenario Results Base versus Combined Management Conservation tillage = -24% Cover crops across all conventional tilled land = -39% Combined management = -75% Project Summary Fine-scale model adequately simulates runoff and suspended sediment on annual basis Less confidence in simulation of TN and TP loading Potential land management alternatives explored to estimate possible benefits Targeting placement of BMPs to highly erodible areas likely to result in higher reductions of loads Final report available from GLC (October 19, 2010) 24 Recommendations for Future Work Examine additional management scenarios: Seasonal variations of tile drains and nutrient application Conversion to conservation tillage, cover crops, or grassland Investigate and potentially refine nutrient algorithms Investigate / ground-truth ephemeral gully erosion algorithms Use model to support watershed action plan development Apply fine-scale models to other Maumee Basin watersheds (e.g., Tiffin) Coordinate with modeling to characterize sediment and nutrient transport in the lower Maumee River / Toledo Harbor 25