Blanchard Watershed Modeling

Transcription

1 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 SedimentationS t ti Increasing SRP loads Algae blooms Maumee Basin Largest tributary sediment source to Lake Erie Highly agricultural ral watershed (~80%) Focus of WLEB Partnership Maumee Bay / Toledo Harbor dredging Annual volume: ~640,000 yd 3 ( ) Annual cost: ~$5 million 2

3 Sources to Western Basin of Lake Erie (2005)

4 Blanchard River Watershed: Project Overview Objectives Continue effort to apply fine scale models dlto 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 Fine scale Watershed Models of the Maumee Basin 4

5 Integrated Project Team USACE Buffalo District Byron Rupp Funding, Technical Review, Project Oversight USACE ERDC Billy Johnson Contracting, Technical Review USDA NRCS Jim Stafford, Steve Davis Soils, Crop Management LimnoTech Joe DePinto, Greg Peterson Laura Weintraub Amanda Flynn, Pranesh Selvendiran Technical Lead, Project Management, Reporting Project Team Heidelberg Univ. Pete Richards Historical WQ Data USDA ARS Ron Bingner, Fred Theurer AnnAGNPS Model Support USGS Greg Koltun Hydraulic Geometry, Climate Univ. of Toledo Kevin Czajkowski, David Dean GIS Data (Topography, Land Cover, Soils) Additional Technical Support Nutrients (OSU Libby Dayton) Point Sources (OEPA) 5

6 Blanchard River Watershed Population : 91,266 Poorly drained dsoils (42% hdi) hydric) Area : 771 miles 2 Cropland > 80% (Beans, Corn, Wheat) 6 major subbasins within 6 counties Drains into the Auglaize River Low slope (typically < 2%) 6

7 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

8 AnnAGNPS Sediment Erosion Sheet and Rill Erosion Overland flow or small concentrated flow paths Calculated based on RUSLE AnnAGNPS algorithms thoroughly tested Sheet and Rill Erosion Ephemeral Gully Erosion Erosion in deep, narrow channels Calculated based on TI EGEM Limitedtesting testing of AnnAGNPS algorithms Ephemeral Gully Erosion 8

9 AnnAGNPS Data Requirements Input Data Type Topography/DEM Stream network/nhd Meteorology Soils LULC/Tillage Reach Geometry Point Sources Feedlots Fertilizer / Manure Application Streamflow Data Water Quality Data Data Sources USGS USGS NCDC SSURGO LANDSTAT, USGS, USDA USGS EPA PCS EPA PCS, Watershed Rapid Assessment, TMDL Report Blanchard Watershed Rapid Assessment USGS, Heidelberg University, OEPA Heidelberg University, OEPA 9

10 Spatial Input Data Model Cell Delineation with Dominant Soils Potential Ephemeral Gully Locations 3,830 cells Average cell size = 52 ha Soil Name Soil Type % Area Blount silt loam 39.77% Pewamo silty clay loam 18.67% Paulding clay 6.45% Toledo silty clay loam 3.31% Lenawee silty clay loam 3.29% All Other Soils 28.52% Approximately 1500 PEG sites Function of: CTIndex (1000) Watershed topography

11 Crop and Tillage Rotation 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 Wheat Corn Corn Soybean Tillage No Till Traditional Till Mulch Till No Till 11

12 Hydrology Model Calibration/Confirmation Dt Datasets t and Time Periods 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 tti 2005 to 2006 (~ 2x per month) OEPA ~100 stations 1991 to 2008 (variable and infrequent) Calibration abao Confirmation

13 Hydrology Calibration Calibration resulted in a 2,000 good to very good 1,800 1,600 prediction of runoff 1,400 1,200 1,000 Runoff slightly over predicted at Cuba and slightly underpredicted at Findlay Annual performance better than monthly or daily Cuba NSE R 2 Time HYSEP PART HYSEP PART Annual Runoff (cfs) Runoff (cfs) 1, Blanchard River at Cuba Annual Average Runoff ( ) HYSEP PART AnnANGPS Blanchard River at Findlay Annual Average Runoff ( ) HYSEP PART AnnANGPS Monthly Daily

14 Hydrology Calibration (continued) 100,000 Average Monthly Runoff (2008) Observed Simulated 90,000 Surfa ace Runoff (ac ft/ /month) 80,000 70,000 60,000 50,000 40,000 30, ,000 10, Month Runoff under predicted late winter/early spring and overpredicted summer/early fall time periods

15 Water Quality Calibration (Sediment) Annual performance very good Monthly anddailydaily performance less robust ranging gfrom fair to good Ephemeral gully erosion was 85% of the total landscape erosion Time NSE R 2 Annual Monthly Daily

16 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 Total P 4,500 Monthly Average TP Load ( ) Observed Simulated Total N 40,000 Monthly Average TN Load ( ) Observed Simulated 4,000 35,000 3,500 30,000 TP (lbs/month) 3,000 2,500 2,000 1,500 TN (lbs/month) 25,000 20,000 15, ,000 10, ,000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Year 0 16 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Year

17 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, dldirect or indirect representations Run scenarios and interpret results 17

18 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 conservation tillage + cropland to grassland + nutrient management

19 Example BMP Scenario Convert dominant highly erodible cells to improved rotation and tillage Continuous Corn with Traditional Till (CTCTCTCT or CTCTBNCT) Rotating Corn and Beans with Conservation Tillage (CMBNCMBN) Moldboard plow Mulch till Converted 7,683 acres 2.5 % of total crop area 56 watershed cells continuous corn with traditional till corn/bean rotation with conservation till 19

20 Sediment Alternative Scenario Results Base versus Combined Management Random cropland conversion 2% Random cropland conversion = -2% Targeted cropland conversion = -54% Combined management = -60%

21 Sediment Maps Base Case Combined Management Scenario Example: Sediment load reduction in Lye Creek Watershed due to improved land management practices 21

22 Phosphorus Alternative Scenario Results 800 Base versus Combined Management A Base case B Drain management C Conservation tillage D Cover crops E Random cropland to grassland conversion F Targeted cropland to grassland conversion H Nutrient management (fertilizer 80% of base case) I Nutrient management (fertilizer 60% of base case) J Nutrient management (fertilizer 40% of base case) K Combined management Tot P (tn n/yr) A B C D E F H I J K Cover crops across all conventional tilled land 25% Cover crops across all conventional tilled land = -25% Reduce fertilizer by 60% = -21% Combined management = -24%

23 Nitrogen Alternative Scenario Results Base versus Combined Management age e Conservation tillage = -24% g Cover crops across all conventional tilled land = -39% Combined management = -75%

24 Project Summary Fine scale model adequately simulates runoff and suspended ddsediment 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 hl erodible dbl areas likely to result in higher reductions of loads Final report available from GLC (October 19, 2010) 24

25 Recommendations for Future Work Examine additional management scenarios: Seasonal variations iti of tile drains and nutrient ti tapplication 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 thelower Maumee River / Toledo Harbor 25