The Daily Erosion (and Runoff) Project: Summary and Lessons Learned Brian Gelder, Daryl Herzmann, Rick Cruse, David James Iowa State University, USDA-ARS-NLAE
What Is NRI Telling Us? USDA/NRCS National Resources Inventory. 2015.
Our mission: The Daily Erosion Project To help farmers, land managers, and the public better understand the dynamics and magnitude of runoff and soil erosion through daily estimation of these processes on agricultural areas and dissemination of the estimates via the web Our goal Soil Erosion Monitoring Center for Central US+ Small watershed estimates of processes
NEXRAD Precip LiDAR Elevation gssurgo Soils Management from ACPF and Landsat
DEP Iowa Database 1,647 HUC12 watersheds 36,900,000+ Acres
DEP Sampling Scheme HUC12 (Each HUC12 approx. 23000 acres) HUC12 Sub-catchment (Stratified sample) (Each sub-catchment approx. 200 acres) (Approximately 125 flowpaths per HUC12) Flowpath (1 Random sample w/i sub-catchment) (Approximately 30-300 feet long) (Only in dispersed flow)
HUC12s & Sub-catchments HUC 12 Boundary Subcatchment Boundary
Sub-catchments & Flowpaths Subcatchment Boundary Flowpath (Modeled) Flowpath (Not modeled)
What s It Like In the Field?
DEP Hillslope Profiles LiDAR-derived elevation models can better predict water flow across the landscape but Doesn t always flow Roads/field entries/railroads create digital dams Hydrologic enforcement cuts across impediments to allow fully flowing hydrologic regime Does not force flow from true depressions Prairie Potholes DEM Cutter program
DEP Hillslope Profiles Once surface is enforced further processing begins Too many flowpaths for WEPP requires random sampling Stratify HUC12s into subcatchments TauDEM Peuker-Douglas method constant drop stream analysis 125 sub-catchments per HUC12 Select 1 AG flowpath per subcatchment Respects impediments to flow; terraces, roads, non-ag land
DEP - Land Use & Management + 2008 2009 USDA ARS Ag Conservation Planning Framework gives us field boundary polygons and latest six year crop rotation Crop cover from NASS Cropland Data Layer Over 430,000 agricultural fields in Iowa > 15 ac 2010 2012 2011 2013
DEP Management Residue Cover Remotely sensed residue cover estimates derived from Landsat TM and ETM+ sensor Soil and residue reflect differently in middle infrared Index relationship can define tillage intensity
DEP Management Residue Cover Post Fall Residue Polygons NDTI = Band 5 Band 7 Band 5 + Band 7
Flowpaths & Land Use Flow Path Subcatchment Boundary
Flowpaths and Soils
DEP Hillslope Profiles OFE 1 OFE 2 OFE 3 OFE 4 WEPP OFEs break at Land-use and Soils boundaries Slope estimated for each OFE from DEM
DEP Climate Files Level III NEXRAD radar data from the NWS and UI 1 x 1 km rainfall Every 5 minutes County level temperature, solar radiation, and wind speed
DEP Webpage DEP Web Page http://dailyerosion.org/map/ Multiple states available Iowa and parts of Kansas and Minnesota Precipitation, Runoff, Detachment and Loss Static web links can be copied and pasted to send someone to the exact same info Multi-day, weekly, monthly, or yearly summaries
DEP Map Interface Zoom to a state, zoom in/out Static web link (+/-), zoom to extent (E) Toggle which variable to view Toggle which layers to view Toggle how to view detailed data Toggle single/multi day search range and date entry(s) Search for HUC12, decrease layer transparency, increase layer transparency, download as.shp, shrink window, expand window
2.8 T/A 983 mm 137 mm 8.8 T/A 8.8 T/A 1003 mm 142 mm 3.6 T/A 912 mm 77 mm 10.6 T/A 1082 mm 160 mm
4.8 T/A 750 mm 65 mm 1.6 T/A 620 mm 30 mm 5.4 5.4 T/A T/A 864 mm 131 mm 8.0 T/A 650 mm 86 mm
Iowa NRI vs. DEP Erosion (ton ac -1 yr -1 ) 12 10 8 6 4 2 NRI vs. DEP Sheet and Rill Estimates * 0 1980 1985 1990 1995 2000 2005 2010 2015 2020 NRI DEP * DEP Mean
DEP Lessons Learned LiDAR Don't trust the vendor's DEMs Develop your own automated process to test the LAS data Use a consistent approach Enforce naming conventions Fully populate all tiles/blocks
DEP Lessons Learned RADAR NexRAD radar is easily confused by wind turbulence surrounding wind farms WEPP Excessively high precipitation levels must be filtered Developing new yield parameters for WEPP is a tricky process as the resulting residue cover changes can necessitate tillage property changes
DEP Lessons Learned Management Data Field level management data is labor intensive FSA availability would help Field boundaries are context sensitive Crops can aggregate easier than tillage Waterway/terrace/wetland location influences calculating residue cover
Questions? DEP Web Page http://dailyerosion.org/map/ Acknowledgements: Iowa State University Agronomy Department Endowment USDA Agricultural Research Service Environmental Defense Fund Iowa Department of Transportation Iowa Institute for Hydraulic Research Minnesota BWSR, DNR Iowa State University, ARS-USDA (National Laboratory for Agriculture and Environment, National Soil Erosion Laboratory), University of Iowa, Colorado State University