The Daily Erosion Project
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The Daily Erosion Project estimates sheet and rill erosion across agricultural areas in the Midwest on a daily basis using weather data, soil data, elevation models, and land use/management information. The project aims to further understanding of runoff and soil erosion dynamics and magnitudes. Erosion is estimated for over 2,000 12-digit hydrologic unit code watersheds in Iowa, Minnesota, and Nebraska using the Water Erosion Prediction Project model. Results are disseminated online. The project has found that erosion typically peaks in spring and is highest in years with heavy precipitation or snowmelt. Maintaining soil cover is important for reducing erosion during high runoff periods.
The Daily Erosion Project
- 1. The Daily Erosion Project Brian Gelder, Rick Cruse, Daryl Herzmann, Claudette Sandoval-Green, John Laflen, and Tim Sklenar, Iowa State University David James, USDA ARS NLAE 1 Real Time Soil Erosion Monitoring and Inventory
- 2. Daily Erosion Project • Our mission – To further understanding of 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 project – We estimate sheet and rill erosion across 2000+ Midwestern HUC12 watersheds every day • Initially launched in 2003 for Iowa • Currently expanding to surrounding states – Fully coverage of Minnesota and Nebraska coming soon
- 4. DEP Hillslope Profiles • LiDAR-derived elevation models can better predict water flow across the landscape but… – Doesn’t always flow • Hydrologic enforcement cuts across impediments to allow fully flowing hydrologic regime – Too many flowpaths for WEPP requires random sampling • Stratify HUC12s into sub-catchments – TauDEM Peuker-Douglas method constant drop stream analysis – 125 sub-catchments per HUC12 • Select 1 agricultural flowpath per sub- catchment – No other land uses currently • Respects impediments to flow; terraces, roads, non-Ag land
- 5. Field polygons (> 15 ac) have • Majority land cover for last six years – Assigned to a rotation to predict current crop • A tillage class derived from satellite imagery + DEP - Land Use & Management 2013 20112010 2012 20152014
- 6. • USDA NRCS gSSURGO 10m soil map raster • Custom attribute extraction – Texture, Organic matter, CEC • Current FY data Soils Data
- 7. DEP Weather • NEXRAD radar data – 5 minute, 1 x 1 km rainfall • 25x25 km wind, temp, and solar radiation • Most code for running DEP is on github – https://github.com/akrherz/dep – At 1:30 AM a program starts checking for rainfall input availability
- 8. What’s It Like In the Field?
- 9. Flowpaths & Land Use FB070802030106 GenLU Corn/Soybeans C/S with Continuous Corn Pasture Conservation Rotation Mixed Agriculture Continuous Corn Extended Rotation Flood-prone Cropland Forest LT 15ac UnAssigned Water/wetland
- 10. Flowpath Parameterization Land Use Soils
- 11. DEP Hillslope Profiles • WEPP OFEs break at Land-use and Soils boundaries • Slope estimated for each OFE from DEM and flowpath length OFE 2 OFE 3 OFE 1 OFE 4
- 12. DEP Map Interface Search for HUC12, decrease layer transparency, increase layer transparency, download as .shp, shrink window, expand window Toggle single/multi day search range and date entry(s) Zoom to a state, zoom in/out (+/-), zoom to extent (E) Toggle which variable to view Toggle which layers to view Toggle how to view detailed data Static web link
- 13. How Fast Are They Eroding?
- 14. How Fast Are They Eroding?
- 15. How Fast Are They Eroding?
- 16. How Fast Are They Eroding?
- 17. HUC12 Mean Slope (%)
- 18. Daily Erosion Project Trends
- 19. Daily Erosion Project Trends
- 20. Daily Erosion Project Trends
- 21. Daily Erosion Project Trends • It's not hard to believe… – Precipitation drives runoff! • Most years precipitation peaks in May – Erosion declines more rapidly than precipitation due to rapidly emerging vegetation that protects soil • More runoff in late winter than precipitation – Snowmelt runoff from snowy winters » 2008, 2010, 2011, 2013, 2016 • 2015 had wet fall – Double precipitation and runoff peaks
- 22. Daily Erosion Project Trends
- 23. Daily Erosion Project Trends
- 24. Daily Erosion Project Trends • It's not hard to believe… – Runoff drives erosion! • Erosion is not common during winter or late summer – Winter has frozen surface soils » Typically not much rain with frozen subsurface – Summer has excellent crop canopy
- 25. Daily Erosion Project Trends • Midwestern water erosion typically occurs during spring field preparation – Greater slopes enable greater delivery • Management practices that maintain cover and reduce runoff during these time periods will be most effective – Low tillage intensity – Cover crops – Grass waterways – Tile drainage
- 26. DEP Questions? • Acknowledgements: – ISU Agronomy Department Endowment – IDEP1, IDEP2, DEP – USDA Agricultural Research Service NLAE – IDEP1, IDEP2, DEP – USDA NRCS – Preliminary Management Work, ACPF Expansion – Environmental Defense Fund – Preliminary ACPF Work – Iowa DOT and Iowa Institute for Hydraulic Research (IIHR) – DEM Enforcement – North Central Regional Water Network – ACPF Expansion DEP Web Pages http://dailyerosion.org/map/ http://dailyerosion.org/
- 27. 1647 HUC12 Watersheds in Iowa 54 HUC8 whole or partial watersheds (blue lines)
- 28. DEP Sampling Scheme HUC12 (Each HUC12 approx. 10000 ha) HUC12 Sub-catchment (Stratified sample) (Each sub-catchment approx. 100 ha) (Approximately 125 flowpaths per HUC12) Flowpath (1 Random sample w/i sub-catchment) (Approximately 10-100 m long) (Only in dispersed flow)
- 29. HUC12s & Sub-catchments HUC 12 Boundary (approx. 10000 ha) Subcatchment Boundary (approx. 100 ha) Subcatchments are defined by the Peuker-Douglas constant drop stream Algorithm in TAU-DEM
- 30. Sub-catchments & Flowpaths Subcatchment Boundary Flowpath (Not modeled) Flowpath (Modeled) 1 random flowpath per subcatchment Must be on agricultural land Approximately 10-100 m long Only modeled in sheet/rill flow
- 31. DEP Accuracy • Assessing accuracy of DEP is difficult as no truly comparable dataset exists – Monitoring at 300,000+ sites would be expensive – Most comparable is from the USDA Natural Resources Inventory (NRI) every 5 years • Results only available at state level – Another comparison was made to see if sloping land fraction was correlated with erosion at HUC8 level • Yes, it is – that's a good thing
- 32. Iowa NRI vs. DEP 0 2 4 6 8 10 12 1980 1985 1990 1995 2000 2005 2010 2015 2020 Erosion(tonac-1yr-1) NRI vs. DEP Sheet and Rill Estimates NRI DEP * * DEP Mean
- 33. DEP Questions? • Acknowledgements: – Iowa Nutrient Research Center – Cover Crops/Residue Cover Mapping – Conservation Practice Mapping – Stacked Scenarios for Phosphorus – Union of Concerned Scientists – Erosion Scenarios – Minnesota BWSR and DNR – ACPF/DEP Expansion – US Department of Housing and Urban Development FEMA – Flood Reduction Scenarios – Nebraska NRCS – DEM Enforcement-ACPF/DEP Expansion Over $1.7 Million in External Funding
- 34. Flowpath Parameterization • For each watershed an overlay is conducted to correlate all WEPP inputs other than climate – XY location (later used to find climate) – Flowpath number – Elevation – Flowpath length – Crop rotation – Tillage management – Soils • Slope is figured as elevation change over distance
- 35. Post Fall Residue Polygons NDTI = Band 5 – Band 7 Band 5 + Band 7 DEP Management – Residue Cover
- 36. USDA/ARS Agricultural Conservation Planning Framework (ACPF) and the Daily Erosion Project • The DEMs, crop rotation, and soils data used in the Daily Erosion Project are derived from the Agricultural Conservation Planning Framework (ACPF) database – Tomer et al., USDA/ARS National Laboratory for Agriculture and the Environment (NLAE) • ACPF database combines with the ACPF Toolbox to do field-level conservation planning – Saturated Buffers – Riparian Functional Analysis – Nutrient Removal Wetlands – WASCOBs – Contour Buffer Strips • The ACPF (part of USA only) is available on the North Central Region Water Network website at http://northcentralwater.org/acpf/