Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Agricultural Drainage, Extreme Weather, and Management Opportunities Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Outline Why do we need agricultural drainage in VA? What are the approaches to drainage & water table management? How does extreme weather drive need for drainage? Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Benefits Artificial drainage Increases land productivity Improves trafficability and timeliness Provides opportunity to control & treat discharges Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Benefits Artificial drainage Increases land productivity Improves trafficability and timeliness Provides opportunity to control & treat discharges Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Benefits Artificial drainage Increases land productivity Improves trafficability and timeliness Provides opportunity to control & treat discharges Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group \ Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Different practices for different conditions Source of water Surface, subsurface, combination strategies Drainage vs. water table control Drainage only or water table control More opportunity to improve water quality What are the approaches to drainage & water table management? Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101 Surface drainage problems Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101 Subsurface drainage problems Does not remove plant available water Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Approaches Problem & Soil CharacteristicsPotential Solution Soil completely saturated (poorly drained) Ditch or tile Low infiltration rate (clay or compacted soils) Surface smoothing Shallow impeding soil layersDitches or tile with inlets Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Surface Fine textured soil, low permeability Water originating on- site ( gpsontario.ca) Land Leveling ( Source: bae.ncsu.edu) Ditching Two-stage Channel Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Subsurface ( Source: G. Sands, UMN) Removes water from the root zone Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Subsurface - Plans Different configurations: Different spacing requirements: ( extension.iastate.edu) ( omafra.gov.on.ca) Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Combined Systems Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Environmental Consequences Water quantity manipulation Water quality alteration Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Ag Drainage 101: Managed Systems Environmental benefits Conservation Practice Standard 554 More efficient use of rainfall, decreased need for irrigation Drainage Handbook Ag Drainage 101: Managed Systems Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group How does extreme weather drive need for drainage ? Need for drainage water management is site specific: Climate Geology Topography Soil characteristics Crops Farming methods and the climate is changing! Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Precipitation Trends in Virginia: Eastern VA: 13-29% Western VA: 10-22% North central VA: -3-7% South-central VA: -2-8% Eastern VAWestern VA Rainfall generally increasing Rainfall intensity increasing as well Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Future Precipitation Trends? Predicted precipitation changes Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group ? Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Water quality implications of extreme weather Increased nutrient and sediment export Increased soil erosion Increased demand on water supply drive need for controlled drainage The question then is not whether one can afford to drain, but whether one can afford not to drain Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group ContactZachary Easton Assistant Professor Emily Bock Grad Research Assist Thank you! Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group Resources National Engineering Handbook USDA- NRCS Ch 10, part 634-Drainage, Water Table Control Ch 14, part 650-Water Management, Drainage Extension publication: extension.umn.edu/agriculture For Virginiacoming soon! Agricultural Drainage Management Stems Task Force Invent the Future Biological Systems Engineering VirginiaTech Invent the Future Watershed Science and Engineering Group List of Drainage BMPs General: controlled drainage Tile systems: Reactive barriers Biofilters Wetlands (surface, riparian) Ditch systems: Reduced dip out frequency mowing Two-stage ditches Reactive barriers, in-ditch filters