Management of Drainage Water in Illinois. Overview Defining the problem Introducing drainage water...
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Transcript of Management of Drainage Water in Illinois. Overview Defining the problem Introducing drainage water...
Management
of Drainage Water
in Illinois
OverviewDefining the problemIntroducing drainage water management
(DWM) How does it work? Where does it apply? Benefits
Planning and applying the practiceAvailable resources
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A Big Water Quality Issue
Hypoxic Zone or “Dead Zone”Excess of nutrients (primarily
nitrogen but also phosphorus and silica)
Algal growth organic matter sinks to bottom, decays, consumes available oxygen
Oxygen levels fall lower than 2 mg/l
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Drainage Water Management Illinois 4
Mississippi River Basin
N Load, lbs/acreLess than 1.81.8 to 4.44.5 to 8.99.0 to 16.016.1 to 27.1
Watershed Average = 2.6 lbs/acre
Average Annual Nitrogen Load in Streams
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Tile drained soils vs high nitrate levels
Problem StatementDrainage is needed for economical crop production in many Illinois fields.
Tile drainage water is a primary source of nitrate to surface water.
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What is Drainage Water Management?
The process of managing the water table elevation and the timing of water discharges from surface and subsurface agricultural drainage systems.
Theory: hold nutrients in field when drainage is not needed for production.
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DWM on a Tile Line
Ditc
h
Raised Water Table
Riser Boards (Adjustable)
Drain Water
Solid pipe
Water Level Control Structure
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Zone of Influence (Impacted Area)
Lines labeled 600, 602, and 604 represent elevation contours
Nutrient Load Reduction
FACT: Less flow from drainage tile Less nitrates to surface water
NO3 + carbon source + bacteria + time = N2 gas
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ManagementPrior to field activities ,remove
flashboards
During growing season, manage water table to provide capillary water to root zone
During fallow season, raise water table (within 6” of the surface)
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Example Management Strategy
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Types of Tile Drain SystemsPatterned drainage
Designed to uniformly drain the land
Random drainageMostly in low spots
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Drainage Management(Parallel System and Flat Topography)
main main
late
rals
late
ral
s
Water level control structureDrainage Water Management Illinois
Topographic Map with Tile Map
Overlay
DWM Feasibility and Limitations• Economics
• Flat topography (0.5% average slope; minimum 15-20 acre impacted area per structure)
• Patterned (systematic) subsurface tile system exists
• Tile map exists
• Land Use• No negative impact on neighbors
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Tile System ConsiderationsGoal: Efficiently drain water for field
activities as needed, store water during the growing season to relieve summer crop stress, and reduce nitrogen loss during the fallow season.
Pattern Tile DesignFlat Land – conventional pattern tilingSloping Land– design for affected zones on the
contour
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Benefits of DWMAs a part of a conservation system, DWM:
Improves water qualityDocumented 35-81% nitrate load reduction in Illinois
Improves soil environment for better vegetative growth
Reduces rate of soil organic matter oxidation
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Benefits of DWMAs a part of a conservation system, DWM also
can:
Reduce wind erosion and particulates (dust)
Enable seasonal flooding for wildlife habitat
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DWM Yield Benefits?Research is inconclusive on yield
benefitsWeather is a big factor – yield
improvement has good potential in dry years
Anecdotal evidence suggests as much as
10-20% yield improvement in some years
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Implementation
Conservation plan DWM Plan (CAP 130) is a good start Systems approach: suite of practices Nutrient Management is especially beneficial
Infrastructure to facilitate management Implement practices from conservation plan
Management (active)
Plan Design Install Manage
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Contents of a DWM PlanID and location infoObjectivesMaps and delineationsControl structure summary tableManagement instructionsSignature page
http://www.wq.illinois.edu/DG/DrainageGuide.html
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Potential DWM Acres in Illinois
• Flat cropland• Likely to be tile drained• Minimum15 acre parcels
Simplification: land ownership and tile configuration not considered
By the Numbers:•24 million cropland acres•10 million drained•~2 million suitable for DWM
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Available Financial AssistanceEnvironmental Quality Improvement Program
(EQIP)
Contact your local NRCS field office for more information
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NRCS: Helping People Help The Landwww.nrcs.usda.gov
USDA is an equal opportunity provider and employer.