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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14

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.