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Drainage water management, also known as controlled drainage, is the practice of using a water table control structure at the end of the subsurface drain pipe to reduce subsurface drainage, and thereby nitrate losses. Methods to quantify the potential effects of drainage water management for entire watersheds are needed to evaluate the impacts of large-scale adoption. A distributed modeling approach was developed to apply the field-scale DRAINMOD model at the watershed scale, and used to assess the impact of drainage water management on nitrate load from an intensively subsurface drained agricultural watershed in west central Indiana. The watershed was divided into 6460 grid cells for which drain spacing, soil parent...
Categories: Publication;
Types: Citation;
Tags: Controlled drainage,
DRAINMOD,
Data Visualization & Tools,
Hydrologic modeling,
Landscapes, All tags...
Nitrate load,
Northeast CASC,
Other Landscapes,
Science Tools For Managers,
Soil parent material,
Tile drains, Fewer tags
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Millions of dollars have been spent on agricultural watershed projects across the nation, but little is known about the long-term impacts of watershed management and protection efforts. Information pertaining to long-term condition and water quality impact of best management practices (BMPs) is scarce. Evaluation methods that estimate the current condition of the practice based on visual inspection and comparison to selected original design dimensions were developed for grassed waterways, grade stabilization structures, field borders and parallel terraces. The evaluation tools were tested for validity using an expert panel approach and for reliability based on inter-rater correlation. The evaluation tool's three-point...
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Subsurface drainage is a beneficial water management practice in poorly drained soils but may also contribute substantial nitrate N loads to surface waters. This paper summarizes results from a 15-yr drainage study in Indiana that includes three drain spacings (5, 10, and 20 m) managed for 10 yr with chisel tillage in monoculture corn (Zea mays L.) and currently managed under a no-till corn–soybean [Glycine max (L.) Merr.] rotation. In general, drainflow and nitrate N losses per unit area were greater for narrower drain spacings. Drainflow removed between 8 and 26% of annual rainfall, depending on year and drain spacing. Nitrate N concentrations in drainflow did not vary with spacing, but concentrations have significantly...
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