Overview of the Mark Twain Lake Salt River Conservation Effects Assessment Project CEAP

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Overview of the Mark Twain Lake/ Salt River
Conservation Effects Assessment Project (CEAP)
Contributing Scientists Robert N. Lerch Newell
R. Kitchen Kenneth A. Sudduth E. Eugene
Alberts E. John Sadler William W. Donald John W.
Hummel Robert J. Kremer Chung-Ho Lin D. Brenton
Myers Raymond E. Massey Harlan L. Palm Gab-Sue
Jang
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Topics

• National CEAP effort.
• Mark Twain Lake/ Salt River CEAP.
• Water quality research projects in support of
  CEAP
• Development and Evaluation of BMPs for Improved
  Watershed Management.

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The USDA Conservation Effects Assessment Project
(CEAP)

• A Cooperative Effort to Assess Environmental
  Effects and Benefits from Conservation Programs

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CEAP has Two Major Components and Reporting
Scales

• The NRCS-led national assessment provides
  estimates of conservation benefits at the
  national scale.
• The ARS watershed assessment studies provide
  for more detailed information on conservation
  effects/benefits in selected benchmark watersheds.

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12 ARS Benchmark Watershed Assessment Studies
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Mark Twain Lake/ Salt River CEAP Project

• Project Objectives
• Establish a comprehensive monitoring network
  within the Salt River basin
• Validate and improve watershed models to better
  assess the impact of field- and watershed-scale
  management practices on surface water quality.
• Development and evaluation of BMPs to reduce
  herbicide, nutrient, and sediment transport in
  surface runoff.

Salt River Basin
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Mark Twain Lake/ Salt River Basin

• Three 8-digit Hydrologic Units
• Nine 11-digit Hydrologic Units
• 2,500 sq miles in area
• Mark Twain Lake is major public water supply in
  the region
• Serves 42,000 people
• EPA 303(d) list for Atrazine until 2003
• Claypan soils
• High runoff potential
• Surface water quality a major concern
• Extensive USGS hydrologic monitoring network
  already in-place

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Basin-Scale Monitoring

• 13 Monitoring Sites
• Automated samplers for runoff events
• 2 grab samples per month
• 9 existing gauged sites
• Rating curves to be developed at 3 sites
• Mass balance for Mark Twain Lake
• Identify 11 digit watersheds contributing highest
  loads to the lake
• Identify watershed specific problems
• Measurements
• Discharge
• Rainfall
• Herbicides (atrazine, acetochlor, metolachlor,
  metribuzin, selected atrazine metabolites)
• Nutrients (total and dissolved N and P)
• Sediment

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Nested Watershed MonitoringLong Branch Watershed

• Evaluate scale dependence of contaminant
  transport.
• Perform model calibrations and validations from
  sub-watersheds to whole watershed scales.

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Goodwater Creek Watershed

• Surface water hydrology
• 35-yr record
• Sediment
• Weather
• Water table depth
• Water quality
• 15-yr record
• Nutrients
• Pesticides
• Surface and Ground water
• Initial SWAT model calibration is based on this
  site

?
? Weather station
? Rain gauges
?Weirs
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Key Questions

• Will we see differences in water quality at the
  watershed scale that can be attributed to
  conservation practices?
• Yes, but only if sufficient implementation has
  occurred.
• What if past implementation of conservation
  practices is insufficient to affect water quality
  at the watershed-scale?

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Expected Outcomes

• Assess water quality differences at the
  watershed-scale.
• Contaminant transport normalized to watershed
  area or area of specific crop types (e.g. kg
  atrazine/ km2).
• Loads as a percent of applied mass in the
  watershed.
• SWAT Model will be used to determine the most
  hydrologically vulnerable areas within watersheds
  (i.e., areas contributing most to contaminant
  transport).
• Field verification of the model needed.
• Develop ability to model BMP impacts on water
  quality.
• Develop site evaluation guidelines for targeted
  implementation of conservation practices.

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Project Status

• Negotiated a cooperative agreement with Missouri
  Corn Growers Association to conduct basin-scale
  monitoring
• Implemented basin-scale monitoring in Spring 2005
• 12 sites installed with autosamplers and
  area/velocity or depth probes
• Rating curve work to be conducted for nested
  watersheds
• Modeling
• Calibrated SWAT to Goodwater Creek discharge data
  at annual and monthly time scales daily
  discharge more challenging
• Spatial and temporal delineation of crop type to
  improve land-use input data
• FAPRI was awarded CSREES proposal in support of
  our CEAP
• USDA-FSA has provided locations of the
  conservation practices within the Salt River

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DEVELOPMENT AND EVALUATION OF BMPs FOR IMPROVED
WATERSHED MANAGEMENT

• Herbicide transport from different cropping
  systems
• Precision Agriculture System (PAS) implementation
  

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Herbicide Transport from Different Cropping
SystemsPlot-Scale Research

• Objectives
• Evaluate the effects of corn herbicide
  application methods and application timing on
  surface water quality.
• Develop equations to predict herbicide
  concentrations in surface runoff.
• Herbicides studied atrazine and metolachlor
• Cropping Systems
• CS1 mulch-till corn-soybean rotation
  herbicides broadcast and incorporated.
• CS2 no-till corn-soybean rotation herbicides
  broadcast, not incorporated.
• CS5 no-till corn-soybean-wheat rotation
  herbicides broadcast, not incorporated adaptive
  approach used to determine atrazine rates and
  timing.
• Split applications, reduced pre-plant rates,
  post-only application.
• Corn phase of the rotation was monitored during
  the growing season from 1997-2002.

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Runoff and Herbicide Losses
Six year averages. Means within rows with
different letters were significantly different (?
0.10).
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Herbicide Concentrations
Atrazine
Metolachlor
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General Model for Predicting Herbicide Transport
in Surface Water
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Herbicide Transport from Different Cropping
SystemsConclusions

• No-till systems (CS2 and 5) did not reduce total
  runoff compared to the mulch-till system (CS1).
• Herbicide loss was generally higher for no-till
  than mulch-till cropping systems.
• A generalized model for estimating herbicide
  concentration was developed based on the observed
  exponential decrease in concentration combined
  with flow and application rate.
• A key management challenge for claypan soils is
  development of a cropping system that both
  minimizes soil erosion and reduces herbicide loss
  to surface runoff.

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Implementation of a Precision Agricultural System
OBJECTIVE From a 14-yr history of water and
soil quality and spatially-variable crop and soil
information, to develop and assess a precision
agriculture system that will improve farming
profitability and better protect soil and water
resources when compared to past management
practice.
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Field 1 Research Site 36 ha field established for
research in 1990
Cropping System (1991-2004) CS1 mulch-till
corn-soybean rotation herbicides broadcast and
incorporated.
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200 Years of Erosion
The spatial variability in soil loss over the
last 200 years controls the soil quality, water
quality, and crop productivity patterns currently
observed within this field.
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Decade Total Nitrogen Fertilizer Left on the
Field (N fertilizer Grain N)
D
E
C
E
D
C
B
A
B
520
A
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Atrazine Persistence
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Spatial Variability in Average Crop Profit
(1991-2004)
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Ground Water
Quality
Soil Quality
(sustainability)
Surface Water
Quality
Production
(profitability)
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PAS Management Approach

• Whole Field
• no-till
• grade to remove ponding problems
• variable rate P, K, and lime
• variable rate N for wheat and corn

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Summary

• CEAP will facilitate
• Water quality assessment at the large watershed
  scale.
• Modeling to
• Identify hydrologically vulnerable areas within
  watersheds.
• Assess water quality impacts of BMPs.
• Integration of research over multiple scales.
• Develop site evaluation guidelines for targeted
  implementation of conservation practices.

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Project Partners

• Missouri Corn Growers Association
• USDA-NRCS
• University of Missouri- Columbia (UMC) Water
  Quality Extension
• UMC School of Natural Resources
• Food Agric. Policy Research Institute (FAPRI)
• MFA, Inc. Cooperative
• Clarence Cannon Wholesale Water Commission