Baffaut sadler-ten years of watershed assessment
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Transcript of Baffaut sadler-ten years of watershed assessment
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Developing and Testing Tools to Improve Targeting of Conservation
Programs and PracticesClaire Baffaut & E. John Sadler
SWCS ‐ Annual International Meeting ‐ July 2014
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Context
Problem• Erosion and pollutant transport continues in spite of significant implementation of management practices
Causes• changes in land use, • changes in management,
• climate change, • but also sub‐optimal placement of BMP in the agricultural landscape
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Vulnerability, practice & effectiveness
Excellent PoorVu
lnerable Resilien
t
Zero effect
Little effect
Little effect
Maximum effect
After Nowak and Cabot, JSWC, 59(6), 2004
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What is targeting?
Geographic targeting Benefit/cost targeting• Areas with the greatest
potential improvement per dollar spent
• Most vulnerable areas– Soil, land use, topography
• Most pristine areas– Management
• Areas with the greatest potential improvement– Soil, land use, topography,
and management
(After World Resource Institute presentation by Michelle Perez)
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Conclusions from WRI study
Compared to current BMP implementation strategy, Benefit/Cost targeting is:
– 12 times more effective for reducing N – 8 times more effective for reducing P– 8 times more effective for reducing sediment– 7.5 times more effective for sequestering carbon
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How do we solve the problem?
Required Characteristics
• Validated• Accurate• User friendly
Tools• Policy: voluntary vs mandatory
• Technical tools:– Identify vulnerable areas– Identify areas with potential environmental improvement
• Optimization tools
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• Review selected targeting tools and their validation techniques
• Identify gaps and next steps
Objectives
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The topographic index (TI)
• Cornell group [Lyons et al. Hyd. Proc. 18.2004]• Identify areas with high probability of saturation in a setting characterized by permeable soils on top of a restrictive layer.
• The most validated index?
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Validation of the Topographic Index
• Comparison of predicted and observed (GPS located) saturated areas in a small watershed (2 km2).
• Additional corroboration by comparison with thermal images that qualitatively approximate wet areas in that same watershed.
• Comparison of high saturation probability with piezometer data (different watershed).
From Lyons et al. Hydrol. Processes 18, 2757–2771 (2004)
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Other existing targeting tools• Hydrology characterization tool (HCT, Brooks and Boll group, U of Idaho)
• Water input index (WII) and sediment retention index (SRI, Dosskey, Forest Service, Nebraska)
• Pesticide index (Shea group, U of Nebraska)• Conductivity claypan index (CCI, Baffaut, Missouri)• Soil vulnerability index (SVI, NRCS)
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Validation Techniques
Tool
• HCT
• WII and SRI
• Pesticide Index
• CCI
• SVI
Validation method1. Professional judgment2. Qualitative comparison to
aerial photos3. Comparison to other
indices4. Comparison to model
results5. Limited comparison to data
1, 5
1,2,3
1,5
1,2,4
1,2,3,4
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Summary:Targeting index evaluation methods• Expert knowledge of an area• Overlay with aerial photos• Comparison to other index methods• Comparison to model results in test case• Comparison to field data in test case
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Gaps / Limitations
• Spatial analysis tools to identify visible critical areas in aerial photos.
• Tools for spatial comparison of maps.• Identification of non‐visible critical areas?• What is the accuracy of models in simulating effectiveness of practices?
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Next steps
• Evaluate models’ accuracy in simulating BMP effects when calibrated in the absence of a BMP.
• Develop and use advanced spatial and GIS analysis tools
• Conduct experimental work to test the validity of targeting.