Implementation of In-Stream, Streambank and Riparian Practices in Conjunction with Upland Practices for Conservation of Water Resources
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This document describes a research project that aims to identify cost-effective combinations of upland, in-stream, streambank, and riparian conservation practices to reduce sediment loads and protect water resources in the Fort Cobb watershed in Oklahoma. The research uses biophysical modeling, economic analysis, and social surveys. Key activities included characterizing streambanks, modeling bank erosion rates, estimating costs and sediment reductions of stabilization practices, and determining farmer motivations for adopting conservation practices. The goal is to develop a prioritization scheme to target specific practices to locations where they can most effectively improve long-term water quality.
Implementation of In-Stream, Streambank and Riparian Practices in Conjunction with Upland Practices for Conservation of Water Resources
- 1. Implementation of In-Stream, Streambank and Riparian Practices in Conjunction with Upland Practices for Conservation of Water Resources G.A. FOX1, D.E. STORM1, J.R. VOGEL1, T. BOYER2, L. SANDERS2, A. STOECKER2, P. STARKS3, D. MORIASI3, J. STEINER3 1 DEPARTM ENT OF BIOSYSTEMS AND AGRICULTURAL ENGINEERING, OKLAHOM A STATE UNIVERSITY, STILLWATER, OK 2 AGRICULTURAL ECONOMICS, OKLAHOM A STATE UNIVERSITY, STILLWATER, OK 3 USDA-ARS GRAZINGLANDS RESEARCH LABORATORY, EL RENO, OK
- 2. Overall Hypothesis Integrated watershed-scale biophysical and socioeconomic research, combined with outreach and educational activities, can effectively identify the most likely to be implemented, cost-effective, and ecologically-beneficial suite of upland, in- stream, streambank and riparian conservation practices to reduce sediment loads and protect long-term water availability even under increased climate variability.
- 4. Fort Cobb Watershed •Reservoir provides public water supply, recreation, and wildlife habitat •Winter wheat and small grains (43%), pasture/grass (34%), peanuts and cotton (9%), forest (5%), other summer crops (4%), roads and urban (5%), and water (<2%) •Fails to meet water quality standards based on sediment and trophic level
- 5. Conservation Practices •Adoption of no-tillage management, conversion of cropland to grassland, cattle exclusion from streams •Various structural and water management practices • From 1992 to 2004, conventional tillage in the watershed decreased from 71 to 44% •Concerns about sedimentation of the reservoir persist • Majority of the sediment originating from streambanks and channels • Using 7Be and 210Pb as radionuclide tracers, as much as 50% of suspended sediment was from streambanks
- 6. Objectives •Biophysical Research: To develop a prioritization scheme using process-based simulation modeling that determines both where to implement upland, in- stream, streambank, and riparian practices and also how many stream miles, in conjunction with upland practice scenarios, require practices at a watershed scale to reach long-term water quality improvements.
- 7. Biophysical Objective Stream Channel Tasks •Characterize streambeds and unstable streambanks, install water level loggers, and conduct cross-section surveys •Estimate streambed and streambank erosion/failure resistance using JETs and BSTs •Estimate long-term erosion rates using aerial photography •Determine optimal in-stream, streambank, and riparian practices based on the site and reach scale bank erosion modeling
- 9. Cross-Section and Profile Surveys •At least one cross-section was surveyed at each site, as well as a longitudinal profile during Summer 2014 •Multiple cross-sections were surveyed at site FM2 • Impacted by a series of three headcuts •Cross-sectional surveys were repeated in Summer 2015 and Spring 2016
- 10. Station (ft) 0 20 40 60 80 Elevation(ft) 86 88 90 92 94 96 98 100 July 2015 July 2014
- 11. Station (ft) 0 10 20 30 40 50 60 Elevation(ft) 80 82 84 86 88 90 92 94 96 98 July 2015 July 2014
- 12. Station (ft) 0 20 40 60 80 Elevation(ft) 80 82 84 86 88 90 92 94 96 98 July 2014 July 2015 Station (ft) 0 10 20 30 40 50 60 70 Elevation(ft) 82 84 86 88 90 92 94 96 98 July 2015 July 2014
- 13. Thalweg Profile Change-FM2 Station (m) 0 50 100 150 200 250 300 Elevation(m) 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 June 2015 July 2014
- 14. Site-Scale Bank Erosion Modeling: BSTEM •BSTEM simulations were developed and calibrated for 8 sites •SWAT generated hydrograph for a 2003- 2013 study period was used •Long-term erosion rates were determined from NAIP images from 2003-2013 and used to calibrate the model •Only four sites experienced erosion during the study period •Stabilization practices were simulated at these sites
- 15. Sediment reduction from stabilization
- 16. Stabilization Costs and Returns
- 17. Reach-Scale modeling: CONCEPTS •CONservational Channel Evolution and Pollutant Transport System (CONCEPTS) •Simulates: • Open-channel hydraulics • Sediment transport • Bank erosion processes • Fluvial erosion • Mass wasting (Langendoen, 2000)
- 18. Reach-Scale Sediment Reductions •Stream divided into segments based upon landowner •Stabilization was applied to various stream segments and combinations of segments •Stabilization practices simulated include: • Riprap Toe • Grade Control • Vegetation and Grading (2:1 and 3:1) bank slopes •Generated relationships between length of stream stabilized and sediment reduction for each stabilization practice
- 19. Grade Control Stabilization Length/Total Length 0.0 0.2 0.4 0.6 0.8 1.0 SedimentReduction -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 95% Confidence Interval 95% Prediction Interval
- 20. Stabilization Length/Total Length 0.0 0.2 0.4 0.6 0.8 1.0 SedimentReduction -0.2 0.0 0.2 0.4 0.6 0.8 1.0 95% Confidence Interval 95% Prediction Interval Riprap Toe
- 21. Vegetation + 2:1 Bank Slopes Stabilized Length/Total Length 0.0 0.2 0.4 0.6 0.8 1.0 SedimentReduction 0.0 0.2 0.4 0.6 0.8 1.0 95% Confidence Interval 95% Prediction Interval
- 22. Vegetation + 3:1 Bank Slopes+ Riprap Toe+ Grade Control Stabilized Length/ Total Length 0.0 0.2 0.4 0.6 0.8 1.0 SedimentReduction 0.0 0.2 0.4 0.6 0.8 1.0 95% Confidence Interval 95% Prediction Interval
- 23. Cost Estimation RSMEANS Facilities Construction Cost Data from 2016 Stabilized Length/Total Length 0.0 0.2 0.4 0.6 0.8 1.0 Cost($) 0 500000 1000000 1500000 2000000 95% Confidence Interval 95% Prediction Interval Stabilization Length/Total Length 0.0 0.2 0.4 0.6 0.8 1.0 SedimentReduction -0.2 0.0 0.2 0.4 0.6 0.8 1.0 95% Confidence Interval 95% Prediction Interval Riprap Toe
- 24. Objectives •Economics and Social Research: • Cost Estimation of gulley and channel erosion abatement structures • Location of farms with sufficient areas of erodible soils for contour, no-till farming • SWAT and mathematical programming for cost-effective selection and BMPs to reduce edge-of-field erosion • Determine socio-economic characteristics that influence adoption of conservation practices
- 25. Spreadsheet: Cost Estimation of Gulley Abatement Structures •Estimate of BMP costs for Reducing Channel Erosion. •Basic Data Requirements: Gulley Width and Depth, RS MEANS Cost Estimates •BPM worksheets prepared for Cross Vanes, Cement Spillway, Vegetated Bank, J-Hook Vane, Live Gulley, Stream Crossing, Small Dam, and Grassed Waterway •STATUS: Testing and Validation
- 26. Example Sheet for NRCS Rip-Rap Drop Chute
- 27. Location of Farms with Sufficient Areas of Erodible Soils for Contour No-till Farming to be Cost Effective •Ho: Per Acre No-till Costs decline with Increasing Crop area of Erodible Soils in each Farm. •EPIC used to Estimate Erosion and Yield by Tillage method by Slope for 15 SURGGO Soil Types. •GIS Delineated Farms by Owner in Willow Creek Sub-watershed, Area of Crops Tabulated for each farm by soil type and slope. •Linear Programming used to Maximize Net Farm Income from the Willow Creek basin subject to upper total limits on soil erosion. •Results Indicate Location of Farms with sufficient combination and area of erodible soils for adoption of No-till and contour farming practices •Status: MS thesis nearly complete
- 28. SWAT and Linear Programming for Cost Effective Selection and Location of BMPs to Reduce Edge-of-Field Erosion Five Mile and Willow Creek Subbasins of Fort Cobb Watershed. Used 2-meter Lidar elevation to create drain lines and locate broken terraces. Calibrated SWAT with HRUs adjusted for terrace condition BMPs evaluated are Notill, Contour Notill, terrace repair, cropland to grassland, pasture management. Linear programming used to maximize watershed net farm income subject to Edge of Field limits on soil erosion. Status: SWAT Simulations in Process
- 29. Landowner Surveys •Determine socio-demographic characteristics that lead to conservation program enrollment in the Ft. Cobb watershed •Determine socio-demographic characteristics that lead to conservation practice adoption in the Ft. Cobb watershed •Rankings for reasons to adopt soil and water conservation practices 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 BenefitsFarm Ecosystem Increases Profit Government Subsity Neighbor showed it works Practice Benefits Downstream Farmer Absentee Landowner
- 30. Conclusions from Landowner Surveys •Significant findings for the Enrollment model in the Ft. Cobb Watershed are: •Farms with higher total farm revenues are more likely to enroll in a conservation program •Female producers are more likely to enroll than males •Those who have attained formal education levels beyond high school are more likely to enroll •Ones attitude or definition of stewardship plays into enrollment decisions •Significant findings for the Count Model are: •The higher the percentage of a producers total income that is derived from farming the more practices they are likely to adopt •Female farmers are also more likely to adopt practices than male producers •The more informational sources one uses for conservation decisions increases the number of practices adopted •Farmers who believe that stewardship is more than just protecting the profitability of their land will adopt more practices (renting vs. owning)
- 31. Extension and Education Activities • A one-day stream restoration workshop by Dr. Doug Shields • more than 50 attendees including government agencies and consulting firms. • A field methods course on rapid geomorphic assessments of stream systems in summer 2016 to eight grad students • taught in summer 2016 to eight graduate students in multiple disciplines. • Annual student water conference with students from across the U.S. • Materials from this workshop and course will be used for future Extension programming. • K-12 demonstrations with the OSU stream trailer to an Environmental Science class at El Reno High School (in the watershed)
- 32. Acknowledgements Funding from Agriculture and Food Research Initiative Competitive Grant no. 2013-51130-21484 from the USDA National Institute of Food and Agriculture.
- 34. Field data collection •HOBO Water level Loggers •Jet erosion tests (JETs) •Bed and bank soil samples •Soil layering •Geotechnical parameters based on soil texture •Cross-sectional survey
- 35. Quantifying Erodibility •Estimate streambed and streambank erosion/failure resistance using JETs and BSTs •Excess shear stress equation - commonly used to model the erosion rate of cohesive soils: o Critical shear stress (tc) o Erodibility coefficient (kd ) er = kd (t – tc)a a = 1
- 36. Adjusting Erodibility Parameters ◦ Vegetation or meanders can impact applied shear stress ◦ Vegetation reduces particle shear stress by 13%-89% (Thompson et al., 2004) ◦ Used α- factor to adjust applied shear stress to account for vegetation 𝜀 𝑟 = 𝑘 𝑑 ατ − 𝜏 𝑐 = α𝑘 𝑑 τ − 𝜏 𝑐 α
- 37. BSTEM Calibration Results Aerial Retreat BSTEM Retreat Monitoring Site (m) (m) α c' Manning's n FM1 0.0 0.0 0.01 Default 0.010 FM2 5.0 6.7 0.18 Default 0.010 FM3 12. 0 ϯ 15.6 0.04 Adjusted 0.010 FM4 0.0 0.0 0.05 Adjusted 0.010 FM5 11. 3§ 11.6 0.08 Adjusted 0.010 WC1 0.0 2.0 0.02 Adjusted 0.010 WC2 0.0 0.0 0.20 Default 0.010 WC3 8.6 3.2 0.01 Adjusted 0.010
- 38. Model setup •10.25-km reach of Fivemile Creek •Input data • 11 surveyed cross-sections • 29 cross-sections from LiDAR •τc and kd randomly generated LiDAR Cross-sections •SWAT Generated hydrograph for 2008-2013 Station (m) 420 440 460 480 500 520 540 560 580 Elevation(m) 430 432 434 436 438 440 LiDAR Surveyed Smoothed and Merged
- 39. Calibration ◦ Water depth from HOBO loggers ◦ Mannings’n Aerial Retreat ◦ NAIP images 2008-2013 ◦ τc and kd
- 40. River Kilometer 0 2 4 6 8 10 12 BankRetreat(m) 0 2 4 6 8 10 12 14 Aerial Retreat CONCEPTS Predicted Retreat Calibration Cross-section α-factor FM1 0.01 FM2 0.1-0.5* FM3 0.27 FM4 0.6 FM5 0.2 LiDAR cross- sections 0.01-2 FM5 FM3FM2
- 41. Location of Farms with Sufficient Areas of Erodible Soils for Contour Notill Farming to be Cost Effective •Ho: Per Acre NoTill Costs decline with Increasing Crop area of Erodible Soils in each Farm. •EPIC used to Estimate Erosion and Yield by Tillage method by Slope for 15 SURGGO Soil Types. •GIS Delineated Farms by Owner in Willow Creek Sub-watershed, Area of Crops Tabulated for each farm by soil type and slope. •Linear Programming used to Maximize Net Farm Income from the WC basin subject to upper total limits on soil erosion. •Results Indicate Location of Farms with sufficient combination and area of erodible soils for adoption of NoTill and Contour farming practices •Status: MS thesis nearly complete