Potential and Performance of Riparian Buffers as BMPs in Hawaiian Watersheds Ali Fares Watershed Hydrology, NREM-CTAHR- UH...
Outline <ul><li>Introduction </li></ul><ul><li>What are Riparian buffers? </li></ul><ul><li>Benefits of buffers </li></ul>...
Non-point source pollution <ul><li>Land-based pollutants are identified as the primary threat to Hawaii water resources an...
<ul><li>Reducing erosion in land and containing eroded material on site would substantially minimize these negative effect...
<ul><li>Buffers are areas of permanent vegetation adjacent to water bodies. </li></ul><ul><li>They are managed for the pur...
Buffer types <ul><li>Riparian buffer  : a band of trees, shrubs, or grasses that border a body of water. </li></ul>06/02/0...
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 <ul><li>Two approaches for buffers design </li></ul><ul>...
Why Variable/Precision Buffers? <ul><li>Using constant buffers, we are assuming that riparian areas receive runoff in a un...
Fixed width buffer <ul><li>Uniform runoff flow needs a fixed width buffer </li></ul>06/02/09 Fares, Hawaii Water Qualtiy C...
Fixed width buffer <ul><li>Non-uniform runoff flow should not be dealt with a fixed width buffer </li></ul>06/02/09 Fares,...
Site topography 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Slope, %    Width, ft 8% 100 20% 125 25%...
Variable width buffer <ul><li>Non-uniform runoff flow should be dealt with a variable width buffer </li></ul>06/02/09 Fare...
Variable width buffer 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Basics of precision buffer design ...
<ul><li>There is a need for precision buffers in Hawaii because of: </li></ul><ul><li>Steep slopes, </li></ul><ul><li>Limi...
DEM and Rain Spatial Distribution 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
Spatial distribution of Runoff & Sediment 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
Buffer width  06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Buffer width is function of desired functi...
Case Studies <ul><li>Effect of width of fencing, riparian buffer width and plant types (native and invasive) on the perfor...
Goal of the Project <ul><li>Stream rehabilitation using native riparian plant species as buffer zones to decrease: </li></...
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
Removal of invasive species 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
Native Plant Used 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Overview of the study site Kaika-Wailua Watershed (Oahu’...
Case study 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 <ul><li>The soil: Ewa Silty clay </li></ul><u...
Materials and Methods 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Results: Sediment Sunn hemp Oats Fallow Sudex
<ul><li>Significant affect of treatments on TSS </li></ul><ul><li>Every cover significantly reduced TSS as compared to fal...
06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 B A B B
Results <ul><li>The Presence of a cover crop reduced the Total Suspended Sediment, on average by at least 74% compared to ...
<ul><li>Hawaiian watersheds are facing the problem of non-point source pollution which pose human and ecosystem health ris...
Mahalo!  Do You have any questions? 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
High turbidity threatening coral reefs 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 25-27 2007 11&quot; of Rain ...
Outline <ul><li>Introduction </li></ul><ul><li>What are Riparian buffers? </li></ul><ul><li>Benefits of buffers </li></ul>...
Benefits of Riparian Buffers <ul><li>Numerous studies have shown the effectiveness of riparian buffers in reducing sedimen...
Economic benefits 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Benefits to the Farmers  <ul><li>Ripar...
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Potential & Performance of Riparian Buffers as BMPs in Hawaii Watersheds

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By Dr. Ali Fares
Department of Natural Resources & Environmental Management, UH Manoa
Hawaii Water Quality Conference 2008

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  • Potential & Performance of Riparian Buffers as BMPs in Hawaii Watersheds

    1. 1. Potential and Performance of Riparian Buffers as BMPs in Hawaiian Watersheds Ali Fares Watershed Hydrology, NREM-CTAHR- UH Manoa. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    2. 2. Outline <ul><li>Introduction </li></ul><ul><li>What are Riparian buffers? </li></ul><ul><li>Benefits of buffers </li></ul><ul><li>Why precision buffers? </li></ul><ul><li>2 Case studies </li></ul><ul><li>Conclusions </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    3. 3. Non-point source pollution <ul><li>Land-based pollutants are identified as the primary threat to Hawaii water resources and its coastal coral reef ecosystems. </li></ul><ul><li>Sediment and pollutant loads from different sources are the major causes. </li></ul><ul><li>These pollutants pose human and ecosystem health risks. </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    4. 4. <ul><li>Reducing erosion in land and containing eroded material on site would substantially minimize these negative effects. </li></ul><ul><li>Riparian buffers were introduced since 1960s as practical conservation management practices to mitigate the impact of agricultural operation on their surrounding environments (lakes, stream, ocean, etc…) </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    5. 5. <ul><li>Buffers are areas of permanent vegetation adjacent to water bodies. </li></ul><ul><li>They are managed for the purpose of filtering pollutants from runoff or ground water. </li></ul>Riparian buffers 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    6. 6. Buffer types <ul><li>Riparian buffer : a band of trees, shrubs, or grasses that border a body of water. </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Riparian buffers Vegetative buffer strips <ul><li>Vegetative buffer strips : It is a gently sloping area of vegetative cover </li></ul>
    7. 7. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 <ul><li>Two approaches for buffers design </li></ul><ul><li>Fixed width buffer (standard) </li></ul><ul><li>Variable (precision) width buffers </li></ul>Buffer design Precision buffer Slope Fixed width buffer
    8. 8. Why Variable/Precision Buffers? <ul><li>Using constant buffers, we are assuming that riparian areas receive runoff in a uniform sheet flow under which the maximum buffer efficiency is observed. </li></ul><ul><li>However, Dosskey et al. (2002) showed that only 9-18% of the total buffers actually contacted runoff water </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    9. 9. Fixed width buffer <ul><li>Uniform runoff flow needs a fixed width buffer </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Dosskey et al. 2005
    10. 10. Fixed width buffer <ul><li>Non-uniform runoff flow should not be dealt with a fixed width buffer </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Dosskey et al. 2005
    11. 11. Site topography 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Slope, % Width, ft 8% 100 20% 125 25% 150 Source: The Maryland-National Capital Park and Planning Commission Width Width = 0.17slope 2 – 2.7slope + 111 (R 2 = 0.99) Slope
    12. 12. Variable width buffer <ul><li>Non-uniform runoff flow should be dealt with a variable width buffer </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Dosskey et al. 2005
    13. 13. Variable width buffer 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Basics of precision buffer design Dosskey et al. 2005
    14. 14. <ul><li>There is a need for precision buffers in Hawaii because of: </li></ul><ul><li>Steep slopes, </li></ul><ul><li>Limited and expensive land, </li></ul><ul><li>Specific vegetative species, </li></ul><ul><li>Availability of the necessary tools and technologies to implement them. </li></ul>Variable width or precision buffers 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    15. 15. DEM and Rain Spatial Distribution 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    16. 16. Spatial distribution of Runoff & Sediment 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    17. 17. Buffer width 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Buffer width is function of desired function (after A.H. Todd, 2000) Buffer width for nutrient removal is narrower than that for sediment removal Water Temperature Moderation Streambank Stabilization Nutrient Removal Sediment Removal Flood mitigation Wildlife habitat Buffer width (meters)
    18. 18. Case Studies <ul><li>Effect of width of fencing, riparian buffer width and plant types (native and invasive) on the performance of RBs and the water quality of adjacent stream. </li></ul><ul><li>Performance of Cover Crops as vegetative buffer strips to Control Water contaminants at the Source in Tropical Agricultural Land </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    19. 19. Goal of the Project <ul><li>Stream rehabilitation using native riparian plant species as buffer zones to decrease: </li></ul><ul><ul><li>Sediment loadings into stream surface water </li></ul></ul><ul><ul><li>microbial contamination to surface and groundwater systems due to cattle grazing, </li></ul></ul><ul><ul><li>decrease stream temperature. </li></ul></ul><ul><ul><li>Evaluate economical viability of these management practices. </li></ul></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    20. 20. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    21. 21. Removal of invasive species 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    22. 22. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    23. 23. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    24. 24. Native Plant Used 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    25. 25. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Overview of the study site Kaika-Wailua Watershed (Oahu’s north shore) Case study 2 Performance of Cover Crops as vegetative buffer strips to Control Water contaminants at the Source in Tropical Agricultural Land Vegetative buffer strips
    26. 26. Case study 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 <ul><li>The soil: Ewa Silty clay </li></ul><ul><li>Treatments: 4 (Sunn hemp, Sudex, Oats, Fellow) </li></ul><ul><li>RCBD with 3 replications. </li></ul><ul><li>Sediment collection in runoff </li></ul>Experimental design Collection bucket
    27. 27. Materials and Methods 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    28. 28. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Results: Sediment Sunn hemp Oats Fallow Sudex
    29. 29. <ul><li>Significant affect of treatments on TSS </li></ul><ul><li>Every cover significantly reduced TSS as compared to fallow. </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Case study Total Dissolved Sediment B A B B
    30. 30. 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 B A B B
    31. 31. Results <ul><li>The Presence of a cover crop reduced the Total Suspended Sediment, on average by at least 74% compared to the fallow treatment. </li></ul><ul><li>Sun hemp seems to add some of the nitrogen it fixes into the soil solution sample collected from the site; thus, it is not recommended to have it as a RB species. </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    32. 32. <ul><li>Hawaiian watersheds are facing the problem of non-point source pollution which pose human and ecosystem health risks </li></ul><ul><li>NPS pollutants runoff into streams, lakes, and wetlands </li></ul><ul><li>Cover crops reduce the NO 3 levels in the soil and sediment loads in the runoff water </li></ul><ul><li>Research is need on the implementation and performance of precision RB under Hawaii conditions. </li></ul>Conclusions 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    33. 33. Mahalo! Do You have any questions? 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    34. 34. High turbidity threatening coral reefs 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 25-27 2007 11&quot; of Rain 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    35. 35. Outline <ul><li>Introduction </li></ul><ul><li>What are Riparian buffers? </li></ul><ul><li>Benefits of buffers </li></ul><ul><li>Why precision buffers? </li></ul><ul><li>2 Case studies </li></ul><ul><li>Conclusions </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    36. 36. Benefits of Riparian Buffers <ul><li>Numerous studies have shown the effectiveness of riparian buffers in reducing sediment, pathogens, and nutrient loads into surface and groundwater in agricultural watersheds. </li></ul><ul><li>Reported retention rates of sediment, N and P were as high as 97%, 85%, and 84%, respectively. </li></ul><ul><li>RBs provide habitat for different organisms; they also reduce surface water temperature. </li></ul><ul><li>RBs serve recreational and aesthetical purposes. </li></ul>06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008
    37. 37. Economic benefits 06/02/09 Fares, Hawaii Water Qualtiy Conference, March 24-25 2008 Benefits to the Farmers <ul><li>Riparian buffer can be a source of stable income to farmers and landowners. </li></ul><ul><li>Various benefit programs across the States: </li></ul><ul><ul><li>Environmental Quality Incentive Program (EQIP) </li></ul></ul><ul><ul><li>Wildlife Habitat Incentive Program (WHIP) </li></ul></ul><ul><ul><li>Wetland Reserve Program (WRP) </li></ul></ul><ul><ul><li>Conservation Reserve Program (CRP) </li></ul></ul>

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