Leona River Potential Loads and Sources for Bacteria
Leona River Potential Loads and Sources for Bacteria and Nitrates Texas Institute for Applied Environmental Research Stephenville, Texas June 4, 2013
Acknowledgements • Lead Agency Texas Soil & Water Conservation Board • Support provided by Nueces River Authority Texas A&M Dept Soil & Crop Sciences & Spatial Sciences Laboratory
Modeling to Evaluate Water Quality and Sources • Load Duration Curves (LDCs) • SELECT (Spatially Explicit Load Enrichment Calculation Tool)
Load Duration Curves (LDCs) Purpose: • To define flow conditions under which desired loads are exceeded • Define potential load reductions
Load Duration Curves LDCs use the following: • Daily stream flow data • Allowable or desired concentration • Measured concentrations and flows
Locations for Load Duration Curve Development USGS 8204005 TCEQ 12988/12989 USGS 8204250 TCEQ 12987 USGS 8204500 TCEQ 12985
Load Duration Curves Allowable or desired concentration Primary Contract Recreation Standard E. coli 126 cfu/100 m. L General Use Screening Level Nitrate 1. 95 mg/L
Assessment Bacteria
Assessment Nitrates
Load Duration Curves Steps 1. Develop Flow Duration Curve (FDC) (time history of daily flow data) 2. Calculate allowable loads (criterion or screening level) 3. Estimate measured loads (measured concentrations and flow) 4. Compare measured to allowable loads
Flow Duration Curves (FDCs) • Daily stream flows for a given time period ranked highest to lowest Flow Condition High Flows Moist Conditions Mid-Range Conditions Dry Conditions Low Flows Percent Time Exceeded 0 -10% 10 -40% 40 -60% 60 -90% 90 -100%
Use of LDCs for Source Identification High Flows Moist Source Graphic: http: //www. kdheks. gov/tmdl/basic. htm#data The Kansas Department of Health and Environment Mid- Dry Low Range Flows
FDC Leona River near Uvalde 1970 – 2010
LDC E. coli - Leona River near Uvalde Criterion 126 cfu/100 m. L
Potential Reductions % Reduction = (Allowable – Measured) Measured * 100 Averaged by Flow Category
LDC E. coli Leona River near Uvalde
Average Percent Reduction E. coli NA indicates not applicable, because most low flows were zero flow.
LDC Nitrates Leona River near Divot E. coli data 1972 – 2012
Average Percent Reduction Nitrate NA indicates not applicable, because most low flows were zero flow.
Load Duration Curve - Summary Potential Reductions Needs • Bacteria & Nitrate – primarily at higher flows associated with rainfall-runoff • Bacteria – lower flows indicated near Batesville • Nitrates – lower flows indicated near Divot
Load Duration Curves Questions ? ? s
Modeling Bacteria Sources SELECT (Spatially Explicit Load Enrichment Calculation Tool) – Developed by Dept. of Biological and Agricultural Engineering and Spatial Sciences Laboratory at Texas A&M University by Dr. R. Karthikeyan, Dr. R. Srinivasan and others
SELECT • Identifies POTENTIAL bacteria loadings by subwatershed • Based on spatial data, such as: – Land use – Soils – Stream network – Animal density – Population information
Spatial Science Laboratory Texas A&M University in College Station • Satellite imagery • Aerial photos • Ground control points • Ground verification
Input Data • Population & Household Densities – Census data • Livestock Densities – County Agricultural Statistics (USDA) • Wildlife – Resource Experts (TPWD & others) • Domestic & Feral Animals – Resource Experts (TPWD & others)
Permitted Facilities • Wastewater Treatment Facilities – Uvalde – Batesville – US Fish & Wildlife Service National Fish Hatchery • Concentrated Animal Feeding Operations – Chaparral Cattle Feedlot (Uvalde) – Live Oak Feedlot (Batesville)
17% 2% 2% 80% 11% 4% 98% 84% 99. 8% 32% 68% 5% 95%
CAFOs Chaparral Cattle Feedlot south of Uvalde (10, 000 permitted head) Live Oak Feedlot southeast Batesville (8, 000 permitted head) Input E. coli production rate 1 E 10 cfu/animal/day assuming “treatment” efficiency of 80%
Cattle #s in Leona Uvalde 5, 516 Zavala 10, 566 Frio 6, 418 Input Fecal Production Rate Cattle 10 E 10 cfu/animal/day
Cattle #s in Leona Uvalde 5, 516 Zavala 10, 566 Frio 6, 418 Cattle distributed on Grassland Herbaceous and Pasture/Hay Input Fecal Production Rate Cattle 10 E 10 cfu/animal/day
Feral Hog #s in Leona 21, 462 Feral Hogs distributed on 100 meter buffer of stream in non-developed areas Input Fecal Production Rate Feral Hogs 1. 1 E 10 cfu/animal/day
Sheep/Goats #s in Leona Uvalde 8, 055 Zavala 1, 269 Frio 168 Sheep/Goats distributed on Grassland Herbaceous, Pasture/Hay, Shrubland & Woodland Input Fecal Production Rate Sheep/Goats 1. 2 E 10 cfu/animal/day
Deer #s in Leona 16. 8/1, 000 acres Deer distributed on Near-Riparian Forest, Shrubland & Woodland Input Fecal Production Rate Deer 3. 5 E 8 cfu/animal/day
Dog #s in Leona 1. 6/household Input Fecal Production Rate Dogs 5. 0 E 9 cfu/animal/day Homes in each subbasin based on 2010 Census Block Data
Homes in each subbasin based on 2010 Census Block Data Masks out areas covered by public wastewater service areas Uses NRCS Soils Data to define Septic Drainage Limitation Class Effluent Rate 10 E 6 cfu/100 m. L with discharge of 60 gal/person/day for systems on soils with septic limitations
Discharge Urban (MGD) Uvalde WWTF outfall #1 0. 2604 Uvalde WWTF outfall #2 0. 6138 Uvalde WWTF outfall #3 0. 0558 Batesville 0. 184 Fish Hatchery 0. 8 Effluent EC rate based on 126 cfu/100 ml
Sources not included SELECT does not yet handle • Exotics • Small wildlife (birds, raccoons, etc)
SELECT • Indicates potential loadings based on a “worst case” scenario • Highlight “hot spots” to consider for control efforts • These are preliminary results open to stakeholder feedback
Contact Information Nikki Jackson Email: njackson@tiaer. tarleton. edu Office Phone: 254. 968. 1920 Anne Mc. Farland Email: mcfarla@tiaer. tarleton. edu Office Phone: 254. 968. 9581
Questions? Thank You Anne Mc. Farland Texas Institute for Applied Environmental Research mcfarla@tiaer. tarleton. edu 254. 968. 9581
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