Leona River Potential Loads and Sources for Bacteria and Nitrates Texas Institute for Applied Environmental Research Stephenville, Texas June 4, 2013

Lead Agency - Texas Soil & Water Conservation Board Support provided by Nueces River Authority Texas A&M Dept Soil & Crop Sciences & Spatial Sciences Laboratory Acknowledgements

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

USGS TCEQ 12988/12989 USGS TCEQ USGS TCEQ Locations for Load Duration Curve Development

Load Duration Curves Allowable or desired concentration Primary Contract Recreation Standard E. coli 126 cfu/100 mL 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 Percent Time Exceeded High Flows0-10% Moist Conditions10-40% Mid-Range Conditions40-60% Dry Conditions60-90% Low Flows90-100%

Use of LDCs for Source Identification Source Graphic: The Kansas Department of Health and Environment High Flows Mid- Range DryLow Flows Moist

FDC Leona River near Uvalde 1970 – 2010

LDC E. coli - Leona River near Uvalde Criterion 126 cfu/100 mL

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.

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 Curve - Summary

Questions ??s Load Duration Curves

SELECT ( S patially E xplicit L oad E nrichment C alculation T ool) – 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 Modeling Bacteria Sources

Identifies POTENTIAL bacteria loadings by subwatershed Based on spatial data, such as: – Land use – Soils – Stream network – Animal density – Population information SELECT

Spatial Science Laboratory Texas A&M University in College Station Satellite imagery Aerial photos Ground control points Ground verification

Population & Household Densities – Census data Livestock Densities – County Agricultural Statistics (USDA) Wildlife – Resource Experts (TPWD & others) Domestic & Feral Animals – Resource Experts (TPWD & others) Input Data

Wastewater Treatment Facilities – Uvalde – Batesville – US Fish & Wildlife Service National Fish Hatchery Concentrated Animal Feeding Operations – Chaparral Cattle Feedlot (Uvalde) – Live Oak Feedlot (Batesville) Permitted Facilities

98% 99.8% 2% 68% 95% 32% 5% 4% 11% 84% 80% 17% 2%

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 1E10 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 10E10 cfu/animal/day

Input Fecal Production Rate Cattle 10E10 cfu/animal/day Cattle distributed on Grassland Herbaceous and Pasture/Hay Cattle #s in Leona Uvalde 5,516 Zavala 10,566 Frio 6,418

Feral Hog #s in Leona 21,462 Input Fecal Production Rate Feral Hogs 1.1E10 cfu/animal/day Feral Hogs distributed on 100 meter buffer of stream in non-developed areas

Input Fecal Production Rate Sheep/Goats 1.2E10 cfu/animal/day Sheep/Goats distributed on Grassland Herbaceous, Pasture/Hay, Shrubland & Woodland Sheep/Goats #s in Leona Uvalde 8,055 Zavala 1,269 Frio 168

Deer #s in Leona 16.8/1,000 acres Input Fecal Production Rate Deer 3.5E8 cfu/animal/day Deer distributed on Near-Riparian Forest, Shrubland & Woodland

Dog #s in Leona 1.6/household Input Fecal Production Rate Dogs 5.0E9 cfu/animal/day Homes in each subbasin based on 2010 Census Block Data

Masks out areas covered by public wastewater service areas Homes in each subbasin based on 2010 Census Block Data Uses NRCS Soils Data to define Septic Drainage Limitation Class Effluent Rate 10E6 cfu/100 mL with discharge of 60 gal/person/day for systems on soils with septic limitations

Urban Discharge (MGD) Uvalde WWTF outfall # Uvalde WWTF outfall # Uvalde WWTF outfall # Batesville0.184 Fish Hatchery0.8 Effluent EC rate based on 126 cfu/100 ml

SELECT does not yet handle Exotics Small wildlife (birds, raccoons, etc) Sources not included

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 Office Phone: Anne McFarland Office Phone:

Questions? Thank You Anne McFarland Texas Institute for Applied Environmental Research