Nonpoint Source Pollution Some basic principles Example study of total pollution loads in the Corpus Christi Bay System (Ann Quenzer’s research) –rainfall-runoff relationship –point and nonpoint source loads –connection to bay water quality Example study of total pollution loads in the Copano Bay System (Carrie Gibson and Ernest To’s research) –Combination of spatial and statistical analysis

References CRWR Online Report 06-6: Bacterial Loadings Watershed Model in Copano Bay, Carrie Jo Gibson, David R. Maidment, and Mary Jo Kirisits, May 2006CRWR Online Report 06-6 CRWR Online Report 98-1: A GIS Assessment of the Total Loads and Water Quality in the Corpus Christi Bay System, Ann Marie Quenzer, and David R. Maidment, May 1998CRWR Online Report 98-1 Handbook of Hydrology: Sec 14.1 and 14.2 on nonpoint source pollution sources Handbook of Hydrology: Sec 28.6 on design for water quality enhancement (Handbook of Hydrology on reserve in Engr Library)

Adapt Water to the Land System Land Characterization (Land use, Soils, Climate, Terrain) Water Characterization (water yield, flooding, groundwater, pollution, sediment) Non Point Source Pollution (mean annual flows and pollutant loads)

Possible Land-Water Transform Coefficients Water Land

Expected Mean Concentration EMC = Load Mass/Flow Volume either on a single event basis or as an annual average QC TT L T EMC =M/V Flow ConcentrationLoad L(t)=Q(t)*C(t)

Map-Based Surface Water Runoff Runoff, Q (mm/yr) Precipitation, P (mm/yr) Accumulated Runoff (cfs) P Q Runoff Coefficient C = Q/P

Water Quality: Pollution Loading Module DEM Precip. Runoff LandUse EMC Table Concentration Load Accumulated Load Load [Mass/Time] = Runoff [Vol/Time] x Concentration [Mass/Vol]

Expected Mean Concentration Land Use EMC Table derived from USGS water quality monitoring sites

Total Constituent Loads Input for Water Quality Model Water Quality: Land Surface -Water Body Connection Bay Water Quality

Total Loads and Water Quality in the Corpus Christi Bay System Presented by: Ann Quenzer and Dr. David Maidment Special Thanks: Corpus Christi Bay National Estuary Program Ferdinand Hellweger Dr. Nabil Eid Dr. George Ward Dr. Neal Armstrong

Purpose To determine the rainfall/runoff relationship To estimate the point and non-point source loads to the bay system To quantify the relationship between the total loads and the bay system water quality

Basic Concept Point and Non-point Estimation Total Loads Routing Water Quality Calculate Flow and Total Loads Linkage of the Two Models Steady-State Model

Watershed Delineation Sub-Watersheds

Precipitation + = Precipitation Trend over Bay System Merged Precipitation Files Oregon State University Precipitation Data

Regression Inputs and Outputs

Surface Water Runoff

Mean Annual Runoff (mm/yr) Land Use + Precipitation

Precipitation and Runoff Gradient Precipitation and Runoff Gradient from South (A) to North (B) along the Bay System Precipitation and Runoff Gradient Locations in the South (A) and North (B)

Runoff Into Each Bay System Middle Bay System 24.5 m 3 /s 34% of total flow Entire Bay System = 72 m 3 /s North Bay System 40.5 m 3 /s 56% of total flow South Bay System 7 m 3 /s 10% of total flow

Bay System Water Balance Entire Bay System

Bay System Water Balance North Bay System Middle Bay System South Bay System

Purpose To estimate the point and non-point source loads to the bay system

Total Constituent Loading Land Surface Load Point Source Load Atmospheric Load ? Sediment Load ?

Land Surface Constituent Loading Load [Mass/Time] = Runoff [Vol/Time] x Concentration [Mass/Vol]

Land Use USGS Land Use (1970’s) Addition of Missing Land Use

Percent Land Use Total Study Area Legend

EMC Table

Point Sources Texas Natural Resources Conservation Commission (TNRCC) Water Quality Segmentation

Loads Routing

Load Routing Methodology

Total Constituent Loads Input for Water Quality Model Connection of Both Models Bay Water Quality

Total Load to Bay System

Atmospheric Contribution Total Nitrogen Atmospheric Load to Land Surface = 2,700 Kg/d which is 35% of Land Surface Load from agricultural land use. This calculation is made assuming the EMC of 4.4 mg/l for agriculture and a Nitrogen concentration of 1.1 mg/l in precipitation

Bay System Segmentation Segmentation Used in the CCBNEP Project Clipped Segmentation from Drs. Armstrong and Ward

Bay System Model Methodology.

Water Quality Analysis Salinity Concentration and Mass Fluxes in Corpus Christi Bay. Fluxes Flow of water Advection Dispersion Loads Transport of Constituents Finite Segment Analysis

Observed vs. Expected Total Phosphorus (mg/l) Total Nitrogen (mg/l)

Observed vs. Expected Oil and Grease (mg/l)Copper (µg/l)

Observed vs. Expected Zinc (µg/l)Chromium (µg/l)

Conclusions u Strong South-North gradient in runoff from the land surface u Nearly all water evaporates from bays, little exchange with the Gulf u Nonpoint sources are main loading source for most constituents u Nitrogen, phosphorus, oil & grease loads are consistent with observed concentrations in the bays u Metals loads from land account for only a small part of observed concentrations in bays – it was concluded later that metals concentrations were too high because the samples had not been obtained using “clean” sampling methods.

Bacterial TMDL Model for Copano Bay Research performed by Carrie Gibson and Ernest To at Center for Research in Water Resources Schematic processor tool developed by Tim Whiteaker at CRWR Research supported by Texas Commission for Environmental Quality

Presentation Outline Background Scope of Work Bacterial Loading Water Quality Model –Non-Point Source Bacterial Loading Calculations/Results –Point Source Bacterial Loading Calculations/Results –Modeling Bacteria Transport: Schematic Processor –Calibration of Model Conclusions Future Work

Project Location Copano Bay watershed Copano Bay

Background Section 303(d) of 1972 Clean Water Act (CWA) Texas Surface Water Quality Standards –Fecal coliform bacteria Oyster water use Contact Recreation Use Aransas River Mission River Copano Bay

Existing Monitoring Data

Scope of Work 1.Identify major bacterial sources in Copano Bay watershed. 2.Calculate total bacterial loadings, Total Maximum Daily Loads (TMDLs), from bacterial sources. 3.Determine amount of load reductions that is needed to meet water quality standards.

Potential Bacteria Sources Non-point bacteria sources Point sources –Concentrated Animal Feedlot Operations (CAFOs) –Livestock (cattle, goats, horses, sheep, hen, hogs, and chickens) –Wastewater Treatment Plants (WWTPs) –Septic Systems –Waterbirds

Non-Point Bacterial Loadings Basic Equation: L = Q * C L = Bacterial loadings (cfu/year) Q = Runoff (m 3 /year) C = Fecal coliform concentration (cfu/m 3 )

Runoff (Q) Calculations Rainfall-runoff equations derived by Ann Quenzer –Based on: land use and precipitation Precipitation Data (inches/year) Land Use Land Cover Data Runoff, Q (m 3 /year) Quenzer Equations

EMC (C) Calculations From Reem Jihan Zoun’s thesis, Estimation of Fecal Coliform Loadings to Galveston Bay Modified dbf table in order not to account for livestock fecal wastes twice Land Use Code CategoryFecal Colonies per 100 mL 11Open Water0 21Low Intensity Residential22,000 22High Intensity Residential22,000 23Commercial/Industrial/Transportati on 22,000 31Bare Rock/Sand/Clay0 32Quarries/Strip Mines/Gravel Pits0 41Deciduous Forest1,000 42Evergreen Forest1,000 43Mixed Forest1,000 51Shrubland2,500 61Orchards/Vineyards/Other2,500 71Grasslands/Herbaceous2,500 81Pasture/Hay2,500 82Row Crops2,500 83Small Crops2,500 85Urban/Recreational Grasses22,000 91Woody Wetlands200 92Emergent Herbaceous Wetlands

Creation of EMC Grid Land Use Land Cover Data Join based on land use code EMC dbf table Fecal Coliform Concentration, C (cfu/m 3 )

Non-Point Bacterial Loading Grid C (cfu/m 3 )Q (m 3 /year)L (cfu/year) * = Annual Bacterial Loading per Grid Cell

Non-Point Loading per Watershed Annual Bacterial Loading per grid cell (cfu/year) Zonal Statistics Annual Bacterial Loading per Watershed (cfu/year) Bacteria Monitoring Stations USGS Gauge Stations Water Segment Endpoints Watersheds Delineated Watersheds using WRAP Hydro

Point Source Calculations: Livestock Cattle, goats, horses, sheep, layers, hogs, chickens Data (annual animal count per county) from: –2002 Census of Agriculture, National Agricultural Statistics Service (NASS) –2004 Texas Livestock Inventory and Production, United States Department of Agriculture (USDA), NASS, Texas Statistical Office

Livestock Loading Results Results Add cfu/year to non-point bacterial loading calculations Livestock Bacterial Loadings Legend Animal_cfu_year 5.37e e e e e e e e e e+017

Point Source Calculations: Avian Texas Colonial Waterbird Census (TCWC) Breeding Pair LocationsLocations of Applied Avian Loads

Avian Loading Results Results Add cfu/year to non-point bacterial loading calculations Legend Birds_cfu_year 1.48e e e e e e e e e+011

Bacterial Loading to Watersheds Results Legend Livestock Non-Point Avian

Water Quality Model Runoff (m 3 /yr) Concentration (cfu/m 3 ) Load (cfu/year) Cumulative Loading per Watershed Cumulative Runoff per Watershed Schematic Processor Created Water Quality Model using Model Builder

Bacterial Loading Transport using Schematic Processor Creation of Schematic Network Watershed Drainage Junction Bay Watershed to Junction Junction to Junction Junction to Bay Reference: Whiteaker, T., D.R. Maidment, J. L. Goodall, and M. Takamatsu, “Integrating Arc Hydro features with a schematic network”, Transactions in GIS, Vol. 10, No. 2, pp , 2006

Schematic Processor Implements DLLs Dynamic linked libraries, DLLs –First-order decay Simulates decay of bacteria along stream segments load passed = load received * e -kt k = first-order decay coefficient (day -1 ) - stored as attribute in SchemaLink t = travel time along streams, t (days) - stored as attribute in SchemaLink Decay

Copano Bay acts as CFSTR –CFSTR Assumptions –Bay is completely mixed and acts as Continuous Flow, Stirred Tank Reactor (CFSTR) –Inflow = Outflow c = L/(Q+kV) c = concentration in bay (cfu/m 3 ) L = bacteria load entering bay (cfu/yr) Q = total flow (m 3 /yr) – stored as attribute in SchemaNode k = first-order decay coefficient (day -1 ) - stored as attribute in SchemaNode V = volume of bay (m 3 ) – stored as attribute in SchemaNode

Schema Links and Nodes

Computations along the network

Moving material through links and nodes

Processing Steps

DLL’s have the processes in them

Schematic Processor Parameters Parameters (Inputs) –SchemaLink (SrcTypes 1 and 2) Residence Time (  in days), Decay Coefficient (k in day -1 ) –SchemaNode SrcType 3 – Copano Bay –Volume (V in m 3 ), Decay Coefficient (k in day -1 ) –Cumulative Runoff (Q in m 3 /year) SrcType 1 – Watersheds –Bacterial Loading per Watershed (L in cfu/year) Determined by User Calculated from Previous Steps in Model Builder

Model Calibration: Aransas River Sta USGS Sta Sta Sta Sta Calibration Locations (Four)

Model Calibration: Aransas River Goal: Adjust upstream k and  values of each calibration location until median concentration of existing data is achieved. Then “set” k and  parameter values and work on the next downstream calibration location (bacteria monitoring station.) Nodes/Links’ parameters that can be varied for each bacteria monitoring station calibration

Modeled versus Existing Data Sta Existing F.C. Median: 260 cfu/100mL Modeled F.C. Median: 260 cfu/100 mL Sta Existing F.C. Median: 72 cfu/100 mL Modeled F.C. Median: 72 cfu/100 mL Sta Existing F.C. Median: 96 cfu/100 mL Modeled F.C. Median: 96 cfu/100 mL Copano Bay (Aransas R. Outlet) Existing F.C. Median: 2 cfu/100 mL Modeled F.C. Median: 2 cfu/100 mL

Modeled versus Existing Data

Conclusions Major point and non-point source bacterial loadings have been calculated. Bacterial Loadings Water Quality Model has been created. Model has been calibrated (adjusting k and  parameters) to existing median bacteria monitoring data. There is uncertainty in the calculations of bacterial loadings and in the determination of parameters.