• The goal = “No Bad Water” • TMDL Intro• S.W.Q. and BASINS 2.0• Model Application(s)• Model Limitations• Future Work

Con

cent

rati

on

Daily Load

Standard

TMDL ActualTMDL Used

TMDLs - Total Maximum Daily Loads

Maximum daily pollutant load to a waterbody whilestill meeting all applicable state water quality standards

TMDL Used = (TMDL Actual) x (Safety Factor)

TMDL Actual = (Standard) x (Waterbody Volume)

Section 303(d)1 of 1987 Clean Water Act - Mandates TMDLs

Texas Natural Resource Conservation Comission (TNRCC)

Surface Water Quality and BASINS 2.0

• EPA Program - HSPF• Supports modeling:

• Non-point sources

• Permitted discharges

• Hypothetical discharges

• Land use changes

• EPA Database• Total US coverage

• Site specific data

BASINS 2.0 TMDL Model Applications

TNRCC Group C – Study Area

BASINS 2.0 TMDL Model Applications

Study Area Rivers + Waterbodies

BASINS 2.0 TMDL Model Applications

TNRCC FY99 TMDL Segments

BASINS 2.0 TMDL Model Applications

Delineated Watersheds for Segments

BASINS 2.0 TMDL Model Applications

Run NPSM on selected Watersheds

BASINS 2.0 TMDL Model Applications

Initial Results(mythical)

Results after inputModification

(mythical)

BASINS 2.0 TMDL Model Applications

NEW TMDL

BASINS 2.0 TMDL Model Limitations

• NPSM is Mysterious!!• We are not yet BASINS masters

• NPSM does not model lakes/reservoirs

• BASINS 2.0 – No grids• Import watersheds derived w/ CRWR PRE-PRO

or

• Hand delineate watersheds (accuracy? repeatability?)

• Model Calibration – • Does output compare w/ field measurements?

• Site specific data

Future Work (i.e. Project + Master’s Thesis)

•Use BASINS 2.1 – Available Jan 2000

•Supports Spatial Analyst

•Other S.W.Q. models, TMDL applications:•WEPP •QUAL-TX

•PRSM •WASP

•CE-QUAL-W2

• Model Calibration - TNRCC Group C Basins + Texas

•Watershed Delineation - w/ higher resolution DEM

•Lakes, Bays, Estuaries, etc. ??•Corpus Christie Bay approach – Mass Balance