Hidrologic and water quality modeling of sims bayou watershed using hspf

HYDROLOGIC AND WATER QUALITY MODELING OF SIMS BAYOU WATERSHED USING HSPF Norma E. Moreno Civil and Environmental Engineering University of Houston SETAWWA CONFERENCE Houston, TX March 08 2010

OUTLINE  Background  Objectives  Area of Study  HSPF Model  Methodology  Results  Development implications on E. Coli concentrations  Conclusions

BACKGROUND •E. coli concentrations in Sims Bayou frequently exceed Texas standards for both geometric mean (126 MPN/dL) and single sample standard (394 MPN/dL) •Sims Bayou is listed on the United States Environmental Protection Agency (US EPA) 303(d) list as impaired stream for contact recreation. •Upon implementation of the TMDL, it would be beneficial to foresee the response of the water body to natural and anthropogenic changes. •Several studies have been used to simulate flows and bacteria concentrations, however very few studies have been performed to assess water quality conditions under different development scenarios. •The evaluation of different scenarios in the watershed will help in determining effective alternatives in the reduction of E. coli and meeting required standards.

OBJECTIVES  Application of HSPF to Sims Bayou Watershed to evaluate hydrology and water quality.  Evaluation of the capabilities of the model in the prediction of E. coli concentrations under different development scenarios.

SIMS BAYOU WATERSHED •Approximately 33 % of the area is tidally influenced •Sims Bayou is developed with an average of 45% impervious areas (above tidal). •Development of the watershed will affect both water quality and quantity

HYDRO-METEOROLOGICAL NETWORK

SIMS BAYOU AMBIENT WATER QUALITY SIMS BAYOU E. coli PROFILE (Jan 2001 - Aug 2009) 1000000 100000 E. coli (MPN/dL) Maximum 10000 Geometric Mean Minimum 1000 Standard Geomean (126 MPN/dL) 100 10 Downstream 1 16656 11135 15876 16655 11133 15877 15878 11132 WQMS ID WQM Geometric Geometric Mean Single Sample Number of Samples % of Samples Number of STATION ID INDICATOR Mean Criteria concentration Criteria Exceeding Single Simple Exceeding Samples Bacteria (MPN/dL) (MPN/dL) (MPN/dL) Criteria (25%) 16656 EC 126 420 394 84 36 42.9% 11135 EC 126 953 394 82 59 72.0% 15876 EC 126 1547 394 75 63 84.0% 16655 EC 126 888 394 88 58 65.9% 11133 EC 126 1129 394 113 91 80.5% 15877 EC 126 880 394 84 59 70.2% 15878 EC 126 1216 394 84 63 75.0% 11132 EC 126 1666 394 103 95 92.2%

HSPF MODEL  HSPF (Hydrological Simulation Program – Fortran) simulates for extended periods of time the hydrologic, water quality, and associated processes on pervious, impervious land, streams and well mixed impoundments  It is considered one of the first comprehensive watershed models and it is distributed from EPA through BASINS or as a stand alone module.  Limitations:  Complicated operation of the model  1D Model - no suited for complex hydraulic systems  Heavily parameterized (sensitive to many inputs)

METHODOLOGY Point Sources of 1. SPATIAL DIVISON WATERSHED Bacteria: •WWTPs, 2. PREPARATION AND INPUT DATA SERIES •Sanitary Sewer Overflows Physical: •Septic Tanks • Land use distribution •Streams Characteristics •WWTPs flows •Meteorological: Non-Point Sources: Rainfall •Build up and wash off algorithm •Evaporation •Event Mean Concentrations (EMC) required •Evapotranspiration

METHODOLOGY 3. RUN MODEL All sub-watersheds Jan 1999 to Dec 2007 4. HYDROLOGY CALIBRATION Statistics used: Sub-watershed 2 Jan 1999 to Dec 2007 Model outputs compared to observed data under different scenarios: •Total Volume •Annual Calibration Parameters: •Seasonal •AGWRC: Basic Ground Water •Rainfall Events Recession Rate •High Flows (>70th percentile) •RETSC: Retention Storage Capacity •Low flows (<30th percentile) •UZNS: Upper Zone Nominal Storage 5. HYDROLOGY VALIDATION Sub-watershed 2 Jan 2008 to Jul 2008

METHODOLOGY BACTERIA CALIBRATION 1. RUN MODEL All sub-watersheds Jan 2001 to Dec 2007 Statistics used: 2. BACTERIA CALIBRATION All Sub-watersheds Jan 2001 to Dec 2007 Model outputs compared to observed data under different scenarios: •High Flows (>70th percentile) •Flows above median Calibration Parameters: •Low flows (<30th percentile) Delivery Ratio: •Flows below median Set at 80%

HYDROLOGY CALIBRATION SIMS BAYOU CALIBRATED FLOWS 10000 Observed Flows at USGS flow gage 08075400 Modeled Flows at Sub-watershed 2 1000 Flow (ac-ft) 100 10 1 0.1 Jan-99 May-00 Sep-01 Feb-03 Jun-04 Nov-05 Mar-07 Date OVERALL (1/1/1999 - 12/31/2007) Total Volume Summer Volume Winter Volume Storm Volume 90th Perc. 30th Perc. 10th Perc. < 30th Per. >70th Per. Data Source (ac-ft) (ac-ft) (ac-ft) (ac-ft) (ac-ft/hr) (ac-ft/hr) (ac-ft/hr) (ac-ft) (ac-ft) Observed 288442.8 95732.6 51312.3 22309830.2 4.3 0.7 0.6 5358.1 159105.6 Modeled 281835.0 84654.3 57350.1 23614168.9 5.1 0.7 0.5 8509.8 156812.3 Error 2.3% 11.6% -11.8% -5.8% -19.1% -2.6% 16.2% -58.8% 1.4% ANNUAL BEHAVIOR (1999 - 2007) Data Source 1999 (ac-ft) 2000 (ac-ft) 2001 (ac-ft) 2002 (ac-ft) 2003 (ac-ft) 2004 (ac-ft) 2005 (ac-ft) 2006 (ac-ft) 2007 (ac-ft) Observed 17835.3 21877.4 50327.7 34125.8 30684.5 37997.6 15066.7 22883.4 58051.4 Modeled 15966.3 24611.5 55631.6 30179.3 29703.2 37203.8 13361.2 32342.9 43047.0 Error 10.5% -12.5% -10.5% 11.6% 3.2% 2.1% 11.3% -41.3% 25.8%

HYDROLOGY VALIDATION VALIDATION RESULTS (01/01/2008 - 07/31/2008) Total Volume Summer Volume Winter Storm Volume 90th Perc. 30th Perc. 10th Perc. < 30th Per. >70th Per. Data Source (ac-ft) (ac-ft) Volume (ac-ft) (ac-ft) (ac-ft/hr) (ac-ft/hr) (ac-ft/hr) (ac-ft) (ac-ft) Observed 1.14E+04 1.75E+03 7.29E+03 2.28E+07 1.60 0.60 0.40 5.94E+02 9.11E+03 Modeled 8.54E+03 1.85E+03 4.35E+03 2.41E+07 0.96 0.48 0.44 6.85E+02 6.64E+03 Error 25.2% -5.9% 40.3% -5.5% 40.3% 19.3% -10.8% -15.3% 27.1%

BACTERIA CALIBRATION

BACTERIA CALIBRATION SUB_W. 2 SUB_W. 3 SUB_W 4 SUB_W. 5 SUB_W 6 WQS 11135 WQS 15876 WQS 11133 WQS 11135 WQS 11132 Obs.5 Pred.5 Error Obs.6 Pred.6 Error Obs.5 Pred.5 Error Obs.5 Pred.5 Error Obs.5 Pred.5 Error Overall GM1 1031.6 1183.7 -15% 1830.5 1161.2 37% 1277.4 1111.1 13% 1260.3 1130.1 10% 1760.1 1255.8 29% High Flow GM 2 1587.3 1366.0 14% 3250.8 1380.7 58% 3448.6 1102.3 68% 3039.4 1244.0 59% 3119.9 1499.3 52% Low Flow GM3 714.6 1428.5 -100% 824.4 1480.8 -80% 466.0 1448.9 -211% 473.8 1314.9 -178% 1305.4 1313.9 -1% Flow > median GM 1149.0 1181.8 -3% 2479.3 1160.6 53% 1893.8 1076.2 43% 2038.9 1116.0 45% 2383.0 1389.9 42% Flow < median GM 714.6 1428.5 -100% 824.4 1480.8 -80% 466.0 1448.9 -211% 473.8 1314.9 -178% 1305.4 1313.9 -1% Log RMSE4 0.72 0.73 0.75 0.74 0.60 Low Flow RMSE3,4 0.83 0.65 0.80 0.66 0.57 High Flow RMSE2,4 0.60 0.77 0.79 0.79 0.64

EVALUATION OF E. coli CONCENTRATIONS UNDER DIFFERENT DEVELOPMENT SCENARIOS Upstream Midstream Downstream Tidal Affected Sub-watersheds 0 1 2 4 Miles

EVALUATION OF E. coli CONCENTRATIONS UNDER DIFFERENT DEVELOPMENT SCENARIOS

CONCLUSIONS  Overall hydrologic and E. coli calibration errors were acceptable but the obtained for low flow regimes were relatively high  The limitations of the model when simulating E. coli under low flow regimes could be caused by an overestimation of the load from sources that are controlling in this condition  The simulation of increased development on the watershed showed that the concentration of E. coli show a significant increment compared to current values until the watershed reaches a development (impervious levels) of 87% average  Comprehensive hydrological models like HSPF allow the user to get a better understanding about the watershed and can be used for evaluating strategies in the reduction of E. coli

ACKNOWLEDGMENTS  Dr. Hanadi Rifai  The Ivanhoe Foundation  My husband E.J.  My friends: Divo, Anu, Nathan, Maria, Emil, Steve, Bora, JJ, Daniel, and Megan

Hidrologic and water quality modeling of sims bayou watershed using hspf

by Southeast Chapter of Texas AWWA on Apr 19, 2010

Accessibility

Categories

Upload Details

Usage Rights

2 Embeds 3

Statistics

Hidrologic and water quality modeling of sims bayou watershed using hspf — Presentation Transcript

http://www.setawwa.org	2
http://www.slideshare.net	1