Critical Condition Modeling and Analysis in TMDL Development and Implementation
Publication: Journal of Hydrologic Engineering
Volume 24, Issue 2
Abstract
The USEPA’s Total Maximum Daily Load (TMDL) program under the Clean Water Act requires taking into account the critical conditions for stream flow, loading, and water quality parameters to develop TMDLs. However, properly defining a waterway’s critical conditions is one of the key challenges in developing a TMDL. Consequently, many current TMDLs address this aspect only in a cursory manner. This paper presents a review of critical condition modeling and analysis approaches and illustrates the strengths and weaknesses of available methodologies to define critical conditions with a view to provide guidance for TMDL development and implementation. Four major approaches for critical condition modeling and analysis are typically employed in TMDL studies: low-flow analysis using steady-state models, continuous simulation using dynamic models, statistically based load-duration curves, and the event-based critical flow-storm approach. By understanding better how to define critical conditions, water quality professionals can develop more-meaningful and improved estimates of TMDLs and formulate appropriate strategies to control pollution from point and nonpoint sources at a watershed level.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The TMDL Analysis and Modeling Task Committee of the American Society of Civil Engineers’ Environmental and Water Resources Institute was formed to address concerns and challenges of the current practice of TMDL analysis and modeling in terms of analysis technique and model selection, data requirement, calibration, validation, and uncertainty reporting. The committee documented its work in a report, “Total Maximum Daily Load Analysis and Modeling: Assessment of the Practice,” published by ASCE in 2017. Authors of this paper are members of the Task Committee and the paper is partly based on the findings of the Task Committee.
References
ADEM (Alabama Department of Environmental Management). 2005. “Total Maximum Daily Loads (TMDLs) for metals (zinc), pH and siltation in the Village Creek Watershed, Alabama.” Accessed November 18, 2017. http://adem.alabama.gov/programs/water/wquality/tmdls/FinalVillageCreekZincpHSiltationTMDLs.pdf.
ASCE. 2017. Total maximum daily load analysis and modeling: Assessment of the practice. Reston, VA: ASCE.
Bicknell, B. R., A. S. Donigian, and T. A. Barnwell. 1985. “Modeling water quality and the effects of agricultural best management practices in the Iowa River Basin.” Water Sci. Technol. 17 (6–7): 1141–1153. https://doi.org/10.2166/wst.1985.0209.
Bicknell, B. R., J. C. Imhoff, J. L. Kittle Jr., and A. S. Donigian. 1996. Hydrological simulation program: FORTRAN, user’s manual for release 11. Athens, Greece: Environmental Research Laboratory, USEPA.
CEPA (California Environmental Protection Agency). 2012. “Santa Maria watershed TMDL—Fecal indicator bacteria.” Accessed November 18, 2017. http://www.waterboards.ca.gov/centralcoast/water_issues/programs/tmdl/docs/santa_maria/fib/index.shtml.
Chin, D. 2009. “Risk-based TMDLs in pathogen-impaired waters.” J. Water Resour. Plann. Manage. 135 (6): 521–527. https://doi.org/10.1061/(ASCE)0733-9496(2009)135:6(521).
DNREC (Delaware Department of Natural Resources and Environmental Control). 2005. “Total maximum daily loads (TMDLs) analysis for Pocomoke River, Delaware.” Accessed November 18, 2017. http://www.dnrec.delaware.gov/swc/wa/Documents/TMDL_TechnicalAnalysisDocuments/18_PocomokeTMDLAnalysis.pdf.
Donigian, A. S., J. C. Imhoff, and B. R. Bicknell. 1983. “Predicting water quality resulting from agricultural nonpoint source pollution via simulation: HSPF.” In Agricultural management and water quality, edited by F. W. Schaller and G. W. Bailey, 200–249. Ames, IA: Iowa State University Press.
DRBC (Delaware River Basin Commission). 1995. “Implementation policies and procedures: Phase I TMDLs for toxic pollutants in Delaware River Estuary.” Accessed November 18, 2017. http://www.state.nj.us/drbc/library/documents/Implementation_phase1TMDL.pdf.
Gautam, B., M. Kasi, and W. Lin. 2006. “Determination of fecal coliform loading and its impact on river water quality for TMDL development.” In Proc., Water Environment Federation Annual Conf. (WEFTEC), 3851–3874. Alexandria, VA: American Water Resources Association.
Hantush, M. M. 2008. “Estimation of TMDLs and margin of safety under conditions of uncertainty.” In Proc., World Environmental and Water Resources Congress 2009. Middleburg, VA: American Water Resources Association.
Hsu, T. H., J. Y. Lin, T. C. Lee, H. X. Zhang, and L. Y. Shaw. 2010. “A storm event-based approach to TMDL development.” Environ. Monit. Assess. 163 (1–4): 81–94. https://doi.org/10.1007/s10661-009-0818-8.
IDEQ (Idaho Department of Environmental Quality). 2015. “Lower Boise River TMDL: 2015 total phosphorus addendum.” Accessed November 18, 2017. http://www.deq.idaho.gov/media/60177413/lower-boise-river-tmdl-total-phosphorus-addendum-0815.pdf.
Kasi, M., W. Lin, R. Magel, and B. Gautam. 2007. “Risk based critical condition analysis for Red river fecal coliform TMDL development.” In Proc., Water Environment Federation Annual Conf. (WEFTEC) 2007, 7014–7032. Alexandria, VA: Water Environment Federation.
Keller, A. A., Y. Zheng, and T. H. Robinson. 2004. “Determining critical water quality conditions for inorganic nitrogen in dry, semi-urbanized watersheds.” J. Am. Water Resour. Assoc. 40 (3): 721–735. https://doi.org/10.1111/j.1752-1688.2004.tb04455.x.
Milly, P. C. D., J. Betancourt, M. Falkenmark, R. M. Hirsch, Z. W. Kundzewicz, D. P. Lettenmaier, and R. J. Stouffer. 2008. “Stationarity is dead: Whither water management?” Science 319 (5863): 573–574. https://doi.org/10.1126/science.1151915.
NVDEP (Nevada Division of Environmental Protection). 2007. “Carson River: Total maximum daily loads for total suspended solids and turbidity.” Accessed November 18, 2017. https://ndep.nv.gov/uploads/water-tmdl-docs/carson_river_tmdl_07.pdf.
OEPA (Ohio Environmental Protection Agency). 2013. “Total maximum daily loads for the Ottawa River (Lima area) watershed.” Accessed November 18, 2017. http://www.epa.state.oh.us/Portals/35/tmdl/OttawaLima_Report_Final.pdf.
SCDHEC (South Carolina Department of Health and Environmental Control). 2010. “Total maximum daily load document RS-05590, big creek watershed: Fecal coliform bacteria.” Accessed November 18, 2017. https://www.scdhec.gov/sites/default/files/docs/HomeAndEnvironment/Docs/tmdl_bigCreek.pdf.
Shenk, G. W., J. Wu, and L. Linker. 2013. “Enhanced HSPF model structure for Chesapeake Bay watershed simulation.” J. Environ. Eng. 138 (9): 949–957. https://doi.org/10.1061/(ASCE)EE.1943-7870.0000555.
Stiles, T. C. 2002. “Incorporating hydrology in determining TMDL endpoints and allocations.” In Proc., Water Environment Federation (WEF)’s National TMDL Science and Policy Conf. Alexandria, VA: Water Environment Federation.
USEPA. 1984. Technical guidance manual for performing wasteload allocations. Book II: Streams and rivers. Washington, DC: USEPA.
USEPA. 1986. Technical guidance manual for performing wasteload allocations. Book VI: Design Conditions: Chapter 1: Stream design flow for steady-state modeling. Washington, DC: USEPA.
USEPA. 1991. Guidance for water quality-based decisions: The TMDL process. Washington, DC: USEPA.
USEPA. 1999a. Draft guidance for water quality-based decisions: The TMDL process (second edition). Washington, DC: USEPA.
USEPA. 1999b. Protocol for developing nutrient TMDLs (first edition). Washington, DC: USEPA.
USEPA. 2001. Protocol for developing pathogen TMDLs (first edition). Washington, DC: USEPA.
USEPA. 2006. “DFLOW.” Accessed November 18, 2017. https://www.epa.gov/waterdata/dflow.
USEPA. 2007. An approach for using load duration curves in the development of TMDLs. Washington, DC: USEPA.
USEPA. 2008. “Nutrient ·and sediment TMDLs for the Southampton Creek watershed, Pennsylvania: Modeling report.” EPA Region 3, Philadelphia. Accessed November 18, 2017. http://www.dep.state.pa.us/dep/deputate/watermgt/wqp/wqstandards/TMDL/Nutrient%20and%20Sediment%20TMDLs%20for%20Southampton%20Creek%20Watershed.pdf.
USEPA. 2009. TMDL program results analysis fact sheet. Washington, DC: USEPA.
USEPA. 2010. “Chesapeake Bay TMDL: Appendix G: Determination of critical conditions for the Chesapeake Bay TMDL.” Accessed November 18, 2017. https://www.epa.gov/sites/production/files/2015-02/documents/appendix_g_critical_period_analysis_final.pdf.
USEPA. 2012. “Section 319 nonpoint source program success story: Implementing management practices reduces nitrate in Virginia’s Muddy Creek.” Accessed November 18, 2017. https://www.epa.gov/sites/production/files/2015-10/documents/va_muddycreek.pdf.
USGS. 2003. Use of the Hydrological Simulation Program–FORTRAN and bacterial source tracking for development of the fecal coliform Total Maximum Daily Load (TMDL) for Accotink Creek, Fairfax County, Virginia. Washington, DC: USGS.
USGS. 2006. “Hydrological Simulation Program—Fortran.” Accessed August 28, 2017. https://water.usgs.gov/software/HSPF/.
USGS. 2007. “Hydrologic analysis and interpretation section A, statistical analysis.” In Chap. 6 of The national streamflow statistics program: A computer program for estimating streamflow statistics for ungaged sites, edited by K. G. Ries III. Reston, VA: US Geological Survey.
VADEQ (Virginia Department of Environmental Quality). 2000. “Nitrate TMDL development for Muddy Creek/Dry River, Virginia.” Accessed November 18, 2017. http://www.deq.virginia.gov/portals/0/DEQ/Water/TMDL/apptmdls/shenrvr/muddyni.pdf.
VADEQ (Virginia Department of Environmental Quality). 2016a. “Bacteria Total Maximum Daily Load (TMDL) development for the Mattaponi River watershed located in Orange, Spotsylvania, Caroline, King William, and King and Queen Counties, Virginia.” Accessed November 18, 2017. http://www.deq.virginia.gov/Portals/0/DEQ/Water/TMDL/apptmdls/yorkrvr/MattaponiBact2016.pdf.
VADEQ (Virginia Department of Environmental Quality). 2016b. “Bacteria and benthic Total Maximum Daily Load (TMDL) revision for the Beaver Creek watershed located in Bristol City and Washington County, Virginia.” Accessed November 18, 2017. http://www.deq.virginia.gov/Portals/0/DEQ/Water/TMDL/apptmdls/tenbigrvr/BeaverCreekTMDLRevision_final_rev-08_02232017.pdf.
WADOE (Washington State Department of Ecology). 2006. “Wenatchee River basin dissolved oxygen, pH, and phosphorus Total Maximum Daily Load study.” Accessed November 18, 2017. https://fortress.wa.gov/ecy/publications/summarypages/0603018.html.
WE&RF (Water Environment & Reuse Foundation). 2003. Navigating the TMDL process: Evaluation and improvement. Alexandria, VA: Water Environment Research Foundation.
Zhang, H. X. 2010. “Changes ahead: Water management professionals should account for climate change when working with TMDLs.” Water Environ. Technol. 37–40x.
Zhang, H. X. 2012. “Climate change and global water sustainability.” In Encyclopedia of sustainability science and technology, edited by R. A. Meyers, 2061–2078. New York: Springer.
Zhang, H. X., and S. L. Yu. 2004. “Applying the first-order error analysis in determining the margin of safety for total maximum daily load computations.” J. Environ. Eng. 130 (6): 664–673. https://doi.org/10.1061/(ASCE)0733-9372(2004)130:6(664).
Zhang, H. X., and S. L. Yu. 2005. “Condition critical: Defining the ‘critical condition’ for a total maximum daily load requires great care, especially when addressing nonpoint pollutants.” Water Environ. Technol. 6 (Jun): 38–42.
Zhang, H. X., and S. L. Yu. 2008. “Critical flow-storm approach to total maximum daily load (TMDL) development: An analytical conceptual model.” Front. Environ. Sci. Eng. China 2 (3): 267–273. https://doi.org/10.1007/s11783-008-0058-0.
Information & Authors
Information
Published In
Journal of Hydrologic Engineering
Volume 24 • Issue 2 • February 2019
Copyright
©2018 American Society of Civil Engineers.
History
Received: Aug 28, 2017
Accepted: Jul 17, 2018
Published online: Nov 16, 2018
Published in print: Feb 1, 2019
Discussion open until: Apr 16, 2019
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.