Summer 2025 - Flipbook - Page 11
Watershed Council Spotlight: The Task Committee on Total
Maximum Daily Load Analysis and Modeling is Advancing its
Science and Practice
Deva K. Borah, Ph.D., P.E., F. ASCE, F. EWRI, Chair of the EWRI
Watershed Council & TMDL Analysis and Modeling Task Committee
The Total Maximum Daily Load or TMDL refers scienti昀椀cally to the maximum amount of a pollutant a
waterbody can have without harm, whereas in regulatory context, it is a document or plan of action
to restore impaired water bodies. Developing such a document (TMDL) is challenging as there exists
no clear guidance in selecting from numerous models and analytical approaches used, among many
others. The TMDL Analysis and Modeling Task Committee | ASCE was formed in 2011 to address
these challenges and to 昀椀ll the gap of a guidance document on selecting and applying analytic and
modeling tools in TMDL development and implementation planning.
The Task Committee 昀椀rst reviewed the current practices of analysis and modeling in TMDLs and
documented its 昀椀ndings in an ASCE EWRI book, “Total Maximum Daily Load Analysis and Modeling:
Assessment of the Practice” in 2017. Secondly, members of the committee published a Special
Collection on Total Maximum Daily Load Analysis and Modeling: Assessment and Advancement:
Journal of Hydrologic Engineering | ASCE Library during the period 2018-2021. These articles
provide state-of-the-art and state-of-the-practice overviews of 15 relevant topics on TMDL analysis
and modeling, of which 昀椀ve articles were published by authors external to the Task Committee.
Based on the above publications and further research, the Task Committee published the ASCE
Manual of Practice 150, “Total Maximum Daily Load Development and Implementation: Models,
Methods, and Resources,” in 2022. It reviews and evaluates current practices and potential future
approaches to TMDL analysis and modeling. The primary goal is to support more comprehensive and
e昀昀ective TMDL development and implementation that will prove to be bene昀椀cial to the public through
eliminating current and future impairments to waterbodies and improving water quality for designated
uses with more con昀椀dence and certainty.
The Task Committee continues to work towards advancing the science and practice of TMDL by
addressing climate resilience, socio-environmental systems, and holistic concepts as applicable
to TMDLs and watershed management and documenting its work in a Special Collection on Total
Maximum Daily Load Analysis and Modeling Advances: Connecting Climate Resilience, SocioEnvironmental Systems, and Holistic Watershed Management: Journal of Environmental Engineering
| ASCE Library. The collection is open to all other authors outside of the Task Committee as outlined
in the Call for Papers: Total Maximum Daily Load Analysis and Modeling Advances: Connecting
Climate Resilience, SocioEnvironmental Systems, and Holistic Watershed Management | ASCE
Library with a manuscript submission deadline of December 31, 2025. The purpose of this Special
Collection is to showcase recent advances in analysis and modeling for TMDL development and
implementation. So far, it includes the following published articles:
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Advancing Surface Water Quality Modeling for TMDL Application: Enhancing SedimentAssociated Processes, Atmospheric Reaeration, and Bed Layer Interactions
Rethinking TMDLs: Perspective Based on Community Survey
Large-Scale Geospatial Analysis of Suitable Siting for Green Stormwater Infrastructure: An OpenSource Tool for Promoting Sustainability and Environmental Justice in Urban Communities
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