Evaluation of Approaches to Determine Mixing and Assimilation of Reuse Effluent

Project ID: 7100
Principal Investigator: Meghan Thiemann
Research Topic: Water Quality
Funded Fiscal Years: 2017, 2018 and 2019
Keywords: None

Research Question

As of now, California agencies cannot discharge to surface water supplies that are used as a drinking water source, but that is expected to change very soon. The California Division of Drinking Water is currently developing draft regulations to address this topic. Some of these agencies may be interested in developing models to predict how contaminants will move through reservoirs and how they can estimate residence time, which will be a component of the regulations. They will need models to show how the discharges, primarily composed of RO permeate, will dilute out in the reservoirs.
The City of San Diego's plan to discharge to the San Vicente Reservoir is one example that has already been studied in considerable detail with reports submitted in the Fall of 2012. Other agencies are considering similar plans, including Arbuckle Master Conservancy District, managing Lake of the Arbuckles in the Chickasaw National Recreation Area, Oklahoma.
This proposal is the result of a scoping proposal awarded in FY 2016 (S&T 1397). This scoping effort performed outreach to local agencies throughout the West, and focused this proposed research on the following question: What is the best

Need and Benefit

As reuse water becomes an ever-larger component of water resource planning, issues associated with measuring and modeling the mixing and dispersion of reuse water will become more prominent. Measuring and modeling reuse water varies from locality to locality based on models used and local and state regulations. Given different approaches to simulate water reuse mixing in reservoirs, a need exists to provide guidance given different conditions. Current analytic approaches to water reuse in reservoirs are done on a case by case basis, which lacks a coherent overarching approach. See further discussion of need under "Previous Work" and attached to the back of this proposal.
This research will provide guidance on how to address disparate regulations and modeling approaches. One major benefit will be to provide detailed guidelines and recommendations on how to approach water reuse mixing given differing physical conditions, and different use of hydrodynamic modeling. See further discussion of benefits under "Previous Work" and attached to the back of this proposal.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Evaluation of Approaches to Determine Mixing and Assimilation of Reuse Effluent (final, PDF, 22.3MB)
By Meghan Thiemann, Dave James, Ali Saber, Imad Hannoun, Catherine Cerri, and Jeffrey Pasek
Report completed on September 30, 2021

This research product summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20