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Geographic Information System-based Decision Support for Wetland Drainage Salinity Management

Project ID: 2846
Principal Investigator: Nigel Quinn
Research Topic: Water Operation Models and Decision Support Systems
Priority Area Assignments: 2011 (Place Holder - Do not use), 2012 (Place Holder - Do not use)
Funded Fiscal Years: 2010, 2011, 2012 and 2013
Keywords: None

Research Question

The Bureau of Reclamation (Reclamation) has an obligation to supply drainage service to its water supply contractors and assist water districts to comply with downstream water quality objectives under a U.S. Environmental Protection Agency (EPA)-mandated salinity total maximum daily load (TMDL). Wetland water managers, who receive Reclamation water supply and produce saline drainage to the San Joaquin River during spring wetland drawdown, have limited capability to manage salt exports. A decision support system, integrated with newly installed real-time monitoring stations, will provide Reclamation and Reclamation's wetland contractors a means of simulating salinity buildup in wetland impoundments, assistance in wetland drainage scheduling, and improvement in the capability to achieve environmental compliance.

The central research question posed that will be addressed by this research is:

* Can seasonal wetland hydrology be generalized within a Geographic Information System (GIS)-based decision support modeling framework with sufficient rigor to meet wetland manager needs for salt management?

The research strategy for answering this question is provided below.

Complementary research questions that will be answered during the conduct of the proposed project are:

* What is an appropriate level of aggregation of individual wetland impoundments that captures spatial heterogeneities while providing a manageable interface for a decision support system?

* What level of aggregation is appropriate for current and future sensor network configurations?

* What are the factors that promote and potentially impede technology transfer of a decision support system to wetland managers (where the stakeholder beneficiaries are new to the concept of salt load management)?

* Can the decision support system be generalized for application to agricultural and wetland salinity management projects Reclamation wide?

Need and Benefit

Reclamation has a responsibility to provide drainage service to its water contractors (this is described in more detail below). The proposed research provides a means of leveraging recent Reclamation commitments to real-time monitoring of salinity in the San Joaquin Basin by providing a decision support system to meet the needs of wetland water managers, most of whom are new to the concept of salt load management. Although the research hypothesis and associated research questions are focused on decisions wetland managers will need to make relative to the scheduling of drainage drawdown and the relationship between these salt loads and the assimilative capacity of the San Joaquin River, the final work product should have applicability Reclamation wide to both managed wetlands and irrigated agriculture.

The core of the GIS-based decision support system will be a flow and salinity simulation model that constructs water and salt mass balances for each modeled area. A key research issue will be to select the appropriate level of aggregation that makes sense and is useful to wetland water managers; is sufficiently refined to address system heterogeneities, yet sufficiently aggregated so that is doesn't overwhelm an analyst attempting to use the system; and takes advantage of existing sensor networks.

The benefit of an appropriately designed and fully functional decision support system will be an enhanced capability for wetland managers to coordinate and schedule saline return flows to the San Joaquin River and to improve compliance with State regulations for salinity. The Central Valley Regional Water Quality Control Board granted an exception to the strict TMDL salt load discharge allocation methodology that would go into effect if Reclamation and its contractors collectively implemented a real-time salinity management system. A successful outcome of the proposed project would be a prototype decision support system that could satisfy part of this requirement. Allowable salt load discharge under a real-time salinity management strategy would significantly increase the annual allowable salt load export from water districts and wetlands on the west side of the San Joaquin Basin--reducing salt-induced economic impacts to agriculture and wetland habitat and reducing costs to Reclamation related to water quality releases to the river from New Melones Reservoir to meet river salinity objectives.

Contributing Partners

Fish and Game, California

Research Products

Independent Peer Review

The following documents were reviewed by qualified Bureau of Reclamation employees. The findings were determined to be achieved using valid means.

Wetland flow and salinity budgets and elements of a decision support system (final, PDF, 12.0MB)
By Chuck Johnson
Report completed on March 31, 2012

The project has provided science-based tools for the long-term management of salinity in drainage discharges from wetlands to the SJR. The results of the project are being used to develop best management practices (BMP) and a decision support system to assist wetland managers adjust the timing of salt loads delivered to the San Joaquin River during spring drawdown. Adaptive drainage management scheduling has the potential to improve environmental compliance with salinity objectives in the Lower
Keywords: salinity, wetlands, real-time, drainage, assimilative capacity

This information was last updated on April 19, 2014
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