BAWSCA Regional Water Supply Reliability Model and Analysis

BAWSCA retained Hazen to select a model platform and develop an independent water supply system model that explicitly represents all supply sources and demands affecting the BAWSCA Member Agencies.

The BAWSCA supply consist of four integrated components: The RiverWare software platform, a volume-balance supply system model built within that platform that links supply sources with water users, historical data for hydrology, demands, and reservoir operation rules, and rules for routing water withdrawals through the system to demand points.

The Bay Area Water Supply & Conservation Agency (BAWSCA) represents the water supply planning, conservation, and development needs of 24 cities and water districts and 2 private utilities in Alameda, San Mateo and Santa Clara Counties. These 26 Member Agencies are responsible for water to over 1.7 million people as well as thousands of corporate and institutional customers in the San Francisco Bay Area.

For more information, please contact Luke Wang.

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Historically, BAWSCA has relied on the San Francisco Public Utility Commission’s (SFPUC) modeling capabilities to inform its long-term planning decisions. While SFPUC-owned resources are the major supply source for most BAWSCA member agencies (approximately 60% of collective water demand), SFPUC’s system model, the Hetch Hetchy/Local Simulation Model (HH/LSM), does not have the capability to explicitly analyze the reliability of BAWSCA member agencies’ local and regional supplies. Nor can the SFPUC always be responsive to the timing of BAWSCA’s analytical needs due to their own prioritization and staffing constraints.

BAWSCA and Hazen selected RiverWare as the model platform and developed a baseline model run representing 2040 infrastructure and demands. The RiverWare model operates at a monthly time step, integrates operating rules and policies from regional multiple supply agencies (i.e. SFPUC, Alameda County Water District, Santa Clara Valley Water District, the State Water Project, and Cal Water) and explicitly represents the major surface water and groundwater sources in the service area.

The model is currently used to quantitatively analyze the likelihood of water supply shortage given historical hydrology and analyze the mitigating effects of policy interventions (e.g. conservation and demand reductions) and potential infrastructure developments (e.g. expansions in recycled water or groundwater service).

Hazen is currently assisting BAWSCA evaluate future regional water supply improvements, including an indirect potable reuse project and an expansion to Los Vaqueros Reservoir.

Project Outcomes and Benefits

Independent water supply model, integrating all local and regional water supply infrastructure affecting the BAWSCA Member Agencies.
First water resource model explicitly linking dynamic operations of SFPUC, SCVWD, and State Water Project supplies affecting water supply utilities in the San Francisco Bay Area.
Developed dynamic modeling framework allowing for simple implementation of future water supply projects and operation rules.
Developed analytical dashboards allowing for quick review of model output and comparison of multiple water supply scenarios that affect water supply reliability.