Water Facilities Master Plan Update
Eastern Municipal Water District, California

Relevant Project features:

  • Updated hydraulic model to incorporate updates from EMWD’s GIS
  • Validated model by comparing pressure zone operations with operational (SCADA) data for peak week 2013 and 2014 conditions
  • Performed hydraulic evaluations to identify system deficiencies and recommended improvements, and developed an optimized capital improvement program, identifying costs and time line for implementation
  • Evaluated the water system under both average and peak demand conditions

West Yost prepared EMWD’s 2015 Water Facilities Master Plan (WFMP) Update for its potable water system. Key drivers for the WFMP included significant changes in growth projections since the previous WFMP, and EMWD’s need to update its capital improvement program (CIP) for re-evaluation of rate and connection fees.

West Yost updated EMWD’s existing system hydraulic model, including incorporating pressure zone boundary changes, adding new pipelines, verifying model pump curves and tank geometry, confirming pressure reducing station settings, and spatially allocating customer consumption information using 2013 consumption data. After completing model updates, West Yost validated the model, through comparisons of results with SCADA for peak week 2013 and 2014. Based on an initial review, 34 pressure zones were validated, comparing hydraulic modeling results with field data to demonstrate that the model adequately reflects current operational trends. 

West Yost worked collaboratively with EMWD to provide key input to the District’s future water supply strategy. Using a skeletonized version of the distribution system hydraulic model that includes key backbone transmission facilities, West Yost identified transmission needs for different water supply alternatives to support EMWD decision-making for its water supply strategy. West Yost also used the backbone model to identify phasing of facilities, to determine sequencing of supplies to serve Perris Valley, EMWD’s largest pressure zone, and to evaluate facilities needs for outage planning.

West Yost prepared a comprehensive analysis of all EMWD pressure zones, to determine supply, storage and pipeline capacity needs for each pressure zone. Hydraulic modeling for the system used extended period simulations, using seven successive maximum demand days to confirm operational trends. West Yost used the buildout scenario to establish facilities requirements, and then performed hydraulic evaluations for a number of different time frames (2016, 2018, 2020, 2022, 2025, 2030, 2035, 2040 and 2045) to establish facilities phasing. Average day scenarios were also evaluated for 2025 and buildout to assess pressures under lower demand conditions.

The analysis found that there were varying needs to provide improvements, depending on service area, growth and water supplies, with an overall CIP of $1.9 billion. West Yost prioritized improvements to address existing deficiencies first. Remaining improvements were generally tied with growth and timing of the improvements was based on the timing of development. Projects that benefit specific developments were also identified, so that funding for improvements could be allocated to the specific development. 

Improvement projects were developed and tested through an iterative and collaborative process. After initial solutions were developed, these were reviewed with EMWD’s internal stakeholder group. Based on input received, alternative solutions were tested and/or improvements were refined to incorporate EMWD suggestions.