
Stormwater & Groundwater
Expert geologists, hydrogeologists and engineering geologists, civil engineers, and environmental scientists designing and implementing solutions for a sustainable water future

PARTNERSHIPS &
COMPLIANCE
With extensive experience and a proven track record, our team excels in groundwater management and stormwater services, including developing new models and conducting peer reviews. We ensure compliance with SGMA, city standards, and adjudicated basin judgments.

EXPERIENCE
Our team offers comprehensive groundwater and stormwater services. We conduct hydrogeologic studies, develop monitoring programs, and provide tailored hydraulic modeling training using EPA SWMM, XPSWMM, SSWMM, and HECRAS software. We also identify deficiencies in collection systems based on 10- and 100-year storm criteria. Our insights guide sustainable practices.

PLANNING &
INFRASTRUCTURE
West Yost excels in developing regulatory compliance plans to facilitate the efficient reuse and recharge of recycled water, emphasizing environmentally responsible practices and offer support for the design, siting, and construction of crucial groundwater & stormwater infrastructure.
Our Stormwater and Groundwater team is comprised of geologists, scientists, and engineers who support our clients in the planning, design, and implementation of programs and facilities that optimize the use of groundwater within their water supply portfolios to achieve their long-term goals for quantity, quality, and conjunctive management of all available water resources. Our stormwater group, is now integrated with groundwater, stands as a leader in stormwater system planning, regulatory compliance, and the design of essential storm system improvements, flood plain management, and water quality. These teams, together, form a robust group of planners, modelers, and specialists.
Our team oversees long-term management plans in compliance with the California Sustainable Groundwater Management Act (SGMA) and adjudicated basin judgments, including leading Groundwater Sustainability Agencies and Watermaster entities. They conduct groundwater and stormwater modeling and hydrogeologic studies, design monitoring programs, and develop regulatory compliance plans for recycled water reuse. Additionally, they provide expertise in well design and field services, supporting clients with monitoring activities regularly.
Stormwater and Groundwater Scope of Services
Our Stormwater and Groundwater resources team offers a full-service approach, including:
Studies and planning • Modeling • Regulatory and permitting assistance Designs for well rehabilitation, new municipal wells, and ASR wells Watermaster services • Funding assistance • Construction phase services • Optimization of existing systems • Groundwater management plans • Master Plans: Stormwater Management Plans, Drainage, Combined Sewer • Climate Resiliency and Sea Level Rise Studies • Floodplain Analysis and Mapping (CLOMRs and LOMRs) (1D/2D) • Facilities Planning, Alternatives Analysis and Feasibility Studies • Stormwater Reuse • Operations and maintenance (O&M) • General consulting in the areas of water resources, hydrology, and hydrogeology
Project Highlights

High-Resolution Models to recalculate the Chino Basin Safe Yield
Chino Basin Watermaster
Our groundwater team developed and implemented a methodology based on scientific principles and detailed numerical models to develop a complete hydrologic description of the Chino Basin over the 1960-2011 calibration period and the 2012- 2071 planning period.

Colusa Subbasin Groundwater Sustainability Plan and SGMA Technical Support Services
Colusa Groundwater Sustainability Agency and Glenn Groundwater Sustainability Agency
West Yost is a valued member of a multi consultant team responsible for development of the Groundwater Sustainability Plan (GSP) for the Colusa Subbasin. We are involved in all aspects of GSP development, including engaging with stakeholders and the public, and producing the GSP for the Colusa Groundwater Sustainability Agency

Coachella Valley Salt and Nutrient Management Plan
Water and Wastewater Agencies of the Coachella Valley
In 2020/21, the water and wastewater agencies in the Coachella Valley (CV) that are responsible for developing a Salt and Nutrient Management Plan (SNMP) for the groundwater basin (CV SNMP Agencies) hired West Yost to lead a multi stakeholder effort, including the Regional Board staff, in the development of the CV-SNMP Workplan.

Planning, Permitting, Design and Testing Services for Aquifer Storage and Recovery (ASR)
City of Woodland and Woodland-Davis Clean Water Agency (WDCWA)
West Yost worked with the Woodland-Davis Clean Water Agency and the City of Woodland to conduct an ASR evaluation as a component of the overall water supply for the Davis Woodland Water Supply Project (DWWSP), designed the first ASR facility for the City, and completed construction of the project, which included injection testing and impact analyses of the ASR well.
Stormwater and Groundwater Team Spotlight
Our groundwater experts include specialists in geology, hydrogeology, engineering geology, civil engineering and water treatment
plant operators. We provide over 150 years of combined experience. Meet some of our team below and on our project pages.

Samantha Adams
Stormwater & Groundwater
Business Sector Leader

Sheri Ken Loy, PG, CEG, CHG
Groundwater
Principal Geologist II

Poyom Riles, PE, QSD
Stormwater
Senior Engineer I
West Yost is an Equal Opportunity Employer
West Yost Word
Grid
State Water Resources Control Board Cross-Connection Control Policy Handbook
Planning for a Vibrant and Sustainable Future – Integrated Approaches for Meeting Climate Change Impacts
Projects
Watermaster Services for Water Rights Compliance and Groundwater Management
Six Basins Watermaster
The Six Basins are a group of adjacent groundwater sub-basins located in Eastern Los Angeles and Western San Bernardino Counties. The pumping rights from the Six Basins were adjudicated in 1998 through a stipulated judgment, which established the Six Basins Watermaster (Watermaster) to implement…

Monitoring for Impact of Groundwater Management Plans on Critical Riparian Habitat
Chino Basin Watermaster and Inland Empire Utilities Agency
The Chino Basin is a large alluvial groundwater basin in Southern California with storage exceeding five million acre-feet. Groundwater in the Chino Basin generally flows from the forebay regions in the north towards the Prado Flood-Control Basin in the south (Prado Basin).
