Multi-Benefit Stormwater Capture Project Improves Community Resilience

Despite experiencing roughly 260 sunny days a year, the city experienced neighborhood flooding due to failing stormwater infrastructure and excessive wet weather flows to the sanitary sewer system. Instead of undertaking expensive upgrades to both the sewer trunk line and wastewater treatment plant, the city opted for a different approach—an ambitious $31 million dollar capture, treatment, and groundwater recharge system at its 6-acre J.M. Pike Park.

Woodard & Curran partnered with Modesto to reimagine the neighborhood park with a multi-beneficial project that removes stormwater cross connections to the sanitary sewer and non-functioning rock wells and improves the recreational amenities for the community. Our stormwater experts designed a 19-acre-foot underground stormwater infiltration and storage vault with more than two miles of 18- to 60-inch storm drainage pipe. The design includes stormwater pretreatment in two locations to remove trash, sediment, oils, greases, and other substances prior to entering the retention system. The project allows the city to remove 36 non-functioning rock wells and nine stormwater-to-sanitary sewer connections.

The addition of this stormwater capture project is improving surface and groundwater quality by managing non-point source pollution from a 101-acre catchment, treating stormwater through pre-treatment and natural soil filtration processes, preventing sanitary sewer overflows, and preventing stormwater and raw sewage spills to impaired waterways. The project will also help the City adapt to climate change by providing additional flood protection, allowing groundwater recharge to increase supply flexibility, and reduce irrigation use at the park.

Additional Benefits Realized

Since the city was breaking ground for the installation of stormwater infrastructure, the Water Division took the opportunity to identify existing water mains and services in the area that were a source of frequent maintenance issues due to age, being undersized, and prone to leaking. As such, the project incorporated the installation of more than 4.5 miles of water main, relocation of 245 water service lines from backyards to the street, and the replacement of another 111 water service lines in place. Existing undersized steel pipes were replaced with PVC mains and fire hydrants and systems were also replaced to meet city standards. This aspect of the project helps improve drinking water system reliability, flows, and pressures.

The scope of the project also included extensive park rehabilitation to improve operations and maintenance, accessibility, and aesthetics. Throughout the park, contractors laid water efficient turf varieties and planted drought tolerant trees and native species, creating habitat for birds, bees, and butterflies. The irrigation system was separated to ensure trees remain watered while allowing the turf to adequately dry, which enhances water conservation during droughts. Installation of rain gardens in addition to stormwater pretreatment devices and bioswales will contribute to stormwater runoff treatment. The park design included construction of a recreational soccer field and a baseball field over the stormwater storage vault, as well as new walking paths, seating, and lighting, all designed to meet Americans with Disabilities Act (ADA) requirements. Signage installed in the park is designed to help visitors understand the stormwater management efforts, as well as provide information on how they can help improve water quality.

A graphic rendering included on an educational sign explains how stormwater infrastructure in the park works. (Leanna Nguyen, Woodard & Curran Graphic Design Specialist)

A map of stormwater infrastructure in the park included on an educational sign. (Leanna Nguyen, Woodard & Curran Graphic Design Specialist)

Delivered within budget and timeline

Woodard & Curran facilitated moving quickly from design to construction phase by accurately estimating construction costs. The team’s opinion of probable construction was less than 3 percent higher than the qualified low bidder for this complex project. In addition to design services, Woodard & Curran provided Engineering Services During Construction (ESDC), which included timely responses to Requests for Information, submittal reviews, and coordination with the contractor to resolve any field issues efficiently. Throughout the project, we worked closely with the city to monitor progress, maintain cost control, and ensure alignment with grant requirements. Both the city and bidders on the project applauded the quality and clarity of our design and drawings, which allowed for the project to be completed within the established timeline and budget.

J.M. Pike Park’s reimagining represents a true multi-objective stormwater capture and use project that eliminates wet weather flows to the wastewater treatment plant, reduces neighborhood flooding, enhances public recreational space, improves the resiliency of the public water supply, and makes public rights-of-way more accessible.