About the City's Wastewater Treatment Plant Landscape Improvement Project

The Wastewater Treatment Plant (WWTP) Landscape Improvement Project was completed in 2022. The landscaping and rain garden is open to the public during WWTP business hours.

The landscape project was developed to save water and reduce landscape maintenance costs by replacing existing landscaping with drought-tolerant landscaping. The previous landscaping at the facility was more than 20 years old and included areas with high-water use plants and turf, as well as steep slopes where water and soil can run off existing landscape grasses and shrubs along the north and west corner of the WWTP Administration building were replaced during this project (mature trees remained intact).

The demonstration rain garden contains decorative rocks and plants, a gravel swale and switchbacks along the southern edge of the parking lot. The rain garden will contain runoff from the building and adjacent sidewalk, and can absorb up to 30% more water than a typical landscape while also filtering out and/or reducing pollutants.

What is a rain garden?

A rain garden is designed to capture and allow rainwater and runoff to slowly infiltrate the soil. A shallow depression is filled with gravel and a high-drainage soil/sand/compost mixture, and is surrounded with native and drought-tolerant plants. Rainwater and stormwater are allowed to slowly flow through the rain garden and is gradually absorbed into the soil. Rain gardens are not designed to have standing water but are designed to increase water absorption into the soil. During high flows and storms, an outlet is designed to prevent flooding.

The landscaping and rain garden features more than 500 drought-tolerant shrubs; 7,800 square feet of new groundcover plants; a new retaining wall; and a demonstration rain garden. It utilizes a new water-efficient irrigation system with “smart” controllers. Additionally, a water distribution system sampling station was installed and will be used by City staff as one of 13 existing water sampling stations located throughout the City to test drinking water produced at the Water Treatment Plant (drinking water is tested weekly throughout the city of Benicia).

Click here for more information about the plants included in the demonstration garden.