Background

Santa Rosa experienced immense population growth between 1980 and 2000, mostly in the form of 16 unregulated residential developments known as colonias on the outskirts of the town.  With no access to centralized water and wastewater systems, colonia residents installed on-site sanitary disposal systems, which in many cases did not meet minimum regulatory standards and thus posed serious environmental and health risks. Between 1992 and 2002, Santa Rosa extended water distribution lines to three of those colonias and wastewater collection lines to one colonia. The North Alamo Water Supply Corporation was planning to supply water to eight colonias, so the City was looking to provide water service to the remaining five colonias and wastewater services to 15 colonias. Moreover, this increased demand was affecting the quality of the services. The water supply system was unable to provide adequate service to current customers or meet minimum quality standards because of insufficient capacity and old, undersized lines. The small wastewater treatment plant was also working at full capacity servicing existing customers. To add new customers, additional capacity was needed.

Project Scope 

Water improvements included increasing the capacity of the water treatment plant by 307,000 gallons per day (gdp) to a total of 1 million gallons a day (mgd), construction of 19,000 linear feet of waterlines and installation of 86 new water hookups. Wastewater improvements included increasing treatment capacity by 291,000 gpd to a total of 681,000 gpd, construction of 87,800 linear feet of sewer lines and five lift stations, installation of 373 sewer connections and the decommission of the existing septic tanks.

The project was later downsized due to insufficient funding. No wastewater systems components were carried out.

Benefits

A new module with the capacity to treat 500,000 gpd of water was built, and the existing plant was retrofitted for a total capacity of 1 mgd, providing a safe and reliable source of drinking water for the entire community. In addition first-time water service was extended to 86 households.