Background

The City of Sierra Vista, through its Public Works Department, is responsible for providing wastewater collection and treatment services, while water services are mainly provided by three private companies. In 2012, wastewater collection coverage was estimated at 92% through 12,898 sewer connections. All of the collected wastewater is treated at a
wastewater reclamation facility in the Sierra Vista Environmental Operation Park, which has a treatment capacity of 4.0 million gallon a day (mgd).

Residents of Sulger currently use on-site septic tanks with leach fields for wastewater disposal. Most of the systems were installed 50 years ago with insufficient setbacks and have deteriorated over time, resulting in surface pooling that requires frequent pumping or the replacement of the entire system. The Cochise County Health Department has tried to
work with the residents to install acceptable leach fields in the amount of space available. However, because of the small size of most of the lots, it is practically impossible to comply with the setback requirements. Non-compliant, failing on-site treatment systems pose an
immediate threat to the environment, as well as a health risk for residents from direct contact with raw sewage and related diseases.

To remedy this situation, the City is proposing a project to expand its wastewater collection system to provide first-time service to the entire Sulger subdivision, including both the area annexed by the City and the unincorporated area belonging to the County.

Description

The project consists of constructing a wastewater collection system for the Sulger Subdivision and includes:

• Installation of approximately 9,700 ft. of gravity sewer lines;
• Construction of approximately 20 precast concrete manholes;
• Installation of 154 residential sewer connections; and decommissioning of septic systems.

Flows from the proposed sewer system will discharge into the main interceptor at 7th Street and will be treated at the wastewater facility in the Sierra Vista Environmental Operation Park, which has sufficient capacity to accommodate the additional flows.

Benefits

The project will reduce environmental and health hazards associated with inadequate sewage treatment and disposal, thus providing a cleaner healthier environment for local residents. Specifically, an estimated 29,000 gallons a day of wastewater will be collected and treated.