Public Works Department
The mission of the Public Works Department is to (1) develop and maintain public facilities and infrastructure effectively and efficiently including the water system, wastewater system, storm drainage system, streets and road system, sidewalk systems, parks system, publicly landscaped areas, airport, municipal buildings and facilities; (2) maintain City vehicles and equipment and (3) oversee the collection of solid waste and recyclable materials in the City of Calexico.
This mission is accomplished through the prudent use of resources, technology, innovations, teamwork, and coordination with other service providers in the City.
Water Treatment and Distribution Operations
Calexico provides potable water service to its residential, commercial and industrial customers within the City limits. The City’s water system treats Colorado River surface water imported 80 miles from the Colorado River by the Imperial Irrigation District (IID) via the All American Canal near the Southern Pacific Railroad. Raw water is pumped through a 42-inch pipeline to the City’s 25 million gallon (MG) reservoir. The water is then pumped from the raw water reservoir through a 30-inch pipeline to the City’s water treatment plant, located at 545 Pierce Avenue, a distance of approximately one mile from the diversion point.
The existing 12 million gallons per day (MGD) surface water treatment plant is a conventional plant consisting of two up-flow clarifiers, gravity filtration, and chlorine disinfection. This water is treated in compliance with the Surface water Filtration and Disinfection Treatment Regulations found in Chapter 17 Title 22, California Code of Regulations, the California Department of Health Services, and Local Agency requirements. The level of treatment and compliance with safe drinking water requirements varies with the quality of the raw water delivered.
Treated water is stored in two above grade, fabricated steel, tanks located at the treatment plant site and the eastside reservoir. These tanks have the capacities of 6.0 million gallons per day (MG), 6.0 million gallons per day (MG) and 4.0 million gallons per day for a total of 8.0 million gallons available for distribution. The City’s total storage capacity for finished water is million 16 million gallons per day (MGD). Total storage capacity including the raw water reservoir is 41 million gallons per day.
The City has one finished water pump station at the water treatment plant (WTP), which maintains water pressure in the City. The current low rate of the finished water pump station is 17,500 gallons per minute (GPM) or 24 million gallons per day (MGD). The discharge pressure of this pump station is approximately 55 pounds per square inch (PSI). Eight pumps transfer potable water from the storage tanks to the City’s distribution system.
The present water system is operated in one pressure zone which is sustained by pumping only. Because the topography is essentially flat throughout the City, there are no reservoirs in the system that can provide hydraulic gradient to sustain even the minimum pressures required by users. The existing water distribution system includes over 75 miles of pipelines ranging from two inches to 30 inches in diameter.