December 4, 2011
Installation of a 12-inch water transmission line that will serve the Odem area is well underway. It will provide drinking water to customers in Odem and in the western service area of the Rincon Water Supply Corp. with a future connection to the Seaboard Water Supply Corp.
Construction of the $1.6 million project is being done by Bridges Specialties. Section 2 of the West Transmission Line includes installation of 10.5 miles of 12-inch PVC pressure pipe purchased by the District in April. It also includes installation of fiber optic communications cable alongside the transmission line.
The Section 2 line will connect to Section 1, a 3.5-mile run of 18-inch diameter PVC pipe and fiber optic cable completed in April which serves the Taft area. The West Transmission Line begins at the new West Portland Pump Station.
The communities west of Portland have been served by a 24-inch steel transmission line installed in 1952. Once the new transmission line is complete the steel line will continue in use as a secondary water source for the Water District system.
Customers in Portland, Taft and the eastern portion of the Rincon system now receive drinking water that is treated at the District's water treatment complex between Gregory and Ingleside. Previously they received water treated at the City of Corpus Christi's O.N. Stevens Plant at Calallen. Customers of the Seaboard Water Supply Corp. will continue to get water from the Stevens Plant.
Work on Section 2 began south of Odem with installation of gates in numerous private fences that cross the Water District's pipeline easement. The new 12-inch PVC line is being installed alongside two existing lines -- the 24-inch steel treated water line and a 36-inch concrete steel cylinder pipe carrying untreated water from the Nueces River.
Members of the Water District Technical Services team are working at the construction site each day to establish an exact GPS location for the new pipeline. Using a GPS positioning tool and a cell phone GPS locator they are able to establish the centerline of the pipe within less than six inches.
They are also recording the depth of the pipe which is required by contract to be at a minimum depth. This data is being collected in a database that will allow more precise access to a section of pipe needing repair or to provide information to a third party that may be crossing the easement or digging in the area.
The 56,000 feet of polyvinyl chloride (PVC) pipe for the new Section 2 line comes in standard 20-foot sections. It has half-inch walls and weighs approximately 14.5 pounds per linear foot. It meets the C900 specifications set by the American Water Works Association (AWWA) with a pressure specification (DR 25) of 165 psi. The pipe comes with an internal gasket system that creates watertight joints.
Medium and large diameter PVC pressure pipe has come into increasing use for water systems in the past 20 years because of its durability and ease of installation. PVC pipe of up to 36 inches was used to connect treatment, storage and pumping facilities added to the District’s water treatment complex over the past three years.
As part of the District’s expansion program fiber optic cable is being installed alongside new pipelines to supplement the system of radio controls for remote locations. This addition to the communications infrastructure will make the overall water delivery system more storm resistant.
