This system diverts water from the Guadalupe River into the GBRA main canal for distribution to industrial, municipal, and agricultural customers in Calhoun County through a series of irrigations canals, checks, pump stations and pipelines.

The system provides a raw water supply for the Port Lavaca Water Treatment Plant and industrial refinery operations operated by Seadrift Coke, INEOS Nitriles and the Dow Chemical Company's Seadrift plant. It also delivers irrigation water to agricultural users, including the Calhoun County rice industry.

As part of the Water Supply System operation, ongoing maintenance to the Lower Guadalupe Diversion Dam and Salt Water Barrier near Tivoli provides efficient diversion and protects the area water supply from salt water contamination. Clearing log jams from the lower reaches of the Guadalupe River provides safe access for navigation and prevents course changes.

In addition, the division conducts water quality monitoring and testing services, as well as billing and contract administration services.

Completed in 1964, this cooperative project between the U.S. Army Corps of Engineers and GBRA provides flood control protection and a stored water supply. GBRA operates the water storage portion to provide municipal, industrial, and agricultural customers with a dependable water supply during drought or low flow conditions.

GBRA is responsible for reservoir water management and release within the 'conservation pool,' between 800 feet mean sea level (msl) and the normal operating elevation of 909 msl. The Corps is responsible for management and release of waters within the 'flood control pool' at elevations of 909 to 943 msl. Water is normally released as soon as possible from this portion of the reservoir which must be kept empty to contain runoff from high rainfall and flood events.

Primarily, the reservoir provides flood control protection for people living downstream of the Dam, but it also supplies many users with their sole source of water. For others, it provides a dependable alternative source of water during drought conditions and low river flows. Reservoir water supplies stored water to cities, industries and agricultural users. Under a permit issued by the State of Texas, GBRA is allowed to divert an average of 90,000 acre-feet per year of stored water to supply contracted water users.

The dam is an earthfill embankment, 224 feet high and 6,830 feet long. At maximum 'conservation pool' level of 909 feet elevation msl, the reservoir covers more than 8,200 surface acres and impounds 386,200 acre-feet of water to a depth of 140 feet. At maximum 'flood control pool' elevation of 943 feet msl, the reservoir impounds a total of 732,600 acre-feet of water.

The Regional Laboratory provides support services for GBRA-operated water and wastewater plants, chemical and bacteriological testing for cities, water districts, industries, consulting firms, and private individuals, and environmental monitoring within the river basin.

The laboratory conducts chemical and bacteriological analysis of of potable water, wastewater and environmental samples utilizing current technology and equipment, including a Perkin-Elmer 5100ZL Graphite Furnace/Flame Atomic Absorption Unit to test water for the presence of lead and 14 other heavy metals.

In addition to its broad water quality planning initiatives and participation in environmental and water quality monitoring programs within the river basin, the laboratory also sponsors and trains Texas Watch water quality monitors, a statewide volunteer program created under the Texas Clean Rivers Act of 1994 to involve citizens in the testing and protection of water resources. The lab also conducts presentations for schools, civic and other organizations on water quality, environmental issues, Texas Watch and other water-related subjects.

The laboratory maintains strong working relationships with federal, state and local government agencies responsible for water quality, as well as corporations and individuals capable of affecting water quality.