Groundwater Monitoring Program
The GCUWCD monitors water quality trends in the Wilcox, Carrizo, Queen City, Sparta, and Yegua-Jackson Aquifers by collecting water samples annually from selected observation wells. The trend monitoring program establishes a baseline of information to reveal groundwater quality trends over time across the district and serves as an initial indicator of changes in water quality that may warrant further investigation. Water samples are currently analyzed for basic cations (Ca, Mg, Na, K) and anions (Cl, CO3, HCO3, SO4) plus pH, conductivity, total alkalinity, total hardness, and nitrates. The GCUWCD, in coordination with the Texas Water Development Board, has been monitoring water quality in the District since 1998.
The water quality data for each observation well is available on an interactive map at the following link:
Earlier water quality data from 1938 to 1963 can be found in the Texas Water Development Board’s Ground-Water Resources of Gonzales County, Texas Report 4
Groundwater Chemistry
The chemical constituents of groundwater originate principally from the soil and rocks through which the water moves; most of the differences in the chemical characteristics of the water in Gonzales County, therefore, reflect the differences in the mineral content of the geologic formations with which the water has been in contact. Generally, the chemical content of groundwater increases with depth and distance away from the Aquifer outcrop. The temperature of the water, which is near the land surface is generally about the same as the mean air temperature of the region and also increases with depth (about 2 degrees Fahrenheit per 100 feet of depth).
