UGS’s Role in Contributing Water-Quality Data to the National Ground-Water Monitoring Network
By Janae Wallace
The Groundwater Program at the Utah Geological Survey (UGS) is excited to be a major contributor of water-quality data to the nascent, but expanding, National Ground-Water Monitoring Network (NGWMN). The UGS has established a groundwater monitoring network in Utah to contribute to the recently established web-based data portal originated by the U.S. Geological Survey (USGS). The NGWMN Data Portal is a clearinghouse that displays water well data throughout the nation; in particular, it exists as a water-quality and water-level network designed to showcase wells having a historical collection of data for a subset of selected water wells established by each state.
The UGS has been a fortunate recipient of funding from the federal government to establish a new network representing Utah. Previously, the UGS Groundwater Program regularly monitored sites at only a few areas of the state: Snake Valley, Castle Valley, and the Uinta Basin. Because the U.S. Environmental Protection Agency (EPA) has provided no-cost laboratory chemistry analysis for water samples and the USGS has funded submission of data to the portal, the UGS has been able to create a state-wide network and expand our monitoring efforts. We have also been a vanguard for other states by adding a new category to the data portal to include water-quality information for springs. Because springs are an important water resource to some of our state’s public water suppliers, the USGS is currently adding a “spring” option to amend the data portal to include and recognize springs as significant water resources for other states.
The Utah monitoring network consists of approximately 100 wells and springs. We selected wells and springs in the principal aquifers of Utah (Basin and Range Basin- Fill Aquifers, Basin and Range Carbonate-Rock Aquifers, and Colorado Plateau Aquifers) and other aquifers that support withdrawals of regionally significant quantities of water. Our primary goal is to document water-quality changes over time by sampling annually, depending on funding. Additional goals include documenting water resources in a well-administered and maintained database and integrating all of our state-level water data with the nationallevel database. All of our data and stations will also be entered into the EPA’s WQX (Water Quality Exchange) for data preservation, which also feeds into the NGWMN Data Portal.
Our site selection criteria follow guidelines of the framework document prepared by the Advisory Committee on Water Information’s Subcommittee on Groundwater; the primary site selection criteria are accessibility and representativeness of aquifers of interest. Most of the sites in the UGS water-quality network are designated for “trend” monitoring, defined in the framework document as samples collected on a yearly basis. We attempt to sample each site during the season of greatest use and resample the sites during the same time of year every year.
To ensure high accessibility, most of the wells in our network are privately owned and regularly pumped. A public water supply source is included only if it is the only representative, accessible well in the area or sampled infrequently for limited water-quality chemistry (for example, only nitrate and/or sulfate every few years), and only if the location is widely known and allowed to be disclosed (such as a campground). We chose wells that have well logs or sufficient aquifer information to ensure that they represent the aquifer of interest.
We sample about 35 springs throughout the state, ranging from smaller springs in mountain blocks or mountain fronts to large regional springs. Selected springs are (1) accessible sampling points that represent major aquifer chemistry where no nearby well is available, (2) large springs that represent the integrated aquifer chemistry for an entire drainage basin, or (3) springs in mountain areas that represent the chemistry of water recharging the adjacent aquifers.
Data acquisition typically occurs during suitable sampling seasons, weather permitting, seven months of the year (April through October). Samples analyzed by the EPA follow stringent guidelines and analytical methods. For quality assurance, we collect one field blank or one duplicate sample during each monthly sampling trip. We provide each sample to the EPA laboratory within mandatory holding times. Analytical results are then compared to previously collected data for quality control and to identify possible anomalies. We also conduct a charge balance of water chemistry to verify the authenticity of data analyses. We regularly review the data in the database to ensure that sampling sites are correctly located and have the correct information associated with them.
As we expand our water-quality monitoring network (as funding allows), we will continue to supply data and maintain our connection to the USGS NGWMN Data Portal, which makes all of our data publicly available. Over time, our new network will allow us to characterize the water quality of key aquifers in Utah and allow us to fill in gaps across the state. Our water-quality sites and data are available online through the data portal at http://cida.usgs.gov/ngwmn/index.jsp, where a user can click on the Utah map to display water-quality information we have collected over the past three years (2014 to present).
Survey Notes, v. 49 no. 1, January 2017