Groundwater resources: WWDO, WSGS release recharge study, interactive mapping tool

During Wyoming Water Development Office (WWDO) Water Update meetings held throughout the state in May, Karl Taboga of the Wyoming State Geological Survey (WSGS) led discussions on the WSGS Statewide Groundwater Baseflow Study, as well as the new Wyoming Groundwater Atlas tool.

Study

According to Taboga, the primary purpose of the WSGS Statewide Groundwater Baseflow Study was to obtain reasonable preliminary estimates on recharge using publicly available data.

“Specifically, what we’re interested in is recharge – or in other words, precipitation that enters the ground and goes into groundwater that later discharges to surface water bodies like springs or streams,” says Taboga.

The data collected from the mathematical model was then compared to data from other existing models.

“We evaluated our results by comparing estimates from the new model to estimates we obtained from other existing models throughout the state, as well as some selected areas,” he explains.

Results

“The results were fairly clear-cut that the highest amount of recharge occurs in areas with the most precipitation,” says Taboga.

While the explanation sounds quite basic, Taboga explains that, for Wyoming, it means the mountainous areas of the state have the greatest amount of recharge, including the northwestern mountainous region, the Medicine Bow Mountains, the Big Horns and the Black Hills.

“The areas of least recharge are the basin interiors, which are those low lying semi-arid places in Wyoming,” he comments.

He stresses that results are based on average annual recharge rates and are on a large-scale basis.

“These are best used in large-scale applications and probably shouldn’t be used on anything other than the sub-basin scale,” notes Taboga.

He continues, “This isn’t something we could say we could use for a particular year or a very small area, like an area that encompasses a few square miles. This is just a tool that would be used essentially by environmental consultants on larger scales.”

Comparisons

Taboga explains the study compared model results to those from a previous Global Information System (GIS)-based recharge model by the Wyoming Geographic Information Science Center (WyGISC).

“We also looked at two models and structural basins in Wyoming that were done by the United States Geological Survey (USGS),” says Taboga.

When results of the study model were compared to the WyGISC model, he notes, “Our results appear to be somewhat more accurate than their measurements.”

Taboga continues, “When we looked at the USGS models, the Powder River Structural Basin and the High Plains aquifer in Wyoming, we found that our numbers had fairly good agreement with the USGS models that employed a different modeling technique.”

Atlas

A new addition to their resources this spring. Taboga explains the Wyoming Groundwater Atlas is an interactive map, which allows users to visualize the location of Wyoming State Engineer’s Office (SEO) wells.

“It allows folks to get in there and look at where wells are located in their area. For the most part, SEO provides that information in tabular form on their e-permit website,” says Taboga.

The online atlas allows users to click on various wells on a map and obtain summary information that would be found on the SEO website.

“What’s really nice about it is because it’s an interactive map, we can see approximate locations of where these wells are, and we can visualize where everything is relative to one another rather than just looking at tabular data,” he continues.

He continues, “It’s a pretty exciting tool in the fact that it takes the data sets from a number of agencies and puts them all in one place where the information can be used pretty easily.”

Feedback

Taboga explains WSGS recently performed numerous water data updates in conjunction with WWDO throughout the state, where they were able to interact with a variety of attendees.

“We got a lot of interest from not only the water professionals but also from ranchers because they can go in there and look at water quality data from USGS tests, where SEO wells are located, the geology in the surrounding areas and also evapotranspiration and recharge,” comments Taboga.

Taboga notes that WSGS plans to update the atlas every one to two years, and suggestions from users are welcome.

“We’re open to suggestions about what people may like to see in the Wyoming Groundwater Atlas moving forward,” Taboga concludes.

Emilee Gibb is editor of Wyoming Livestock Roundup and can be reached at emilee@wylr.net.