In February 2004, residents of the Horse Creek area, located three miles southwest of Absarokee, Montana, were granted a temporary Controlled Groundwater Area (CGWA) by the Montana Dept. of Natural Resources and Conservation (DNRC). The resulting groundwater study described herein, is a collaborative effort between DNRC, private hydrologists and local water users. The study goal is to better understand the relationship between aquifer recharge, discharge and use so that reasonable estimates can be made for the long-term health and viability of the area's groundwater system.

Measurements are made on a monthly basis and water chemistries are taken at all sites. Springs are checked for flow rates and wells are sounded for depth. Two monitoring wells have full time data loggers that track discharge and recharge on a five-minute sampling basis.





Flow rates are calculated by determining the length of time it takes to partially fill a graduated flask. The quantity of water in the flask is divided by the time recorded to give a flow measurement in gallons per minute.

Additionally, water temperature, pH and specific conductivity are measured. This information helps hydrologists tie the water to a particular aquifer.

Wells are sounded for depth (water level from the top). Data from the full time well loggers is downloaded to a database. These data are the best measurements for discharge and recharge of the associated aquifer.