Isotope Monitoring and Water Balance Assessment of the St. Mary’s/Milk River basins

This project will continue the development of a long-term stable isotope monitoring network for the St. Mary and Milk River basins that supports source water separation and identification. A coupled isotope-hydrologic model of the basins will be applied to simulate isotopic separations and source water signatures. The model will also be used to assess the potential impacts to the water balance and source water separations under various climatic and diversion scenarios. Recent investigations have shown that the isotopic signatures of the St. Mary and Milk rivers are distinct and can be used to track sources and sinks of water in the system. This project will finalize a low-cost analysis and monitoring protocol that will assist the AOSMMRs in interpreting the natural flow and channel losses of the Milk River for improved calculation of natural flow estimation.