Total streamflow across the Marias River was last observed at 556 cfs, and is expected to yield approximately 1,103 acre-ft of water today; about 26% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 2,145 cfs, with recent peaks last observed on 2011-06-10 when daily discharge volume was observed at 18,600 cfs.

Maximum discharge along the river is currently at the Marias River Near Shelby Mt reporting a streamflow rate of 556 cfs. This is also the highest stage along the Marias River, with a gauge stage of 3.42 ft at this location. This river is monitored from 3 different streamgauging stations along the Marias River, the highest being situated at an altitude of 3,099 ft, the Marias River Near Shelby Mt.

The Marias River is a tributary of the Missouri River, spanning a length of approximately 210 miles in Montana. The river is named after the French explorer, Marias, who first discovered it in 1806. The hydrology of the Marias River includes a snowmelt-dominated flow with high seasonal variability. There are several reservoirs and dams along the river, including Tiber Dam and Lake Elwell, which are primarily used for irrigation and hydroelectric power generation. Recreational activities such as fishing and boating are popular among tourists and locals. Agriculture is also a significant industry along the Marias River, with crops such as wheat, barley, and hay being grown in the area. Despite being a relatively small river, the Marias River has played an essential role in the history and economy of Montana.