The Lower Henrys Watershed (HUC 17040203) covers an area of approximately 1,054 square miles in southeastern Idaho. The watershed is predominantly mountainous and is characterized by its cold and snowy winters. The hydrology of the watershed is dominated by three major rivers: the Blackfoot, Portneuf, and Bear Rivers. These rivers play a critical role in the watershed, providing surface water for irrigation, drinking water, and recreation. The specific snowpack varies depending on the elevation and geographic location within the watershed. The reservoirs within the watershed are primarily used for irrigation and flood control. The primary constituents of the reservoirs are sediment and nutrients, which can contribute to algal blooms in the summer months. There is a trend towards increased precipitation and warmer temperatures in recent years. These changes could have significant impacts on the hydrology of the watershed and the availability of water resources.