The Toledo Bend Reservoir watershed (HUC 12010004) covers an area of approximately 9,440 square miles and spans both Louisiana and Texas. The hydrology of the region is largely influenced by the Sabine River, which feeds into the reservoir. The region experiences a humid subtropical climate with hot summers and mild winters. Snowfall is rare, but when it occurs, it typically melts quickly due to the mild winters. Surface water in the reservoir is primarily used for recreational activities and as a major drinking water supply for the region. The reservoir contains a variety of constituents including nutrients, sediment, and organic matter. An interesting climatic trend in the area is the increasing frequency and intensity of extreme weather events, such as hurricanes and floods, which can have significant impacts on the reservoir and its surrounding communities.