The Mermentau Headwaters Watershed (HUC 08080201) is located in southwestern Louisiana and covers an area of approximately 1,076 square miles. The hydrology of the watershed is dominated by the Mermentau River, which is fed by several small streams and tributaries. The region experiences a humid subtropical climate, with hot summers and mild winters. Snowfall is rare in this area. Surface water in the watershed is used for irrigation, recreation, and drinking water supply. The watershed also contains several small reservoirs, which are used for flood control and recreation. The most common reservoir constituents are sediment and nutrients. Interesting climatic trends in the region include an increase in extreme weather events, such as hurricanes and severe storms, as well as changes in precipitation patterns. These trends have the potential to impact the hydrology and water quality of the Mermentau Headwaters Watershed in the future.