Study Area:

The Upper Choctawhatchee Subbasin (UCS) is in Southeast Alabama. It is a Subbasin of the Hydrologic Unit Code (HUC) of 03140201 (Seaber, Kapinos et al. 1987). The area is in East Golf Coast Plain physiographic section of Alabama. It is heavily forested, mainly Evergreen land cover type (FRSE), based on National Land Cover Database (NLCD) land cover classification derived from Multi-Resolution Land Characteristics (MRLC) Consortiums (MRLC-Consortium 2019). The second large land cover is Agricultural Land with 15.4 percentage of the UCS area. The main crops are cotton and peanut. Other crop types are corn, soybean, pecans, and sorghum (Hinson, Rogers et al. 2015). The percentage of all classes of urban land cover adds up to 8%. It comprises of different land cover classes. Table 1 illustrates the main land use and their coverage area. The total drainage area is 3940 km2.The UCS is located between longitudes -86 and -85.26 and latitudes 31 and 31.88. The topographic characteristic of the area can be described as alluvial flood plains, prairies, sharp ridges, and gently rolling hills. Geologic structures are originally made from sediment; these units underlie the Coastal Plain and consist of sand, gravel, porous limestone, chalk, marl, and clay (Hinson, Rogers et al. 2015). According to the Index of Biotic Integrity, the biological stream condition of the subbasin and the Pea River Subbasin (located at the west of the UCS) is as follows: 64% is rated very poor to fair, 30% Is rated good and 6% is rated excellent (O’Neil, Shepard et al. 2006; Hinson, Rogers et al. 2015). Farmers have been using traditional ways of irrigation, thus undeveloped agricultural practices as a sign of lack water management could pose threats to the already-degraded ecosystem. Climate in the region is considered to be sub-tropical, consequently, it is humid with hot summers and mild winters. Annual mean temperature is around 18.5℃. Average daily temperature for cold time of the day is 18.5℃ as opposed to 32℃ as the hottest moment. Average annual precipitation ranges from 1295 mm to 1422 mm (USWeatherService 2019). Figure 1 illustrates the area of study.