Specifications include, but are not limited to: Per statute, the Texas Water Development Board (TWDB) is tasked with developing numerical groundwater flow models of the major and minor aquifers in Texas. The Cross Timbers Aquifer was designated as a new minor aquifer in December 2017. The aquifer consists of four Paleozoic-age water-bearing formations including, from oldest to youngest, the Strawn, Canyon, Cisco, and Wichita groups. The aquifer is primarily composed of limestones, shales, and sandstones. This project will compile and analyze data related to climate, geology, hydrostratigraphy, water levels, crossformational flows, aquifer recharge, surface water features, hydraulic properties, natural and man-made discharge, and water quality in the study area. Specifically, this project will also collect, analyze, and interpret available data related to the Cross Timbers Aquifer including possible flows between the overlying Trinity and Seymour aquifers and underlying geologic units, and flows between the Paleozoic units that comprise the aquifer. The project will also investigate and recommend an appropriate boundary for the future model. We have tentatively set the study area from where the Strawn Formation meets the Ouachita Fold Belt to the east, the southern Oklahoma Aulacogen (Fault Zone) to the north, the eastern edge of the Blaine Aquifer to the west, and where the Permian units are truncated by the Llano Uplift Area to the south. In addition, data analysis will include predevelopment to at least 2015 or more recent times. This project will develop the conceptual model that will later be used to develop a groundwater availability model of the aquifer.