The Arbuckle-Simpson Aquifer (ASA) Phase II project is developing a science-based Site-Specific Assessment Scheme (SAS) to evaluate proposed groundwater withdrawals within the ASA. Building on the regional studies completed during ASA Phase I, the project combines an interdisciplinary approach to evaluate how groundwater use may affect connected springs and streams. ASA Phase II includes strengthening the regional hydrogeologic framework; conducting detailed investigations at four representative groundwater use settings; and developing a standardized assessment framework that will be applicable to sole source karst aquifers like the ASA, support future groundwater use evaluations and long-term monitoring in accordance with Oklahoma Water Law.