As they relate to water resources, different types of compacts and interstate agreements are intended to equitably divide and apportion waters within and between states in order to settle existing or future controversy concerning the utilization of those waters. Colorado has numerous intrastate agreements among its stakeholders, and in terms of its interstate waters, nine interstate compacts, two Supreme Court equitable apportionment decrees, two memoranda of understandings/agreements and two international treaties govern how much water the state is entitled to use and consume (Colorado Division of Water Resources [DWR], 2006; Colorado Water Conservation Board [CWCB], n.d.; State of Colorado, 2015; Colorado Foundation for Water Education [WEco], 2015). Although these different compacts and agreements determine the amount of surface water allocated between and within each state, due to the connected, inter-dependent nature of surface and groundwater, they also impact how much groundwater can be pumped by each state.
The following sections outline a few of Colorado’s intrastate compacts, its nine interstate compacts, two Supreme Court equitable apportionment decrees, two memoranda of understandings/agreements and two international treaties.