GROUNDWATER LAWS AND POLICIES AFFECTING THE HEADWATERS OF THE COLORADO RIVER BASIN

Groundwater contributes more than 50 % of the flow of the Upper River Basin. Surface water is not as important a contribution to the headwaters of the Colorado River Basin as is groundwater. Governance of groundwater is largely relegated to the states, except for a few instances. Water policies in the basin are largely surface water focused. Every state in the basin has a unique approach to the allocation and management of groundwater rights, but broadly falls under the categories of correlative rights, reasonable use, or prior appropriation. Most states address areas of highest concern only when a groundwater problem exists and do not address impacts to the entire basin or the connection of the groundwater problem to surface water. Groundwater management districts occur for only about 13 % of the area of the State of Arizona. The Federal government can assert reserved water rights in limited instances, such as demonstration of historic or congressionally designated rights. Some states have a process for designating environmental flow rights, such as instream flow rights, but these designations are for surface water in the channel, not the groundwater that contributes to the surface water. An acknowledgment of the connection between surface and groundwater resources would be a major step to improving management of groundwater. An interstate groundwater compact, like the Colorado River Compact for surface water, would help the development of improved policies in the basin.