This report investigates the role of instream flows as part of a program to protect and recover certain water-dependent endangered species. For the purposes of this report, instream flows are defined as non-consumptive, in-channel flows of water. We examined two case studies of endangered fish species programs that included instream flows, one on the upper Colorado River and one on the San Juan River. Cost savings with cooperative recovery programs are calculated. Scenarios involving increased instream flows are evaluated to estimate what the cost savings might be to water developers from additional instream flow appropriations and acquisitions by the Colorado Water Conservation Board.