Reduced to its most fundamental level, the management problem addressed by this project is the basic conflict between the fact that fish need water and the reality that the amount and quality of the water available has been dramatically altered by human activities. For fishes dependent upon specific flows for successful reproduction, the quality and quantity of available water are likely the primary determinants of habitat quality. In many cases, the minimum requirements of water quantity and quality needed to support self-sustaining fish populations are unknown and thus there is no way for resource managers to effectively assess habitat quality and its ability to support fish populations under current or future conditions.