It is increasingly recognized that a river’s flow regime is a master variable dictating river health. A current challenge for water resource managers, hydrologists and aquatic ecologists is predicting the acceptable levels of manipulation to the natural flow regime before a threshold is reached that causes unacceptable impacts to the aquatic ecosystem.
Connecticut provides a representative case study of the river management paradox experienced globally. In 2005 the state passed Public Act 0154 with the goal of protecting aquatic ecosystems by maintaining the “natural variation of flows” within state streams. However, human needs including water supply, public health, flood control, and industry are met by manipulating these natural variations. As is common with policy mandates, the goals of PA 0154 are colossal, the timeframe for promulgation inadequate, and the potential objectors diverse and resourceful.
This study proposes a comparative analysis of a subset of streams within the lower New England Northern Piedmont ecoregion (of which Connecticut is a part) across a gradient of water withdrawals to explore site-specific stressor response relationships. Streams representing varying degrees of water supply diversions will be compared with reference streams using indicator variables with established hydro-ecological relationships. Seven indicator variables have been selected based on these relationships and available data. Data results will be used to project a best-fit curve for each indicator identifying regionally specific stressor-response relationships.