Against the Flow: Emerging Conflicts Between Endangered Species Protection and Water Use

The Endangered Species Act (ESA)1 was intended by Congress to afford listed species the highest of priorities.2 Its uncompromising standards have made it the statute of choice among members of the environmental community in challenging resource development projects where federally listed species are involved.

Species are formally listed as either threatened3 or endangered4 pursuant to section 4 of the Act.5 A listed species' habitat may also be designated as critical habitat and thus afforded protection. Once a species is listed as [23-3] threatened or endangered or once a habitat is designated as critical, the ESA and its attendant impact is officially triggered.6

It is well recognized that habitat destruction is the major threat to threatened and endangered species.7 Perhaps nowhere is the conflict between resource utilization and species protection more apparent than with respect to our nation's waters.

The diversion and use of water to meet the needs of industry, agriculture, and growing municipalities in the West is regarded by many as a paramount prerogative under state water rights. Yet the exercise of such rights is not without its impacts. Water use leaves less water in the stream. Water diversions may also change the nature and timing of historic peaks and valleys of river flow. Alterations in return flow patterns may encourage different ve