Opportunities for ecological improvement along the lower Colorado River and delta

Abstract

The lower Colorado River mainstem and delta have been severely damaged by a variety of human-related activities, including river impoundment, agriculture, water diversions, introduction of exotic plants and fishes, and ground-water pumping. In some areas, the native wetland habitat that formerly dominated this region has disappeared completely. Nevertheless, there are areas where significant wetland habitat persists as a result of incidental circumstances or purposeful restoration actions. These areas provide important conservation and restoration opportunities. In this investigation, nine restoration efforts along the lower Colorado River from Parker Dam to the delta region were evaluated to learn how lessons from these experiences can benefit future ecological restoration efforts. In addition, we assessed the general ecological condition of this reach to identify critical native wetland plant communities and recommend strategies for protecting these areas in the future. It is apparent that wetland ecosystems in both the delta and the mainstem would benefit if effluent waters were allocated to support wetlands rather than allocated to evaporative basins. Other important strategies for improving the ecological condition of the river should include altering reservoir releases, improving the effectiveness of revegetation efforts, and developing bi-national, collaborative approaches involving local communities and landowners to identify and carry out projects that benefit both them and the ecological condition of the river.