The over allocation of the Colorado River's water has led to the ecological devastation of its delta and lowermost channel. The Colorado River annually delivered over fifteen million acre-feet (~1.85x1010 m3) of water to its delta but in recent years that number has been zero. In 2012, via a bi-national agreement known as Minute 319, environmental pulse flows equal to approximately 1% of the natural annual river discharge were negotiated by the United States and Mexico to be released over a five-year trial period. While this engineered environmental flow has the potential to be a restoration success story, there is a crucial gap in our knowledge: no studies on the ecology of the molluscan community in the lowermost channel of the river are available to provide a benchmark for evaluating the success of this restoration effort. The first pulse will be released in the early spring of 2014, providing a small window in which to establish a baseline for current conditions. This proposal thus seeks support to use a relatively simple community-based approach - comparison of molluscan living and time-averaged death assemblages - developed by conservation paleobiologists to establish a baseline. The samples collected will provide a unique perspective on the composition of the pre-pulse-flow community that is not available from any other source, which will allow the asking of future questions about the success of the pulse flows.
