As a longtime Sierra Club member and strong environmentalist, I am heartened that you opposed Poseidon's efforts to build potentially harmful facilities. But I think we need to be careful not to oppose...and in fact to encourage...desalination in the longer term. Continuing to draw down groundwater aquifers is at least as damaging to the environment, and pulling water from the Colorado River and San Francisco Bay is increasingly opposed by local groups and others who want a larger share of those dwindling sources. In the long run, we have two options here in southern CA: Reduce the demand for water or find another source. Since most of the water goes for agriculture, reducing residential demand can have only a limited effect, which will be largely offset by a population that continues to grow. The answer has to be desalination. We just have to make sure that it is done correctly