This grant will establish a network of natural scientists, social scientists and legal scholars to facilitate interdisciplinary, inter-institutional, and international research on the Colorado River delta of the U.S. and Mexico. The network will focus on how natural and human-caused variation in water supply affects the biotas and landscapes of the Colorado River delta in the United States and Mexico. Participants are from research institutions, universities, community colleges, government agencies and NGOs in both countries. The grant will support workshops, exchange visits, and a bilingual website that provides access to key literature. The landscapes and biotas of the Colorado River delta, once regulated by natural fluctuations in the river's flow, have now passed into the control of human society. The Colorado River delta is thus a microcosm for the transformation of the Earth's surface for human needs. Network activities will improve the scientific basis of water and environmental policy in this rapidly growing region. Broader impacts also include improved collaboration and coordination of research efforts among disciplines, between U.S. and Mexican scientists, and among academic, agency, and NGO scientists. Opportunities for under-represented minorities will be enhanced through the participation of community college students.