THREE ISSUES OF SUSTAINABLE MANAGEMENT IN THE OJOS NEGROS VALLEY, BAJA CALIFORNIA, MEXICO     San Diego State University Universidad Autonoma de Baja California Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias Southwest Center for Environmental Research and Policy

SAND MINING 1. Impacts 2. Management 3. Regulation in the United States 4. Strategies for the Ojos Negros valley 5. Summary COQUILLO 1. General 2. Yellow nutsedge 3. Purple nutsedge 4. Comparison 5. Sustainable control strategies 6. Strategies for the Ojos Negros valley 7. Summary DROUGHT 1. Definition 2. Impacts 3. Characteristics 4. Mitigation 5. Strategies for the Ojos Negros valley 6. Summary PORTAL TRES PROBLEMAS