CLIMATE CHANGE AND INCREASED IRRIGATION DEMAND HAVE CAUSED A SURGE IN HYDROELECTRIC DAM CONSTRUCTION IN THE MEKONG RIVER BASIN. WHILE THESE INTERVENTIONS HAVE RESULTED IN AGRICULTURAL BENEFITS AND FOOD SECURITY IN SOME AREAS THE ECOLOGICAL CONSEQUENCES TO LAKE AND WETLAND ECOSYSTEMS ARE SIGNIFICANT BUT NOT FULLY UNDERSTOOD. THE COMPLEXITY OF INTERACTIONS AT THE INTERFACE OF LAND USE DECISIONS CLIMATE CHANGE AND LAKE/WETLAND ECOSYSTEMS IN THE LOWER MEKONG RIVER BASIN (LMRB) PRESENTS A GRAND CHALLENGE TO SUSTAINABLY MANAGE NATURAL RESOURCES AND BUILD RESILIENT COMMUNITIES. IT IS NOT CLEAR HOW DAM CONSTRUCTION AND IRRIGATION EXPANSION IN UPSTREAM AREAS WILL AFFECT PHENOLOGY AND BIOGEOCHEMISTRY IN DOWNSTREAM WETLAND ECOSYSTEMS SUCH AS TONLE SAP LAKE. THUS THERE IS A CRITICAL NEED TO QUANTITATIVELY UNDERSTAND AND MODEL DYNAMIC INTERACTIONS ACROSS THESE REMOTELY CONNECTED LAND AND WATER SYSTEMS. THE PRIMARY GOAL OF THE PROPOSED RESEARCH IS TO IMPROVE OUR UNDERSTANDING OF HOW HUMAN ACTIVITIES (DAMS AND ASSOCIATED IRRIGATION) AFFECT ECOLOGICAL PROCESSES IN WETLANDS AND TO PROVIDE A SCIENTIFIC BASIS FOR IMPROVED OPERATION OF DAMS TO HELP MITIGATE THE EXPECTED EFFECTS OF CLIMATE CHANGE. THE OBJECTIVE OF THIS PROPOSED EFFORT IS TO ASSESS AND MODEL THE IMPACTS OF DAM CONSTRUCTION AND ASSOCIATED IRRIGATION ACROSS THE LMRB ON THE PHENOLOGY AND BIOGEOCHEMISTRY OF KEY WETLAND ECOSYSTEMS. THIS PROPOSED PROJECT ADDRESSES "SUBELEMENT 2: ECOLOGY AT LAND/WATER INTERFACES - HUMAN AND ENVIRONMENTAL PRESSURES" OF THE 2016 ROSES CALL FOR PROPOSALS. USING REMOTELY SENSED DATA PROCESS-BASED HYDROLOGY AND BIOGEOCHEMISTRY MODELS AND TRADE-OFF FRAMEWORK ANALYSIS WE PROPOSE TO: 1. MAP AND QUANTIFY CHANGES IN DAM SITE CHARACTERISTICS AND CATCHMENT LAND USE/IRRIGATION USING SATELLITE AND AIRBORNE IMAGES FROM NASA JAXA AND ESA PLUS CLIMATE OBSERVATIONS FROM THE LMRB; 2. SIMULATE THE EFFECTS OF EXISTING AND PROPOSED DAMS AND ASSOCIATED IRRIGATION ON STREAMFLOW WETLAND/LAKE LEVELS AND SEDIMENT TRANSPORT ACROSS THE LMRB; 3. QUANTIFY SPATIAL AND TEMPORAL CHANGES IN STREAMFLOW DUE TO DAM AND IRRIGATION MANAGEMENT AND THE IMPACTS THESE HAVE ON WETLANDS; AND 4. ANALYZE TRADE-OFFS IN ECOSYSTEM SERVICES ACROSS SPACE/TIME AND ECOLOGICAL AND ADMINISTRATIVE BOUNDARIES WITH A FOCUS ON AGRICULTURAL PRODUCTION HYDROPOWER GENERATION AND WETLAND FUNCTION. EXPECTED OUTCOMES 1. IMPROVED UNDERSTANDING OF DYNAMIC INTERACTIONS AT THE INTERFACE OF DISTANTLY CONNECTED LAND DECISION/DAM AND WETLAND ECOSYSTEMS IN THE LMRB; 2. A REGIONAL NETWORK IN THE LMRB TO PROMOTE AND APPLY SPATIAL TECHNOLOGIES AND PRODUCTS FROM NASA AND OTHER AGENCIES TO ADDRESS REGIONAL CHALLENGES IN WATER ENERGY AND FOOD SECURITY; 3. A SUITE OF PRODUCTS INFORMATION AND ANALYTICAL TOOLS THAT INCLUDE DETAILED CHARACTERISTICS OF DAMS IRRIGATED LANDS AND WETLANDS; 4. FUTURE TRAJECTORIES OF REPRESENTATIVE WETLAND PHENOLOGY AND GREENHOUSE GAS EMISSIONS; 5. IMPROVED UNDERSTANDING OF TRADE-OFFS AMONG ECOSYSTEM SERVICES AND STRATEGIES TO SUSTAINABLY MANAGE DAMS WITH FULL CONSIDERATION OF LAKE/WETLAND ECOLOGY. SIGNIFICANCE AND SOCIETAL RELEVANCE THE PROPOSED EFFORT INTEGRATES INTERDISCIPLINARY SCIENCES PROCESS-BASED MODELING AND REMOTE SENSING TO IMPROVE THE UNDERSTANDING OF THE IMPACTS OF HUMAN ACTIVITIES (DAM CONSTRUCTION&OPERATION IRRIGATION) ON LAKE/WETLAND ECOSYSTEMS. WE WILL ANALYZE TRADE-OFFS BETWEEN ECOSYSTEM SERVICES IN SPACE AND TIME AT THE INTERFACE OF LAND AND WATER SYSTEMS. A COMBINATION OF WATERSHED SCALE MODELING WITH COMMUNITY LEVEL CASE STUDIES PROVIDES AN EXAMPLE OF HOW EARTH SYSTEM PROCESSES CAN AFFECT THE LIVELIHOODS OF LOCAL COMMUNITIES WHICH MAY BE GENERALIZED TO OTHER GEOGRAPHIC AREAS. THE ACTIVE INVOLVEMENT OF GRADUATE STUDENTS AND LOCAL PARTNERS CULTIVATES THE NEXT-GENERATION OF RESEARCHERS AND ENHANCES THE CAPACITY OF LOCAL RESEARCHERS TO TACKLE CHALLENGING PROBLEMS IN THE LMRB.