WE PROPOSE TO DEMONSTRATE AND IMPLEMENT REMOTE-SENSING BASED VIRTUAL STREAM GAGES TO IMPROVE OPERATIONS OF GOVERNMENT AGENCIES THAT COLLECT AND RELY ON STREAMFLOW DATA: U.S. GEOLOGICAL SURVEY STREAMFLOW INFORMATION PROGRAM FOR ALASKA (USGS) - COLLECTS AND PUBLICALLY DISSEMINATES STREAMFLOW DATA ALASKA DEPARTMENT OF TRANSPORTATION (AKDOT) - USES USGS STREAMFLOW DATA TO DESIGN BRIDGES AND HYDRAULIC STRUCTURES AND TO OPERATE THE STATE HIGHWAYS DURING FLOODS . NATIONAL WEATHER SERVICE-ALASKA-PACIFIC RIVER FORECAST CENTER (NWS-RFC) - USES USGS DATA TO RUN OPERATIONAL HYDROLOGIC MODELS AND MAKE FLOOD FORECASTS AND WARNINGS THIS EFFORT WILL MARK A HISTORIC MILESTONE IN ADOPTING OPERATIONAL SPACE-BASED STREAMFLOW (DISCHARGE) MEASUREMENT. USGS IS THE LEAD FEDERAL AGENCY FOR MONITORING RIVERS IN THE US AND A WORLD LEADER IN TECHNIQUES AND METHODS FOR RIVER DISCHARGE MEASUREMENT. THE AKDOT AND NWS-RFC ARE LONG-TERM PARTNERS OF THE USGS AND ARE REPRESENTATIVE OF THE HUNDREDS OF GOVERNMENT AGENCIES IN THE US WHOSE OPERATIONS DEPEND ON STREAMFLOW DATA. THIS PROPOSED COLLABORATION WILL: 1) OPERATIONALIZE SPACE-BASED METHODS FOR USGS RIVER MONITORING IN ALASKA 2) DEMONSTRATE USE OF REMOTELY SENSED STREAMFLOW DATA BY OTHER PUBLIC AGENCIES 3) DEVELOP AN ENSEMBLE APPROACH FOR COMPUTING RIVER DISCHARGE LEVERAGING MULTIPLE SATELLITES (JASON-3 SENTINEL-2 SMAP ICESAT-2 AND LANDSAT) AND DISCHARGE ALGORITHMS 4) DEVELOP METHODS AND WORKFLOWS THAT CAN BE ADOPTED NATIONALLY AND GLOBALLY SPATIALLY DISTRIBUTED ESTIMATES OF DISCHARGE PROVIDE CRITICAL INFORMATION FOR WATER-RESOURCE AND INFRASTRUCTURE MANAGEMENT. WHILE THIS NEED COULD BE MET THROUGH A DENSE-SPATIAL COVERAGE OF GROUND-BASED MONITORING STATIONS IN REALITY GROUND-BASED MONITORING NETWORKS ARE LIMITED BY HIGH COSTS AND ESPECIALLY IN ALASKA BY REMOTE AND HAZARDOUS FIELD CONDITIONS. FOR EXAMPLE THE SPATIAL DENSITY OF GAGING STATIONS IN THE LOWER 48 STATES IS 16 TIMES HIGHER THAN IN ALASKA. SO NEW METHODS ARE NEEDED TO INCREASE THE EXTENT AND DENSITY OF STREAMFLOW DATA COVERAGE. A VIRTUAL STREAM GAGE NETWORK (VSN) WILL BE DEVELOPED AND TUNED WITH GROUND-BASED OBSERVATIONS. TIME-SERIES STREAMFLOW DATA WILL BE POSTED AS AN INTERNAL PRODUCT ON THE USGS NATIONAL WATER INFORMATION SYSTEM (NWIS) ONLINE DATA PLATFORM FOR USE BY USGS AND PARTNER AGENCIES. THROUGH THIS EFFORT USGS AK STAFF WILL BE TRAINED TO OPERATE THE VSN AND USE THE NEW TECHNIQUES AND METHODS FOR DATA COLLECTION QUALITY CONTROL AND ONLINE DISSEMINATION. AKDOT AND NWS-RFC WILL BE INVOLVED THROUGHOUT THE EFFORT AND WILL BE TRAINED ON APPLICATION OF THE RS STREAMFLOW DATA. WE ANTICIPATE THAT THE METHODS DEVELOPED IN THIS EFFORT FOR PRODUCING REMOTELY SENSED (RS) STREAMFLOW DATA AND ALIGNING DATA PRODUCTION WITH THE NEEDS END-USER AGENCIES WILL BE A MODEL FOR WIDER ADOPTION IN THE US AND GLOBALLY.