Spatial and temporal variability of vegetation greenness have been determined for coastal Texas using biweekly Normalized Difference Vegetation Index (NDVI) data derived from the Advanced Very High Resolution Radiometer (AVHRR). Results are presented on relationships between ground cover vegetation characteristics, surface freshwater flow, and NDVI within the Lower Galveston Bay (Texas) watershed as they relate to salinity changes in Galveston Bay during 1985-1991. Variance in NDVI occurred in response to cyclical changes in climate and water management practices and is shown to be a strong indicator of non-gauged freshwater flow which affects the salinity regime of the Galveston Bay estuary