Interrelationships among landscape, NDVI, and stream water quality in the U.S. Central Plains

Abstract

During late spring through summer of 1994 and 1995, 290 randomly selected stream sites in Nebraska, Kansas, and Missouri were sampled once for several parameters including conductivity, turbidity, total phosphorus, nitrate–nitrite nitrogen, the index of biotic integrity, and a habitat index. Based on landscape data from watersheds that were delineated for each sampling location, interrelationships were examined between these water quality parameters and land use/land cover, the normalized difference vegetation index (NDVI), and vegetation phenological metrics derived from the NDVI. Statistically significant relationships were found between NDVI values and the derived metrics with the stream condition parameters (r values to 0.8, α = 0.05). The NDVI or vegetation phenological metrics (VPMs) were more highly correlated to the selected stream condition parameters than were the land use/land cover proportions. Knowledge of the general land use/land cover setting within the watersheds, however, was important for interpreting these relationships. The most common variables associated with the stream data were early spring NDVI values or VPMs associated with the date of onset of greenness. These results demonstrate the utility of NDVI and VPMs as broad-scale environmental indicators of watershed conditions.