Potential influence of climate and anthropogenic variables on water security using blue and green water scarcity, Falkenmark index, and freshwater provision indicator.

Land use change and climate variability have significantly altered the regional water cycle over the last century thereby affecting water security at a local to regional scale. Therefore, it is important to investigate how the climate, land use change, and water demand potentially influence the water security by applying the concept of water footprint. An integrated hydrological modeling framework using SWAT (Soil and Water Assessment Tool) model was developed by considering both anthropogenic (e.g. land use change, water demand) and climatic factors to quantify the spatio-temporal variability of water security indicators such as blue water scarcity, green water scarcity, Falkenmark index, and freshwater provision indicators in Savannah River Basin (SRB). The SRB witnesses a significant change in land use land cover (e.g. forest cover, urban area) as well as water demand (e.g. irrigation, livestock production). Overall our results reveal that, SRB witnessed a significant decrease in blue water due to the climate variability indicating that the precipitation has more control over the blue water resources. Whereas, green water was more sensitive to changes in land use pattern. In addition, the magnitude of various water security indicators are different within each county suggesting that water scarcity are controlled by various factors within a region. An integrated assessment of water footprint, environmental flow, anthropogenic factors, and climatic variables can provide useful information on the rising (how and where) of water related risk to human and ecological health.

Winter storm Uri and temporary drought relief in the western climate divisions of Texas.

Texas ranks first in the United States in the variety and frequency of most natural disasters, such as flooding, wildfires, hurricanes, winter storms, and droughts. In February 2021, the winter storm named Uri caused an abnormal decline in the air temperature in the southcentral United States, notably in Texas. Right before Uri, most of Texas was going through a drought spell. Thus, this study analyzed how Uri influenced the drought severity, soil profile moisture content, and vegetation cover (Normalized Difference Vegetation Index, NDVI) across Texas. Data used in this analysis was obtained from the web-based geospatial applications gridMET and Crop-CASMA. The collected datasets include the Palmer Drought Severity Index (PDSI), Snow Water Equivalent (SWE), soil moisture, and NDVI at different spatial resolutions. These datasets were aggregated to the county scale using the zonal statistics analysis. The strength of the correlation between SWE and soil moisture was quantified based on the Pearson correlation coefficient. The percentage change in live vegetation cover due to the impact of the frigid temperature and snow coverage across the state was quantified by analyzing the average weekly NDVI before and after the winter storm. There was a reasonably strong correlation between the SWE contribution of Uri and the increase of the rootzone soil moisture (Pearson's r = 0.42). Similarly, the SWE showed a higher correlation with daily rootzone soil moisture with a Pearson's correlation coefficient of 0.49 on March 1. Furthermore, our results revealed a reduction in the NDVI values to less than 0.60 across Texas during the third week of February. Overall, Texas NDVI values seriously decreased due to Uri. Despite its disruptive effects on the state infrastructures and the economy, Uri snow lessened the drought conditions relatively for a short time.