Recent interest in the health hazards of unsafe drinking water has led researchers to the study of water supply which involves a look at how water goes from “catchment to the consumer”. Water Safety Plans (WSP) which are risk assessment and risk management reports are developed prior to the development of a water plant. Researchers are becoming more interested in how spatial analysis using GIS can be incorporated into WSP analysis.
Using a water safety plan for a groundwater supplier in North Rhine-Westphalia in Germany, researchers used GIS to evaluate how land-use patterns and watershed relationships affect the quality of the water supply. First, spatial analysis is used to map areas of vulnerability in the population such as schools or hospitals. This analysis is called a kernel density estimation and is used to understand which populations are most vulnerable to water shortages and water pollution (figure 1). The second part of the analysis is to map areas of high risk for groundwater contamination based on the land-use pattern. For example, agricultural areas present a higher risk for contamination of groundwater from pesticides than undeveloped land. Researchers used landsat images to derive these land-use patterns and the compiled map allows for a visual of how and where land-use patterns and water contamination intersect.
To understand how watershed processes affects the area, chlorine concentrations (mg/l) were calculated and mapped spatially to view how the river interacts with the aquifer. Levels high in chlorine indicate regions where the low aquifer water levels allow the river to infiltrate the aquifer. This calculation allows researchers to understand the dynamics of aquifer recharge and to see which sites of the aquifer are more vulnerable to the river’s dynamics. Lastly, a similar analysis can be conducted using nitrogen calculations to map the regions where agricultural production impacts the greatest parts of the aquifer. Overall, researchers estimated areas of high risk to lack of water access and contamination, giving an overview of the challenges for providing access to clean and quality water.
Wienand, I., U. Nolting, and T. Kistemann. (2009). Using Geographical Information Systems (GIS) as an instrument of water resource management: a case study from a GIS-based Water Safety Plan in Germany. Water Science & Technology (60.7) 1691- 1699.
I think this is an extremely valuable study considering how important access to clean water is for people, especially in developing countries. There are so many different factors that contribute to unhealthy water and this study provides a great example of how we can help monitor where clean water is, as well as monitor which water we need to focus on cleaning up. This would be an interesting study to use to do an analysis of various agricultural land practices and how they affect the surrounding water. Comparing dairy farms and other farmlands could provide interesting information on how these various practices are affecting our water supply.
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