Advances in science and technology have allowed us to ensure that our drinking water is clean and safe. However, there are still around one billion people in the world today who do not benefit from these improvements, lacking access to clean and safe water. To address this disparity, the World Health Organization (WHO) has Water Safety Plans (WSP), which are used by water suppliers to systematically assess and manage risk.
A study was conducted in North Rhine-Westphalia, a western state in Germany, to use Geographic Information Systems (GIS) as a framework for implementing a WSP in the supply of groundwater. The aquifer studied supplied water for over 36,000 inhabitants of a German town, and water treatment merely consisted of reducing acidity and occasional chlorination.
The WSP was outlined in three steps, with GIS applied in each. In the first step, system assessment and design, data was collected about land use near the drainage basin and the identification of vulnerable populations in the distribution of water. There was intensive agriculture in the northern part of the watershed, raising the possibility of nitrate pollution from fertilizer. GIS techniques were used to map out the probability of pollution in different areas of the watershed as well as clusters of populations vulnerable to water pollution, such as schools and nursing homes.
The second step was to establish a monitoring system, in which spatial analysis techniques were used to measure the interaction of river water and groundwater by the amounts of chloride as well as nitrates. Researchers used an environmental risk index to determine safe levels of nitrates and chloride in the water, and then set “threshold values.” When the levels of nitrates or chloride in the water surpassed the threshold values, the water supplier would then implement corrective action, such as working with farmers to decrease pesticide use.
In the final step, management and communication, researchers used GIS techniques such as error mapping and cross validation to ensure that their measurements were accurate.
The study found that nitrate levels exceeded threshold values in the northern part of the watershed, the site of intensive agriculture. After implementing corrective action, the use of GIS in water management was found to be successful as researchers witnessed the decrease of nitrates in the groundwater (Figure 5).
Citation: Wienand, I, Nolting U, Kistemann T. Using Geographical Information Systems (GIS) as an instrument of water resources management: a case study from a GIS-based Water Safety Plan in Germany. Water Science & Technology [serial online]. October 2009;60(7):1691-1699. Available from Academic Search Complete, Ipswich, MA. Accessed January 21, 2012.
This is a great application of GIS to a pressing problem. In Germany the nitrate were a result of intensive agriculture, but I would hypothesis when WPS is used in other parts of the world, particularly in places with less advanced (service oriented) economies like Germany, the models may show other sources of nitrate effecting the ground water. For example a country with a heavy dirty manufacturing economy may find airborne nitrogen compound given of my industry having a greater impact. I am familiar with the US and the US shows some of the same patterns where areas like Southern California of the great plain, (where major agriculture takes place) you see the same kind of risk maps.
ReplyDeleteIt's fascinating to see that GIS is so integral to literally solving problems in the real world. I hadn't thought about using GIS to map risk and probability, but now I see that this is key to using GIS as a tool to prevent issues and plan solutions. Water contamination is a huge issue throughout the world, and in the upcoming years water shortages (in part due to impure water supply) will be a growing problem. GIS technology and maps like these will surely become more and more common as well as more and more necessary/useful. I can also see how this kind of research and mapping can be useful in legal cases, where residents of an area might want to take action against companies who produce waste that damages local resources. Thanks Ellen!
ReplyDeleteI agree with Anne, I hadn't really thought of GIS as a tool to PREVENT issues instead of just mapping them out. Obviously, predicitions can be mappped fairly easily by the GIS community, but using it on a subject so incredibly important to sustain civilization is absolutely incredible. Being from West Texas, I can sympathize and empathize with the desperately needed adoption of water conservation policies. Hats off, Germany.
ReplyDelete