GIS in Water Management

Water is an essential resource for sustaining life and the economy, but water resources are scarce. Virtually all human uses of water require freshwater. However, of all water on Earth, 96.7% is saltwater, while over two thirds of freshwater is frozen in the glaciers of Antarctica and Greenland. Thus, we are left with only 0.9% of the globe's water for our use. This fact, combined with the needs of the growing population, obliges efficient management of water resources. Well-organized water management systems may help people use the limited water resources wisely. Applying geographic information systems (GIS) in water management greatly improves its effectiveness. To facilitate water management, many [Page 1317]hydrologically oriented pieces of software have been developed. Together with an abundance of spatial data generated specifically for hydrologic analyses, such software offers the necessary environment for using GIS in water management.

The management of water resources involves the design, implementation, and development of an organizational, technical, and legal structure for optimizing the exploitation, protection, and monitoring of water systems. Water management tasks range from preserving water for environmental protection and irrigation, to maintaining sewage systems in towns, to the supervision of international water resources on the surface (rivers, lakes, and wetlands) as well as underground (aquifers). Some highly complex water resources are managed under defined local regulations and/or international treaties. The World Bank projects that by 2030, 3 billion people will be living under conditions of severe water shortage. Countries receiving their water supply from across national boundary waters with limited availability experience increasing tension over water rights. Such stress over scarce water resources creates the risk of conflict.

Water management practices may be organized into the following major categories:

• Water treatment for drinking water and wastewater
• Water resources for agricultural, industrial, transportation, domestic, environmental, and recreational purposes
• Flood protection practices along rivers exhibiting flood dangers caused by sustained rainfall or rapid snowmelt and along seacoasts exhibiting flood dangers caused by severe sea storms, tsunamis, or hurricanes
• Irrigation for assisting the growing of crops in dry areas and in periods of rainfall shortfalls
• Groundwater, aquifers, and water tables

In all the above categories of water management, GIS is applied. Management of water resources and flood protection are the two main areas where GIS has been used for many years. For hydrologic analyses, GIS is an essential and indispensable tool.

GIS facilitates the ability to store, retrieve, process, and display spatial data, including data related to surface and groundwater resources and water utilities. GIS-based watershed resource inventories provide information about elevation, slope, topography, soil properties, geology, land cover, flood zones, water reservoirs and their capacity, water quality, precipitation and other relevant climate variables, and demographic and socioeconomic issues. Data management of any watershed would not be feasible without a well-designed database, which is provided by GIS.

GIS is critically important when the spatial dimension of phenomena and their dynamic changes need to be modeled. GIS technology can help with finding spatial relationships in complex systems, with locating problems, and with planning alternative solutions using a variety of means, including simulations. With this, GIS provides a framework for a computer-based water management system that can be effectively applied to both large and small scales.

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