Demarcation of groundwater potential region using GIS techniques: a case study in Nintavur DSD

An efficient planning of groundwater expansion using modern techniques is essential for the proper consumption and management of this precious but reduction natural resource. With the advent of powerful, professional techniques for water management have advance, of which GIS and RS (Geographical Information Systems and Remote Sensing) are of great significance. Groundwater resources potential has been evaluated in Nintavur DSD using GIS and RS techniques. With the help of Survey of Sri Lanka toposheets and satellite data, various thematic maps like base map, drainage map, geology map, geomorphology map, slope map, drainage density map, population density map and land use map of the study area have been prepared using Arc GIS software. These thematic maps have been integrated and appropriate weights have been assigned to various factors controlling rate of groundwater. The results show that there are four categories of groundwater potential zones ranging from very good to poor. The categorization of groundwater potential zones is in general agreement with the acquired yield data of the existing dug wells. This depicts the favourable potential zones in the study area for evaluation of groundwater resources. Finally it is concluded that the GIS and RS techniques are very efficient and useful for the demarcation of groundwater potential zones

Using geo-spatial technology to flooding potential model in Galoya river basin

Galoya River basin affected by flash flood during the north-east monsoon period. The Department of Irrigation, Metrological Department and Disaster Management Center to predict flash flood events. However, these programmes have a number of scarcities for several forecast areas in nation. Developing a GIS based model that integrates basin physiographic characteristics will allow the hydrologist to better predict flood events. In this study, I have developed geospatial model to establish the flooding potential for the upper Gal Oya river basin. The dynamic GIS parameters used to model development are slope and flow accumulation, land cover and vegetation, soil hydrologic, drainage classes and precipitation. All these layers were converted to raster datasets, using the basic attribute field responsible for flooding potential analysis each model parameter was assigned weights at the time of reclassifying, a rank of least flood potential (1) to most flood potential (9). Finally, each layers were overlayed with a weighted overlay analysis. For the weighted overlay analysis, each layer was given certain weights evaluated by their influence in flooding potential. The final flooding potential map was obtained as colored map with scale 1 to 9. This model can be easily simulated in any other basin in the nation by changing the input parameters. Study area under different flooding potential scale. More than 70% of the area is under the low to medium vulnerability with respect to flooding potential. Rest of is under high to very high flooding potential area

Web based geo-information systems: case study in Smmanthurai divisional secretary division

Geographical Information Systems are widely used tools for analyzing, processing and visualizing of geo-data. The new medium of the World Wide Web (WWW) provides a big platform to publish GIS maps to a large number of users. This new application characteristic can be called web GIS. Since the amount of spatio-temporal data stored in databases and GIS increased enormously, web GIS applications become a promising tool to display these data to a broad audience. How these datasets are displayed technically depends on the applied visualization method. One of the most important powers of GIS is the capability to publish and share geo-spatial information on the Internet among large numbers of people. Sharing of geospatial information is an important and effective way of working in many kinds of applications. Geo-spatial information includes not only maps or locations of landmarks/facilities, but multiple attribute data, socio-economic data, ground photos, aerial photographs, satellite images, etc., which may have static or dynamic characteristics. By sharing this information on the Internet, accessibility, time response, and understandability are drastically improved compared to conventional paper distribution of maps or character based Web systems. Users will have more freedom to choose information or layers to see and synthesize maps that will fit their own requirements