application of gis in site selection for dams ppt

[HOTGUYS2121]

application of gis in site selection for dams ppt

ABSTRACT Analysis of Color Aerial Photographs inconjuction with several software programs, on the HRH Tasneem Bint Ghazi for Agriculture Research was used to evaluate the relative effectiveness of this product, and the potential role of each software programme for preparing several thematic layers as an input to GIS data model in order to locate Dams in the two main drainage basins, Wadi ad Dafali and Wadi Umm Qatffa. The study area is an approximately 12 km2 tract located in western Jordan and includes major segments of two physiographic province, the Jordan Rift and Hilly terrain. From the results of the six thematic layers in Wadi ad Dafali basin, there are two suitable locations for dam sites. From the results of the six thematic layers in Wadi Umm Qatffa basin, there is no suitable dam site exist in the basin due to the effects of structural and lithological factors. KEYWORDS: Color Aerial Photographs, Tectonic Lines, Dams and ArcGIS LOCATION, SCOPE AND ACCESS. The study area is an approximately km2 tract located in western Jordan (Figure1), and includes major segments of two physiographic province, the Jordan Rift and Hilly terrain. The first comprises part of the Jordan Rift, 200 m below sea level. This is a tectonic depression filled by Upper Tertiary and Quaternary deposits (such as the Lacustrine Lisan Marl, the alluvial fan deposits of the Pleistocene age, and the Recent fluvial deposits related to the river Jordan and its tributaries). The second terrain system comprises a hilly terrain reaching up to 580 m. in elevation. Here the moderate rainfall, the folded strata, and the presence of faulting have combined to form a hilly region of diversified scenery and innumerable outcrops of sandstones, marl, shales, clays and limestones. The hilly region has been heavily modified by fluvial erosion during the fluvial periods of the Pleistocene-Recent.

The study area can be reached via the asphalted road Subeihi-Zay. There is one main asphalted road in the study area, whereas many tracks; some of them date back to Roman ages, make most of mapped area accessible by four wheel drive vehicles in normal weathers, although some of these tracks become muddy and inaccessible following winter rains.

JUSTIFICATION FOR CHOICE OF HRH TASNEEM BINT GHAZI FOR TECHNOLOGY RESEARCH STATION The study area possesses a broad range of the surface conditions and has economic problems typical of the those which occur throughout the Jordan Rift Valley and Hilly Terrain such as : severe soil erosion, poor and thin soil, mass-wasting, vegetation sparse and rare surface water, consequently results in this area should have a wider applicability. The area is backward and underdeveloped. This study shall prepare a detailed environmental impact analysis of proposed Dams and irrigation management plan in the Wadi Umm AL- Qutffa Basin and Wadi ad Dafali. Therefore, it attempts to asses the present problems of the area and provides suggestive measurement for the irrigation improvement of both Basins after the construction of the proposed Dam. Various information layers were integrated through GIS software ArcGIS using overlay methods. Suitable site selection of the proposed Dams using the ArcGIS has been performed. STATEMENT OF OBJECTIVES The study has three major objectives: 1. To generate thematic maps of various natural resources. 2. To integrate the thematic maps through the GIS software ArcGIS. 3. To define the location of the proposed dams in the study area. METHODOLOGY The major goal of this study is to develop a viable methodology for producing GIS data model for preliminary location dams, using ArcGIS

This study is carried out by combining the features of color aerial photography, topographic sheets and secondary maps data to produce the necessary information layers of natural resources. The input data resulted all of the above diverse sources are translated into the thematic maps by the methods of: Visual interpretation. Classification. Manipulation. Integration. Editing and Analysis. The data translated into thematic maps employ the GIS software ArcGIS. The multi layer thematic maps generate necessary information to provide detail insight to make site-specific decisions. In this study, color aerial photographs data plays a vital role in the generation of the overlays.

BUILDING LAYERS AND ATTRIBUTES
It is impossible to perfectly capture reality inside a computer. Instead, GIS users must somehow abstract real-world phenomena, or entities, into a geometric representation of those entities. The three basic geometric shapes used: points, lines, and areas. These shapes are often called geometric objects, geometric features, or feature types. The project has been divided to several features, trying to capture all the data needed to analysis and manipulation, the area has been divided in to two sets: one described general information about the study area build from the registered digital base map, and the other for each basin build from the scanned, registered hard copy map.

ANALYSIS AND QUERIES
The integration of different data layers involves a process called overlay. At its simplest, this could be a visual operation, but analytical operations require one or more data layers to be joined physically. This overlay, or spatial join, used for integrate data for Dams most suitable sites. GIS query is to determine which location or locations satisfy certain conditions. In this case the user knows what characteristics are important, and wants to find out where the features are that have those characteristics. In our project query and overlay help us to find:
1. The number of streams in each stream order.
2. Lengths of the streams and area of the basins.
3. Location of the points which have highest and lowest number of lineaments.
4. Determination of the most suitable location of dams and water wells based upon our own interpretation.

In engineering sites selection for dams we have to take the following requirements in our consideration:
1. Low drainage density: less sediment that the streams carry in order to increase the life-time of the dam.
2. Hard rock in the site of the dam.
3. Higher rainfall.
4. Low tectonic lines contour-density: to avoid internal movement of water.
5. The dam-site is in anti-dip valley, in order to collect water.
6. High rainfall percentage.
7. Less evaporation.
8. The largest catchments area is to collect the largest amount of water.
9. Choose a place that doesn t affect the natural aquifers. 10. Choose a place that we can use the gravity forces to transport water to where we need.

RESULTS AND DISCUSSION
In a carefully surveyed, large-scale map of a single drainage basin in Wadi ad Dafali (Figure 3). The main stream display right-angle bends (i-e., Rectangular drainage pattern), whereas its tributaries display irregular branching in many directions and at almost any angle less than a right angle, (i-e., dendritic drainage pattern).

CONCLUSION
The old adage better information leads to better decision is as true for GIS as it is for other information systems. A GIS, however, is not an automated decision making system but a tool to query, analyze, and map data in support of the decision making process. GIS technology has been used to assist in tasks such as presenting information at planning inquiries. A methodological approach in conducting a research using GIS was presented selecting location of dam s sites as a case study. The GIS can be utilized in two ways. First, to input, store, organize and analyze the data available. Secondly, the spatial analysis, visualization and query capabilities of GIS can be employed in selecting the dams sites for a precondition set of criteria. This paper has shown the GIS, can be a powerful tool in planning, managing a research work involving spatial data analysis, particularly in site suitability studies.