1: Source identification:
The remote sensing technology is an effective tool for the identification of suitable sites for locating new hydropower projects especially in the inaccessible areas like Himalayas where the water recourse potential is high. Remote sensing data available in the near infrared region (0.8um - 1.1 um) provides clearly the contrast between land and water features can easily be discernable.
Most of Meteorological data (river flow data, temperature, solarity, relative humidity, wind speed etc.) and Aerial Climatographical data (digital/paper maps of precipitation, evaporation, temperature, snow cover, relative humidity, wind direction etc.) are obtained and interpreted with the help of GIS in knowledge base environment.
2: Site selection:
Building a hydropower station in a rugged terrain such as in the Himalayas requires thorough studies of geological lithologies, water drainage patterns, surface and subsurface structures. The geological, structural configuration is essential to understand the strength and weakness of the area so that the project could be implemented in the suitable terrain. If hydropower is to be generated from dam water then selecting suitable dam sites requires careful consideration of environmental impacts. Satellite imagery is used for the identification of catchment boundary; drainage network, perennial streams, land use and vegetations cover for these projects. Remote sensing and GIS have the potential of relatively accurate analysis of a site location. Digitizing the elevation contours and spot heights from topographic maps and using capabilities of various GIS softwares generate Digital Elevation Model (DEM) of these catchments. The catchment boundary, drainage network and location of major habitation are overlaid on these DEMs for further analysis.
3: Environmental planning:
Basic environmental issues for hydropower project developments, catchments area treatment, aforestation and rehabilitation and resettlement are solved with the help of GIS solutions.
Digital Terrain Model Data (DTM): Digital Terrain Models are prepared for computation of slope, channel length, catchment area, head available for power generation and location of suitable sites for civil structures. Repetitive satellite data for these catchments are effectively used to locate the region of deforestation and impact on forest development.
5: Transmission Line Network:
To execute transmission line network, precise planning, costing, scheduling etc are required. To optimize the cost of transmission line lot of survey is required like,
1.Shortest and alternative route from the generating station to load centers
2.Topographical and geographical nature of the terrains
3.Physical constrains (railway crossings, road crossings expansion of villages and towns, etc.)
4.Environmental factors (reserved forests and high tree areas, national parks and wild life sanctuaries etc.)
Selection of suitable areas, the optimum path finding, the profile analysis, the engineering design of towers and wires and the cost estimation can be done using GIS and satellite images. The steps involves,
3.6: Ranking of the sites:
- Planning of master guidelines of route construction including voltages, number of lines, starting and ending substations.
- By interpreting the satellite images of the area depicting it's geographical features, environmental features, several alternative routes can be designed and compared. In comparing the alternative, technical cost and social cost (environmental impact, rehabilitation, irrigation etc.) of laying of the transmission lines can be included in the model.
- Preparing basic routes
- Preparing detailed route with optimal concept
- Implementation of an actual route.
All infrastructure development for hydel projects follow a set procedure of survey and investigation before taking up implementation.
These steps involve, Pre-Feasibility Report, Feasibility Report, and Detailed Project Report. Since the balance potential hydropower sites in the country are of the order of 450. At the pre-feasibility report stage a 'Ranking' or 'Order of Priority' should be evolved so that least socio-economic, environment and infrastructure development costs and best return in hydro-power generation ensuring river basin-wise resource optimization .
The technical and non-technical criteria are,
(i). Reconstruction and rehabilitation
(ii). Accessibility to site
(iii). Height of dam
(iv). Length of tunnel/ channel
(v). Hydro-power potential
(vi). Type of scheme (run-of-the river or storage development)
(vii). Status of project
(viii). Status of upstream or down stream hydel development
(ix). Inter-state aspects
(x). International aspects.
Central Electricity Authority has adopted certain maximum and minimum value between number range from 6 to 15 for each of the above 10 criterias. Accordingly sites have been graded from 'A>80' to 'E<20'.
Space technology using satellite and aerial remote sensing with GIS technology provide faster result in terrain mapping and scientific assessment of the ground conditions especially for mountainous regions where majority of sites are located. Image analyses of satellite digital data and creating spatial geo-reference information of terrain, using GIS tools, provide basis to address indices in the ranking study faster than the traditional method at comparatively comfortable cost.
Interfacing geographic information system with knowledge-based expert system enhances the GIS capability by adding new dimension to it and future scenarios for study. With the launching of Indian remote sensing satellites (IRS) high-resolution data are available with repetitive coverage over same region.
GIS technique is found to be suitable and cost effective for the identification of hydel sources, mapping suitable sites, environmental planning, digital terrain modeling, transmission line network planning and ranking of the hydropower projects.
- Power on demand by 2012 "The role of GIS, GPS and Remote sensing in power sector", published by, CSDMS, IT for geography.
- Proceedings of workshop on 'Remote Sensing and GIS applications in Water Resources Engineering', organized by CBIP in association with geographical Committee of International Water Resources Association (India).
- Ian Haywood, Sarah Cornelius, and Steve Carver 'An Introduction to Geographical Information Systems', published by Pearson Education Asia.
- Ivan Bratko, 'Prolog, programming for Artificial Intelligence', published by Pearson Education Asia.
- Ranking studies of Hydro Electric Project, published by Central Electricity Authority of India, Oct.2001.
- Power line Magazines.
- Workshop on Managing Hydroelectric Power Plants, by Power Management Institute, (Feb. 4-8, 2002)
- Hydro Electric and pumped Storage Plants, Book by M.C.Jog.
- Eugene Charniak,"Artificial Intrlligence",published by Pearson Education Asia
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