DOCUMENT SERIES HAZWAMS/25/2002-2003
CONDUCTING ENVIRONMENTAL IMPACT ASSESSMENT :
SITE SELECTION FOR COMMON HAZARDOUS WASTE
CENTRAL POLLUTION CONTROL BOARD
kesÀvêer³e Òeot 40.00
Slope Percent :
Natural slope of a site is important from the drainage consideration. But, land with higher slopes may pose difficulty in the construction and may need leveling up. To prevent water logging, the site should not be concave i.e. there should not be any depression. Therefore, following scales have been developed for evaluating the slope percent of the sites :
1.5 - 1.2
1.2 - 0.75
0.75 - 0.50
1.5 - 2.5
2.5 - 7.0
7.0 - 15
In general the site topography is to be convex in relation to the surrounding so that the rain-water is drained away from the site naturally. So, a site with convex topography can be regarded as excellent and that with concave is regarded as bad.
Flood Proneness :
In general, the flood prone areas are rejected. But the site can get flooded incase of very high rainfall and without proper drainage. There is a possiblity of water contamination if the site gets flooded. So due weightage is given depending upon extent of flood proneness in a scale of 5 to 1 corresponding to excellent to bad.
Though, generation of toxic fumes is not expected due to very nature of the waste to be disposed off, handling of waste in the disposal facility may create air pollution in form of dust formation. Prominent wind direction may affect the population on the downstream side of the facility. So any village within a distance of one km downstream of the sites can be vulnerable to any air pollution due to the operation of the landfill. The sites have to be ranked as per the degree of impact on the downstream. The location of the facility should be in such a manner that there is no or minimum effect at the downstream habitation.
Following relative value scale is developed for ranking the sites: Downstream
1 - 0.5
0.5 - 0.2
0.2 - 0.1
< 0.1 (adjacent to site)
Out of all the infrastuctures required at a landfill site, the approach road and the power supply are the most important. All the sites have been therefore, evaluated relatively from excellent to bad in a scale of 5 to 1 as per the availability of road and power supply.
Hydrology / Hydrogeology / Geology / Geotechnology :
50% weightage is given to Hydrological, Hydro-geological, Geological and Geo-technical situation of the site as these are the environmental conditions which will affect the design of the landfill. l
Hydrological Conditions :
Distance from Surface Water Body
Surface water bodies & drinking water sources should be protected and site should not be close to these sources. Following scale have been therefore, developed for ranking the sites:
Groundwater Table Depth :
Groundwater table should be as low as possible because of its possible contamination. The level of groundwater should be more than 1 meter below the bearing surface of the landfill. More the clearance between the ground level and the post-monsoon groundwater table depth, more depth is available for excavation of the landfill. If the groundwater is high, the facility has to be designed as a stock-pile. Following scale for groundwater table have been therefore developed for ranking the sites :
GW table (m)...
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