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Typical permeability values for various rock types Lithology

Range of likely permeability (m/d)

Silt Fine silty sand Weathered basement (not fractured) Medium sand Gravel

0.01-0.1 0.1-10 0.01-10 10-100 100-1000

The geological characteristics of the region will naturally have a bearing on the technology selection for on site sanitation. The kind of geological layers in the ground would be important. 10. Geohydrological Data for Sriganganagar and Hanumangarh While analyzing ground water trends from these districts, as shown in the maps, following facts emerge. In Sriganganagar and Hanumangarh districts, the geological strata are very significant. The soil and the strata up to about 20 to 30 ft (8 to 10 metres) is a layer of compact clay and silt with plenty of gypsum. As a result, this layer is having very low permeability for water. The travel time for water through this layer may be of several months or years. The vertical sections show that the top layer comprises of clay or clay + silt from fluvial origin in most of the areas of these two districts. The thickness (depth) of this layer varies from approx 10 to 20 ft (occasionally wind blown sand forms a thin surface layer). This layer is fairly compact and imperious to water.


Dhamaka latrines in Rajasthan, India.  
Dhamaka latrines in Rajasthan, India.  

Study about appropriateness of design, possibility of conversion to sanitary latrine and extent of groundwater pollution caused Dhamaka lat...