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Parts of Thar Desert, Rajasthan
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Background Information
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Climate
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The area has a dry climate and falls in the Arid zone. It is classified as ‘lc’ zone, as per the agroclimatic classification of Rajasthan (Rajasthan Agricultural Statistics).
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Rainfall is erratic and normal annual rainfall in Jaisalmer district is 181 mm. Season-wise rainfall in 2010-2011 is detailed below.
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(in mm) |
| Annual Normal |
June ’10 – Sep ‘10 |
Oct ’10 – Dec ‘10` |
Jan ’11 – Feb ‘11 |
March ’11 - May ‘11 |
Total (June ’10 to May ’11) |
% Deviation from Normal |
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181.2 |
361.2 |
11.3 |
5.0 |
3.0 |
380.8 |
110.20 |
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The annual maximum potential evapotranspiration in the district is 1850 mm and it is highest in the month of June and lowest in the month of December.
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Physiography
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The Pilot study area forms part of extensive Thar Desert area of Rajasthan. The major part of the study area is predominantly covered with flat, limestone terrain. There is little or no soil cover and thin vegetation.
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Drainage
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There is no well-developed drainage in the area. The area is part of Barmer sub-basin in the Indus River Basin.
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Geomorphology
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The main landforms in this area are desert sand dunes of Aeolian origin. They are the more dominating geomorphic features in the western & northern parts of the study area. The sand dunes are longitudinal (NNE-SSW) and mostly stabilised in nature with sporadic vegetation. At few places, these are covered with second set of sand dunes. These second set is mostly of Barchan type sand dunes.
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Figure 5.4: Stabilised Sand Dunes. |
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Figure 5.5: Barchan Sand dunes on the stabilised old sand dunes. |
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Soils
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The soils in this area are mostly desert soils, aeolin soils. They are loamy, coarse in texture and calcareous.
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It is planned to conduct infiltration tests in different soils with different proportions of clay, sand, etc. and in different land use conditions including canal command area to estimate the infiltration from different water sources.
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Land use
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Land use in Jaisalmer District (2010) is detailed below. Most of the land is culturable waste.
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(area in hectares) |
| Area under non-agriculture use |
Barren and unculturable land |
Culturable waste land |
Current fallows |
Other Fallows |
Forest |
Land under Misc. tree crops and groves |
Net Area sown |
Permanent pastures and other grazing |
Total geographical area |
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147,437 |
363,715 |
2,347,402 |
41,570 |
64,543 |
44,873 |
298 |
725,685 |
103,631 |
3,839,154 |
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Source : www.data.gov.in
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The net sown area represents about 18% of the district area. The land used for irrigation is only about 2.7%.
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The area under irrigated agriculture includes irrigation by IGNP canals and tube wells. Details of irrigation in Jaisalmer district are in the following Table.
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(in hectares) |
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IGNP |
Tubewell |
Other wells |
Other sources |
Total |
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Gross irrigated area |
153,147 |
55,654 |
428 |
10 |
209,239 |
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Net irrigated area |
71,683 |
34,060 |
428 |
10 |
106,181 |
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(source : Rajasthan Agriculture Statistics – At a Glance for the year 2010 – 11)
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Figure 5.6: Canal system in and around study area. |
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Source : CGWB |
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Geology
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The general geological succession in Jaisalmer district is as follows: |
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Formation and Lithology |
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Quaternary (Pleistocene to Recent) |
Aeolian sand & alluvium, gravel sand , silt, kankar & clay |
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Tertiary |
Sanu sandstone, Bandha and Khuiala limestone |
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Mesozoic |
Lathi, Jaisalmer, Baisakhi, Bhadesar, Parewar, Abur formation - Sandstone, shales with intercalated limestone, siltstone, clay stone |
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Proterozoic (Post Delhi) |
Granite |
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Most of the study area is underlain by limestones, covered by alluvium and sand dunes. |