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Vol. 3                                    No. 2                         April 2001

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Cholistan’s story

Astudy has been conducted in the Colistan desert to derive strategies for possible eco-regeneration and runoff collection through special efforts. The department of geography, University of Karachi in Pakistan through this research has reinstated that ecological regeneration is possible through adequate water harvesting strategies.

Cholistan, is an extension of the Great Indian Desert, which includes the Thar Desert in Sindh province of Pakistan and Rajasthan desert in India. The entire area is divided into two parts, Lesser Cholistan, which constitutes of a series of saline alluvial flats, alternating with low sandy ridges. Greater Cholistan is the name given to the southern part of the desert, which consists mostly of sand dunes, ridges and depressions.

The climate of Cholistan is arid (see Table 1), a sub-tropical continent type characterized by low and sporadic rainfall, high temperature, low relative humidity and a high rate of evaporation and strong summer winds. Most of the rainfall is between July and September. The annual rainfall varies from 100 to 250 mm. The evapo-transpiration rate in the desert stands at a 3000 mm a year. Alarmingly this is ten times the rate of rainfall, making large tracts of the areas extremely arid and barely habitable.

Table1: Extent of desertification

Desertification
Class
Extent (ha) Percent

Problems

Moderate 58,700 2.0
Wind erosion,vegetation cover,sodicity, and climatic condition
Severe 2,079, 400 81.0 vegetation, cover,soil physical, propertiesn, wind erosion and climatic condition
Very severe 441,900 17.0 Sodicity, vegetation cover,soil physical properties
Total 2,580,000 100.0  

Source: Pakistan Desertification Monitoring Unit

The people of Cholistan depend mostly on rainwater, which is collected in natural depressions or human made ponds locally called tobas, during the rainy season. The tobas supply water for a maximum of three to four months. Major water losses from the tobas are seepage and evaporation. On the other hand, the characteristic of the soil profile of the region shows that it is a finely textured soil. The study specifies that the topography of Cholistan is dense, impervious, nonporous to very poorly porous, non to very poorly drained, saline-sodic, capable of generating maximum runoff after absorbing minimum water.

In Cholistan the catchment area lies adjacent to the fields on the same level, and is known as micro-catchment system. Micro-catchment systems are effective for use in growing trees and shrubs and are also effective in collecting water and precipitation. Controlling the water lost by evaporation is one of the most cost-effective methods of maintaining adequate water supplies and should be an integral part of any open-top water storage facility. Although relatively expensive, a roof over the storage is an effective means for controlling evaporation. Floating covers of low-density synthetic foam rubber are effective for controlling evaporation from vertical walled open-topped storage. The study perceives that topographic form is the main factor, which plays a vital role towards the development of the Cholistan desert as rangeland. Various relief positions control the occurrence of soils and availability of moisture for vegetation growth. The old Hakra riverbed (the Hakra river supplied water until 1200 BC, and about 600 BC the flow became irregular and consequently disappeared) will act as a drainage way for the area and will collect most of the runoff. The soil of such channel bed is mostly sandy loam with moderate water holding capacity. The availability of moisture in the channel will provide greater support for grass and legumes as supplementary fodder. This area can be suitable for raising cattle due to its favorable relief and availability of drinking water.

This study helps us to know that the desert tract is full of vegetation resources that can be exploited on commercial basis. Emphasis should be given to wild plant resources that may be used as supplementary food items having economic utility value as fodder, fuel medicine and industrial utilisation.

Apart from ecological regeneration of the area, the study emphasises that it is essential to work on land-based activities to improve the rural economy. According to the study this would be possible by creating stable resource-based and increased employment opportunities, and by involving people in decision making, to fulfill their needs and interests.

The study recommends that such programmes require a comprehensive policy along with an administrative and technological framework to provide the adequate impetus to address the social, economic and environmental issues of the region. In the process it will also help in combating the process of desertification and restoration of ecological balance.

For further information:
Farooq Ahmad
Department of Geography
University of Karachi
Pakistan


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