Rain water harvesting can mitigate water scarcity in Pakistan
June 23rd, 2012 | Technology Times | No Comments
WATER IS a valuable gift from God which has been given prime importance in the Holy Quran. It is one of the three important things that every human is blessed with freely: grasses providing pasture for cattle, water, and fire without which existence of life on earth is impossible. In the Quran Allah says: “We sent down water from the sky in measure and lodged it in the ground. And we certainly are able to withdraw it. Therewith for you we gave rise to gardens of palm-trees and vineyards where for you are abundant fruits and of them you eat” sura 23, verses 18 and 19. These Quranic verses remind us the Islamic perspective of water harvesting and its importance in agriculture.
God has gifted us Pakistan with diverse climatic condition. It has altitudes ranging from sea surface to several thousand meters high, enjoying four weathers a year and more than 6000 plant species. Therefore, agriculture has gained much interest in the country. However, in the current climate change scenario, a major portion of our countrys rain-fed and sun-burnt areas are in trouble. Our water reservoir supplies are low, rivers and dams are drying up; harsh and hot summers are resulting in prolonged drought conditions. Out of 24.8 million hactres of cultivable land area of Pakistan, nearly 6.6 million hactres are rain fed and dependant on indigenous water harvesting systems. In such situation, traditional methods of rain water harvesting can be highly beneficial to cope with water shortages in rain fed areas of the country for sustainable agriculture.
There is a wide variety of indigenous water harvesting systems prevailing in Pakistan. A detailed study on different water harvesting systems prevailing in Pakistan has been carried out by Water Resources Research Institute, National Agriculture Research Centre Islamabad. These indigenous water harvesting systems can be broadly categorized into mountain irrigation systems, Runoff farming systems, torrent-space-irrigation systems, Perennial-spate-irrigation systems, Riverflood-spate-irrigation system etc. This study can be highly beneficial in solving many problems of current prevailing drought condition at low costs in many parts of the country.
There is usually a scarcity of drinking water in the hilly areas of Pakistan during winter. The people have to bring water from far flung areas, even so there use to occur heavy rains on weekly basis. In such areas, people should be inspired towards the collection of rain water from roofs. This can be done using rain gutters and pipes. From these pipes, the water runs into a tank. This tank should be sealed to prevent contamination of the water.
Before taking into account the water harvesting techniques, some important points should be taken into account. For example, the ground slope is a key limiting factor to water harvesting. Therefore, water harvesting is not recommended for areas where slopes are greater than 5 per cent due to uneven distribution of run-off and large quantities of earthwork is required which is not economical for farmers. The texture and structure of soils should be considered because soils having larger quantities of sands, there occurs higher rate of water infiltration than the intensity of rain and no run off of water occur.
There are numerous benefits of rain water harvesting. For example it directly reduces the cost of potable water. Moreover, the soil erosion can be avoided to some extent by harvesting the rain water. The underground water reservoirs can be increased and improvement in the water table can be observed which can be utilized during bad days. The rainwater harvesting can reduce salt accumulation in the soil which can be harmful to root growth. When collected, rainwater percolates into the soil, forcing salts down and away from the root zone area. This allows for greater root growth and water uptake, which increases the drought tolerance of plants. The traditional methods of water harvesting can be highly beneficial for sustainable agriculture in rain fed areas and will help in mitigating the current water scarcity problems.
The water harvesting practices can boost agriculture production in the rain fed areas of the country. Moreover, the government should encourage the construction of small dams and bunds to store the rain water during rainy reason. In hilly areas, the government should campaign for collection of roof water. The initiative should be taken from the government buildings in different institutes. The rain water harvesting will not only improve the current underground water reservoirs but will also help in saving power utilized for pumping of water.
The writer is PhD Degree holder from Quaid-e-Azam university
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