Mirani Dam: is it viable?
The government maintains that the project on completion will provide irrigation water for the lands on both sides of the non-perennial River Dasht. Water inflows from the catchments are around 226,000 acre feet, estimated to bring with it silt flows of 7,000 acre feet per annum.
According to estimates, the project would help, raising annual average production of the existing orchards, vegetables, and fodder and wheat crops by 85 per cent. Of this 36 per cent increase is expected in Kharif and 49 per cent in Rabi while during the period of maximum availability of water 122 per cent raise in the cropping intensity would be possible. It is also estimated that fish production in the reservoir will be another feature of the project.
According to the official claims, this ‘environment-friendly project’ will have no negative effects, and only 1,100 persons will have to be shifted to the alternate place and only 4,800 acres of the flood affected area will submerge due to the project construction. For many analysts, the project is highly controversial.
The claim that this mega-project will develop the area is much exaggerated because many significant but unpleasant facts have been conveniently overlooked by the designers and planners. Many experts on large dams insist that if the dam is completed with presently approved features then it will be a disaster and the loss from the project will surpass the net benefits.
The very purpose of the dam is being disputed. According to informed sources the government of Pakistan is constructing the dam primarily for the consumption of military-industrial complex at Gwadar and for the water supply of the future population of Gwadar estimated at 2.5 million within 10 years. It is estimated that 150 million gallons of water per day will be required for Gwadar.
The informed sources have disclosed that there will be no water for agriculture purposes in the Dasht valley after catering the water needs of Gwadar mega project. In this way, there is a great resemblance of Mirani dam with that of the Hub dam, where the people of Balochistan were promised water for irrigation but after some period almost the entire water is being supplied to Karachi for industrial and domestic consumption. According to local politicians, the government is following the same tactics in the case ofthe Mirani dam.
The gross storage capacity of the dam is estimated as 0.302 million acre feet, with a (average annual release) sustainable storage capacity of 114,000 acre feet. A 150,000 acre feet of water is estimated to be the dead storage capacity of the dam. With an estimated life span of 30 years, the total cost of the project is estimated at Rs6 billion. The contract for it was awarded in June 2002 and the work has commenced, which is scheduled for completion in four years.
On the economic front, it will deprive thousands of families downstream whose livelihood depends on flood irrigation on both embankments of River Dasht stretching in a length of nearly 200 km. On the command region dozens of well-populated villages from Kalatuk in the east up to Rhodbun in the west will be submerged and millions of date trees either will be inundated or will be badly affected due to rise in the level of ground water.
Environmentally, the stoppage of water of Kech and Nehing rivers at the dam will also devastate a natural forest region from Mirani up to Dasht Delta near Jiwani. This will also result in depriving thousands of people of Dasht of their only energy source.
According to a senior engineer in Balochistan irrigation department, the cardinal point is the viability of the project. The life span of the dam is planned to be 30 years. The Dasht is a non-perennial stream whose flow depends on rainfall in the catchment area consisting of barren mountains.
The total sediment load per year flowing into the reservoir would be of the order of 7,000 acre-feet. Enhanced sedimentation has already caused failure of reservoirs, delay-action dams, irrigation channels and other control structures; the best example is the Bund Khushdil Khan in northern Balochistan.
The result of sedimentation will be the raised water level in the reservoir with consequent inundation and submersion of the populated areas and cultivated lands beginning from the village of KoshKalat in the east of the dam to Rodbun in the west of the dam. Dam experts and hydrologists firmly believe that the lifespan of the dam will not go beyond 10 years.
Rainfall maps in Balochistan represent mostly a hypothesis rather than facts. Such maps are based on point measurements that are extrapolated to over mapping areas mostly by unverified models. Consequently these maps are of limited practical value as far as agricultural development is concerned. The average annual rainfall for the catchment is estimated to be 4.2 inches. But flood water is the unknown resource in term of amounts and frequency in Balochistan. In the absence of an automated monitoring network for floods and rain, the precipitation figures and averages are meaningless in arid zones if taken as absolute figures.
One of the major hazards associated with the dam project is the destruction of the flood agricultural lands below the dam site. At least 30,000 farmers and tillers are depending on the annual flooding of Dasht River for their livelihood. Depriving the flood water may force thousands of farmers to resort to forced migration to other places causing huge social problems. This stoppage will also affect the recharge of under ground water on both side of the Dasht River causing a steep rise in irrigation expenses for the farmers of down stream as they have to bore deeper and deeper for their tube wells.
Social and economic implications of the Mirani Dam are foreseeable and alarming. A population of nearly 30,000 people will be forced to move, because the dam will inundate their villages, beginning from the village of Kalatuk in tehsil Turbat up to Rhodbun in tehsil Tump and these people and some 10,000 land owners of the area will lose their farmland through flooding. It will take years for the uprooted families to settle down in new areas and take many more years for the farmers and agriculturists to grow and make productive the date trees and other orchards.
The problem of resettlement of thousands of people is immense. These people will receive little compensation and a large proportion will end up becoming destitute and homeless. This will cause an irreparable gap in the already sour relationships between the state and the local population.
This dam is said to have been designed by a few mediocre planners, having a history of dismal failures in this province as for as designing and planning of dams and projects are concerned.
It is high time to think of initiating sustainable development alternatives. Some 90 years ago a comprehensive survey was conducted on the feasibility of small dams on river Dasht, Kech and Nehing by British authorities and copies of the report could be found in the provincial archives. The surveyors had proposed four small dams on Kech, Nehing and Dasht rivers. A small dam was proposed between Shahrak and Hoshap on Kech, another above Gomazi on Nehing. Two dams were suggested on Dasht river at Mirani Gourm (the present site for Mirani Dam) and near Suntsar in lower Dasht.
These suggestions of nearly a century ago are the most feasible, less destructive and more beneficial than the current absurd project design for Mirani Dam. Development of micro-dams on Kech, Nehing and Dasht rivers will minimizes the negative impacts of the mega project.
These dams will raise the under-ground water level from Mand to Hoshap with the effect that not only hundreds of new Kareze can be explored but all the redundant Kareze can get a new lease of life. This will roughly create some 40,000 acres of agriculture land in the entire Kech District without causing any serious damage to the already existing orchards and farm lands.
No doubt, Balochistan is in the dire need of water-related development but it must be done after a comprehensive analysis and study of reliable data. We, as a matter of fact, need to learn from the mistakes of other nations. There are examples around the world of dams having been built in barren catchment areas, producing silt-laden runoff and ending in failures much before the stipulated time. The Mirani Dam is likely to complicate the economic and environmental situation of the area, as many experienced people in Baloch circles and non-governmental hydrologists are skeptical about the success of the Mirani Dam with its present size and design.