REVISED 30th August 2013 “THE ...

REVISED 30th August 2013 “THE CONCEPT OF LARGE WATER TANKS IN THE RIVER BED” ( Solution to problem of water shortage and draught ) There are some regions which are not dependant on monsoon for water and sufficient water flows in the rivers throughout the year. There is no problem of water shortage in these regions. Other regions are partially or fully dependant on monsoon for water. Sufficient water is available in the dams and the rivers in these regions when there is average or above average rain fall in the monsoon. However, many places are far off from municipal water supply systems. Hence, such remote places suffer from scarcity and shortage of water even when there is average rain fall in the monsoon because the rivers almost become dry in few months after monsoon is over. When rain fall is below average then entire region faces water shortage problem. Situation becomes critical when there is draught. Following innovative concept, explained in detail, is suggested to solve the problem of water shortage or water scarcity and of drought in the regions dependant on monsoon for water. After 3 to 5 months from the end of monsoon practically water does not flow in most of the rivers and the river bed is almost dry. Trenches to be dug up in the dry river bed, after the last dam on the river and also from the point from where the river starts flowing in low-lying area. The width of the trench should be that of the river. It’s length & depth will depend on the volume of water required for the particular village/ city . For example, length can be from 100 to 1000 Meters and even more if necessary. Depth can be up to 30 Meters and even more if necessary and feasible. First trench having required depth and length is to be dug up. River-bed of minimum of 30 Meters in length to be kept as it is after the first trench . Subsequently, second trench is to be dug up. After second trench, again river bed of minimum of 30 Meters in length to be kept as it is and so on . Likewise, we can dig up chain of trenches from the point from where river starts flowing in low-lying area. Number of trenches required to be decided as per volume of water worked out and the locations of trenches to be selected as per site conditions and their proximity to villages/cities. Digging of entire stretch of river bed for trenches is not being suggested. During monsoon rain falls over the entire region and rain water, through many streams and rivulets, finally enters the river and it will get accumulated in the trenches first. As monsoon progresses trenches will be full of water and then they will start overflowing downwards. Level of water in the river goes up in the course of time which depends upon the rain fall whether it is below average or average. If dams are constructed on the river then rain water in the catchment area gets stored in the dams. If rain fall is average or above average in the catchment area then dams overflow in to the river and the level of water flowing in the river increases substantially. After rainy season is over level of water flowing in the river gets reduced slowly and after few months the river becomes dry. This happens in case of most of the rivers. Since, trenches are dug up, water in the trenches remains stored throughout the length of the river and these fully flooded trenches with water are termed by me as ‘LARGE WATER TANKS IN THE RIVER BED’ . If not stored in the trenches, the water would just flow into the sea and would get wasted. Once water is stored in the trenches we can plan , in many ways , how to use it and for what purpose. For example, volume of water stored in one trench having length of 1000Meters , depth of 30 Meters and width, i.e. width of river, say 20 Meters works out as under. Volume of water = 1000M *30M*20M =6OO,000 Cubic Meters ( One Cubic Meter = 1000 Litres = 1 Kilo Litre ) Volume of water in one trench = 6,00,000 Kilo Litres ( 1000M*20M*30M ) = 6 Lacks Kilo Litres The figures mentioned in Meters, anywhere in this proposal, for depth and length of trenches , are illustrative and arbitrary. Depending upon site condition and requirement of volume of water length and depth of trench to be changed. Rate of excavation per cubic metre is higher as the depth increases and also it is more if river bed is hard or of rocks. Hence, if excavation cost is the limiting factor then depth can be much less, even up to 5 meters, and length to be worked out for required volume of water to suit excavation cost and available funds. Trenches , of adequate depths and lengths , also to be dug up in “Rivulets & Streams” of water in which sufficient water flows during monsoon. Stored water in these small trenches will also be substantial and will prove to be very useful for agriculture and for many other purposes. A ) Following are the anticipated problems and difficulties with remedies. 1) Silt or sediment will get accumulated in trenches. Silt or sediment to be removed once in two or three years or as the case may be. It depends upon the quantity that gets accumulated and it will also vary from region to region depending on the type of ground . Most of the silt or sediment will get accumulated in first two or three trenches. Perhaps, the subsequent down the line trenches will have very less accumulation. Silt or sediment must be getting accumulated in the dams and other irrigation projects also. It is easier to remove sediment from trenches than from dams. If accumulation is high and its regular removal from the trenches is necessary then depth of the trenches to be reduced to such a level that it will facilitate easy removal of the sediment or silt. Though not insurmountable, the accumulation of sediment in the trenches appears to be a major problem. Hence it needs to be studied from various angles during Trial Project suggested under’ C ‘ 2)Sewage disposal of village or city & effluents of factories will enter trenches. Question is how it is not creating any problem at present if the discharges are let into the river, especially when water is released from the dams? Initially, we can select locations of trenches which will be above the points of discharges of sewage & effluents. Installation of Effluent Treatment Plants and creation of Sewage Farms to be made compulsory, if necessary. 3) River bed may be very hard or of rocks. -- Explosives and strong dynamites should solve the problem. 4) Is it possible to dig 30 Meters deep below the ground ? -- Coal-mines or other mines are 1 to 5KMS deep below ground. Metro is constructed deep below ground . -- As such technology to dig deep below the ground is established B) Following doubts which can be raised and their answers. 1) Stored water in the trenches will get evaporated. -It’s percentage will be much less as what must be happening in case of dams. 2)Stored water in the trenches may percolate. - It cannot be instantaneous. It is very slow. Even if it percolates, ‘Water-Table’ condition of area across the river will get improved and it may be advantageous next year if monsoon is delayed or is below average. Any way stored water is not wasted. 3) River-Banks will be unstable and may cave into the river. --River-Banks are not to be touched during digging of the trenches hence their natural stability or equilibrium is maintained. Besides, the walls of the trenches to be given a required slope during excavation. Water stored in the trenches does not flow and is almost stand still. As such the stored water in the trenches will not allow side walls of the trenches to collapse or to cave in. It is also a remote possibility that River-Banks will become unstable or cave into the river. However, the aspect to be observed in the trial-trench dug up for experiment. C) Trial Project is suggested as under. The concept may sound a bit absurd but I feel it is worth trying. Small trench of 100 Meters in length and depth of 15 Meters to be dug up in the river before monsoon when the river bed is dry. The cost of excavation of such a small trench will not be high and it may be within the powers of the local authority. During monsoon water will get stored in the trench. The volume of water that will be stored in the above trench with width of say 20Meters works out as under. Volume of water = 100M*15M*20M =30,000 Cubic Meters =30,000KiloLitres(1CubicMeter=1000Litres=1Kilo Litres) Various aspects of the trench and stored water to be studied & recorded for eight to nine months in light of the various points mentioned above under A & B . If necessary and feasible, two more trenches ,one having depth of 5Meters and the other one having depth of 10Meters with appropriate lengths can also be dug up to study the various aspects simultaneously. If trial is successful and if results are encouraging then, taking into consideration the observations & study-report of trial-trench, projects of various capacities with necessary changes or modifications, can be executed, step by step, in other regions /districts/states/nations. D) Advantages of successful projects are as under. 1) Availability of water after monsoon is over. It will boost agricultural production and water will be useful for industries, power plants etc. 2) Even though, when there is no water shortage or drought due to good monsoon, stored water in the trenches is an additional source of water. Farmers may take two/three crops in a year. Besides, the water can be utilised for industries and for many other purposes. 3) As width of trench is kept same as that of river no additional land is required. Hence, land acquisition is not necessary and because of which no rehabilitation of population which sometimes is necessary in other irrigation projects. 4) Trenches will not affect other existing irrigation projects and the ones yet to be implemented. 5) Probably good quality sand may get accumulated in the trenches which is required for civil constructions. 6) Severity of flood during heavy monsoon will get reduced as huge quantity of water remains stored in the trenches which otherwise would spread in the affected areas. 7)The earth or soil that is excavated during digging of trenches and accumulated silt/sediment removed from the trenches later on are supposed to be fertile and will be very useful for agriculture. E ) Economical feasibility of the project, in general, is as under. 1)Only one time investment in the cost of excavation of trenches. 2) Cost of removal of silt or sediment accumulated in the trenches , once in three years or as the case may be. 3) Cost of equipments installed to supply water stored in the trenches to users. 4) Maintenance cost of above equipments and it’s system. The total cost of above may balance out against the various factors mentioned below. a) Expenditure, which was being incurred prior to execution of the project, on water-tankers and other systems for supply of water from other sources, to drought-affected area. b) Local municipal authorities can charge for supplying water, stored in the trenches, for commercial purposes to compensate maintenance cost. c) Many advantages mentioned earlier under ‘ D ‘. However, feasibility report in detail to be prepared for particular site or region based on required volume of water and other relevant data. It is a project for ‘WATER’ which is a basic necessity. Hence, purpose and approach of economical feasibility report should not be the same as adopted for any unit being set up for business. F) Conclusion: I strongly feel , rather I am confident , that the concept has a potential to solve the problem of scarcity & shortage of water and of drought, if it is understood well and is further implemented properly. P. K. Sohoni. ( Chartered Engineer ) ------------------------------------------------------------------------------------------ Name of author: P.K. Sohoni ( Chartered Engineer ). Address : 30, Prarthana Samaj Road,Sane-Wadi , Vile-Parle(E), Mumbai-400057, Maharashtra, INDIA Tel. 22-26112139 Email Address: prakashsohoni16@gmail.com Note:- I am keen to meet experts / technologists / authorities to discuss the proposal across table and convince them that the concept is theoretically OK or get myself convinced that it has a flaw. If according to them concept is theoretically OK but still it is not workable then I would like to know from them the unforeseen and insurmountable difficulties & problems because of which concept is not workable.