Water is the elixir of life. It is one of the most important factors in the sustenance of any civilization. The ancient Indian texts mention the method of making check-dams on natural slopes to harness rain water for agricultural and domestic use. In the modern State of Telangana, India, the check-dams and tanks made by the Kakatiya rulers are still a major source of irrigation. In fact the very first Government elected after the creation of the State of Telangana embarked upon an ambitious project of renovation and revival of all such dams and tanks in the state under the banner of "Mission Kakatiya". This involves strengthening of the dams and de-silting of the tanks. The silt is being used for mixing with farm land to increase fertility. At the same time, the water storage capacity of the tanks is getting increased. In a country where the pressure of population and the increasing demand for water is producing considerable stress on the existing sources, such rain water harvesting needs to be encouraged to provide the solution to the problem, particularly in the rural areas.
The students of Civil Engineering at the University of Illinois, Urbana Champaign have been studying the problem of acute water shortage due to the deficient, skewed and changing pattern of rains in the State. In India, the scale of drought and its consequences are dependent as much on nature as on state policies and mechanisms.
It was our objective to give a small demonstration of not only harvesting rain water but also of improvement of the surrounding environment while utilizing locally available materials and voluntary labor. This model could be easily replicated in the villages not only in Telangana State but across India.
While trekking on a rocky ridge on a weekend near our home we noticed that some rock formations looked as though water had flown on them or ages.
Due to indiscriminate rock cutting, the current pattern of the terrain did not support a drop of water. Obviously, human intervention had completely altered the natural course of water and had turned the entire area into a rocky waste. We decided to survey the contours of the area and see if rain water could be harvested and the overflow could be put back into the channels made on the rock surfaces. On the basis of the contour map of the area we decided to construct two check-dams in a cascading pattern. This would give us the advantage of harvesting more water with smaller structures.
We marked the location of the two check-dams on the ground and with the help of the volunteers from the local police battalion, the first check dam was made using granite stones which were lying around in the location. The height of the check dam was kept in such a manner that the water would not spill out from any side except through the overflow channels made in the dam. Pipes and iron strips from dismantled buildings were sized and utilized to make a strong railing on both sides of the check dam to make a safe walkway on top.
Further, four pipes of 4” diameter each were arranged to form the overflow from the check dam. This over flow falls into the second check dam which is made at a lower level. The second check-dam at a lower level has been made with steel reinforced cement concrete. This method was adopted because a considerable volume of steel rods of 12 mm diameter was available from a demolished building. Further, the length of the wall was more and the construction would be faster. The wall has been constructed on sheetrock. The 12 mm diameter steel rods were placed in holes drilled in the rock for anchoring at a gap of 6” in a zigzag pattern. 6mm diameter horizontal rods were tied to the vertical rods to complete the steel frame.
Locally available form-work was utilized and concrete filled in two spells to make a wall which is 8” wide at the base and 6” wide at the top. The wall was made water-tight on both sides at the base by smoothening the wall-rock joint using cement concrete mixed with waterproofing chemicals.
Six sloping buttresses were also made at regular intervals to give additional support to the wall from outside. These buttresses were made using stone masonry. One 4” diameter valve was also fixed at the bottom of the wall to evacuate the tank if necessary.
Two pairs of 2” diameter overflow-pipes were fixed at two locations to take the overflow and release it on the rocks where the water had flowed earlier. Considerable earth was deposited on the outer side of the wall and hardy flowering plants were planted to give a natural cover to the wall and provided habitat for the birds.
A cultural dimension was added to the project by converting the sheetrock under two huge borders into a stage and by constructing galleries for seating on the other side of the upper water-body to watch the performance on the stage.
Another platform was made near the stage to serve as a green-room for the performances on the stage. A large platform was constructed at a vantage location between the water bodies to serve as a party area. A retaining wall was constructed to ensure that mud does not flow into the water bodies in case of heavy rain. A smaller retention wall was constructed to divert the flow of water towards the upper water body.
The rocky ditches on the way to the water bodies were filled up with earth and hardy plants and trees were planted to give green cover and flowers. A pathway of cement tiles bound by concrete on both sides was also laid from the main road up to the water bodies. Local talent was encouraged to construct concrete a statue of Lord Shiva on a pedestal inside the upper water-body and a statue of Lord Buddha on a rocky pedestal. Fish of different varieties were introduced into the two tanks to create a lifecycle. Cement pipes of 8” diameter were placed at the bottom of the tanks to provide shelter for the fish.
The satellite pictures of the location during May, 2015 and during October, 2015 clearly show the difference to the area in a span of six months.
This project has been implemented jointly by:
Prasoon Trivedi, B.E. Civil Engineering. M.S. in Water, Energy and Environment Sustainability, Civil Engineering Department, University of Illinois, Urbana Champaign, USA. Presently working at Environmental Logic at Trenton, NJ. Prasoon can be contacted at ptrived3@illinois.edu and Prashant Trivedi, B. Tech (Civil) Engineer at DEC Infra, Hyderabad.