With the current water crisis we all have suddenly woken up to the possibility of our taps running dry and hence we (and our Government) have renewed our focus on water management.
In this water management one very important aspect is storing the water at the source itself using Check dams (also called as stop dams) which helps in harvesting the run-off water of various rivers, rivulets and nalas, and contributes in raising the adjacent groundwater table giving numerous benefits to the surrounding rural and urban populations.
Exact origins of Checks dams remain obscure but some claim that this technology was developed in Second century! nevertheless, their usefulness has only increased in these last Eighteen centuries.
In our Indian context there are numerous reports and articles which showcase the benefits of the check dam hence the author would not like to go into details of it.
A before-and-after comparison of the Jhabhua region, MP after the check dam (source: yourstorey.com)
Question comes to mind that given the fact that Check dams are an ancient time proven technology then what is the need for innovation and change?
Well for once Check dams have always been a temporary structure which require maintenance and upkeep. Their construction is time taking and almost after every wet season they require maintenance and have leaking tendencies.
Also with time silt removal becomes a major challenge reducing the water retention capacity of the dam and hence reducing its effectiveness in water management.
Check dams are rigid structures offering no flexibility in water flow management. In flash floods they easily break resulting in catastrophe for the local region and in low season they don’t allow water downstream.
Due to above disadvantages the Western World has gravitated towards newer technology of Rubber Dams.
Brief history of Rubber Dams:
In 1957, the world's first rubber dam was born in Los Angeles, USA with the dam height of 1.52m, length 6.1m and the dam bag plastic cloth having thickness 3mm, strength of 90kN/m. Since then, the world has begun to build rubber dams. China began the development and construction of rubber dam in 1965 and in June 1966 that China's first rubber dam - Beijing YouAnmen rubber dam finished. The dam is 3.4m high and 37.6m long, the rubber dam bag has replaced twice since it is finished but it still operate very well so far.
Rubber dam has developed rapidly in China since the 1990s, as of October 2006, China has built about 2000 rubber dams. In recent years, it has been developing at a rate of about 300 new buildings per year. In China, the highest rubber dam is 6m, single span of up to 176m and the longest multi-span is about 1135m.
Rubber dam is divided into water-filled and air-filled. The filling time of water-filled dam is longer than the air-filled. In terms of cost, the two types dam are similar.
When compared with the conventional dam, the following features are:
1. Cost saving. It can reduce investment costs.
2. The construction period is short. Dam bags only takes one to two weeks to install.
3. The dam body is a flexible soft structure, can resist earthquakes, waves and other shocks.
4. less maintenance and easy management. The service life of rubber dam bags is generally up to 25 years.
5.Has good water stopping and leakage prevention effect, the dam bag is anchored on the concrete floor, basically can achieve the effect of no water leakage, after the filling medium in the dam bag is emptied, the dam bag is close to the floor, will not make the original section shrink, do not need to build intermediate pier, hoist frame, etc., so no water blocking.
6. The flexibility to control the height of the dam by inflating/ deflating the rubber allows for far better water management and control. It can incorporate other automation technologies like level sensons etc through which an entire state or country data can come at single place and water levels can be controlled and monitored from single location.
7. Can be used for urban landscaping.
Due to the looming water crises India needs to rapidly construct check dams for water management and at the same time have flexibility to control and monitor the water flow, hence Rubber dams can be suitable upgrades meeting both these requirements of time and control.
