Friday, October 30, 2009

Cost Effective Drought Proofing Project

By Chiman Delwadia, Birmingham, AL

Project Coordinator, Helping Hands, USA, .(JavaScript must be enabled to view this email address)

Introduction

This year, there is not enough rain in many parts of the country and there is a drought-like situation in many states. Central and state governments are gearing up to start drought relief works. If we use this opportunity to focus on rainwater harvesting projects, as described here, we can turn this curse into a blessing. We know that the American government had provided badly needed work to the people during the depression and at the same time built the best road system in the world. Our governments can also solve our water scarcity problem and increase agriculture productivity significantly if they use drought relief work funds and “100 days of employment guarantee scheme” funds for this purpose.

Problem

  Our problem is that we do not have adequate irrigation system and 60% of the agricultural land still depends only on monsoon rain. Our problem is not only lack of water but management of it too. In fact, God pours two million liters of water per acre every year (with 18” annual rain) but unfortunately, we, the people, let it flow away into the sea and then cry for more water. Farmers of Israel produce abundant crops in desert-like country by saving rain water and using drip irrigation system. Why can’t we do the same?

Solution

Farmers of Saurashtra region in Gujarat state, at some extent, have done just that by building “check dams” every where. World renowned water expert, Mr. Fred Pearce, in his book, “When river runs dry”, wrote that in China Chairman Mao had forced his people to do rainwater harvesting but here a retired police officer, saints and ordinary people took lead and did miracle. These projects not only saved their crops in dry spells but increased agriculture production significantly. It is remarkable that ground water tables are coming up in this region while it is going down in other parts of the country.

Cost issue

These farmers built conventional check dams using the design provided by the state government design office. As per this design, the cost of a typical check dam of 100’ X 5’ is two lacks Rupees which is too high and that’s why farmers have to depend on the government or other donors to fund these projects.

New Design

To solve this problem, we have designed a new type of check dam, an arch dam, which will cost only 10% of the government cost estimate. In this design, most of the water pressure is transferred to banks and only 6” thick concrete structure will suffice to withstand the design pressure. We have also verified our design by doing computer simulation at the engineering college in USA.

New Construction Material

We went one step further and decided to build such a dam using fly ash (a waste material at power plants and factories) rather than normal cement concrete mix. As the life span of the fly ash concrete blocks is 40 years, these structures can save crops during dry spells for many years. 

Disposal of power plant waste material

Electricity boards in all states have many power plants. Power plants burn millions of tons of coal every year and produce huge amount of waste material in form of fly ash. They have a problem of disposal of this waste material. If they can give this material, free of charge, to make fly ash blocks, it will solve their problem of disposal of waste material and at the same time will make it possible to build very low cost rainwater harvesting structures for farmers. Thus, we can kill two birds with one stone.

Test models

We have built first test dam using cement concrete, adding 20% fly ash. We have built second dam using pre-built 2’ X 2’ concrete panels and built three more dams using 1.25’ x .75’ x 0.5’ blocks made from 100% fly ash. These structures stood strong against the heavy flood when it rained 10 to 20 inches in couple of days during the 2009 monsoon season. This proved soundness of our design and removed any doubts anybody had.

Additional Features

We have placed a 3” diameter pipe at the bottom of the dam to allow emptying the dam, if necessary. This pipe can also be used to pump water from the dam into nearby wells. This will make it possible to harness multiple floods during one year and maximize rainwater harvesting. Farmers can also increase storage capacity before last rain of the season by adding layers of blocks or sand bags on top of the dam. As farmers can place boards on the top of arch shaped dam, it is convenient for them to cross creeks during monsoon season.

For Farmers

This kind of check dam, with 5’ height, will cost only Rs 200 per foot length. If farmers build series of such check dams on 10’ to 100’ wide creeks every possible place, they will be able to save their crops during dry spells. Farmers can even grow three crops in a year if enough water is stored under ground and used drip irrigation system. They must realize that this is a better solution than spending tens of thousands of Rupees in digging wells or drilling bore holes where there is no guarantee that they will find water. 

For the Government

As this scheme can generate large scale employment, the government can justify funding these projects as drought relief works or as “100 days of employment guarantee schemes”. As all the electricity boards are semi government bodies, the government can direct boards to recycle their waste material as much as possible and give fly ash, free of cost, to build fly ash blocks for check dams. 

This concept looks deceptively simple but it is a very powerful weapon to fight against poverty and put farmers on path of prosperity.

For more information on design and construction, please contact me.
Thank you! 

 

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