By: Soonya
The new Telangana government needs to be congratulated for taking up a mammoth exercise of repairing and re-generating the cascading tank system invented and mastered by our ancestors.
While we keep investing in tank repairs and desilting of tanks and strengthening the bunds of the tanks, it is critical to approach the issue holistically.
It is a no-brainer, that tanks are low cost eco-friendly and eco-sustainable irrigation systems, however I believe, it is also critical to focus on the following measures in my limited study and research on the issue.
1. Hydrating soils by building swale systems
2. Building of ponds/dams on Key points
3. Creating forests, and grass-lands
Key Points, Key Lines, ponds and small dams
P.T Yoeman, a mining engineer from Australia after a tragic accident of forest fire on his farm, which devoured his family member, devoted his time in 60’s to explore why forest fires happen.
He found that shrub and grass with no moisture in the soil do dry out and become the fuel that allows forests fires to fan out to large areas and which later become uncontrollable and destroy vegetation.
He also found that much of the rain water runs away and forms gullies along slopes and hills and gathers speed thus also taking away much precious top soil.
With his knowledge of mining he figured out that if rain water is stopped at the Key Point and diverted along a contour on either side of the slopes or hills one will be able to stop the destructive run-offs.
Building small dams on Key Points and allowing excess water to move on contours, and planting trees on the contours also slows down the water run off.
A Key Point is where a hill slope changes from convex to concave shape.
A Key Line is the contour running through the Key Point.
He found by doing so, many underground springs got activated (what we call OOTA in Telugu) and soil moisture was available and the grass and other shrubs could be green round the year and obviate the possibility of forest fires from spreading.
Grasslands are shrinking and earlier were available for grazing for goats, sheep and other cattle, which were an integral part of Telangana agriculture.
You can learn about key lines from Doherty here:
Listen to Yeoman himself:
Some key line based water systems. You can see the dramatic transformation in Portugal designed by Sepp Holzer here:
Earthworks for rainwater retention
Also the PRI (Permaculture Research Institute) in Australia led by Geoff Lawton has demonstrated the value of Swales in conserving water and hydrating lands.
A swale is a 2 meter wide and 1 meter deep furrow with curved slopes inside and where the dug earth is put as a bund on the contour on the lower side of the slope.
http://youtu.be/UFeylOa_S4c
Swales when full, allow the rain water to seep through the loose soil on the bund gently.
The philosophy of Earthworks of Permaculture is summarized below:
1. Slow down the pace of rain water
2. Let the rain water flow the longest distance on a given surface
3. Let the water take the longest time to travel
4. Excess water needs to be captured in small ponds/dams
Geoff Lawton demonstrated how it is possible to green even deserts. (See Oasis in Desert) with law rain fall of 150 to 200 mm of rain. And to add to the challenge most of the rain is concentrated during short periods, probably for a few days and few hours.
http://youtu.be/F0UNYGi4v8Q
Telangana is fortunate, and there are very few rain-shadow areas like Anantapur, in Telangana, and the state receives more than 350 mm of rain even in the so called drought conditions.
The average rainfall in Telangana according to various sources is between 500-750 mm. per annum
With the global warming, the rain events, which used to be spread over days, weeks and months are getting changing. We do see rain events where, in a few hours we receive 30 to 100 mm of rain!
If the earth does not have the capacity and capability to absorb so much of water in such short spells of rain events, the rain water creates devastating events of top-soil erosion and floods, which are inimical to the water security of a region.
Soil Organic Matter and water
There is enough research to show that earth’s ability to hold water is directly proportional to the soil organic matter (SOM).
At 2% SOM, under a rain event of 5 inches of rain (about 127 mm) the earth can retain about 30% of the water and at 5% SOM it retains about 50% and at about 8% it retains about 85% of water!
Indian soils are heavily depleted of SOM, especially given the arid and semi-arid conditions in the Deccan plateau OC (organic carbon). Adding to the hot climates and sun beating down on earth, regular and deep tilling exposes the SOM which evaporates in to the atmosphere adding to the CO2 in the atmosphere.
It is estimated that many soils have less than 0.5% of SOM!
SOM and ‘Modern’ agriculture
Understanding the devastating effects of tilling of the soil, NRCS (Natural Resources Conservation Services) of US Department of Agriculture, has been encouraging farmers in the US to go for either low-till or no-till practices. It is believed with encouragement and education NRCS could convert 30% of land used for agriculture into either no-till or low-till.
While our ancestors who practiced traditional systems of cropping, understood nature and respected nature, the so-called modern practices, which we borrowed from the west indiscriminately, is compounding the challenges of soil erosion and destroying the soil’s ability to allow penetration of water and capacity to hold water.
Heavy tilling machinery like powerful tractors during ploughing create a hard pan at about 6-8 inches below the surface of the soil making rainwater penetration difficult.
That’s the reason we see muddy waters after a rain flowing into our rivers. It is the productive top soil which is the life-line of plants that is washed away.
Agricultural machinery manufacturers in US have come up with seed-drills which either punch a small hole in the soil, discharge the seed and cover with soil or cut a very thin and low depth furrow and leave the seed and cover it up.
The crop residues, especially the roots are left in the soil to let them decompose and thereby increase the SOM. Roots of crops, research shows leave 3 times more carbon in the soil compared to stovers of maize or jowar left on the soil.
NRCS demonstrated changes in soil structure, its ability to hold water and thereby reducing the need for irrigation frequently and also the reduction of soil erosion, which is a major concern for agricultural productivity.
Please listen to Ray Archeuleta of NRCS demonstrating the negative effects of tilling both on the top soil erosion challenge and water holding and percolating capacities of soils on You Tube.
Food Forests in and around every village
There was a time every village in Telangana has forests around it which provided a perennial source of various foods and timber for construction and fuel wood. Today they are almost on the verge of extinction if ever they are existing.
The local forests needs to be protected, created where none exist and protected around every village.
The forest department is criticized for its ‘mono-culture mania’. If you drive to Vikarabad, you see Eucalyptus trees planted on the hilly terrain on either side before you reach Manneguda. Environmentalists find fault with the mono-culture plantations. What is more distressing is that the forest deparment destroyed all the root stock of the local forest species and planted Eucalyptus!
One redeeming feature is that they dug some furrows in between the rows of the trees to trap rain water. Unfortunately we do not see any scientific use of levels or contour leverage.
Local forests soak rain water, do not allow rain to hit the soil and make it hard and leave its ability to soak rain. With the canopy slowing the rain drops and taking the momentum of the rain drops and letting them fall gently on the earth. The debris of leaves and other mulch further protects the soil. Also the organic matter allows the soil biology to thrive thus creating millions of pores every square foot in the earth for storage of water and the slow release into the wells, other water sources such as tanks allows water table to recharge.
Here is a link which gives a tour of Food Forests in various climes.
http://youtu.be/QG_vRG66wkA
Grass lands
As much as food forests are needed around a village, it imperative that we also protect and create grasslands around villages for foraging, browsing of domestic animals.
The role of grasslands in hydrating soils, retention of moisture, and absorption of rain water for recharging of groundwater resources is immense.
We can learn from Alan Savory who did some remarkable work in Zimbabwe. Here is the link:
Re-imagining water for Telangana
It is critical to think about water and water security for the people of Telangana today and make Telangana water secure for future generations.
Telangana is a blessed land. What we need is the courage to re-imagine our future, and not be afraid to experiment, explore and innovate.
We need the wisdom to think holistically.
We need the sagacity to create a sustainable and eco-friendly future for our future generations.
The CM of Telangana has exhorted everyone to re-imagine, re-invent Telangana.
Hope we take the right decisions, make investments with the long term in view and the prosperity of future generations.