Climate-proofing of Watersheds – A Few Soil and Water Conservation Models Across India

Field bunds

Field bunds are constructed where the slope is very flat and agricultural operations can be done safely. The water stored in the bunds improves the moisture of the soil for the production of crops. 

Drainage Line Treatment

The formation of drainage lines usually starts in hilly and non-arable areas where velocity and amount of runoff are high. The quantity of water further increased when the drainage line passes through the arable areas in the lower reaches of the watershed. Looking to the velocity of flow and sequential increase in the quantity of water in the stream, the drainage line treatment should start from upper reaches of the watershed. The measures should be adopted after careful consideration of the quantity of runoff, velocity of runoff, and cross-sectional area of drains. 

Bund planting

Forest tree species and multi-purpose tree species are planted on farm bunds under the Agroforestry systems. This ensures bund stabilization and contributes toward nitrogen fixation, fruit, and fodder requirements. 

Thoor plantation

On pastureland, Cactus species can be planted on the boundaries of pastureland to prevent livestock from open grazing. Used as live fences. 

Water absorption trench (WAT)

WAT has proved useful for soil and water conservation and improving the ground water table. 

Recharge pits

Recharge pits are useful in soil and water conservation and improving the ground water table. Kitchen Garden Vegetable crops are grown in Kitchen garden for consumption at the household level. Ensure better nutritional security especially for women and children. 

Continuous Contour Trenches (CCTs)

CCTs are constructed along slopes to arrest accelerated soil erosion and conserve rainwater. These are constructed along contours. 

Farm Pond

Crucial for rainwater harvesting and life-saving irrigations for additional 2 months after the monsoon season.

Ber Budding

Pasture/ fodder planning with livestock management is seen as an important climate-proofing / adaptation measure in this region. In order to augment fodder availability for goats by capitalizing on the available ber trees. In ber budding, locally available Zizhyphus rotundifolia is budded with improved varieties like Seb, Gola, Tikadi varieties of Zizhyphus mauritiana. 

Gradoni

These are narrow terraces built along the contour on the hillside with the outside rim higher than the inner edge. The terraces are generally discontinuous and are staggered between rows. The runoff water not only loses velocity at the terrace, but also is collected in the terrace because of the negative slope. Erosion is thus reduced and seedlings planted in the gradoni receive additional water. These are about 1 meter wide and not necessarily continuous) made along the contours of a slope with a tilt inwards to the slope. They are suited for afforestation in uniformly steep sloping areas. These are recommended to be constructed economically for the area having slope up to 20 % only with considerable soil depth. 

Gully plug

Gully plugs are constructed using stone boulders across gullies to prevent accelerated soil erosion and check soil runoff. Grass seeding in pastureland Stlylosanthes hamata, Cenchrus species can be sown in pasturelands to ensure the availability of grasses for livestock. 

Stone-pitched Thawla

These are small pits dug on hill slopes and patched with stones to conserve soil moisture. A sapling is planted in the Thawala. Thawalas are also constructed around existing saplings along slopes. 

Katas / Mundas / Bandhas

The katas, mundas and bandhas were the main irrigation sources in the ancient tribal kingdom of the Gonds (now in Western Orissa). Most of these katas were built by the village headmen known as gountias, who in turn, received the land from the Gond kings. Land here is classified into four groups on the basis of its topography: aant, (highland); mal (sloped land); berna (medium land); and bahal (low land). A kata is constructed north to south, or east to west, of a village. A strong earthen embankment, curved at either end, is built across a drainage line to hold up an irregularly-shaped sheet of water.

The undulations of the country usually determine its shape as that of a long isosceles triangle, of which the dam forms the base. It commands a valley, the bottom of which is the bahal land and the sides are the mal terrace. As a rule, there is a cut high up on the slope near one end of the embankment from where water is led either by a small channel or tal, or from field to field along terraces, going lower down to the fields. In years of normal rainfall, irrigation was not needed because of moisture from percolation and, in that case, the surplus flow was passed into a nullah. In years of scanty rainfall, the centre of the tank was sometimes cut so that the lowest land could be irrigated.

Percolation Tank: 5 % model, promoted by PRADAN NGO.

Ahar-Pyne

This traditional floodwater harvesting system is indigenous to south Bihar. In south Bihar, the terrain has a marked slope — 1 m per km — from south to north. The soil here is sandy and does not retain water. Groundwater levels are low. Rivers in this region swell only during the monsoon, but the water is swiftly carried away or percolates down into the sand. All these factors make floodwater harvesting the best option here, to which this system is admirably suited. An ahar is a catchment basin embanked on three sides, the ‘fourth’ side being the natural gradient of the land itself. Ahar beds were also used to grow a rabi (winter) crop after draining out the excess water that remained after kharif (summer) cultivation.

Pynes are artificial channels constructed to utilize river water in agricultural fields. Starting out from the river, pynes meander through fields to end up in an ahar. Most pynes flow within 10 km of a river and their length is not more than 20 km. The ahar-pyne system received a death-blow under the nineteenth-century British colonial regime. The post-independent state was hardly better. In 1949, a Flood Advisory Committee investigating continuous floods in Bihar’s Gaya district came to the conclusion that “the fundamental reason for recurrence of floods was the destruction of the old irrigational system in the district.”

Bengal’s Inundation Channel

Bengal once had an extraordinary system of inundation canals. Sir William Willcocks, a British irrigation expert who had also worked in Egypt and Iraq, claimed that inundation canals were in vogue in the region till about two centuries ago. Floodwater entered the fields through the inundation canals, carrying not only rich silt but also fish, which swam through these canals into the lakes and tanks to feed on the larva of mosquitoes. This helped to check malaria in this region.

According to Willcocks, the ancient system of overflow irrigation had lasted for thousands of years. Unfortunately, during the Afghan-Maratha war in the 18th century and the subsequent British conquest of India, this irrigation system was neglected, and was never revived.

According to Willcocks, the distinguishing features of the irrigation system were:

1. the canals were broad and shallow, carrying the crest waters of the river floods, rich in fine clay and free from coarse sand;
2. the canals were long and continuous and fairly parallel to each other, and at the right distance from each other for purposes of irrigation;
3. irrigation was performed by cuts in the banks of the canals, which were closed when the flood was over. 

Dungs or Jampois: Dungs or Jampois are small irrigation channels linking rice fields to streams in the Jalpaiguri district of West Bengal.

Johads: These are traditional water harvesting structures found in Rajasthan.

Check Dams: These are small water harvesting structures.

Bandharas

These are check dams or diversion weirs built across rivers. A traditional system found in Maharashtra, their presence raises the water level of the rivers so that it begins to flow into channels. They are also used to impound water and form a large reservoir. Where a bandhara was built across a small stream, the water supply would usually last for a few months after the rains. They are built either by villagers or by private persons who received rent-free land in return for their public act. Most Bandharas are defunct today. Very few are still in use.

Kohli Tanks

The Kohlis, a small group of cultivators, built some 43,381 water tanks in the district of Bhandara, Maharashtra, some 250-300 years ago. These tanks constituted the backbone of irrigation in the area until the government took them over in the 1950s. It is still crucial for sugar and rice irrigation. The tanks were of all sizes, often with provisions to bring water literally to the doorstep of villagers.

Virdas

Virdas are shallow wells dug in low depressions called jheels (tanks). They are found all over the Banni grasslands, a part of the Great Rann of Kutch in Gujarat. They are systems built by the nomadic Maldharis, who used to roam these grasslands. Now settled, they persist in using virdas. These structures harvest rainwater. The topography of the area is undulating, with depressions on the ground. By studying the flow of water during the monsoon, the Maldharis identify these depressions and make their virdas here.

Essentially, the structures use a technology that helps the Maldharis separate potable freshwater from unpotable salt water. After rainwater infiltrates the soil, it gets stored at a level above the salty groundwater because of the difference in their density. A structure is built to reach down (about 1 m) to this upper layer of accumulated rainwater. Between these two layers of sweet and saline water, there exists a zone of brackish water. As freshwater is removed, the brackish water moves upwards, and accumulates towards the bottom of the virda.

Kere

Tanks, called kere in Kannada, were the predominant traditional method of irrigation in the Central Karnataka Plateau, and were fed either by channels branching off from anicuts (check dams) built across streams, or by streams in valleys. The outflow of one tank supplied the next all the way down the course of the stream; the tanks were built in a series, usually situated a few kilometres apart. This ensured a) no wastage through overflow, and b) the seepage of a tank higher up in the series would be collected in the next lower one.

Khadin

A khadin, also called a dhora, is an ingenious construction designed to harvest surface runoff water for agriculture. Its main feature is a very long (100-300 m) earthen embankment built across the lower hill slopes lying below gravelly uplands. Sluices and spillways allow excess water to drain off. The khadin system is based on the principle of harvesting rainwater on farmland and subsequent use of this water-saturated land for crop production. First designed by the Paliwal Brahmins of Jaisalmer, western Rajasthan in the 15th century, this system has great similarity with the irrigation methods of the people of Ur (present Iraq) around 4500 BC and later of the Nabateans in the Middle East. A similar system is also reported to have been practiced 4,000 years ago in the Negev desert, and in southwestern Colorado 500 years ago. 

Tankas

Tankas (small tank) are underground tanks, found traditionally in most Bikaner houses. They are built in the main house or in the courtyard. They were circular holes made in the ground, lined with fine polished lime, in which rainwater was collected. Tankas were often beautifully decorated with tiles, which helped to keep the water cool. The water was used only for drinking. If in any year there was less than normal rainfall and the tankas did not get filled, water from nearby wells and tanks would be obtained to fill the household tankas. In this way, the people of Bikaner were able to meet their water requirements. The tanka system is also to be found in the pilgrim town of Dwarka where it has been in existence for centuries. It continues to be used in residential areas, temples, dharamshalas and hotels.

Bamboo drip irrigation: This is a 200-year-old system, used by the tribal farmers of Khasi and Jayantia hills in Meghalaya.

Biogas: Biogas plants useful for ensuring clean biogas for cooking purposes to individual households. 

Plantation of fodder trees in silvipasture land: Salar saplings (Boswellia serrata). This is a good tree fodder tree species; Dhaman is a preferred local grass in pasturelands for livestock. Dinanath grass, can be sown on slopes and pastureland. Hybrid Napier grass – CO 4 variety CO 4 variety of hybrid Napier grass grown as demo. Nil Gai do not eat this grass! Fast-growing grass species and an excellent grass used as fodder for livestock. 

Silvi-Pasture development: Keeping in mind the climate change aspect, if there is any shortage in availability of grass fodder, to cover up the gap, trees of different varieties like Neem, Subabul, Salar, Kher, Kherni, Khakre, Arshua, Ardul are planted within this pasture land. A clear understanding have been developed with the owners of the pastureland as group to protect the pasture land and to follow the “Charai Bandi” (No open grassing allowed) for minimum of 2 years to allow the trees to grow. In addition, seeds of ‘Karar’ and ‘Hamata’ variety of grasses and seed of Subabul and Kher are also planted. The entire pasture land has been protected with both stone and vegetative (Thoor) fencing with definitely social fencing. 

Mini Agro met Lab

Mini Agro-met observatory lab can been established in a watershed to adapt to weather based farming practices by the farmers. It is operated by the trained ‘Weather Manager’ selected from the village. He used to collect all weather data on daily basis and recorded in a systematic manner. The lab is consisting of basically four instruments viz.

1. the Stevenson Screen with Minimum & Maximum temp thermometers, a dry and wet bulb for measuring the relative humidity
2. a non recording Rain Gauge
3. an Anemometer for measuring the wind velocity and
4. a Wind vent for measuring the wind directions. 

Farmer Field School (FFS)

FFS is based on learning by doing concepts. For the Kharif season 2013, 12 progressive farmers from different villages in the watershed area can be been identified and demonstration on improved crop production technology addressing to climate variability has been laid out on their respective fields. All the selected farmers are provided with inputs like improved variety of seeds like – Maize seed (Navjot) and seed of ‘Urad’ (T-9 variety) along with proportionate fertilizers like DAP and Zink sulphate etc., with a training on the package of practices for intercropping. 

Mixed farming: Farming involving crop and animal production which is functionally linked (e.g., use of manure on crops, use of ex-plough).