Jorhat, April 26: A former scientist at the Tocklai Tea Research Institute has developed a climate-resilient model which can help combat drought during the lean rain periods from December to March, raising annual tea leaf production by up to 40 per cent.

Prashanta Kumar Bordoloi presented his novel water-harvesting concept before an international audience at the fourth African Regional Conference on Irrigation and Drainage, Aswan Dam, Egypt under the aegis of the International Commission for Irrigation and Drainage, today.

Bordoloi, who is now director, outreach, and professor and head of the civil engineering department of Kaziranga University, said the concept could be used for other crops as well as for pisciculture, recreation and water sports.

Bordoloi said the technology also improved the micro-climate of the place and that the study was conducted on two plantations - Aenakhall and Rosekandy tea estates - in the Barak Valley, where water management is a big problem because of the hilly topography and nature of soil, which mostly has poor drainage quality and low permeability.

"Tea plantation in the valley started in 1856 in the plains areas and by 1875 hillocks and beel areas also were brought under plantation. With seven months of the year receiving excessive rainfall followed by five months of deficit rainfall, Cachar planters have been struggling to conserve their valuable topsoil from being eroded by torrential rainfall as well as protect their plantation from getting waterlogged through drainage as well as combat drought by both agronomic and engineering means," he said.

The geological setting of the valley, which had its origin because of tectonic activity, ground water resources are poor and the plantations are mostly suffering for want of dependable source for irrigation to combat drought, he added.

"The low kunchi areas, the intervening valley fill zones that are frequently subjected to flooding during the monsoon, as well as waterlogging because of poor drainage, are advocated for harvesting rainwater for irrigation in winter. Following the success of the earthen dam fills, the Tea Research Association, under which Tocklai Tea Research Institute operates, is assisting the industry by identifying the area and capacity of the valley-fill areas with different heights for fixing the height of dams for water harvesting with satellite imagery and by taking into account the rainfall in the valley," he said.

Bordoloi said in the case study of Aenakhall tea estate, the low-lying area ( kunchi) was surveyed using a plan table and a contour map was prepared following a standard survey.

The estate has 498 hectares under plantation and the total capacity of the four reservoirs is nearly 120 hectare-metre. The reservoirs can cater to the need of irrigation water of upto 600 hectares of tea for four rounds of irrigation from December to March at a rate of 50mm per setting, using the sprinkler system.

"The quantity of tea leaves increased tremendously in the first flush (December to March), a time during which hardly any leaves are plucked," he said.

Apart from meeting irrigation demands, the artificial reservoirs have improved the microclimate of the locality, which is yet to be quantified, apart from value addition to the property from the tourism angle.

"On an average, 3mm of water is lost in evaporation per day in winter, which also has a beneficial effect on improving the microclimate. It is known that humidity results in better leaf growth of tea plants," he said.

An alumni of Rutgers University, New Jersey, Bordoloi has been invited by the American Academy of Science to chair a session in the eighth international environmental science and technology conference in Houston from June 6 to10.