Forest-based approach key to drought proofing

Rainfall in India has been deficient over the past 2 years impacting the availability of water for domestic, agriculture and other purposes.

Back-to-back droughts, drought-induced migration of people from Bundelkhand region of Uttar Pradesh and Madhya Pradesh, and particularly the spurt in farmer suicide cases in Marathwada region of Maharashtra attributed to drought-caused failure of agriculture, have caught the national media attention.

The Union and the state governments are struggling to match the relief measures. As per the Karnataka State Natural Disaster Monitoring Cell, 135 taluks in 27 districts are reeling under severe drought conditions and the water balance in dams and reservoirs is at its lowest in the recent past. As on April 7, 2016, the lowest percentage storage was in the Tungabhadra reservoir (5%; 4.93 out of 100.86 TMC of gross storage capacity) and highest was in the Narayanpura reservoir (44%; 14.50 out of 33.31 TMC) in the State.

Authorities concerned with water management in India have opted for engineering solutions such as storing water in dams and transporting through canals and inter-linking the rivers, so that floodwaters from one region could be transported to water-deficient regions. This blue-infrastructure consisting of dams and canals has been successful in enhancing the food production and augmenting the availability of water to meet domestic needs in rapidly growing urban areas.

However, the increase in irrigation water in the command areas (area irrigated by a water source such as a canal) of the blue-infrastructure has not been without side effects such as large-scale soil salination and excessive use of chemical fertilisers polluting the local tanks and streams. Additional investment becomes necessary to deal with these side effects.

Moreover, reduction in rainfall can reduce the utility and economic viability of the blue-infrastructure and prompt to adopt measures that can enhance rainfall. Climate engineering solution to initiate rainfall locally such as ‘cloud seeding’ has been tested with limited success in the past. Also, the implication of such water-management infrastructure for sustainability of river and command area ecology is deeply contested.

Confronted with the scenario of successive droughts on one side, and the politics and economics of operation, maintenance and the side effects of blue-infrastructure on the other, it seems useful to look for more reliable, equitable, cost-effective and sustainable options. The green-infrastructure ie, a network of forest patches distributed over the whole landscape, provides a nature-based solution to manage water effectively at a much lower cost and without the side effects of blue-infrastructure.

Scientific literature suggests that only about 40% of the rain water received in the interior continental areas is such, which evaporates from oceans. Forests and other inland ecosystems (grasslands, croplands and wetlands) contribute the remaining 60%.

Rainmaker

The available peer reviewed scientific literature findings further emphasise forests as the entities that cause rain, recycle rain, act as hydrological pumps and intensify the hydrological cycle, and thereby enhance the distribution and availability of fresh water on the terrestrial continental areas.

Acting as ‘hydrological-pump,’ forests transport water from coastal areas to the interiors. But for this service provided by forests, much of the interior continental areas globally would be arid. In case of Karnataka, the area west of the Western Ghats ridge receives very high orographic rainfall (6000mm) due to physical obstruction of moisture-laden winds by the ridge.

However, the east facing slopes and adjacent plains receive lower rainfall (1500mm) and much of which is due to the augmentation of water vapors by Western Ghat forests through transpiration. Further, in the eastern plains the rainfall drops drastically (700mm) supporting lower productivity and a drier ecology.

Research suggests that forest patches of significantly more than 2 sqkm size are able to influence the local climate through evaporative cooling and enhanced relative humidity (due to transpiration), and wind turbulence caused by surface roughness created by forest canopy. These factors contribute to episodes of rainfall locally and over a larger landscape. 

Well-researched information is therefore now available to us to practically apply and benefit from the ‘hydrological-pump’ service provided by forests. A network of forest patches dispersed over the eastern plains in Karnataka can potentially help in drought proofing and promoting the economic and social development in the State.

However, given the constraint of land to establish such a network of forest patches of significant size, the option could be to promote large-scale tree planting in the eastern plains area by supporting landowners of all categories in a mission mode. Karnataka Forest Department (KFD) is already implementing one such programme to incentivise tree planting in private lands (Krishi Protsaha Yojane) in the State, however its scale at present is low. An active policy approach to enhance and strengthen the green-infrastructure in the State, which is pivoted by the KFD and evolves from frequent feedbacks could be effective in dealing with droughts sustainably.

Also importantly, adaptation to climate change would critically depend on the availability of fresh water, as it is fundamental to food production and human health. Realising the vital role of forests in hydrological cycle, maintenance and enhancement of forests is being increasingly relied upon as a robust and sustainable low-cost option for successful adaptation by the society.

Further, enhancing and strengthening the green-infrastructure is not only ‘no-regret’ but also a ‘win-win’ option, with or without climate change induced droughts. And finally, given the effectively serving blue-infrastructure in place, this forest-based approach to enhance the water security of Karnataka should be considered as supplementary to it.

(The writer, an Indian Forest Services officer, is Additional Principal Chief Conservator of Forests,  Water Resources Department)