Why are floods necessary in Kaziranga?

Published - August 25, 2018 08:34 pm IST

Every year, the Brahmaputra takes away chunks of land from Kaziranga National Park that on paper is 1,030 sq km in area. The park now measures 884 sq km and is shrinking. But the river gives more to the address of the world’s largest population of one-horned rhinos than it snatches from - mostly hog deer, swamp deer, wild boar and a few other animals that fail to reach higher ground in time. This year, though, the 117-year-old park - a UNESCO World Heritage Site since 1985 - hasn’t been inundated, and this is worrying for the park authorities.

Why are floods necessary?

Floods, Central Water Commission data say, cost Assam an average ₹128 crore annually. The deluge happens up to four times a year between April and October. Unlike farmlands across the Brahmaputra floodplain, monsoon floods are essential to Kaziranga’s ecosystem. The national park’s vast grasslands and beels (wetlands) are revitalised annually by the Brahmaputra’s overflow. According to park director Akashdeep Baruah, Kaziranga’s plant and animal life are intrinsically linked to the floods that help recharge its wetlands and deposit mineral-rich alluvial soil to facilitate growth of grass and shrubs that are the main source of fodder for herbivores. Besides, the floodwaters, while receding, flush out aquatic weeds and unwanted plants from 92 permanent and about 250 seasonal beels besides Difolu, a stream almost bisecting the portion of the park on the southern bank of the Brahmaputra. The beels together account for 5.6% of Kaziranga’s total area.

What are the challenges?

Park officials say Kaziranga experiences a relatively dry spell or insufficient rainfall every four years. The floods that hit the park in 2016 were said to be the worst in a decade but 2017 was worse with more than 85% of Kaziranga inundated, displacing thousands of animals. Some 400 animals, including 31 rhinos, perished in last year’s deluge. The Brahmaputra appeared threatening in May, but the flow was not sustained mainly because Arunachal Pradesh upstream has had 40% less rainfall this year. It takes two days for the Brahmaputra to inundate the Kaziranga region after its tributaries in Arunachal Pradesh overflow. Assam, too, has had 35% less rainfall, though it has been just enough for the park’s channels and wetlands - watering holes for the animals - to be filled up. At this rate, 25-30% weeds (primarily water hyacinths) and animal wastes are expected to be flushed out naturally. Officials are keeping their fingers crossed, as “there’s still time till September and early-October” for floods to drain out the “natural trash”. If not, the Kaziranga landscape could face a problem vis-à-vis regrowth of vegetation, specifically in the grasslands that cover 60% of the park. An added worry has been the poor burning of grass around spring this year due to pre-monsoon rainfall. The burning is necessary for creating space for fresh grass.

Where is the real threat from?

During the not-so-devastating floods, animals in Kaziranga flee to higher grounds within the park. These include 111 highlands built in the late 1990s, each 12 ft high and large enough to accommodate up to 50 large animals. There are 33 more being built, each 16 ft high, with a total area of 22 hectares. But when 70-80% of Kaziranga is under water, the animals usually flee to the hills of Karbi Anglong south of the park beyond a National Highway running along its edge. Speed of vehicles is regulated during floods, but some animals invariably get killed. Of greater worry for wildlife officials and green activists is the destruction of the hills because of indiscriminate stone quarrying. An assessment by officials reveals some of the major quarries are on animal corridors and thus affect the movement of Kaziranga’s denizens. The quarrying has increased over a year, and extracted materials have been dumped at 38 sites along a 10 km stretch adjoining the park. If the floods happen in the next few weeks, Kaziranga’s animals could find their escape route blocked or altered.

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