This year, the rainfall has been beyond average in Bhutan and the Baksa area. Rainfall started just after Rongali Bihu and the farmers were happy as they could prepare their land much earlier and their fields had just the right amount of water for land preparation and for raising the nursery, all the time. But their happiness did not last long. Nature, provoked by anthropogenic activities, had a different story to script.
Pagladiya, as the name suggests, is the mad river of Assam. It changes its course whenever we try to intervene its flow. For many years, there were no such activities to draw her wrath, but in 2017, the construction of an embankment started on the downstream of the bridge on the Dhamdhama-Tamulpur road, historically the Gohain Kamla Ali. 2018 passed, the monsoon was normal, without much event.
2019 was different. The water accumulated upstream in the hills, started to flow down to the Baksa region. The speed of water was high, because most of the boulders have been extracted from the river bed in the dry season. Also, the gradient too is high. At the point where it enters India, the altitude above MSL is around 200 m and around 100 m at the bridge, a slope of 300 cm in 1 km (compared to Brahmaputra’s slope of 15 cm in 1 km).
To save one or two villages, two embankments were constructed on both sides of the river, on the downstream of the bridge. This season, when the rains started, water level started to increase gradually, and it slowly started eroding the west bank in Jhartaluk village, hardly 500 meters upstream of the bridge. And within a week, the bank at some parts were complete eroded and subsequently, the channel migrated to a new course, 1 km to the west and inundating new villages. Now we do not know which course will the river take: it might rejoin its old course around 4 km downstream of the bridge or join the Chengnoi and then feed the Burhadia river.
There were not any human casualties but the people living there are not used to living with water, except a few households living very close to the river bank. The embankments constructed will also be submerged some day and they might even be breached too. But a small act of the department has resulted in destruction of more than 400 hectares of land and most of the lands will be covered by sand. Only after the water dries up, we will know where it has eroded and where it has deposited sand and who are those lucky ones to have a layer of fertile soil.
Public representatives, government, administration and everyone visited the location. There will be more work under various government programmes, but one basic activity will never be undertaken. Even if it is undertaken, it will never be completed and another one will be started. The basic problem will remain, even if it is solved, it will resurface as all solutions are temporary and complete waste of public money.
This is not an isolated case of river mismanagement. Everything starts with the right intention and in earnest. Somewhere in the execution stage, when the number of unrelated stakeholders increases, the problem arises. On top of that, localized approach of solving river problems and myopic views of the engineers (for whatever reason including shortage of fund and time it may be) add to the issue.
Many in Assam are demanding that the annual flooding of the state be declared a national problem. Here, we have failed to identify our actual problem. In fact, if one conducts a survey among the flood affected areas of Assam, they will never say flood is a problem for them. Over the years, they have been able to adapt themselves to flood by constructing stilt houses, using boats or banana rafts and it is the flood that fills their soil with fertility and their ponds with fishes. But there is no such adaptation when it comes to erosion.
It is erosion and not flood that is causing us to lose precious national property called fertile land and hence we must demand that erosion be declared a national problem.
Another problem that we are facing is the problem of silt deposition. Due to deforestation and landslides, sediment generation in the fragile foothills of the Himalayas still continues, which are ultimately deposited in the places where the speed of river water reduces. The silt not only changes the course of the river, but also leaves a layer of sediment in areas where it flows.
When it floods, you can swim, but when it erodes, it takes away your home and the soil beneath your feet. Instead of macro-management, a micro-managing approach must be taken. Rain is localized, but with surface flow, the same rainwater causes erosion and flood at different places. If we can hold the localized water for a given period in that area, which can then be released in a controlled way, we may be able to control erosion and floods.
This strategy should start from the upstream of the river basin. In the case of the Pagladiya, it should start in Bhutan. The present Pagladiya river basin occupies an area of 1171 sq. km, out of which 465 sq. km (nearly 40%) falls in the territory of Bhutan. The rainfall there is almost 3500 mm per year. If 80% of this rainfall is distributed to the peak four months, per month rainfall in the Bhutan area is 700 mm and the volume of water to be controlled is huge. An international effort with Bhutan for control of this volume of water is very necessary for managing water in the foothills and Baksa region.
In the plains, rainfall is slightly less. But we can think of storing rainwater at the wadi level (a wadi is a freshwater ecosystem and a type of fluvial landform, i.e. a type of geological feature that is related to rivers) and at the paddy field level.
The climate is so erratic that once this rainy season is over, there will be a very long dry period and then people will start to demand that Assam be declared a drought-prone state. This will send a very wrong message. At one point of time, we demand flood to be a national problem and at another, we demand to be declared a drought-affected state. Since from at least one point of view, the floods are not really a problem for the adaptive and resilient population and it is the erosion that is the main culprit. And so, it is erosion should be declared a national problem.
1) Manage water flows locally;
2) Declare erosion as a national problem and design policies and programmes keeping in view of reducing erosion of fertile lands.
The Pagladiya can be an extremely good pilot case for international rainwater management project. Already a century-old water management system exists which is managed by the community to carry water to the fields and homes. The traditional bandh and canal structure can also be expanded and used for water retention and as water shock absorbers.
Someday, Bhutan will construct a hydel project just like Kurichhu Hydro-Electric Power Station, and we should not be left at the mercy of the rain gods and the Bhutanese Government. By then, let’s be prepared.
I would like to thank Dr Sarat Phukan who teaches in the Department of Geological Sciences, Gauhati University for some of the inputs used in this article.