Taming Floods And Landslides
Every monsoon in Nepal is terrible as it causes floods and landslides. A flood is the overflow of surface runoff mostly in the dry land. Floods take lives of many Nepalis and damage their property each year. With her uneven landscape, the country is in a risky zone so far as the water-induced disasters are concerned. Deforestation is said to be a cause of floods, but it is less significant in Nepal because we are doing good in forest conservation. However, our land is very fragile and unpredictable. The high angled slope, terrace farming, unscientific construction of infrastructure, extraction of natural resources, among others, are the major causes of floods and landslides.
Unscientific urbanisation is a major contributor to floods in many countries. In every city, a large percentage of surface runoff gets accumulated and dropped into the urban sewerage system. However, roads are wrongly designed in developing countries like ours. The waterlogged areas are not considered while designing roads and sewerage system. In Nepal, roofs, street gutters, paved footpaths, and parking areas contribute for the accumulation of surface runoff.
Our practice of managing municipality waste is also poor. If we look at the major rivers in the Kathmandu Valley, we can find an unmanageable quantity of empty water bottles, plastic and other non-degradable wastes being dumped in the rivers. When surface runoff gets dropped into the river, the flow level starts increasing. This is because already deposited waste in the river blocks the natural flow which reduces the river speed and increases the level of water.
A study conducted by the United Nations concludes that more frequent floods are a result of global warming. Floods are intensified by climate change in Nepal, too. Climate change alters the pattern of precipitation. It distorts the process of snow melting in the mountains to increase the volume of water in the glacial lakes. The increased water volume due to increased temperature causes glacial lakes to burst. The irregularity of snowmelt may play a role in increasing the flow of rivers. The outburst of glacial lakes may sweep away the river corridor settlements. The flash floods may hit the hydro reservoirs. As per a study by Mule (2001), Nepal has 2,323 glacial lakes. This points to a high potentiality of glacial lakes being burst. That is why the settlements and infrastructure along the river corridors are at risk.
Unscientific road construction in a fragile landscape is a cause of landslides and floods in Nepal. Constructing rural roads using a bulldozer is fast but its use is quite devastating. The use of bulldozers has several consequences on the environment. For example, it cuts the nerve of groundwater so the extinction of natural spring due to dry-off of underground aquifer can be predicted. It destroys plants, cultivated lands, and the natural stability of the ground. We can see the deposited debris over paddy field that has come from the uphill bulldozer road. Most of the rural and urban municipalities or their representatives have now owned bulldozers. They are operating bulldozers to build roads without following the norms of engineering. Nowadays, bulldozers are used even for minor civil engineering works. We can observe that the priority of municipalities is to build roads without considering their functionality. Building the bulldozer road is a kind of business. That is why this trend is unlikely to end easily.
While travelling through downhill roads in monsoon, we can see them being blocked with debris coming from the uphill. They cut the naturally steep ground turning it into a gully that not only collects the surface runoff for floods but also causes landslides. The degradation of natural land further destroys agricultural land, human settlements, and infrastructures. The deposition of sand, soil, gravel and organic materials in the river bed increase the flood level.
Enforcement of the Local Self-Governance Act in 1999 opened the door to extract riverbed materials in an uncontrolled way. Various local levels were found exploiting rivers. After the promulgation of the constitution in 2015, the local governments have been mining materials for revenue. Some municipality representatives or their relatives are involved in the extraction business.
Those having strong connection with power centres have established crushers without considering their impact on the physical environment. The improper extraction of materials dismantles the slopes’ stability, natural vegetation, and rock beds. Similarly, the extraction of gravel from Chure has been a debatable issue. Extraction of gravel from Chure degrades the landscape towards its desertification. The road track for collecting gravel has loosened the soil of Chure through which surface runoff passes in monsoon. The uncontrolled extraction not only degrades Chure but also increases floods in the Terai.
Mostly, flood and landslide are the immediate results of anthropogenic exploitation of natural resources. In order to minimise the intensity such disasters, urban infrastructures should be well-engineered. The rivers and streams should be kept clean. Municipalities need to consider the environmental issue before mobilising bulldozers. The extraction of the natural resources from rivers should be regulated. For that, municipalities can adopt a policy strategy by consulting the experts. The state governments need to be aware of the sensitivity of the landscape. Extraction of gravel from Chure should be stopped, or regulated. The state governments should issue the license to crushers after evaluating their environmental impact assessment report, and environmental management plan.
Controlling floods and landslides is not to disturb the natural flow of the water course and ground stability. In order to bring the natural flow of rivers under control, city infrastructure should be well-designed. Land use pattern should be regulated. Opportunities should be given to surface runoff to reach ground aquifer.
Municipalities should establish an early flood warning system in the zone of influence. Programmes and strategies should be developed to enhance the emergency response capacity of stakeholders. NGOs, CBOs, and educational institutions should formulate the programmes to raise community awareness. There should also be an emergency preparedness plan with municipalities. They can mobilise local FMs and telecommunications to disseminate messages for quick response.
To sum up, floods and landslides are a response to our unscientific exploitation of resources. As the environmental element is less in focus of policymakers from different levels, the unscientific extraction could result in such disasters. However, the loss of life and property can be controlled if we respect the rule of nature.
(The author is an environmental specialist)