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Environmental Impacts Of The Gorkha Earthquake

earthquake-nepalThe 7.8 magnitude earthquake that jolted central Nepal on April 25, 2015 has had considerable impact on various aspects and sectors of life. Though the devastating quake and its powerful aftershocks shook the whole nation, 14 districts in the central region of the country were most severely affected. A 7.3 magnitude aftershock that occurred 17 days after the main tremor also caused additional losses of lives and destruction of homes and other infrastructure. It was a major tremor to hit the nation after the powerful earthquake of 1934.
According to the National Planning Commission, a total of 8,700 lives were lost in the April quake and its aftershocks while over 22,000 others were injured. More than half a million houses were completely destroyed, and an additional 200,000 houses were damaged.
Besides the loss of lives and destruction of property, the tremor named Gorkha Earthquake for its epicenter being at Gorkha district’s Barpak, left a wide trail of destruction in the environment as well. This impact is going to have far reaching consequences in the ecological health, geology, forests, bio-diversity, wildlife, fresh water sources and more.
Nepal’s hill topography was fragile and weak even before the April 2015 earthquake due to factors such as deforestation, extreme climatic conditions, landslides, soil erosion and precipitous slopes. This geological condition was made still more vulnerable by a frenzy of rural road construction that has been going on since the past several years. The trend of haphazard and rampant exploitation of natural resources in recent years had made the environmental situation even worse. The powerful earthquake brought widespread destruction affecting human settlements, water supply, transportation infrastructure and livelihood.

Geological Impacts
According to the Nepal Earthquake 2015 Rapid Environmental Assessment report published by the Ministry of Science, Technology and Environment, the Gorkha Earthquake triggered thousands of landslides and cracks in 31 districts of the country, significantly damaging settlements, infrastructure, agricultural land, forests and water sources. The earthquake and hundreds of its persistent aftershocks ripped off eastward from its epicenter, causing a fault rupture of up to 150 km running east of Gorkha district.
“An area of approximately 120 km by 50 km around the Kathmandu Valley was lifted up by 1 metre and shifted south,” the assessment report says.
The environmental assessment recorded a total of 2,782 landslides in 14 highly affected districts, which generated an estimated 19,118,538 cubic metres of sediments. This has increased the sediment loads in the downstream areas. According to the report, about 75 per cent of these quake-induced landslides occurred in the Indrawati, Sunkoshi, Tamakoshi, Dudhkoshi and Likhu sub-basins of the Koshi River system.
The rivers will carry large amounts of debris that include rock fragments, boulders, sand, silt and clay. This debris movement will ultimately raise the river levels and change the river course. Such a process causes flooding and sedimentation of farmlands, forests and human settlements.
Many of the rock falls and dry landslides occurred near villages and caused loss of lives, injuries, loss of livestock and property, and infrastructure damage. Damaged infrastructure includes roads, trails and irrigation canals. More of the weakened infrastructure is lying vulnerable to further damage during the next monsoon season.
Chameli Sitaula of Katheri in Salyankot VDC said that her village lying beneath a huge cliff is at risk of landslides and rock falls. The rocky slope above the village has developed dangerous cracks. There was a rock fall which luckily did not directly hit the houses. There was no rain in the area last monsoon season, which badly affected paddy plantation. However, she said that the dry spell in the wake of the quake proved to be a boon in a sense. Had there been intense rainfall following the earthquake, the village would have surely come under bigger rock falls and landslides.
However, lack of rain during the previous monsoon months is not the end of the story. The cracks are still there, and the land is far from becoming stable, steady and secure. The danger is lurking for the next rainy season, and we are very much worried about it because we have nowhere else to go, she said.
The chances of avalanches and glacial lake outburst floods (GLOFs) are still higher during earthquakes as they distablise the ice mass and moraine dams supporting the glacial lakes. The assessment report states that an avalanche of ice and rocks that hit Langtang village in Rasuwa district north of Kathmandu completely buried the village. This disaster killed 200 local people and foreign tourists and rendered around 500 people homeless.
The process of ice melt in the Himalaya was already accelerating due to climate change. The earthquake has only worsened the disaster risks. Scientists say that the largest glacial lakes – Imja, Tsho Rolpa and Thulagi – have posed greater risks after the earthquake.
Many of Nepal’s hill districts depend on the water springs for water supply. After the April 2015 earthquake, many water springs dried up while others saw reduced flow. New springs are also reported to have appeared in some places, but they might not be at a convenient locality from settlements. The earthquake has distabilised and changed the regular underground water conduits and affected the water table. Changes in the water quality and water levels in the wells are also reported.
“Changes in the water sources will have significant impacts on rural water supply and may invite conflict between communities and wildlife,” the report points out.

Impacts On Forests and Biodiversity
The earthquake damaged forest resources in 31 districts. The losses that occurred in 14 most affected districts are valued at Rs. 63.9 billion. According to an assessment made by the Post Disaster Needs Assessment (PDNA) team, mainly pine forests and sub-temperate types of forests were highly affected. Major forest losses occurred in the Langtang Valley and the Manaslu Conservation Area in central Nepal. The forest areas in the quake-affected districts are likely to face human pressure and subsequent deforestation as timber and other forests resources will be in high demand to rebuild homes.
After the decimation of local species of plants by the earthquake, there is great risk of colonisation by invasive ones. Local vegetation regeneration and reforestation take a long time, and selection of appropriate species that conserve the soil are important.
Seven protected areas, namely Sagarmatha National Park, Makalu Barun NP, Langtang NP, Shivapuri-Nagarjun NP, Gaurishankar Conservation Area, Manaslu CA and Annapurna CA were affected by the earthquake. Gosaikunda and Gokyo lakes were also affected. These protected areas are home to some wildlife species of global significance such as the red panda, musk deer and Himalayan tahr. Their important habitats like the blue pine forest, temperate oak forest, sub-alpine forest and birch forest were damaged in Langtang National Park.
Quake-triggered landslides have damaged wildlife habitats and restricted the free movement of animals. Breeding of wild animals and birds is also suspected to be adversely affected. For instance, the landslides and avalanches may have destroyed the habitats of bird species nesting and living on cliffs.
The environment ministry’s assessment report says that loss or damage to the existing ecosystem and their services is likely to affect the livelihood, food security, health and safety of the local people. Availability of biological resources plays an essential role in Nepal in addressing poverty, hunger and food security in the rural areas. Loss of medicinal and edible herbs may already have affected the traditional healing system and food supply. Losses may amount to millions to individuals and the government in terms of revenue, when the collection of the high value Himalayan herb, Yarsaguba, is affected.
Loss of water resources due to landslides triggered by the quake may have created a critical problem in some villages. This adds to the woes of already drying water sources because of climate change. This problem can be the cause of internal migration in many places. Water shortage has become more severe as earthquake-affected districts saw very scanty rainfall last monsoon season. Acute food shortage is also likely in these districts as plantation of the main cereal crop, paddy, was badly affected.
The impact on eco-tourism is no less as nature-based tourism contributes significant revenue to the national economy. Many lodges and home-stay buildings were destroyed in the earthquake. The calamity severely affected around 13.5 per cent of the trekking trails with greatest damage occurring in Langtang National Park.
“The March-May tourist season was cut short by the earthquake, when many tourists left early or cancelled their trips,” the assessment report says. Reconstruction of tourism infrastructure and recovery of service capacity is urgently needed in order to contribute to the national economy, the report suggests.
According to the environmental assessment report, the watersheds in the Koshi and Gandaki river basins were adversely affected by the earthquake. A number of landslides and cracks had occurred in the catchment tributaries of these rivers. More landslides are expected in the upcoming monsoon season when the cracks and crevasses receive floods of water, and weakened soil and rocks lose stability. The chain effect will move beyond the areas directly affected by the quake as floods and erosion will affect the communities, wildlife, forests and agricultural land in the downstream areas.
The report says that rhinos and tigers in Chitwan National Park and Arna (wild buffaloes) in the Koshi Tappu Wildlife Reserve will be affected.

Climate Change Exacerbates Problem
Climate change has brought the unpredictable trend of extreme rainfalls and prolonged droughts. Both have disastrous consequences. The intense rains exacerbate the events of landslides, soil erosion and rock falls in areas weakened by the earthquake. Drying up of water sources due to climate change has been made worse by the earthquake. Melting ice mass is more vulnerable to slide into an avalanche in the event of an earthquake. Dry spells that have been widely witnessed after the earthquake are going to cause food deficit and water shortage in the affected areas. Extreme rains and flooding will carry big amounts of sediments that will raise the river level and hit the farmlands and settlements downstream. Glacial lakes pose greater risks during earthquakes with chances of a GLOF. Though climate change does not cause earthquakes, its impacts on people and wildlife are more severely felt after an earthquake.

Solid Waste Generation
The earthquake added extra challenges in solid waste disposal and management as it generated huge amounts of debris from collapsed and damaged structures. Significant amounts of this debris comprise hazardous materials. According to the Solid Waste Management Technical Support Centre, around 3.9 million tons of rubbles were generated after the earthquake. It added huge challenges to the municipalities, already struggling to manage the municipal solid waste.
For instance, the quantity of quake debris in Kathmandu has been estimated to be 60 times more than what is normally handled in a year. All the affected municipalities are having difficulty finding an appropriate site to dispose off the debris from the disaster. Separating and specially treating the hazardous materials in the debris remain an unaddressed challenge.
The earthquake debris includes toxic chemicals and heavy metals from household electronic equipment, lighting systems and gadgets. Contaminated debris requires environmentally safe handling and disposal. “However, the government lacks proper guidelines and framework to manage this problem, and the Solid Waste Management Act of 2011 does not address the management of disaster waste,” says the assessment report.

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