Underpasses to reduce roadkill in Nepal

Cutting through the dense jungles of the Tarai national parks, the East-West Highway is turning into a death trap for Nepal’s endangered and protected wildlife. Now, Nepal is building more underpasses so animals do not have to risk crossing highways.

Of the 1,028km East-West Highway, nearly 400km slice through national parks in Parsa, Chitwan, Bardia, Banke. Another 122km stretch of roads cross wildlife corridors connecting protected areas, as well as linking Tarai forests with the mountains to facilitate wildlife migration.

Nepal’s conservation success story means that there is now more wildlife movement between national parks, while upgraded highways have increased the number of vehicles and their speed. In the past three years alone there have been 400 road kills involving wild animals.

The 30km Narayanghat-Mugling Highway was recently improved to meet Asian highway standards, and this meant not only did it have to ensure adequate road safety features but also address conservation needs.

The highway features the first two of Nepal’s four new wildlife underpasses in the Aptarai and Ramnagar in the section where the road passes through an important animal migration corridor.

The underpasses were also equipped with 14 camera traps by the World Wildlife Fund (WWF) and its ‘Hariyo Ban Program’ to better understand wildlife migration in the Barandabhar Forest Corridor and to monitor whether the underpasses are effective.

The WWF has now released its findings from the study, and concludes: ‘Wildlife crossing structures are essential for all linear infrastructure projects traversing critical forests, incorporating designs based on international practice and available guidelines in all planned projects seem imperative in the future.’

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According to the Department of National Parks and Wildlife conservation, the road kill problem is getting worse. There were 119 animals run over by vehicles in national parks in 2018/19, down from 124 in 2017/18 and 133 in 2016/17. In some years this was up to a third of the total number of recorded wildlife deaths in national parks. However, conservationists say the number could be much higher if highways through unprotected forests are also counted.

“With such massive new investment in large infrastructure project, the impact on biodiversity and wildlife will be heavy, and we need mitigation measures such as underpasses and overpasses not only to save wildlife but also for human safety,” says WWF Nepal Representative Ghana Gurung.

The WWF monitoring of the underpasses after the Narayanghat-Mugling Highway was upgraded from August 2017 till June 2018 shows that more than half of the animal movement occurred in winter when wildlife moved to sources of water.

The WWF’s Pramod Neupane says the use of underpasses will increase as animals get more familiar with the structures. He adds: “Our research proves that underpasses are effective in facilitating safer wildlife movement, and we need to replicate this in other critical jungle corridors in the Tarai.”

Only a quarter of the movement was during the monsoon months, while the pre-monsoon dry season saw the least movement. Most of the wildlife using underpasses were deer, wild boar and other medium-sized animals, and only 10% of the animals were large mammals like tigers, leopards and rhinos.

“It seems the underpasses are not being used to their full extent because they are too small for large animals like wild elephants, and also because of the litter from the highway some of the underpasses have become constricted so bigger wildlife cannot easily pass through,” explains Padma Raj Nepal of the Division Forest Office in Chitwan.

Manoj Aryal at the Department of Roads says the Chitwan study has shown that underpasses are effective in reducing wildlife deaths. After studies showed 30 spots along the 160km stretch of the East-West Highway between Narayanghat and Butwal that wild animals frequent, the Department is constructing four more underpasses and one overpass.

Other wildlife underpasses are planned on the highway from Patalaiya of Bara to Dhalkebar of Dhanusha on the East-West Highway, which passes through the Charkose Jhadi and Parsa National Park.

In Bardia, various line ministries in Province 5 in coordination with the Division Forest Office in Bardia have prepared a detailed project report for a 45m overhead wildlife bridge in an important migration corridor where wildlife movement is very high.

The overpass will allow tigers, rhinos and wild elephants migrating through jungle corridors connect Bardia National Park with Katarniaghat Wildlife Sanctuary in India. The overpass will cost Rs81 million and construction will begin once the Environment Impact Assessment is done.

Adds Aryal: “In the past, the cost of building such passes were considered unnecessary. But the success of the Chitwan experiment has shown that safe passage for wildlife is vital in reducing wildlife death along our highways.”