Ilan River gets new lease on life

Reconstruction work is taking place along the Ilan River to improve resistance to floods and create an easily accessible recreational riverside area. The NT$250 million project is part of the government's effort to promote ecological engineering in public construction. PHOTO: CHIANG YING-YING, TAIPEI TIMES

Sitting on the new grass growing next to the Ilan River (宜蘭河), Lin Yu-chen (林妤真), a 14-year-old girl from Ilan Junior High School's fine arts class, paints a pastoral landscape in bright teal blues and bold emerald hues.

The interplay of colors in Lin's watercolor painting reflect the diversity of the riverside plants, which were grown carefully by the Ilan County Government based on concepts integrating flood control and ecological conservation.

Along the middle reaches of the 15km-long river, steep concrete embankments are being replaced by gentle slopes covered with riverside plants such as water willow (水柳), Leersia hexandra (李氏禾) and verdant grass. A scenic route along the meandering river in a 2.2km section between Ilan Bridge and Chungshan Bridge is now a haven for hikers, runners and bicycle riders.

"The river reconstruction project demonstrates that engineering within ecological constraints has helped people to live in harmony with nature," said Kuo Ching-chiang (郭清江), vice chairman of the Cabinet's Public Construction Commission.

The green slope of the embankment next to the Ilan River offers lots of space for families to spend time together. PHOTO: CHIANG YING-YING, TAIPEI TIMES

According to Kuo, the commission has been promoting ecological engineering in public construction since last year to preserve the natural heritage and improve resistance to floods.

Ilan County Commissioner Liu Shou-cheng (劉守成) said he was satisfied with the NT$250 million flood-control construction project, which is aimed at preserving biological diversity as well as creating an easily accessible recreational riverside area.

Lin Yu-chen, a student from Ilan Junior High School's fine arts class, paints the pastoral landscape of the Ilan River in watercolor. PHOTO: CHIANG YING-YING, TAIPEI TIMES

The story began in 1997, when Premier Yu Shyi-kun, an Ilan native, served as county commissioner. Yu believed the promotion of tourism based on ecological preservation would greatly benefit the rural county. About 465,000 residents live on a broad plain covering 320km2 of land.

Having persuaded the Water Resources Agency and the Council of Agriculture's Soil and Water Conservation Bureau to adopt innovative, eco-friendly engineering methods based on concepts employed in Germany and Switzerland, the local authority turned the river into one of the finest examples of a symbiosis of ecological engineering and disaster prevention.

"The river reconstruction project demonstrates that engineering within ecological constraints has helped people to live in harmony with nature."

Kuo Ching-chiang, vice chairman of the Cabinet's Public Construction Commission

Yu returned to his hometown for the annual government-sponsored Ecotechnology Expo, which was held in Ilan last Saturday. The premier joined hundreds of residents, including agile youngsters and energetic senior people, on a bicycle ride along the newly-reconstructed river.

Later that evening, hundreds of Ilan residents and tourists sat on the green slopes of embankments, enjoying music performed by the Ilan Philharmonic Orchestra.

Yu said he was deeply moved by the residents' enthusiastic response, especially that of the younger people.

"It's important to make future generations aware of the advantages of eco-engineering and sustainable development," he said.

Well-designed public projects should be able to simultaneously achieve the goals of environmental protection, landscape preservation, eco-tourism and river reconstruction, he said.

Lee Chien-chuan (李健全), vice chairman of the Council of Agriculture, said the reconstruction of the river entailed 26 sub-contracts costing NT$130 million over the past two years, and has provided the public with safe access to the river.

New types of eco-friendly embankments were designed to suit the area following an investigation of its plant and animal life, as well as the physical and chemical environment.

"It's nice to see that the traditional engineering method of lining the watercourse with cement has been abandoned here," said Hung Ju-jiang (洪如江), professor emeritus of civil engineering at National Taiwan University.

Hung said that concreted watercourses make it impossible to preserve the habitats of the river's denizens.

Juan Chung-hsin (阮忠信), an assistant professor at National Ilan University's Natural Resources Department, said the ecological impact of the reconstruction project remains uncertain.

"A reconstruction project in a section of a river might not be beneficial to the whole system," Juan said, adding that an ecological impact study spanning several years should be started immediately.

Meanwhile, a little further down-stream, a renovation project conducted by the Water Resources Agency at Chuangwei Township (壯圍) will broaden the watercourse to 76m, three times the original width, in order to decelerate the flow of the water.

Innovative engineering methods could also be adopted here, according to Chen Shen-hsien (陳伸賢), director-general of the Water Resources Agency.

However, building cement embankments in mountainous areas might still be the most effective way of controlling rivers during typhoon seasons, Chen said.

"Safety remains the priority when carrying out flood control construction," Chen said.

After passing Chuangwei, Ilan River flows into Lanyang River (蘭陽溪), which later absorbs the Tungshan River (冬山河) before entering the Pacific Ocean.

Originating on the 3,536m high Nanhu Mountain (南湖大山) in the Central Mountain Range, the 73km-long Lanyang River sweeps masses of sandstone downstream, forming the alluvial plain.

The Lanyang River estuary is one of most important coastal wetlands in Taiwan. The estuary is one of the nation's three major fishing grounds and attracts more than 230 kinds of birds. More than half of them are migrant water birds.

Jeng Ming-shiou (鄭明修), a zoologist at Academia Sinica, said using environmentally friendly construction methods should be promoted in Taiwan, because the health of its coastal ecology depends on the vitality of its rivers.

Jeng said people should help to protect the riverine habitats, so that the river can be kept clean naturally.

"If the river breathes healthily, people can live in harmony with it," Jeng said.