Taipei City Government

Once jokingly referred to as a “big concrete ditch,” Zhinan River has delivered an impressive ecological report card one year after completion of the Jingmei River–Zhinan River Confluence Revetment Restoration Project promoted by the Taipei City Government’s Hydraulic Engineering Office (HEO). According to the latest ecological monitoring results for 2025, rare species such as the critically endangered yellow-margined box turtle and the Chinese sparrowhawk, a protected species, have returned to the area, demonstrating the remarkable effectiveness of near-natural engineering methods in restoring urban rivers.

The HEO stated that the data speak for themselves. Monitoring data for 2025 show that biodiversity has more than doubled overall, and the ecological carrying capacity of the downstream Zhinan River survey area has improved significantly. Bird surveys recorded 64 species from 32 families, with a total of 429 sightings, representing substantial growth in species richness compared with the pre-construction period in 2022. Among them were six endemic species of Taiwan, including the Taiwan blue magpie, Taiwan barbet, and Taiwan whistling thrush.

The most eye-catching finding in this round of monitoring was undoubtedly the reappearance of the critically endangered yellow-margined box turtle. In the past, both sides of Zhinan River were lined with steep, three-sided concrete embankments, forming an almost insurmountable barrier for reptiles such as turtles and cutting off their routes between waterside foraging grounds and forest habitats.

The HEO explained that the project successfully removed approximately 6,861 square meters of concrete revetment, all of which was recycled on site and reused as stone masonry material. The formerly steep embankments were transformed into gentle waterside slopes and riparian forest belts. This strategy of “loosening the embankment” broke down physical barriers and created a valuable movement corridor for the keeled box turtle.

The improved habitat has also attracted the return of top predators. The monitoring team recorded as many as nine Chinese sparrowhawks in the airspace above Zhinan River, the highest number documented among all HEO monitoring sites in 2025. The crested serpent eagle, crested goshawk, and mountain scops owl were also recorded consistently, indicating that the local ecological chain is becoming more complete and healthy.

Vitality is equally strong at the boundary between land and water. Survey records showed 18 species of odonates in the area. In particular, the riffle zones created by the project have significantly increased the numbers of species that prefer flowing water, including the black stream glider and the Taiwan-endemic Euphaea formosa. Populations of damselflies such as the orange-tailed sprite and the red sprite have also increased substantially due to the establishment of vegetation along the gently sloping river banks. For amphibians, surveys recorded 10 species from 5 families, including 28 sightings of the robust buerger's frog.

The transformation of Zhinan River stemmed from a shift in river management thinking. Upholding the principle that “rivers should not be governed solely by flood control standards, but should also provide living space for nature,” the HEO adopted near-natural engineering methods to restore the river’s natural meanders and varied topography by “lowering floodplains and creating riffles.” This has reestablished a diversity of pools, riffles, and gravel bars as habitat for wildlife.

The stone weirs and riffle zones formed with stacked rocks have effectively increased dissolved oxygen in the water while also providing spawning grounds for aquatic insects and fish, which in turn attract common kingfisher and herons to perch and forage. Monitoring has found that less commonly seen resident birds such as the striated heron have already begun using these newly created gravel bars as hunting grounds.

In addition, the project narrowed the original 5-meter-wide pathway to 2.5 meters, returning more space to nature, and supplemented the area with 36 species of native plants, including yanagi ichigo and Chinese chaste tree, to create a riparian zone capable of natural succession. This has made it easier for animals active along the forest edge, such as the taiwan crab-eating mongoose and formosan masked palm civet, to move between the river bed and the forest in search of food.

After its completion in late June 2024, this revitalized river received multiple honors, including an Award of Excellence in the inaugural Taiwan Rivers of Hope Awards and the international 2025 IFLA Asia Pacific Landscape Architecture Award. The project not only provides the public with an inviting waterside space, but also sets a new benchmark for urban river restoration across Taiwan, proving that when space is returned to nature, life can once again flourish in the city.