Dagou Stream Ecological Water Management Park Introduction
Located at the end of Dahu Mountain Villa Street in Neihu District, Dagou Stream is a naturally formed stream that flows down from Baishihu Mountain, which has an elevation of 485 meters. Most of the upstream areas along both banks are secondary forest, while the downstream section flows through the residential drainage system after passing through the Yuanjue Waterfall, merging into Dahu Park via the box culvert beneath Dahu Mountain Villa Street. The total length of the watershed is approximately 3,500 meters, covering an area of 340 hectares. To balance safety and conservation, the rehabilitation of Dagou Stream in Neihu District is designed and constructed using a near-natural, porous method, providing habitats for flora and fauna. It has currently fostered a rich ecological resource, with investigations by the Geotechnical Engineering Office showing the presence of species such as the Formosan Blue Magpie, Chinese Tree Frog, Taiwan Tree Toad, Taiwan Black Starry Skipper, Purple Hairstreak, Greenish Blue, Little Egret, Kingfisher, and Yellow-spotted Cricket, making it an excellent outdoor ecological classroom. The downstream area of Dagou Stream was originally an agricultural zone, but due to urban development, it was re-zoned for the Dahu Mountain Villa residential community. To meet road requirements, the stream was replaced by a drainage box culvert. In the past, heavy rains would often overwhelm the drainage system, leading to erosion and loss of soil and stones in the stream, with significant damage occurring during Typhoon Winnie in August 1997. Dagou Stream is located upstream of the Dahu Mountain Villa community, and its rehabilitation features stone-paved banks, with porous spaces conducive to wildlife habitation while reducing erosion. Additionally, to provide a hydrophilic recreational environment, a water-friendly walkway has been constructed along the streambed, serving as a garden for nearby residents. In creating a natural ecological environment, the rehabilitation of Dagou Stream employs fish ladders (drop structures) and foundation works to reduce the drop in riverbed elevation, slow down the flow rate, and decrease erosion energy. Furthermore, the creation of shallow water areas helps to retain stream water, fostering breeding habitats for fish, shrimp, water plants, and other wildlife, thus maintaining stream ecology. Additionally, along the wider waterways, hydrophilic platforms and walkways have been established to allow nearby residents and visiting tourists to enjoy and interact with the water. (Source: Taipei City Government Public Works Department Geotechnical Engineering Office)
