The Shilin catchment area is currently served by two main drainage trunk systems—eastern and western. The Western Trunk System (Shilin Catchment Area 2) primarily manages stormwater run-off from the area west of the reclaimed land along the Keelung River and north of Zhongzheng Road. Its main and secondary drainage lines are distributed along Shishang Road, Section 5 of Chengde Road, and Section 2 of Tonghe East Street, with the downstream flow directed to the Shilin 2 Pumping Station, which has a pumping capacity of 9 cubic meters per second (cms) and serves a catchment area of approximately 37 hectares. The Eastern Trunk System (Shilin Catchment Area 1) handles runoff from the area east of the reclaimed land along Jihe Road to the hillside re-gions surrounding the Shilin Official Residence and Ming Chuan University. It includes drainage lines along Jihe Road, Zhongzheng Road, and feeder channels near the Shilin Horticultural Exper-iment Branch that discharge into the Jihe Road trunk line. This system has a pumping capacity of 55 cms and serves a catchment area of approximately 205 hectares.
Historical flooding data and hydrologic model simulations for the Shilin catchment show recurring overflow issues in specific zones. During intense rainfall, the water level in the Zhongzheng Road trunk line rises significantly, making it difficult to drain low-lying areas along both sides of Zhongzheng Road between Section 5 of Zhongshan North Road and Wenlin Road. Additionally, the open channel at the Fulin Road storm drain entry point is prone to elevated water levels due to backflow from downstream, often leading to overflow conditions near the intersection of Section 5 of Zhongshan North Road and Fulin Road. To effectively address these issues, HEO planned the construction of a new detention basin in the green space north of the Shilin Official Residence. This basin helps regulate runoff from the upstream mountainous area and reduces the drainage burden on downstream open channels along Fulin Road.
Catchment Area Improvement Map
Hydraulic modeling confirms that the drainage system near Zhongshan North Road is unable to fully manage stormwater runoff. Furthermore, five aging culverts currently discharge runoff from Jiantan Mountain into the open channel at the Shilin Official Residence, creating excessive inflow and overloading the drainage capacity, as evidenced by photos showing water levels nearing the channel’s edge. Due to traffic constraints and the presence of Taipower’s ultra-high-voltage lines, expanding existing infrastructure is not feasible. The detention basin site was therefore carefully selected to avoid protected trees and utility conflicts, while remaining adjacent to the open channel to assist in runoff diversion. Runoff from Jiantan Mountain flowing toward Fulin Road and Lane 100, as well as from Lane 470 of Zhongshan North Road, will be intercepted and diverted into the basin, relieving pressure on the downstream network. Using a rainfall simulation of 88.8 mm/h, the design targets a contributing catchment area of 23.73 hectares and accounts for the surrounding overflow volume. The detention basin is designed with a capacity of 11,000 m³, divided into an upper basin, landscaped as a green space, and a lower basin for core detention function. On April 6, 2021, HEO conducted a community briefing to collect local feedback, which was incorporated into the design. A second community presentation was held on June 9, 2023, to explain the construction plan and timeline to residents, paving the way for implementation.
Open Channel Photo 1
Open Channel Photo 2
Open Channel Photo 3
Open Channel Photo 4
Project Name: Shilin Official Residence North-Side Detention Basin Construction Project
Location: Green plaza west of Lane 100, Fulin Road
Construction Period: 25 months
Project Budget: NT$460 million
Project Scope: The detention basin will be constructed as a two-level structure. The upper basin will provide both flood detention and landscape/recreational functions, while the lower basin will be used exclusively for stormwater detention. The project includes one jacking shaft and one re-ceiving shaft, with a jacked pipeline measuring 1.35 meters in diameter and extending 176 meters in length. Two pumps, each with a capacity of 0.5 cubic meters per second, will be installed.
Conceptual Rendering of the Shilin Official Residence Detention Basin
Cross-Sectional Rendering of the Shilin Official Residence Detention Basin
(1) Enhance the drainage performance of the Shilin catchment area.
(2) Reduce the risk of water accumulation and surface flooding near the intersection of Section 5 of Zhongshan North Road and Fulin Road.
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