Jump to the content zone at the center

Keeping the Waters at River

Rivers and streams are usually gentle and soft. But they may become causes of great disaster during typhoons and torrential rains if the rainwater overflows are not discharged into rivers beyond embankments or into the city sewers in time. This is a serious threat to the safety of residents' lives and their property. In order to prevent floods, apart from dredging the river courses, removing waste and maintaining river embankments regularly, it is imperative that the existing water pumping stations and relevant facilities be renewed and expanded. With the vigorous efforts poured into flood prevention construction in recent years, we are confident that the city will be able to withstand strong typhoons of the scale of "NARI".

Inherently and Particularly Related to "Water"

Taipei City is geographically situated at the center of a basin with a low topography. It is surrounded by the Keelung, Jingmei, Xindian and Tamsui Rivers, which converge at the Guandu estuary. In addition, the tributary streams like Shuang, Huang, Huanggang, Guitzikeng, Neigou, Dakong and Sifen Streams also run across the Taipei basin.
The river channel at the estuary is naturally narrow, and due to tidal flows, the water of the river is often at a high level. During rainy seasons, or times of torrential rains and typhoons, the volume of the water in our rivers increases rapidly often causing floods. Many places got their names because of their proximity to water, such as Nangang (lit. south port), Neihu (lit. inner lake) and Xizhi (lit. ebbing of the tide). From these, we can say that Taipei City is inherently close to water due to its geographical features.
On average, Taiwan experiences 3.6 typhoons a year; the average volume of annual rainfall may be as high as 4,500 mm in mountainous regions and approximately 2,900 mm on the flat.

Fighting Against Nature for Land and Being Neighbors with Water

Due to rapid city development, the population is constantly moving towards the outer edges of Taipei basin. As a result, there hasn't been sufficient hinterland reserved to be used for flood and high water prevention purposes. Even places like Nangang, Neihu and Xizhi, which were prone to flood in the past, are now densely populated. Some houses have even been built adjacent to river courses. Once typhoons or torrential rain hits, these residences are certain to flood.
On top of that, the land area used for construction is far greater than the land used for vegetation in the Taipei basin due to rapid developments. In times of heavy rains, the soil on level ground is not able to provide sufficient seepage and floods occur in low-lying areas. Flood preventive dredging of riverbeds outside the city embankments and the construction of drainage and water pumping stations are effective ways to prevent flooding in urban areas.

Periodical Dredging to Ensure Smooth Flowing Rivers

Since Taipei City is situated at the middle-down streams of the surrounding waterways, the mud and sand sediments from upstream tend to accumulate and build up in the river channels. Periodical dredging can prevent severe accumulation of sediment that hinders water from running smoothly.
In the single year of 2017, the amount of soil dredged up from the river sections and channels in the city's jurisdiction was as high as 1,740 m3.

River Running in Front of My Home

Many major rivers and minor tributaries run across the Taipei Basin. The river-dredging project has been progressing section by section every year. Residential areas adjacent to riverbanks have always been the first victims of flooding during typhoons and high waters. But after dredging, these residents can finally enjoy flood-free living quarters with beautiful water scenes. "River running in front of my home" is no longer a nursery rhyme, but a portrait of true life.

Simultaneous Implementation of Multiple Flood Prevention Strategies
Flood Control Construction is a Long-Term Mission That Goes on Without Pause

With consideration of the natural and modified conditions of the city, the hydraulic engineering of Taipei City must strike a balance between ideals and realities.
In order to carry out successful flood control construction in a densely populated urban area such as Taipei, relying solely on the techniques of flood-diversion invented by Yu the Great (a legendary monarch who introduced flood control techniques in ancient China) would not be sufficient; Gun's (Yu's father) strategy of confining the water must be used as well. Therefore, Taipei City's strategies of flood prevention and control must be focused on building embankments along the rivers; river dredging and management are supplementary measures. In addition, water pumping stations are to be set up at the outlet of main water drainage pipelines inside the embankments in order to draw out rainwater in the city when the water level of rivers is approaching ground level to ensure the safety of the city.

Reinforcing and Raising the Embankments; Choosing the Lesser Evil

It is truly unfortunate that Taipei City experienced two serious blows dealt by NARI and XANGSANE typhoons before the completion of flood prevention construction and mechanisms. The images of chaos and damage are still fresh in the minds of our residents. The good news is, now Taipei City has flood prevention capabilities to withstand typhoons of NARI and XANGSANE's scale!
This claim "holds water" because 109,141 meters out of the 131,231 meters of flood prevention facilities in the city jurisdiction's flood prevention construction plan have already been completed; meaning a completion rate of above 83%. The total length of newly built embankments from 1999 till now is approximately 7,380 meters, while the embankment heights have risen by about 19,560 meters; capable of preventing river water from spilling over the embankments.

Striving for Perfection in Spite of Choosing the Lesser Evil

Without a hinterland reserved for flood prevention, resorting to the building of embankments as part of Taipei City's flood prevention strategy for residential areas adjacent to rivers is inevitable.
Reinforcing and raising embankments will obstruct views from certain buildings, hinder water activities, and distance the residents from their environments; such is the price of embankment construction.
To remedy the situation in order to make water activities possible for these residents, much thought and consideration was put into the planning, including footbridges over embankments, extensive use of materials that were environmental friendly, ecological and suitable for water activities, beautification of embankments, inclusion of more recreational facilities and so forth. Also, more resting space was created.

At the Frontline Amidst Storms

Even the slightest action of the personnel on duty at the water pumping stations will make a difference to the safety of residents' lives and property. These personnel are always standing on the frontline to battle natural disasters under harsh weather conditions, and one can easily imagine the hardship and pressure they face on a regular basis. After we have been through so much rough weather unscathed, let us not forget to show our appreciation for these unsung heroes.

Water Pumping Function is Most Crucial in Battling Heavy Rains

A total of 418 water pump units are operational across 66 dedicated pumping stations and 21 temporary ones are used to safeguard the city against flood. Their primary function is to draw water from the city drains and discharge it to the rivers beyond the embankments. These machines are especially crucial when the rainwater accumulated in the city which can not drain away due to high stage of rivers.
Repairing and building of pumping stations including machinery at the appropriate time is a critical step in flood prevention strategies.
Establishing a thorough maintenance system for the water pumps is the only way to ensure the well-functioned machinery in case of emergency.

How do You Fight a Flood When the Pumping Stations are Flooded Themselves?

When NARI Typhoon struck Taipei, due to part of the embankments being incomplete, the river water managed to spill over the embankments and breached the city district, disabling a total of 35 pump units at various pumping stations. To prevent the repeat of this in the future, enhancing the defensive capabilities of the water pumping stations against floodwater has become a new focus for the flood prevention measures of Taipei City.
After reviewing the "standard height of elevation for protection against floodwaters" across the pumping stations, it was decided that facilities that were subject to flooding were raised above the standard protection height to enhance their defense against floods. Other facilities that were not suitable for increased elevation would be protected by watertight accessories or replaced with waterproof ones. The power supply system was also improved with the addition of high voltage double circuits. And now, residents do not have to worry about pumps being station's failure.

David vs Goliath

Do you still remember the severe flooding in the east area of Taipei City wrought by NARI? As the crucial embankment connecting to those at the Dakong Stream, the Sifen Stream (upstream tributaries of the Keelung River) and the Keelung River was not completed, the excessive amount of rainfall caused an influx of river water into the Nangang district. The water made its way toward the Songshan district, and pumping stations along the way were flooded. These pumping stations, which worked perfectly in drills and exercises prior to the typhoon, were unable to handle the massive overload and malfunctioned. Relying on district pumping stations to handle sudden massive amounts of flood waters is no different from expecting an underdog to take over a giant.