Engineers estimated that the natural sedimentation rate would give the reservoir a useful life of at least 71 years without any sediment removal.
However, just four months after the reservoir began filling, Typhoon Gloria struck Taiwan, and the resulting floods washed 19 million cubic metres (670 million ft³) of sediment into the reservoir – taking 23 years off its expected lifespan.
As the reservoir filled, it also inundated several historic landmarks, including the former summer villa of Chiang Kai-shek, the Amuping Stone Bridge and a nearby Earth God shrine.

Irrigation was the primary goal of the Shihmen reservoir; about 22,000 hectares (54,000 acres) of new farmland came into production after the dam was built, bringing the total to 57,000 hectares (140,000 acres).
The annual crop was more than doubled due to an increased water supply for pre-existing farmland.
Individual farmers' income rose by almost 20 percent.
About 27 kilometres (17 mi) of canals were added to the existing irrigation system, including the new Shihmen Canal, bringing the total to 175 kilometres (109 mi), and a treatment plant with 30,000 tons per day capacity was constructed to provide municipal water supply.
Despite the scale of the project, the increase in agricultural production was estimated to feed 500,000 people, or less than two years of population growth.
The importance of the dam for irrigation has been decreasing since the 1990s as Taoyuan County saw significant urbanization; in the meantime, demand for cleaner domestic water has risen.

The government allocated NT$21 million to develop the Shihmen Reservoir as a recreational area.
Boating facilities and about 31 kilometres (19 mi) of new roads were constructed to improve access to the reservoir.
The reservoir would also be stocked with game fish, and its shores would eventually be developed with "temples, museums, monuments, pagodas, hostels and residences."
After the dam was completed, it brought prosperity via tourism to this rural area, helping to diversify its economy from one solely reliant on agriculture.
However, due to the project's high capital cost, the actual annual return on investment was only 1.5 percent: "It stands as an engineering monument of which the Chinese people may be proud.
But it was purchased at far too high a cost in terms of tens of millions of dollars of alternative developmental opportunities foregone."
Engineers estimated that the natural sedimentation rate would give the reservoir a useful life of at least 71 years without any sediment removal. However, just four months after the reservoir began filling, Typhoon Gloria struck Taiwan, and the resulting floods washed 19 million cubic metres (670 million ft³) of sediment into the reservoir – taking 23 years off its expected lifespan. As the reservoir filled, it also inundated several historic landmarks, including the former summer villa of Chiang Kai-shek, the Amuping Stone Bridge and a nearby Earth God shrine.
Irrigation was the primary goal of the Shihmen reservoir; about 22,000 hectares (54,000 acres) of new farmland came into production after the dam was built, bringing the total to 57,000 hectares (140,000 acres). The annual crop was more than doubled due to an increased water supply for pre-existing farmland. Individual farmers' income rose by almost 20 percent. About 27 kilometres (17 mi) of canals were added to the existing irrigation system, including the new Shihmen Canal, bringing the total to 175 kilometres (109 mi), and a treatment plant with 30,000 tons per day capacity was constructed to provide municipal water supply. Despite the scale of the project, the increase in agricultural production was estimated to feed 500,000 people, or less than two years of population growth. The importance of the dam for irrigation has been decreasing since the 1990s as Taoyuan County saw significant urbanization; in the meantime, demand for cleaner domestic water has risen.
The government allocated NT$21 million to develop the Shihmen Reservoir as a recreational area. Boating facilities and about 31 kilometres (19 mi) of new roads were constructed to improve access to the reservoir. The reservoir would also be stocked with game fish, and its shores would eventually be developed with "temples, museums, monuments, pagodas, hostels and residences." After the dam was completed, it brought prosperity via tourism to this rural area, helping to diversify its economy from one solely reliant on agriculture. However, due to the project's high capital cost, the actual annual return on investment was only 1.5 percent: "It stands as an engineering monument of which the Chinese people may be proud. But it was purchased at far too high a cost in terms of tens of millions of dollars of alternative developmental opportunities foregone."
Shihmen Dam