The multiple purposed Shihmen reservoir in northern Taiwan is facing an increasingly serious problem of sediment deposition. To cope with this problem and to prolong the life span of the reservoir, integrated conservation measures in its watershed have been taken. The activities in 2007 included land-use management, disaster prevention and monitoring, environmental protection, and management of hillside community development. During the year, 147 projects related to slopeland conservation, restoration of collapsed bare lands and debris-flow stricken areas, 69 community-based educational activities on soil and water conservation with 4,063 participants organized, and websites for environmental conservation and related information planned. By 2007, the rectification rate rose from 45 percent to 51 percent, 35 hectares of collapsed bare lands restored, and an estimated 5.5 million cubic meters of sediment prevented in upstream slopelands.
To prevent sediment-related disasters in watersheds and to minimize flooding in the easily inundated areas, the works focused on riverbed scouring and silting, potential debris-flow torrents and flooding-prone areas. Soil and water conservation work was carried out in 35 rivers, 235 tributaries, watersheds, and the aboriginal settlements that are close to potential debris flow torrents. By 2007, 1,242 projects related to soil and water conservation in the watersheds and flood prevention in aboriginal settlements were accomplished and 401 related to disaster prevention completed. These efforts contributed to the reduction of an estimated 7.84 million cubic meters of sediment in watersheds, the protection of 33 hectares of slopelands, the safety of 0.663 million people, and the control of flooding in 16,000 hectares of flooding-prone agricultural land that saved an estimated NT$1.7 billion in agricultural losses.
