圖書典藏及影音數位平台

本署目前正推動水利法逕流分擔與出流管制專章的修法工作。本研究將配合立法的推動，研擬精進相關技術手冊，作為後續政策推動的依據。

Water Resources Agency in Taiwan now is promoting the realization of the Runoff Allocation and Outflow Control policy. This idea is to change the concept of flood control from the usage of water courses only to integrated management in both land and water. Since the Runoff Allocation and Outflow Control policy is a new concept, the operational principles are required for further implementation. As a result, this project proposes the Draft of Runoff Allocation and Outflow Control Technical Manual, based on the practices in USA, Japan, as well as the Runoff Allocation and Outflow Control trial results in Taiwan’s 5 cities, this project has. The practice of outflow control is that when land development projects are at certain scale or above, the developer should submit the drainage/outflow control plan, to avoid the increase of surface runoff caused by land development and ensure the safety of flood control throughout the region. The contents of the Draft of Outflow Control Technical Manual includes (1) Calculations of runoff before and after land development and regulation of outflow control, (2) Scheme for peak discharge reduction, (3) Inspection standard for outflow control facilities, (4) Impact assessment of land development on outside drainage, (5) Project planning for outflow control facilities and (6) Management and maintenance planning for outflow control facilities. The authority-in-charge shall draw up a runoff allocation plan based on the public announcement of implementation scope of the specific river basins or catchment areas of regional drainage made by the central authority-in-charge. The government department will take over after the runoff allocation plan is completed. It mainly uses public facilities with the function of detention so that the land can be used for flood control. The Runoff Allocation Plan will be divided into 3 stages which are (1) Runoff Allocation Assessment Report, (2) Runoff Allocation Planning Report, and (3) Runoff Allocation Engineering Planning Report. According to the objectives of the plan, the hydrological and hydraulic model is used to calculate the excess runoff beyond the design basis for each control point in the runoff allocation area, and the flood volume that cannot flow into the waterways in the low-elevation area, then the two results mentioned above are combined to estimate the runoff allocation volume required for the target area. The Runoff Allocation Plan is proposed based on the principles of runoff control, runoff dispersion, temporary storage, co-existing of low ground and runoff accumulation, supported by the suitable engineering and non-engineering method, and supplemented by disaster prevention measures.