In order to prevent the severance between upper and lower area of riparian ecosystem, 24 fishways are scheduled to be set around the weirs. Especially, first time domestic installation of natural river type fishways including small rapids and swamps inside of it will be placed in 14 spots, hence the diverse aquatic species will come to move upstream and downstream.
For gradual water flow, slope-type drop structures are to be newly constructed in total 161 spots throughout the four rivers. The specific type and size will be determined on the eco-friendly consideration of securing the mobility of autochthonous species like fishes. Around the drop structures, spawning grounds and rest areas will be prepared on the basis of ecological harmony.
Highly reservation-worthy swamps like Dalseong and Haepyeong swamp will be protected. However, under the inevitable case of prevention for flood, the damaged areas will be minimized and alternative artificial swamps will be constructed. With regard to the Nakdong River, 921.1 thousand m2(11 spots) which are 2.1 time larger than ones(427.5 thousand m2) expected to be unavoidably damaged during the project. The bottom of the rivers are planned to be modified as gentle grade so that it induce ecosystem to form natural swamps.
Movable weirs are designed in the structure of effective discharge for sediment. By applying diverse method of opening to the sluice gate, for example, up-raising, rotation or lay down types which seem to be able for eco-friendly management.
