実態分析に基づく弾力的な維持流量の提案  [in Japanese] DESIGN OF A RESILIENT MAINTENANCE FLOW BASED ON THE STATE ANALYSES  [in Japanese]

Access this Article

Author(s)

Abstract

<p> 現在の維持流量には,流量変動を考慮する方法が無い,動植物の生息環境に関する評価で一部の種のみを取り上げている,モニタリング方法が確立していない等の課題がある.100水系の維持流量の運用実態を分析した結果,流量変動については7割が通年一定で設定され,項目別の必要流量の季節性が十分に反映されていないことが分かった.動植物の生息環境評価では,シジミ類を対象とする3水系を除き,概ね12種類の魚類の必要水深と流速によって決まっていることを明らかにした.より効果的な維持流量を設定するためには,流量の規模,頻度,時期,継続時間,変化率の5要素に着目し,流量変動を考慮するとともに,維持流量放流前の段階からモニタリング計画を策定し,結果を還元しながら最適な維持流量へと更新する弾力的な設計方針を構築する必要がある.</p>

<p> The current estimation method of maintenance flow has three challenges: lack of methods to consider flow variabilities, only a few target are considered to evaluate the habitat, and lack of monitoring method. This research analyzed the current condition of the 100 class A rivers which have maintenance flow standards. The result revealed that 70% of the maintenance flow was set as constant throughout the year, while few rivers consider seasonality of flow. As for habitat conservation, the maintenance flow was found to be roughly determined by the minimum water depth and velocity of the 12 target fish. In order to set more effective maintenance flow standards, it is necessary to take into account not only magnitude of flow but also to frequency, timing, duration and rate of change. It is also necessary to incorporate monitoring into the guideline and to have a flexible system by reviewing the maintenance flow together with revision schedule of the river improvement plans.</p>

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 74(5), I_361-I_366, 2018

    Japan Society of Civil Engineers

Codes

Page Top