Feasible Diversion and Instream Flow Release Using Range of Variability Approach

Abstract

A methodology based on the range of variability approach ͑RVA͒ is presented for determining the feasible combinations of flow diversion and instream flow release for a projected diversion weir. The RVA is designed to support efforts to manage water system operations in a manner that minimizes impacts on natural hydrologic variability, and thereby minimizes ecological impacts. This approach is used to evaluate the prediversion flows and establish the riverine management targets in terms of 32 hydrologic parameters called indicators of hydrologic alteration ͑IHAs͒. The goal is to make the postdiversion flows attain the target ranges at the same frequency as that which occurred in the prediversion flow regime. A weir-operation simulation approach is employed to compute the postdiversion flows. Based on the simulation results, the degree of hydrologic alteration under various combinations of flow diversion and release is evaluated and plotted as a contour diagram for each IHA. Overlapping the contour diagrams of the 32 IHAs, three overall hydrologicalteration regions are constructed. The feasible region, i.e., the overall low-alteration region, is defined by the combinations of flow diversion and instream flow release for which none of the 32 IHAs is significantly altered. The feasible combinations of flow diversion and release are further evaluated with their corresponding water-supply shortage indices. The proposed methodology allows for the incorporation of both water-supply and environmental protection concerns in water resources planning and management. The merits of this methodology are demonstrated with an application to the proposed Taitung diversion weir in Taiwan.

Hydrologic Alteration Associated with Dam Construction in a Medium-Sized Coastal Watershed of Southeast China

“…The variation of the extreme events changed with geographic areas and climate patterns. Our study indicates the earlier occurrence time of extreme low streamflow event and later occurrence time of extreme high streamflow event after dams construction in the JRW, which is consistent with these asonal variation of the hydrologic conditions in other watersheds in South China [8,24,67]. This means the mode of dams regulation on streamflow regime in the JRW was similar to those in South China.…”

“…Furthermore,the decreased rise rate and increased fall rate in the JRW also suggested the rate changing from high flow to low flow slowed down and the rate change from low flow to high flow speeded up, implying that the streamflow peak might be delayed (Table 3) and the variability of streamflow changed (Figure 4). Similar results were also found in Huaihe River, Yellow River, Taiwan and Great Plains [13,24,67,70].…”

Assessment of Hydrologic Alterations Caused by the Three Gorges Dam in the Middle and Lower Reaches of Yangtze River, China

“…Richter et al [2] applied IHA and proposed the range of variability approach (RVA) with the aim of setting streamflow-based river management targets that incorporate the concepts of hydrologic variability and aquatic ecosystem integrity. RVA has been proven to be a practical and effective means of assessing HA and has been applied to many river basins around the world that represent a variety of watershed and hydrologic regime types [14][15][16]. Galat and Lipkin [17] employed RVA to analyze the natural range of variation of the flow regime of Missouri River before and after main-stem impoundment.…”

A Study on the Impact Range Calculation at the Downstream of Dam

“…유량변화에 관하여 Magilligan et al(2003), Olden and Poff(2003), Poff et al(2006Poff et al( , 2007 Richter et al (1996,1997,1998), Shiau and Wu(2004), Magilligan and Nislow(2005), Graf(2006), Lajoie et al(2007)의 연구가 있었다. 하도변화에 관한 연구는 Galay(1983), Williams and Wolman(1984), Xu(1990;1996a;1996b;2001), Brandt(2000), Fassnacht et al(2003) 등이 있다.…”