A dual active‐restrictive approach to incorporating environmental flow targets into existing reservoir operation rules

Abstract

[1] Environmental flow schemes may be implemented through active or restrictive strategies. The former may be applied via reservoir releases, and the latter can be executed by reducing water demands. We present a dual active-restrictive approach to devising the optimal reservoir operation rules that aim to secure off-stream water supplies while maximizing environmental benefits. For the active part, a multicomponent environmental flow target (including the minimum and monthly flows) is incorporated in the operation rules. For the restrictive counterpart, we use a novel demands partitioning and prioritizing (DPP) approach to reallocating the demands of various sectors. The DPP approach partitions the existing off-stream demand and newly incorporated environmental demand and reassembles the two as the first-and second-priority demands. Water is reallocated to each demand according to the ratios derived from the prioritized demands. The proposed approach is coupled with a multicriteria optimization framework to seek the optimal operation rules for the existing Feitsui Reservoir system (Taiwan) under various scenarios. The best overall performance is achieved by an optimal dual strategy whose operational parameters are all determined by optimization. The optimal environmental flow target may well be a top-priority constant base flow rather than the variable quantities. The active strategy would outperform the restrictive one. For the former, a top-priority base flow target is essential; for the latter, the off-stream demand can become vanishingly small in compensation for the eliminated base flow target, thus promoting the monthly flow target as nearly the top-priority demand. For either the active or restrictive strategy, a prioritized environmental flow demand would provide a path toward the optimal overall performance. A significantly improved overall performance over the existing operation rules is unlikely if the active and restrictive parameters are both favorable to the off-stream demand.Citation: Shiau, J.-T., and F.-C. Wu (2010), A dual active-restrictive approach to incorporating environmental flow targets into existing reservoir operation rules, Water Resour. Res., 46, W08515,

The economic value of coordination in large‐scale multireservoir systems: The Parana River case

“…Optimization of multireservoir operation is reviewed in Labadie [] and Yeh []. Recent examples include active‐restrictive approach for optimal reservoir operation to provide off‐stream water demands and supply multiple environmental flow targets in Shiau and Wu [] and a path‐based water distribution optimization model that includes reservoir operating rules to identify water trade strategies in Cheng et al . [].…”

Portfolio optimisation for hydropower producers that balances riverine ecosystem protection and producer needs

“…Many new reservoir operating methods have been proposed to better sustain environmental flows (e-flows, the volume of water that should remain in a river and the variation of this provision over time to maintain specific indicators of ecosystem health) in rivers (Richter, 2010;Shiau and Wu, 2010;Brown and King, 2012). These methods are river protection approaches at the hydropower generation stage.…”

Comprehensive Management and Modeling of Water Quantities: Utilizing an Existing Watershed Model for Comprehensive Water Management and Planning, and Optimal Design of Outlet Control Structures for Ecological Detention Ponds

“…Since the outlet controls are stationary in time, release controls cannot be modified over time, such as has been done previously to create ecologically oriented reservoir outflows (Shiau and Wu 2010;. However, the reservoir-detention pond analogy can be used to motivate detention pond release operation policies for multiple downstream objectives using past and current research of ecologically oriented reservoir operations as an example.…”

“…Using the 33 parameters, a statistical signature of the health of the ecosystem is determined. IHA has been used extensively in a variety of ecological and engineering applications (see Shiau and Wu 2004;Richter et al 2006;Shiau and Wu 2006;Suen and Eheart 2006;Mathews and Richter 2007;Shiau and Wu 2010;. However, many IHA parameters have been found to be inter-correlated (Olden and Poff 2003;Gao et al 2009).…”

“…The IHA approach has been implemented into a variety of ecological and engineering applications, including reservoir optimization (Shiau and Wu 2010), BMP placement , optimized watershed development , altered flow ecological assessments (Kirby 2003;Shaw 2001), and ecological flow policy recommendations (Mathews and Richter 2007;Richter et al 2006). However, this author has not found any studies that use the IHA methodology as a measure of hydrological model fit.…”