Optimizing system capacity expansion schedules for groundwater supply

Abstract

[1] Groundwater plays a vital role in regional water resources management. In conventional design, a full-scale network system is installed initially to use groundwater resources. However, the system capacity may exceed water demand in the early stages because water demand generally increases with time. Therefore, this work proposes a novel optimal capacity expansion model capable of determining an optimal schedule to expand system capacity according to increasing water demand. The proposed algorithm hybridizes a genetic algorithm (GA) and constrained differential dynamic programming (CDDP). The chromosomes of the GA represent a possible design alternative, a groundwater network with capacity that expands with time. The CDDP algorithm is then used to compute the optimal pumping policy associated with the chromosome. Simulation results indicate that the capacity expansion model saves more total present value cost than conventional designs for the same annual interest rate and water demand. Results of this study demonstrate promise for the proposed model in facilitating a cost-effective groundwater network design with capacity expansion for regional groundwater supply.

Application of multiobjective optimization to scheduling capacity expansion of urban water resource systems

“…Although the construction of large infrastructure at the start of the planning period exploits the economies of scale, the time discounting of costs and the uncertain dynamics of growth may nonetheless favor smaller projects staged over the planning period. To analyze this trade‐off, a number of studies have considered scheduling expansion [ Braga et al ., ; Chang et al ., ; Gillig et al ., ; Grossman and Marks , ; Kim and Yeh , ; Knudsen and Rosbjerg , ; Lund , ; Mahmoud , ; Voivontas et al ., ; Watkins and McKinney , ].…”

Adaptive, multiobjective optimal sequencing approach for urban water supply augmentation under deep uncertainty

“…In the past, optimal sequencing approaches have considered traditional sources of water, such as reservoirs and groundwater, and have attempted to minimize cost objectives [e.g., Chang et al ., ; Connarty and Dandy , ]. More recently, multiple objectives [e.g., Beh et al ., ; Mortazavi‐Naeini et al ., ] and alternative sources of water, such as desalinated water, storm water, rainwater, and reclaimed wastewater [e.g., Beh et al ., ; Downs et al ., ; Ray et al ., ] have been considered.…”

Economics

“…In many cases groundwater resource capacity may initially exceed water demand because demand tends to increase over time. With this in mind, Chang et al (2009) presented a model that can be used to determine an optimal schedule for expanding system capacity. Gallagher et al (2009) studied a water management approach that seeks to increase the sustainable use of local resources in the City of Oxnard, California.…”