Pumping schedule assignment using chromatic graphs to reduce groundwater pumping energy consumption

Abstract

In this paper, groundwater pumping schedules are examined, in terms of pumping energy consumption minimization. Chromatic graphs are used for the first time to assign groundwater pumping schedules. Assuming that a finite number of users pumps from a common aquifer, we examine the following 3 pumping scenarios: (a) all users pump simultaneously (b) users pump during one out of 2 different periods (c) users pump during one out 4 different periods. A computational code, based on Theis equation, is constructed to calculate the drawdowns and, subsequently, the energy consumption, for various well locations, numbers of wells, flow rates, pumping period durations and aquifers' characteristics. We use Nearest Neighbor Graphs and Chromatic Graphs, to represent the interactions of the well users.. We compare the results obtained when Chromatic Graphs are used, to the optimum, which is obtained using Genetic Algorithms. Our results indicate that: (a) performance of chromatic graphs is good (b) when 2 pumping periods are used, it is sufficient for each player to cooperate with their nearest neighbor and pump alternately. In typical cases the energy consumption reduction can be around 10–40%. The benefit is even higher if 4 pumping periods are used.