Performance Indexes Analysis of the Reservoir-Hydropower Plant System Affected by Climate Change

Assessing the effects of climate change phenomenon on the natural resources, especially available water resources, considering the existing constraints and planning to reduce its adverse effects, requires continuous monitoring and quantification of the adverse effects, so that policymakers can analyze the performance of any system in different conditions clearly and explicitly. The most important objectives of the present research including: (1) calculating the sustainability index for each demand node based on the characteristics of its water supply individually and also calculating the sustainability index of the whole water supply system, (2) investigation the compatible of changes trend among various reservoir performance indexes and (3) evaluation the changes in performance reservoir indexes in the future time period compared to the baseline tie period under three Concentration Pathway (RCP) RCP2.6, RCP4.5 and RCP8.5 scenarios for all water demand nodes and the entire water supply system. To this end, first, climatic parameters data affecting on the water resources such as temperature and precipitation were gathered in the baseline period (1977–2001) and the climatic scenarios were generated for the future period (2016–2040) using the Fifth Assessment Report (AR5) of the International Panel on Climate Change (IPCC). Then, the irrigation demand changes of the agricultural products with the Cropwat model and the value of inflow to the reservoir with the Artificial Neural Network (ANN) model were calculated under the climate change effects. In the next step, the climate change effects on the water supply and demand were simulated using Water Evaluation and Planning model (WEAP), and its results were extracted so as the water management indexes. The results show that the temperature will increase in the future period under all three RCP scenarios (RCP2.6, RCP4.5 and RCP8.5) compared to the baseline period, while precipitation will decrease under the RCP2.6 scenario but will increases under RCP4.5 and RCP8.5 scenarios. Under the trend of changing in temperature and rainfall, the irrigation demand in the agricultural sector in all scenarios will increase compared to the baseline period. However, the inflow of reservoir will decrease under the RCP2.6 and RCP4.5 scenarios and will increases under RCP8.5 scenario. Evaluation of WEAP modeling results shows that the sustainability index of the entire Marun water-energy system will decrease in the future period compared to the baseline period under the RCP2.6, RCP4.5 and RCP8.5 scenarios by 13, 10 and 8%, respectively. The decrease in the system sustainability index shows that in the absence of early planning, the Marun water-energy supply system will face several challenges for meeting the increasing demand of water in different consumer sectors in the coming years.