Operation of two major reservoirs of Iran under IPCC scenarios during the XXI century

Abstract

We assess the effects of prospective climate change until 2100 on water management of two major reservoirs of Iran, namely, Dez (3.34 × 109 m3) and Alavian (6 × 107 m3). We tune the Poly‐Hydro model suited for simulation of hydrological cycle in high altitude snow‐fed catchments. We assess optimal operation rules (ORs) for the reservoirs using three algorithms under dynamic and static operation and linear and non‐linear decision rules during control run (1990–2010 for Dez and 2000–2010 for Alavian). We use projected climate scenarios (plus statistical downscaling) from three general circulation models, EC‐Earth, CCSM4, and ECHAM6, and three emission scenarios, or representative concentration pathways (RCPs), RCP2.6, RCP4.5, and RCP8.5, for a grand total of nine scenarios, to mimic evolution of the hydrological cycle under future climate until 2100. We subsequently test the ORs under the future hydrological scenarios (at half century and end of century) and the need for reoptimization. Poly‐Hydro model when benchmarked against historical data well mimics the hydrological budget of both catchments, including the main processes of evapotranspiration and streamflows. Teaching–learning‐based optimization delivers the best performance in both reservoirs according to objective scores and is used for future operation. Our projections in Dez catchment depict decreased precipitation along the XXI century, with −1% on average (of the nine scenarios) at half century and −6% at the end of century, with changes in streamflows on average −7% yearly and −13% yearly, respectively. In Alavian, precipitation would decrease by −10% on average at half century and −13% at the end of century, with streamflows −14% yearly and −18% yearly, respectively. Under the projected future hydrology, reservoirs' operation would provide lower performance (i.e., larger lack of water) than now, especially for Alavian dam. Our results provide evidence of potentially decreasing water availability and less effective water management in water stressed areas like Northern Iran here during this century.

Impact assessment of reservoir operation in the context of climate change adaptation in the Chao Phraya River basin

“…For instance, Lauri et al (2012) analysed the cumulative impact of climate change and reservoir operation in the Mekong River using the VMod RHM and concluded that the impact of the reservoir operations, both existing and planned, would be larger than the effect of climate change during the dry and wet seasons. The focus of interest of some studies was the assessment of the future water supply from the existing storage capacity to meet the growing water demand under a reduced precipitation climate scenario using the RHM's of (i) Hydrologiska Byråns Vattenbalansavdelning (HBV) in the Lower Zab River (one of the main streams of the Tigris River), northeast Iraq (Mohammed & Scholz, 2017), (ii) Poly-Hydro in the Dez and Sufichai River basins, Iran (Akbari-Alashti et al, 2018), and (iii) GR4J in different Australian catchments (Nguyen, Mehrotra, & Sharma, 2020).…”

Hydropower Potential in the Alps under Climate Change Scenarios. The Chavonne Plant, Val D’Aosta

“…Poli-Hydro is a semi-distributed, physically based model, already used in several previous studies [3,[23][24][25], so we report here the main traits of the model. Poli-Hydro divides the catchment into cells accordingly to the DEM raster, and within each cell it calculates soil water balance at a daily scale.…”

Hydropower from the Alpine Cryosphere in the Era of Climate Change: The Case of the Sabbione Storage Plant in Italy

“…Poly-Hydro is a semi-distributed, physically based, glacio-hydrological model, already used and validated in several studies [4,7,45]. Poly-Hydro is able to reproduce different components of the hydrological cycle, and cryospheric processes.…”