Thermal structure and response on local climate and hydrological changes in a reservoir with an icebound season.

• A revised temperature model is built to study the thermal stratification. • The reservoir has a reverse thermal stratification and two overturning in a year. • Low water level can weaken the stability and lengthen the spring overturning. • High inflow volume can strength the stability and defer the spring overturning. Thermal structure plays a significant role in the aquatic ecosystem of reservoirs. In this paper, thermal structure of a large reservoir for water supply in northeast China has been studied. Considering the reservoir has a 150 days icebound period and the ice cover can affect the heat transfer process, we built a revised numerical simulation model based on EFDC to study the temporal and spatial variation of thermal stratification. The absolute mean error (AME) and mean absolute relative error (MARE) between modeled and observed water temperature are 0.40 °C and 7.15%, respectively. The results indicate that the validated model can successfully reproduce the temporal and spatial variation of water temperature. The model results indicate that the reservoir has a reverse thermal stratification in icebound season and there are two over-turning events in a year. Six hypothetical scenarios including the extreme change in the air temperature, inflow discharge, and the water level had been built to quantify the influences of changes in climate and hydrology conditions on the thermal structure. This paper provides a simplified method for the simulation of the water temperature in the reservoir with an icebound season, which can provide a reference for other reservoirs. [ABSTRACT FROM AUTHOR]