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.

热力结构在水库水生生态系统中起着重要作用。本文研究了东北某大型供水水库的热力结构。考虑到储层有150天的冰封期，并且冰盖会影响传热过程，我们建立了基于EFDC的修正数值模拟模型，以研究热分层的时空变化。模拟水温和观测水温之间的绝对平均误差（AME）和平均绝对相对误差（MARE）分别为0.40°C和7.15％。结果表明，经过验证的模型可以成功地再现水温的时空变化。模型结果表明，该储层在冰封季节具有逆热分层，一年中有两次翻转事件。建立了六个假设情景，包括气温，入流量和水位的极端变化，以量化气候和水文条件变化对热力结构的影响。本文为模拟冰封季节水库水温提供了一种简化方法，可以为其他水库提供参考。