基于冻土水文模拟的松花江流域水资源演变规律

Evolution law of water resources in Songhua River basin based on hydrological simulation of frozen soil

为分析松花江流域水资源的演变规律,基于寒区水-热-氮素循环模型(the water and energy transfer processes and nitrogen cycle processes model in cold regions,WEP-N)和水资源评价方法,对径流发生突变的1998年前后(即1999—2018年和1956—1998年)进行比较,松花江流域年水资源总量减少217.0亿m^(3),减幅达到22.2%。其中,地表水资源量减少是水资源总量减少的主要组分,占水资源总量减少的比例为96.9%,不重复地下水资源减少量占3.1%。基于多因子归因分析方法分析可知,气候变化是松花江流域水资源减少的主要因素,对松花江流域全年水资源总量、地表水资源量、不重复地下水资源量减少的贡献率分别为81.6%、74.9%、286.6%,取用水的贡献率分别为18.4%、25.1%、-86.6%。从年内不同时期分析可知,非冻融期是全年水资源量减少的主要时期,占全年水资源总量减少的82.6%,冻融期占17.4%。和北方的海河流域、黄河流域相比,水资源减少幅度和主要影响因素各不相同,主要取决于气候变化和人类活动强度变化幅度的不同。与位于华北和西北的两大流域海河流域和黄河流域对比,气候变化对松花江流域水资源衰减的影响与海河流域相当,明显大于黄河流域,而人类活动对松花江流域水资源衰减的影响明显小于两大流域。

Under climate change and human activities, the evolution law of water resources in the Songhua River basin had changed drastically. Most of the existing studies were about the influence of climate change and human activities on the measured runoff, and few of them were concerned with the evolution law of surface and groundwater resources in the basin during the freeze-thaw period and the non-freeze-thaw period. In other cold regions with high-intensity human activities, the existing researchers also paid less attention to water resources.The water and energy transfer processes and nitrogen cycle processes model in cold regions(WEP-N) was used to model the water cycle in the Songhua River basin. Based on the WEP-N model, the monthly average surface discharge, soil discharge, base discharge, groundwater recharge, precipitation, and river evaporation of each subbasin in the basin were calculated. Water resources evaluation method, the surface water resources, non-repeated groundwater resources, and total water resources of the Songhua River basin were evaluated during the whole year,the freeze-thaw period, and the non-freeze-thaw period before and after 1998(1999-2018 and 1956-1998).The result showed that the annual total water resources, surface water resources, and non-overlapped groundwater resources in the Songhua River basin were 97.74 billion, 83.73 billion, and 1.40 billion m^(3) during the base period(1956-1998) and 76.04 billion, 62.70 billion and 1.33 billion m^(3) during the change period(1999-2018),respectively. Due to the change in climate and water consumption, the annual total water resources in the Songhua River basin decreased by 21.7 billion m^(3), with a rate of change of-22.2%. Among them, the decrease in surface water resources was 21.02 billion m^(3), with a rate of change of-25.1%. The reduction of non-overlapped groundwater resources was 0.68 million m^(3), with a rate of change of-4.9%. The decrease in the annual surface water resources accounted for 96.9% of the reduction of total water resources. Groundwater resources(nonoverlapped with surface water) accounted for 3.1%. The contribution rates of climate change to the reduction of annual total water resources, surface water resources, and groundwater resources in the Songhua River basin were81.6%, 74.9%, and 286.6% based on the multifactor attribution analysis respectively. The contribution rates of water use were 18.4%, 25.1%, and-186.6%, respectively. From the analysis of different periods in the year, the reduction of total water resources during the non-freeze-thaw period accounted for 82.6% of the reduction of annual total water resources. The freeze-thaw period accounted for 17.4%.The decrease in annual total water resources was caused mainly by the decrease in the annual surface water resources. Based on the multifactor attribution analysis, the result showed that climate change was the main factor for the reduction of water resources in the Songhua River basin. From the analysis of different periods in the year,the non-freeze-thaw period was the main period for the reduction of annual water resources. Compared with the Haihe River basin and the Yellow River basin in the north, the reduction extent of water resources and the main influencing factors were different, which mainly depended on the intensity of climate change and human activity.Compared with the Haihe River basin and the Yellow River basin in north China and northwest China, the impact of climate change on the attenuation of water resources in the Songhua River basin was almost the same as that in the Haihe River basin, which was larger than the Yellow River basin. However, the impact of human activities on the attenuation of water resources in the Songhua River basin was smaller than that in the two basins.