冰雪消融期松花江哈尔滨段干流水动力模拟及其时空分布特征分析

受春季冰雪消融的影响,我国北方地区的河流会形成桃花汛期,期间河流的水位、水深和流场较其它季节会发生较大变化,从而对流域水环境管理和水资源保护的利用产生影响.为科学地对松花江哈尔滨段在冰雪消融期水动力变化情况进行分析,利用ArcGIS 10.0对DEM影像进行矢量化,在Delft3D-RGFGRID中创建正交曲线网格,基于EFDC模型建立松花江哈尔滨市段二维河流数值水动力模型.模拟了2014年1月-10月间的整个河段不同时空条件下的水动力变化情况,根据哈尔滨市水文站2013年、2014年实测数据对模型的参数和模拟结果进行率定和验证,模拟水位与实测水位最大相差0.33 m,相对误差<10%,吻合度高.模拟结果表明:整个江段平均水位在桃花汛期可达116.38 m,丰水期进一步上升至116.54 m,枯水期为115.64 m,平水期为116.23 m.朱顺屯和阿什河口断面水深在丰水期都明显大于桃花汛期,呼兰河口和大顶子山断面两汛期的水深几乎持平,大顶子山断面水深在各时期都较浅,附近易发生冰塞.朱顺屯、阿什河口、呼兰河口大顶子山桃花汛期流速分别为0.55、0.61、0.43、0.57 m·s^-1;丰水期流速分别为0.59、0.66、0.47、0.63 m·s^-1,各断面桃花汛期的流速与丰水期流速相当,略小于丰水期,流向平稳无涡旋.该模型可以较好的模拟河道水力要素随时间及空间演变规律,以便在不同典型水文年进行水力模拟和预测,可为松花江冬春季通航管理、水资源配置、水质模拟、水质目标管理、水环境容量计算和污染物总量减排提供决策依据.

The Harbin section of the Songhua River in melting period: Hydrodynamic simulation and spatial and temporal hydrodynamic features

Owing to ice melting in spring, the rivers in North China enter the spring flood season, when the water level, water depth and flow field of the rivers change greatly, affecting water environment management, protection and utilization of water resources. In order to make a scientific analysis of water dynamic change in the Harbin section of the Songhua River during the ice melting period, DEM images were vectorised by using ArcGIS 10.0. The orthogonal curvilinear coordinate grids of the study area were setup by the RGFGRID program of Delft3d software. In this paper, a two-dimensional mathematical model of the Harbin Section of the Songhua River was established by using EFDC model. The hydrodynamic conditions in different time and space of the section between October and January in 2014 were simulated, and the data measured in Harbin Hydrological Station was used to verify the simulation results. The maximum difference between the simulated and measured water levels was 0.33 m, with a relative error less than 10%. The simulation results showed that mean water level was 116.38 m in the spring flood season, 116.54 m in the wet period, 115.64 m in the dry season, and 116.23 m in medium season. The water depths in Zhushuntun Section and Ashe Estuary Section in the wet period were significantly higher than that in the spring flood season; the water depths in Hulan Estuary and Dadingzi Mountain Sections in the flood period were almost same as in the spring flood season. In Dadingzi Mountain Section the water depth was shallow always, where ice jam took place easily. In the spring flood season the flow velocity of Zhushuntun, Ashe Estuary, Hulan Estuary and Dadingzi Mountain Sections was 0.55, 0.61, 0.43 and 0.57 m·s^-1, respectively; in the wet period the flow velocity of them was 0.59, 0.66, 0.47 and 0.63 m·s^-1, respectively; The flow velocity of them in the spring flood season was closed to(or slightly less than) that in the wet period, when the flow was gentle without vortex. This model can simulate the river's hydraulic elements changing with time and space, so as to simulate and predict the hydraulic condition in different typical hydrological years. This study would provide basis to decision-makers in water navigable management, winter and spring water resources allocation, water quality simulation, water quality target management, water environment capacity calculation and reduction of total pollutant emission.