风浪作用下的底泥悬浮沉降及内源释放量研究

分别于春夏秋冬4个季节对太湖梅梁湾水体开展了5次野外实验,利用沉积物捕获器收集沉积物,采用Gansith公式法计算了沉积物的再悬浮通量,并建立了其与风速的关系;对代表不同风浪作用下的太湖悬浮物进行了7次静沉降实验,计算了悬浮物的静沉降通量,并建立了其与悬浮物浓度关系.以3.7 m/s为界对低泥悬浮沉降过程进行分解和概化,计算了2005年每日的悬浮沉降量,并利用近10年的风速资料估算了太湖年均内源释放量,结果表明,太湖每日的内源释放量受风速影响显著,和风速变化趋势较为接近,然而不同营养盐的释放状况却各不相同.太湖内源年均进人水体的净底泥量有19.03万t,冬季最大.夏季次之;就营养物质释放量而言,COD约4.96万t、总氮约7 773.0 t、总磷约275.5 t.其中秋季营养物质释放量最小,夏季最大.

Suspension-sedimentation of Sediment and Release Amount of Internal Load in Lake Taihu Affected by Wind

Abstract: The bottom mud in Taihu Lake was simulated indoors in a wave tank. The rules of starting principle of the bottom mud were analyzed under different kinds of disturbing intensity in this paper. The common wave intensity of Tai Lake could be systematically simulated in the wave tank. The critical sheer stress of bottom mud in Tai Lake is 0.050Pa by the experiment. The calculated result of flow field and suspended solids from the advanced model of FVCOM conforms to the observation data in Taihu Lake very well, which proves validity of the model. Because the conflict of field observation data in time and space greatly influences the accuracy of model parameters, simulating the suspended solids indoors is very important to the cure of Eutrophication in Taihu Lake.