基于浑浊度监测山区河流悬浮泥沙含量的试验研究

针对山区河流悬浮泥沙含量监测缺乏实时性的问题，对浑浊度及悬浮泥沙含量进行监测，分析光照强度、流速、颗粒粒径和水体含沙量对浑浊度的影响，建立浑浊度与悬浮泥沙含量的关系模型式。结果表明： 1）光照强度对浑浊度的影响最大，根据二者之间的关系，将光照强度（E）划分为3个区间：E≤6 800 lx、6 800 lx <E≤22 000 lx、E>22 000 lx，对应于3个区间，确定了浑浊度与悬浮泥沙含量的关系模型； 2）水流流速主要影响上层泥沙颗粒的分布，流速为0.16 m/s时测量区域的浑浊度大于流速为0.018 m/s时的浑浊度； 3）泥沙颗粒的粒径大于扬动流速能带动的临界粒径时，其会沉积在渠底，因此，泥沙级配中大于临界粒径的颗粒占比越大，悬浮泥沙含量越小，浑浊度越小； 4）水体含沙量越大，水沙输移过程中携带悬浮泥沙的量也越多，测量区域上层水样的浑浊度越大； 5）采用本研究确定的浑浊度与悬浮泥沙含量的3个关系模型，预测得到的悬浮泥沙含量与实际悬浮泥沙含量的平均相对误差分别为7.22%、10.00%、8.58%。根据在自然条件下不同光照强度区间测得的浑浊度，可以得出该测量区域的悬浮泥沙含量。由于浑浊度可以现场连续、快速测得，所以将此方法引入山区河流悬浮含沙量实时监测是可行的。

Experimental study on monitoring suspended sediment content in mountainous rivers based on turbidity

Aiming at the problem of lacking real-time monitoring of suspended sediment content in mountainous rivers， the turbidity and suspended sediment content of the rivers were monitored， and the influences of light intensity， velocity， particle size and water sediment content on turbidity were analyzed. A relationship model between turbidity and suspended sediment content was established. The results show that： 1） Light intensity has the greatest influence on turbidity. According to the relationship between the light intensity and turbidity， light intensity （E） is divided into three intervals， E ≤ 6 800 lx， 6 800 lx < E≤ 22 000 lx and E > 22 000 lx. In corresponding to the three intervals， the relationship model between turbidity and suspended sediment content is determined. 2） The flow velocity mainly affects the distribution of sediment particles in the upper layer. The turbidity of the measured area at the flow velocity of 0.16 m/s is greater than that at the flow velocity of 0.018 m/s； 3） When the particle size of the sediment particles is larger than the critical particle size driven by the lifting velocity， it will be deposited at the bottom of the channel. Therefore， the larger the proportion of particles larger than the critical particle size in the sediment gradation， the smaller the suspended sediment content and the smaller the turbidity； 4） The larger the sediment content of the water body， the more suspended sediment carried in the process of water and sediment transport， and the greater the turbidity of the upper water sample in the measured area； 5） Using the three relationship models of turbidity and suspended sediment content determined in this study， the average relative errors of predicted suspended sediment content and actual suspended sediment content are 7.22%， 10.00% and 8.58%， respectively. According to the turbidity measured in different light intensity intervals under natural conditions， the suspended sediment content in the measured area can be obtained. To sum up， since the turbidity can be measured continuously and quickly on site， it is feasible to apply this model to real-time monitoring of suspended sediment concentration in mountainous rivers.