Load Transport Rate Research Articles

Loss Characteristics of Non-point Pollutant from a Mixed Agriculture Watershed

In order to explore the temporal and spatial variability of non-point source pollution in an agriculture watershed, the water quality and quantity characteristics of five flood events at Shuangqiao station in Siheshui watershed (south China) were monitored. Five pollutants, including BOD5, TSS, TP, TN, and NH3-N, were measured and analyzed. The characteristics of pollutant concentrations and load-transport rates were investigated. It is shown that the pollutant concentrations in the flood events are remarkably larger than those in the non-flood events. The temporal sequences of peak values between pollutant parameters and runoff flows are explored. It indicates that the time interval would be short if the high-intensity rainfall occurred in the initial period of a flood event. Most of the peak values of pollutant concentrations preceded the flow peaks. The correlation coefficients between TSS and other pollutant concentrations are analyzed. It is shown that there is a significant correlation between the concentrations of TSS and TP in the flood events.

Bedform effect on the bed-load transport rate using a comparison between two bedform (flat and standing bedform)

In this research, the impact of bedform on the bed - load transport rate was studied through experiments. The experiments were conducted on two cases, one when the bedform was flat, and the other when the bedform was standing wave. The arrival time is the time of bed - load reaches a reference surface at the end of the flume. Noted that the arrival time of the bed - load to the end flume when the bedform as flat differs from the arrival time when the bedform as standing wave, It was found that the arrival time in the case of flat bedform is less comparing to the case when the bedform is standing wave. Index form factor (L*/L) was proposed to distinguish between the flat bedform and the standing wave bedform, this factor was introduced in dimensional analysis with the other variables affecting the prediction of bed - load transport rate formula. Linear regression was found to predict formula for index form factor L*/L and also prediction formula for computed the bed - load transport rate (qs) with high R-square. The results from predicted formula were verified by comparing them with other researchers’ formal’s using statistical measures. At long last, it was found that the amount of the bed - load transport rate when the bedform was a flat is greater than the amount of the bed - load transport rate when the bedform was standing wave. Since the value of the bed - load transport rate has to do with the decision to maintain the unlined channels and thus it affects the cost of maintenance of the unlined channels.