A Portable Device for On‐Site Measurement of Sediment Concentration Through Volume‐Mass Replacement

Abstract To enable on‐site and near‐real‐time sediment concentration measurements, a novel type of portable device with a constant volume sampling bottle was developed in this study. The device consisted of a sampling bottle, a measuring assembly, and a platform for auxiliary data management. Five representative soils and eight sediment concentrations were used to validate the device accuracy and application. Moreover, a novel concept of sediment effective density (SED) was proposed. Under SED, a linear regression was fit between the measured and actual sediment concentrations. The results revealed that the slopes of the fitting line were close to 1, and the R 2 values were greater than 0.999 for five soils. Moreover, for total samples, the root mean square error (RMSE) and Nash–Sutcliffe efficiency coefficient (NSE) values were 5.59 g/L and 0.9996, respectively. Additionally, an average SED of 2.51 g/cm 3 was calculated in this study. With an average soil SED of 2.51 g/cm 3 and an average soil solid density of 2.65 g/cm 3 , the RMSE and NSE were 11.85 and 18.50 g/L and 0.9981 and 0.9954, respectively. This result demonstrated that the designed device accurately measured sediment concentration under various conditions. Furthermore, relative to the traditional oven‐drying method, the device could measure sediment concentration near‐real‐time and with high accuracy, which could be useful for researchers with excellent potential. It was recommended to measure the SED in a laboratory or runoff plot because the sediment sources could be identified and obtained. In a field or river, it was recommended to use 2.51 g/cm 3 as the SED, which was more accurate than 2.65 g/cm 3 .