MEMS-UMinho, University of Minho, Campus de Azurém, Guimarães, Portugal.
MEMS-UMinho, University of Minho, Campus de Azurém, Guimarães, Portugal.
Sci Total Environ. 2022 Feb 20;808:152164. doi: 10.1016/j.scitotenv.2021.152164. Epub 2021 Dec 4.
The sedimentary processes play a major role in every aquatic ecosystem, however, there are few automated options for in-situ monitoring of sediment displacement in the streambed of waterways. We present an automated optical instrument for in-situ continuous monitoring of sediment deposition and erosion of the streambed that requires no calibration. With a production cost of 32€, power consumption of 300 μA in sleep mode, and capacity to monitor the bedform of a waterway, the sensor was developed to evaluate the sediment dynamics of coastal areas with a wide spatial and temporal resolution. The novel device is intended to be buried in the sand and uses 32 infrared channels to monitor the streambed sediment height. For testing purposes, a maximum measuring length of 160 mm and 5 mm resolution was chosen, but these values are scalable. Sensors can be built with different ranges and precision according to the needs of the fieldwork. A laboratory experiment was conducted to demonstrate the working principle of the instrument and its behaviour regarding the turbidity originated by suspended sediment and the settling and deposition of the suspended particles. The device was deployed for 119 days in an estuarine area and was able to detect patterns in the sediment deposition and resuspension during the tidal cycles. Also, abnormal events occurred during the experiment as floods and algae blooms. During these events, the sensor was able to record exceptional erosion and sediment deposition rates. The reported automated instrument can be broadly used in sedimentary studies or management and planning of fluvial and maritime infrastructures to provide real-time information about the changes in the bedform of the watersheds.
沉积过程在每个水生生态系统中都起着重要作用，然而，对于监测水道床底泥沙位移，目前几乎没有自动化的选择。我们提出了一种用于原位连续监测泥沙沉积和侵蚀的自动化光学仪器，该仪器无需校准。该传感器具有 32 欧元的生产成本、300μA 的休眠模式功耗以及监测水道床形的能力，旨在以宽时空分辨率评估沿海地区的泥沙动态。该新型传感器拟埋入沙中，使用 32 个红外通道监测床底泥沙高度。出于测试目的，选择了最大测量长度 160mm 和 5mm 的分辨率，但这些值是可扩展的。根据现场工作的需要，可以构建具有不同范围和精度的传感器。进行了实验室实验以演示仪器的工作原理及其对悬浮泥沙引起的浊度以及悬浮颗粒的沉降和沉积的行为。该仪器在河口地区部署了 119 天，能够检测到潮汐周期中泥沙沉积和再悬浮的模式。此外，在实验过程中还发生了异常事件，如洪水和藻类大量繁殖。在这些事件中，传感器能够记录到异常的侵蚀和泥沙沉积速率。该自动仪器可广泛应用于沉积学研究或河流和海洋基础设施的管理和规划，以提供有关流域床形变化的实时信息。
