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使用物联网的河流流量和径流监测

The ongoing climate threat has strengthened the need to measure river flow rates. River flow (also known as streamflow) can be monitored using Velocity and Level sensors. 物联网(物联网) technology has made remote monitoring of river levels possible – providing real-time insights and alerts, 即使在最偏远的环境中.

要点

  • River flow (or streamflow) can be accurately measured using 物联网 (物联网) sensors.
  • 流阶段, velocity and depth/width need to be known in order to calculate the flow rate.
  • 监测经过测量和未经测量的流域是可能的.
  • 传感器可以通过电池、太阳能或电源运行.
  • 传感器包括水下和水面安装的传感器(i.e. 雷达).
  • 支持4G、LoRaWAN、卫星三种传输方式.
  • Sensors can be installed in streams, creeks or large-scale river networks.
  • 数据可以从云中可视化、下载和分析.

为什么要测量河流流量?

测量河流流量和径流是很重要的,原因如下:

  • 监测洪水状况并发出警报.
  • 避免低水位,并管理饮用水/灌溉用水供应.
  • 42、规范水流,确保野生动物生存.
  • 管理水利设施(例如,灌溉系统).

如何测量流量?

为了测量水流,需要计算一些参数.

  1. 流阶段
  2. 河速度
  3. 河流的深度和宽度

这些可以通过手动或使用传感器获得.

流阶段

流阶段 is simply the height of the water surface from the stream bed; many rivers around the world traditionally use a staff gauge to measure river levels. 仍然, these are prone to human error and fail to provide continuous readings for modelling purposes if required. 现在,安装一个 水位传感器 每隔一段时间记录读数.

河速度

雷达传感器使用多普勒雷达测量速度
雷达传感器使用多普勒雷达测量速度

传统上, governing bodies have used a mechanical current meter to evaluate the river’s velocity. 电流表起着水轮机的作用, 由金属杯组成的绕轴旋转的轮子. 每转一圈就传输一个电信号, 转速与河流的流速成正比.

由于这些电流表的使用方式, the meter needs to be installed directly above the river and is only really suitable for periodic measurements.

A more modern solution would be a radar-based surface velocity sensor mounted above the river to measure velocity using the doppler effect.

河流的深度和宽度

To accurately measure river flow, you should know the width and height of the river.

Calculating the area of a river weir/trapezoid can be done using the Cipolletti calculation
Calculating the area of a river weir/trapezoid can be done using the Cipolletti calculation

已测量的集水区、堰和涵洞

One of the constraints of river flow monitoring is that accurate monitoring can only be done in uniform stream gauges. 这些仪表通常以涵洞或堰的形式存在, where (depending on the shape) you can apply different calculations (i.e. Cipolletti计算). 这些被称为测量集水区.

Ungauged集雨

You can still calculate the area without a weir, but the process is a bit more involved. The measuring process would involve breaking the river into sub-sections and measuring each subsection. 一旦确定了长度和高度, you can use the parameters to calculate the area of each river subsection.

非均匀河流的计算可以分段进行
非均匀河流的计算可以分段进行

高度就是深度, 通过液位传感器计算, but it changes depending on subsection as the standard shape for uniform gages is a trapezoid.

河面积计算

Once all the parameters are made available, the Area of the river can be calculated using 深度x宽度 calculations of each subsection or using the relevant formula for the weir/trapezoid.  You can calculate the streamflow rate by multiplying the area with the velocity value, 输出河流的流速/每秒立方英尺的流量.


河流流量传感器类型

用于河流监测的超声波探头
The node is installed on the bridge with the radar / ultra-sonic sensor pointing towards the river.

物联网 sensors measure different parameters relating to river level and river flow before transmitting data wirelessly to the cloud. 大多数传感器类型可以使用电池+太阳能, 而在某些情况下, 更先进的传感器可能需要较小的电源供应. Once the data has been transmitted, it can be viewed and downloaded using a cloud platform or app.

The two important sensors are to measure the river’s height/area and its rate of flow (velocity).

超声波距离液位传感器

An ultrasonic sensor works by emitting sound waves toward an object and detecting the sound reflecting. The sensor then measures the time between each point to determine the distance between the sensor and the object being measured. 传感器发出的声音是高频的, 人耳听不到的, 但它允许聚焦“光束”(42KHz).

传感器安装在河的固定高度上. The sensor measures the distance between the installation point and the river surface, 所以如果知道这条河的深度, any change in the distance calculated by the sensor will indicate the rise/fall of the river height.

传感器的采样间隔决定了电池的使用. 传感器可以配置为每隔几秒钟采样一次, 但建议的间隔时间为15分钟,以节省电池的使用. In high flood risk areas, you may set the interval to every minute for readings.

雷达表面速度传感器

Non-contact sensors mounted above the river are designed for measuring surface velocity in open channels and rivers using radar technology. They work by detecting radiation reflected off the water surface and utilizing the Doppler effect.

As the wave receiver (sensor) is stationary and the source (river) is moving away from the receiver, 本例中计算速度的公式为:

In which c is the speed of the waves in the medium (approximately 3 x 108 ms-1), f为传感器观测到的频率,f0 发射的频率(来自河流)和vs 是河流的流速吗.

The surface velocity sensors and distance level sensors can be deployed in a single package, 从而导致一个紧凑的河流流量监测解决方案.


数据传输

Data from the sensors can be transmitted using one of the following technologies:

Combining these technologies means remote river flow monitoring can be undertaken in urban, 农村和极其偏远的环境(利用卫星).

数据可视化

与河流相关的数据可以通过网络仪表板查看, 应用程序或下载以作进一步分析. If your organisation uses GIS or a similar system, we can integrate the data into this environment.

进一步的信息

我希望我能解释河流流量监测的基本原理. I regularly speak to clients throughout the world interested in both river level and river-flow (streamflow) monitoring. If you would like to learn more about our range of solutions and how we can assist, 请与我联系.

有用的链接:

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Muaz在MTG商业团队工作, 与81818威尼斯的国际客户合作, 帮助他们解决物联网问题, 传感器和技术挑战. Muaz was educated at the University of Manchester and holds a degree (honours) in Electrical and Electronic Engineering.

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