Why Use A Non-Contact Monitoring Approach?
As successful river flow monitoring network is vital for getting early flood warnings in a catchment.
The current monitoring approach used by many national networks is a contact based approach. This approach is often susceptible to failure during flood events and suffers from uncertainty during high flows. This is due to the extrapolation of the stage-discharge relationship and the need to account for backwater effects and flows across the floodplain.
The non-contact approach offers an alternative monitoring method that seeks to overcome some of the deficiencies outlined above. The approach can be undertaken from a fixed sensor location, with illustration of how this might look below, or from a mobile sensor such as a UAV.
More detailed information on the approach, including specifications and technical details of sensors used in this reseach, is available in the ‘Resources‘ section.
How Does The Non-Contact Monitoring Approach Work?
An example of a non-contact monitoring setup
A non-contact approach works through having:
- river and floodplain velocities calculated through image analysis
- This uses Particle Image Velocimetry algorithms developed for hydraulic experiments.
- In a natural setting this is done using naturally occurring features (e.g. foam, seeds, woody debris and turbulent structures).
- river levels extracted from images, and measured using low-cost ultrasonic distance sensors.
- a surface water slope which is based on multiple level measurements at intervals of several hundred metres.
The overall approach offers a low cost design, low power requirements and the ability to provide real-time data transmission.
Using Non-Contact Monitoring Data In Hydraulic Models
Using the non-contact approach applied by Newcastle University it is possible to to extract key hydrological parameters:
- River stage (m)
- Rate of stage change (m/min)
- Velocity (m/s); and
- Discharge (m3/s)
In addition to providing an understanding into catchment hydrology and flooding processes at a given location, the hydrological parameters can be used during a hydraulic modelling process.
The use of non-contact monitoring data in the setup of a hydraulic model