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.
An example of a non-contact approach from a fixed location can be seen here and a n example of a UAV based non-contact approach can be seen here.
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
Newcastle Flood Observatory 