February 2021

Issue 59

Soil Moisture - Use in Forecasting

The Australian BoM makes the outputs of their AWRA-L soil moisture model available for public download. This gridded dataset provides a great means of helping you assess your catchment conditions in terms of dryness (for initial and continuing losses).

The grid represents daily relative moisture levels (as a percentage) across Australia, on a roughly 5km grid.

Relative Soil Moisture

If you are running real-time hydrology as part of your forecasting system, you will likely have your antecedent catchment conditions simplified into logical groups such as "very wet", "wet", "average", "dry" or "very dry". These groupings make it easier to work with initial and continuing losses in your hydrologic modelling.

The relative soil moisture levels can help you determine which grouping is the most suitable to use at a given point in time.  Whilst specific figures will vary from catchment to catchment (and by the time of year), a high value of >90% may indicate a "very wet" catchment, whilst <10% may indicate a very dry catchment.

A time series plot (like the one in the above image) could be useful to help you match the weather patterns you have experienced over certain periods of time with the resulting soil moisture levels, to further improve the "feeling" you get on how wet or dry the catchment is at any point in time.

Relative Soil Moisture vs Rainfall over 2020 (Source: BoM website)

The image above shows the link between relative soil moisture (black line on upper chart) and rainfall (black line on lower chart) at Toowoomba. You can see the relative soil moisture spiking after each significant rainfall event and declining in periods of little rainfall.

Further, detailed information on the BoM's soil moisture model can be found on their website: http://www.bom.gov.au/water/landscape/ 

Quick Overland Flowpath Analysis

When we released waterRIDE 10, the focus was on the new "one waterRIDE" interface and enhanced workflow. However, we also snuck in quite a few tools that you may not have had the chance to explore. Once such tool is the flowpaths tool that will use a gridded DEM to determine all flowpaths across the landscape.

Residing on the Modellers Tools section of the Analyse panel, the Catchment tool provides a range DEM based catchment processing tools including:
   - pit removal
   - flow accumulation (flowpaths and catchment areas)
   - watershed (catchment to a point)
   - flowpaths through subcatchments
   - Strahler Order stream classification

Overland Flowpaths: Left (0.5ha catchment), Right (0.1ha catchment)

The image above shows outputs of the flow accumulation tool run on a 1m DEM. The left image is filtered to show flowpaths with a minimum catchment area of 0.5ha whilst the image on the right is filtered to show a minimum 0.1ha.

At present, the tools run on a binary grid file (*.rst), which means you may need to export terrain from any existing waterRIDE grids, or you may wish to use the DEM Builder tool in the Terrain section of the Import panel to build a seamless DEM from your tiled terrain grids. This analysis is also limited to terrain grids with less than around 250,000,000 cells (we haven't ported the code for infinite grids, yet).

waterRIDE CLOUD Q&A Sessions - Have you booked yours?

If you were thinking about moving to waterRIDE CLOUD or want to know more, we are currently running quick 20-30min virtual sessions to allow all stakeholders within an organisation to see what it's all about and ask any questions you may have.

These quick sessions aim to cover:
    - flooding data access, interrogation and management
    - data sharing (internally and externally)
    - automated flood certificates
    - real-time flood forecasting
    - data processing, analysis and flood intelligence
    - data portability and remote access
    - speed of operation

Please send an email to the waterRIDE email if you would like to setup a session.

January Release - 10.0.48

Version 10.0.48 of waterRIDE FLOOD was released in January. Those with valid maintenance plans should have received the automated email. If not, please let us know as we are now using an external email platform (the same that we are using for waterRIDE CLOUD notifications).

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