Rivers and Seas Watch

Rivers and Seas Watch helps you stay informed about storm overflow releases across our region. Here you can access our interactive map and find useful resources including FAQs and information about tidal modelling.

Visit Rivers and Seas Watch

An overview

Rivers and Seas Watch is our online service which provides near real-time information about storm overflow releases across our region. When a potential storm overflow release is identified by our monitoring equipment (EDMs), a release event is created and shown on Rivers and Seas Watch. Every storm overflow outfall in our region is shown.

How to use Rivers and Seas Watch

Rivers and Seas Watch has three main features:

The interactive map
Release history
Useful information and FAQs

You can also sign up for email updates to keep updated about specific bathing sites and receive alerts when there has been a storm overflow release that may have impacted bathing water quality.

We'd love to hear your feedback, let us know what you think of the service and its data.

Interactive map

To use the map, simply locate the area or bathing water you’re interested in. You can do this by zooming in or using the search bar. Then click on:

A bathing water pin to see details of any recent releases associated with that bathing water, the outfall(s) associated with the bathing water, and navigation to the release history. Some outfalls are associated with more than one bathing water.
An outfall circle to see details of any recent releases, the bathing water(s) it is associated with, and navigation to the release history.

Icons and legend

Outfall circles changes colour depending on how recently there has been a storm overflow release.

Bathing water pins change colour depending on how recently there has been a release from any associated outfalls that could impact bathing water quality.

Red: Release(s) in the last 24 hours
Amber: Release(s) in the last 72 hours
Green: No releases in the last 72 hours

Release history

Our Rivers and Seas Watch release history allows you to filter by date, bathing water, outfall, status and impact. You can also customise the table columns.

We also included the option to download results from the table, using the ‘actions’ button.

To see our annual storm release data, you can visit our flow and spill reporting pages.

Flow and spill reporting

The review process and how it works

We have an extensive review process to make sure the storm overflow release data we provide is as accurate as possible. Find out more about this process below.

Automatic review - genuine or not genuine

We review every potential release using on-site monitoring equipment and smart systems to decide if there was a genuine storm overflow release or whether it was a false alarm-not genuine. Sometimes the data needs be manually reviewed for accuracy and is labelled under review until our spills team have investigated

Automatic review - impacting or not impacting

To determine whether a release has impacted water quality, we use tidal modelling to predict storm overflow behaviour. To do this we factor in wind, tide strength, and direction. This gives each event an impacting or not impacting status.

Manual review

If there isn't enough data for the systems to make an accurate determination, our spills team carry out manual checks. These can be either digitally - by checking different data sources or manually by going out to investigate equipment.

Update if needed

If an event status, duration or impact is adjusted for accuracy, the release information is updated in Rivers and Seas Watch. This process – both automated and manual – allows us to provide the you with accurate near real-time information.

Tidal modelling

What is tidal modelling?

One of the key components of ensuring we provide the most accurate storm overflow data possible is our tidal modelling.

Tidal modelling means creating scenarios, called models, and testing mock storm overflows in them to see how they behave in each different condition.

When a real storm overflow alert comes in, our automated systems use the models to predict how the real release will behave so we can notify our customers immediately if the release is likely to have impacted bathing water quality.

How are tidal models created?

Our tidal models have been created using several data sets including the location of the outfall, the duration of the release, tidal and weather conditions and the position of the moon and the sun. All this can change how the release behaves once it enters the water.

We have 2000 different scenarios that our automated systems cross-reference, finding the closest match to the real-life release. These have been robustly checked against survey data such as tidal levels, current speed and direction, and dye tracing, ensuring that the model is performing as close to a real storm overflow release as possible.

Why is tidal modelling important?

Tidal modelling allows us to predict the affects that environmental factors have on any storm releases, an ensure our storm overflow monitoring service is updated to show the most accurate information possible in near-real time.

It allows us to understand which bathing waters each outfall has the potential to impact and it helps us determine whether an individual release event effects bathing water quality.

Beachbuoy Independent Review

We asked a group of independent experts to conduct an assessment of our previous storm overflow monitoring service, Beachbuoy, and its ability to provide consistent, reliable and credible near real-time warnings of potential water quality impacts from storm overflow releases, and to provide a series of recommendations to improve the accuracy and user trustworthiness and confidence of the system.

We’re committed to acting on the recommendations and have incorporated them as both short and long-term goals for our new service, Rivers and Seas Watch, details on timeframes are outlined in report.

Before publication, time was given for the report to be reviewed by our stakeholder community – providing them with an opportunity to feedback and ask questions to the independent experts via individual sessions, email exchanges and our working group meeting. Minutes from the meeting can be found here: Beachbuoy WG January 31 2024 Minutes

We’re committed to acting on many of the recommendations as part of our new and improved service, Rivers and Seas Watch, complete with all inland outfalls and improved usability in features.

To request previous or unredacted versions of this report please email beachbuoy.independentreview@southernwater.co.uk

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