Managing surface water is about making sure that water drains safely from homes and
gardens, roads, fields, businesses and public spaces. Good surface water management is
about making sure that rain can drain effectively to the environment, using a combination of
natural and manmade drainage networks.
Much of our drainage is into a single pipe system – Combined Sewer (CSO). On the Island, even in urban areas, there are not many two pipe systems (foul and surface separated). If the volume of water entering the drainage network overwhelms the system, it can sometimes cause heavily diluted sewage to be released into rivers and the sea. This is not the only cause, but it is one that we the general public can do something about.
Southern Water analysis has shown that, in general, discharges are over 95% rainwater. Of this, 30% of flow comes from roads, 40% from roofs, and 15% from garden and open spaces. They have calculated that if they can remove 40% of storm water, they can reduce CSO discharges by 80%.
If we don’t act now, then things will get worse
New housing and urban creep. Home extensions, conservatories and paving over front gardens for parking – can all add to the amount of water going into our sewers and drains. Green spaces that would absorb rainwater is covered over by concrete and tarmac that will not.
Climate Change means we now have less water when we need it, a larger number of ‘extreme rainfall’ days and more intense short duration storms.
What our local water company is doing to reduce discharges
Southern Water have set up a Storm Overflow Task Force. Within this there are Pathfinder Projects where they will develop and trial a more collaborative approach to surface water management. There are different approaches being tried across the region and the Isle Wight has its own pilot Pathfinder Project. This includes:
- Upstream Source Control (i.e., stopping the water getting in to the CSO)
- System Optimisation (i.e., improving the way their pumps, storage tanks etc work
- Enhancing infrastructure (i.e., building a bigger storage tank)
The latter two options are internal to Southern Water, but the first option is one where the general public will play a large and important role.
The full details of Southern Water’s Pathfinder project can be found here.
What we, the community can be doing to reduce discharges
Support Southern Water investigations by providing time and date stamped evidence
Send in photos and videos of overland flow, flooded areas and level of surface ditches to Southern Water. They need time, date and clear location as this has to be matched to met office data.
Report blocked highway gullies to Island Roads
We find this app easiest, but you are welcome to give them a call.
Don’t put fat, oil, grease or unflushables into the system
They cause blockages, blockages back up into homes or escape through manholes.
Prevent water from entering the Combined Sewer system, or reduce the flow in
Water butts and soakaways etc are part of the Pathfinder Project. If possible, disconnect existing drainage from this system
Do not have impermeable driveways and gardens
We have written a whole page about this here.
Are storm overflow discharges legal?
Under certain conditions, yes. In England, the Environment Agency issues permits for individual storm overflows which set conditions for when they can be used and how they should be monitored and maintained.
There are around 15,000 storm overflows in England, their locations and discharge data are available to view on an interactive map from The Rivers Trust.
The Government has a plan that contains actions for water companies, the Government and the public to help reduce the impact of storm overflow discharges.
- by 2035, water companies will have to improve all storm overflows discharging into or near every designated bathing water; and improve 75% of overflows discharging into high priority nature sites
- by 2050, this will apply to all remaining storm overflows covered by our targets, regardless of location
Under the plan, overflows that are causing the most harm will be addressed first, and it will be reviewed in 2027 to see where it can go further. Not everyone agrees that this plan is quick or robust enough.
Who monitors discharges?
Previously it was up to Water Companies to advise the regulator, the Environment Agency when they had exceeded their permits. This wasn’t a particularly well thought through plan and now 100% of overflows will have monitors installed. These are called Event Duration Monitoring (EDM) devices and if you are really interested you can read more here. However, its vital these work properly if they are to reduce discharges.
Who monitors the regulator?
There are people who feel that monitoring is flawed. We came across this document what discusses several failings within the system.
Surfers Against Sewage track real-time CSOs (combined sewage overflows) and PRFs (pollution risk forecasts). The app monitors the water quality at over 400 locations around UK rivers and coastlines. You can view an interactive map and our advice is not go swimming in the sea after rainfall. Southern Water have also produced Beach Buoy This tool provides near real-time information about storm release activity near coastal bathing waters. The interactive map, pop ups and release table, give information about any releases and their frequency. You can also sign up for email notifications for your local bathing water. However it doesn’t cover all CSOs.
The Solent Protection Society monitor available data and campaign. There is a lot of relevant data on their pages.
Is it hopeless?
No, it’s not. There are a lot of failings in the system and much improvement needed by the regulator. However, there are good things that the Water Company is doing – Pathfinder’s early results on the Island are very positive, and there are many actions that we can take that will reduce the number of discharges.