This case study demonstrates how sump pump systems are used in real world flood mitigation projects.
In 2020, during the height of the COVID-19 pandemic, our engineering partners at FPS Environmental were asked to investigate flooding at a riverside property in Shropshire following a major storm event. The site survey identified various flood pathways, including surface water and backflow from the drainage network. If you want the background on how these systems are designed and installed, see our guide to what a sump pump is and how to install one.
While this case study highlights the real world use of a packaged sump pump chamber, it is important to note:
This website, floodandwaterpumps.co.uk, provides product sales only. Any site-specific design, flood investigation, or engineering advice must be carried out by a qualified consultant or Civil Engineer.
What caused the flooding?
The flooding occurred following a period of intense and prolonged rainfall.
The property boundary abuts the river bank, and although the river did not breach the wall at the end of the garden, the surface water drainage for the property (all the drainage for the hardstanding and roof drainage, with a channel drain around the property) connected into the river and was not fitted with a non-return valve. This meant that although water did not overtop the wall, it overflowed out of the drains.
Coupled with water pooling on the road and running into the property boundary, which fundamentally wanted to flow back to the river but was then trapped by the wall, the property suffered flooding.
It appeared that the previous owner may have attempted to reduce the flood risk by adding new drainage channels, but fundamentally these all drained via the same shallow chamber into the river, without a non-return valve.
This resulted in internal flooding significant enough for emergency services to pump water away during the event.
A non-return valve was subsequently fitted, similar to the one pictured below:
Why a sump pump system was needed
After reviewing the site conditions, it became clear that the drainage methods were insufficient during high river events. A passive gravity system simply could not operate when the river level rose above the outfall point. This is the same principle we cover in our APP HD-15 high-level overflow case study.
A packaged sump pump chamber offered the ideal solution
- It uses an automatic float switch, so it turns on and off as required. Aside from routine maintenance and inspection, it operates passively.
- It could be connected to the existing surface water network via a high level overflow. This means that when the non-return valve is closed and water cannot escape to the river at low level, the pump activates and discharges water to the same outfall, but over the wall rather than below water level.
- It manages surface water, preventing water from accumulating around the property, while also capturing any groundwater that rises above ground level.
- The chamber was installed with a 4 inch pipe from the shallow surface water inspection chamber at high level into the sump chamber. In normal conditions, water continues to discharge through the lower gravity connection. The pump only operates during flood conditions when the lower outfall is submerged or closed.
- The arrangement allowed all existing drainage channels around the property to continue functioning as intended.
- The installation was highly cost effective.
- The installation was discreet, as pictured.
The product used: FPS Iguazu Sump Foul Pro packaged pump station
You can view the exact product installed here: FPS Iguazu Sump Foul Pro packaged sewage pump station.
The system includes:
- A robust polyethylene chamber (MDPE)
- Automated float switch control
- EVAK Hippo 100 sewage pump
- Non-return valve for discharge
This was installed using green suction delivery hose and, importantly, a conduit for the electrical cable, so that the pump can be replaced more easily in the years to come.
Benefits of the sump pump
Following installation, the property now benefits from:
- Floodwater removal during high river conditions
- Reduced risk of surface water accumulation
- Protection against backflow issues
- Peace of mind during storm events
Although no system can completely eliminate flood risk, a correctly specified sump pump is a major improvement in resilience, particularly for riverside or low-lying properties. This kind of measure sits at the heart of property flood resilience.
Important note on engineering advice
This case study is presented solely to demonstrate real world product use. FloodandWaterPumps.co.uk does not offer:
- Site visits
- Hydraulic assessment
- Flood risk modelling
- Engineering design
- Drainage calculations
Looking to install a sump pump?
If you are interested in a similar product, you can explore our full range of sump and packaged pump stations, or our sewage pumps for foul applications.
For site-specific recommendations, always consult a qualified engineer.
