Riparian Ownership and Responsibilities: What Landscapers Must Know About Ditches and Culverts
With rainfall being the major topic of discussion during the early part of 2026, with (seemingly) week after week of incessant downpours, many garden sites under water or at maximum field capacity, the need to recognise the importance of any existing means of removing water from site by any ditches, culverts and swales has become ever more pressing.
Why Landscapers Must Understand Riparian Law.
As landscape contractors or garden designers, you may be asked to fill in or pave over a ditch or low laying area in a garden, one that may become flooded at certain times of the year. Be careful not to accept the customers word that there is no problem with infilling or diverting ditches and culverts – often called swales in some regions. The word ‘ripa’ comes from the Latin for riverbank or stream.
A riparian owner is someone who owns property which is next to a watercourse or has a watercourse running through it. Under common law, riparian owners have certain rights and responsibilities relating to the stretch of watercourse that flows through or alongside their land – that does not just mean farmers, that means garden owners too.
Red Flags for Garden Designers, Surveyors and Specifiers
Some riparian owners may not realise that the ditch at the bottom of their garden belongs to them, so making them responsible for its maintenance. There may be a culvert under your property; you are legally still responsible for its maintenance and free flow of water. It could also be that water rises in a property from underground springs but then flows through the garden, so it is not simply those owners of streams with banks who are riparians!
Riparian owners have certain rights, but are also legally obliged to fulfil certain responsibilities under laws enacted to help manage flood risk and protect the environment.
Riparian Owner Rights
Riparian owners have the right to receive a flow of water in its natural state, without undue interference in quantity or quality.
Riparian owners have the right to protect their property from flooding from the watercourse and to prevent the erosion of the watercourse banks or any nearby structures – For most works within 8 metres of a watercourse you must apply for formal consent from the Environment Agency.
Riparian Owner Responsibilities
To maintain the watercourse and to clear any obstructions (natural or otherwise) so that normal flow of water is not impeded.
To maintain any approved structures on your stretch of the watercourse. These may include culverts, weirs and mill gates.
To maintain the banks and bed of the watercourse (including any trees and shrubs growing on the banks) and any flood defences that exist on it.
To accept the natural flow from upstream neighbours and transfer it downstream without obstruction, pollution or diversion.
If you are considering any work, you need to:
- Check whether permission is required from the local council or Environment Agency
- Find out the best times to undertake maintenance activity. The Environment Agency should be able to advise in which seasons to take action,
- Safety first, consider the safety of those undertaking work and those around you.
Case Study Regarding Appreciation of Surveying Requirements
Owner of a 400 year old house and garden had a spring fed pool and stream which runs through it. The stream then runs under a boundary wall and into the garden next door through a culvert, under the road and on down the watercourse on the other side of the road. Some years ago, the previous owner of the property next door covered the culvert with paving although it was still possible to hear the water running under the property when in full flow.
The owners of the property next door to the ancient cottage decided to extend their property with a lovely oak framed extension at the rear. When digging for the foundations, they came across the culvert which had collapsed when the footings were being dug out. Apparently at the time (in the summer) there was no water flowing through the culvert. The stream does dry up in times of drought through the summer. The builder apparently then decided to replace the culvert with a pipe without seeking any advice or permissions and the extension was built. Planning permission was granted for the extension, but no permission was sought to alter the culvert from the County Council.
Repercussions of Failure to Think Ahead
Roll forward three years, there was a huge storm in the area, and what would normally happen is that run off water would go into the stream, flow through the culvert and out down on into the local river. However, the volume of water was far too much for the replacement pipe under the extension and as a result the water level rose up over four feet behind the wall and poured in to the owners walled garden through the gates and on down to the house. Two feet of water filled the house within 30 minutes and the neighbouring property also had some minor water incursion, but as property was higher and there is a lower side walk way, the majority of water flowed away quickly.
The property had been in the hands of neighbouring estate for over 100 years and had never flooded during that time, so an investigation was carried out for the owner privately. The insurance company paid for all the drains to be checked throughout the property, and there was a clear flow under the property, but they did not look at the culvert next door as it was not known at that time by the owner of the property that the neighbour had touched it.
The stream and culvert are clearly marked on the deeds of both properties. An investigation discovered that although planning permission for the extension to the property was granted, no permission was sought to alter the water course, which although it ran through a culvert under the property, it was effectively an open watercourse. RETROSPECTIVE PLANNING PERMISSION IS NOT GRANTED FOR WORK CARRIED OUT WITHOUT THE CORRECT PERMISSIONS.
Ongoing legal issues arose………….
The property owner had discussions with the neighbour, who said that they were not aware that the culvert was there until the builder found it and they had no idea they had to seek separate planning permission before touching it. However, the council have taken a dim view, particularly as property was flooded as a result. They have been to see the neighbouring property and confirmed that permission would not have been granted to alter the culvert. The owners have to restore the culvert to its original size, which means digging up the floor in their extension and the rest of the house to connect it all back to its’ original capacity. A very expensive operation!
Level Changes May Alter Drainage Responsibilities
Please be aware, when designing or working in a garden that has a ditch, water course, stream or any other sign of a water channel system, you should check with the Local Authority, and ask the client to check their deeds to ensure that they do not fall foul of Riparian Rights.
Planning Permission is Often Not Enough
Before touching a water course (closed or open) you may have to seek several permissions. If water is flowing then there is land drainage permission from the Environment Agency. A separate planning permission may be required from the County or local council before any work is carried out. Rules may vary on who to contact, but the rights and responsibilities remain the same.
How many property owners know of these ancient but very important current Laws?
How important is this knowledge to surveyors, designers and specifiers? The simple answer is extremely important, as the requirement to make assessments based on careful inspections is a major part of due diligence when producing and formulating plans.
Failure to advise a client to seek appropriate consent may expose the designer or contractor to professional negligence claims.
