Watercourses and Riparian Ownership

Main rivers

Main rivers are usually larger streams and rivers, but they also include those smaller watercourses that help with drainage. Officially, a main river is defined as a watercourse shown as a ‘main river’ on a main river map.  It can also include any structure or equipment used for controlling or regulating the flow of water along its course, either in or out of a main river. The Environment Agency has powers to carry out flood defence works applying to main rivers only.

Ordinary watercourses

An ‘Ordinary’ watercourse is every river, stream, ditch, drain, cut, dyke, sluice, sewer (other than a public surface water sewer or highway drain) and passage that water flows through, but which does not form part of a main river. Watercourses occur naturally, and they serve to drain the land and help in supporting animal and flower life. Historically, watercourses have taken water run-off from buildings and roads, as well as fields and parks. In the process of development, many have been culverted or changed in other ways. 

In normal conditions the watercourse may be a dry channel in the ground, but in storm conditions it may become a raging torrent.

Riparian responsibilities

If you live by – or you own property that is next to – any watercourse, or you have a watercourse that flows through your property, you are a 'riparian landowner'.  This means you have 'riparian' rights and responsibilities which have been established in common law for many years.

If the land on the other side of the watercourse is owned by a third party then it is likely that this person is the ‘joint riparian owner’ for the length of watercourse adjacent to the boundary. Unless the landowners’ deeds show otherwise, it is always assumed that each person owns the area up to the centre line of the watercourse.

A riparian owner is responsible for accepting water from their upstream neighbour and transferring it – along with any existing drainage from their own property – freely, to their neighbour downstream. More responsibilities of the riparian landowner are detailed as follows:

  • Responsibility to pass flow onwards without obstruction, pollution or diversion that affects the rights of others.
  • Accept flood flows through their land, even if these are caused by inadequate capacity downstream. There is no common law for a landowner to improve the drainage capacity of a watercourse.
  • Maintain the bed and banks of the watercourse (including trees and shrubs growing on the banks) and for clearing any debris, natural or man-made, including litter and animal carcasses, even if it didn’t originate from their land.
  • Must not cause any obstructions – either temporary or permanent – that would prevent the free passage of fish.
  • Responsible for keeping the bed and banks clear from any matter that could cause an obstruction either on their own land or by being washed away by high flow to cause an obstruction at a structure downstream. Rivers and their banks should not be used for the disposal of any form of garden or other waste.
  • Must keep any structures clear of debris. These structures include culverts, trash screens, weirs and mill gates.
  • The responsibility for protecting the property from seepage through natural or man-made banks. Where such seepage threatens the structural integrity of a flood defence it may become the concern of the Environment Agency.


Property buyers rarely read the conveyance document but Section 26 of the Law of Property Act 1925 provides that "a conveyance of land shall be deemed to include and shall by virtue of this Act operate to convey with the land all buildings, hedges, ditches, fences, ways, waters, watercourses, liberties, easements, rights and advantages whatsoever appertaining or reputed to appertain to the land or any part thereof". However, this section operates in the absence of any contrary intention expressed in the conveyance.

If you wish to change the watercourse

Plans for any works on ordinary watercourses other than general cleaning and routine maintenance (such as the removal of weeds or debris) must be approved by Calderdale Council as Lead Local Flood Authority. Consents for the work must be secured before starting any work. This applies to any modifications which might affect the flow characteristics or capacity, and includes the installation of dams, weirs, mills, channel diversions and, in particular, culverting or piping.

The Environment Agency has a page explaining your rights and responsibilities as a riparian owner in more detail. You can view this here: www.gov.uk/guidance/owning-a-watercourse

What happens if ordinary watercourses are not maintained?

The riparian owner must not cause or perpetuate a nuisance, such as creating obstruction to the flow of water in a stream by causing the channel to become blocked. Calderdale Council has no responsibilities (except where it is a landowner) for land drainage. However, it has permissive powers and can (but is not obliged to) serve notice on individuals and carry out works in default if watercourses have become blocked resulting in a flood risk or a health hazard. These powers are contained in the Land Drainage Acts 1991 and 1994, and sections 259 – 265 of the Public Health Act 1936.

Calderdale Council as Lead Local Flood Authority (LLFA) has a responsibility to investigate flood incidents under Section 19 of the Flood and Water Management Act 2010.

The LLFA also has powers under Sections 23, 24 and 25 of the Land Drainage Act 1991 with regard to issuing of consents, enforcement against un-consented works and general enforcement of riparian landowner duties.

The following is a summary of the most relevant sections of the Land Drainage Act 1991 to the Local Authority:

  • Section 14: Power for a local authority to perform works for the prevention or mitigation of flooding risk other than in connection with a main river or the banks or within an internal drainage board area.
  • Section 25: The power to serve notice on persons requiring them to carry out necessary works to maintain the flow of any water course, and the power to carry out works in default and recover its reasonable expenses should the riparian owner fail to carry out their responsibility.
  • Section 15: Disposal of or deposit matter removed from a water course on land adjoining the water course.