Flood and Water Management / Drainage

Surface Water Drainage and SuDS

Please note we are working on updating our documents. If you need a copy please contact us.

Milton Keynes Council is a Lead Local Flood Authority (LLFA) and as such is a statutory consultee to the planning process for surface water on all major developments. The consultation requirement and description of major development is detailed within the Town and Country Planning (Development Management Procedure Order). This applies to all new major planning applications. However it should be noted that Milton Keynes Council may also comment on non-major applications.

In assessing an application, the LLFA and Local Planning Authority will need to be satisfied that:

  • all proposals meet national and local policies
  • the proposed minimum standards of operation are appropriate;
  • a minimum standard is set out to which the sustainable drainage systems must be maintained;
  • through the use of planning conditions or planning obligations there are clear arrangements in place for ongoing maintenance over the lifetime of the development, including clearly identifying who will be responsible for maintaining the sustainable drainage systems and that funding for maintenance is fair for householders and premises occupiers

Flood Risk and Surface Water Policy Requirements

Plan:MK (the Local Plan for Milton Keynes) was adopted on 20th March 2019. As outlined in the plan, the early masterplan for Milton Keynes sought to reduce flood risk via the development of an innovative approach to flood risk based on a strategic water management system and planned green infrastructure provision.

However as outlined in the Level 1 Strategic Flood Risk Assessment (2015), there are a number of areas across the Borough at risk of flooding from various sources and it is expected that, even with no further development, the impacts of climate change are likely to increase this risk. It is therefore necessary that a robust and sustainable approach is taken to reducing and mitigating the potential impacts that climate change may have upon the area.

Policies FR1 – FR3 of Plan:MK includes locally specific strategic flood risk management policies to maintain and continue the exemplar sustainable drainage model of Milton Keynes which prohibits development within the floodplain and seeks flood management and drainage infrastructure to be provided as strategically as possible and as part of a maintained, multi-functional blue-green infrastructure.

Guidance for Developers

Milton Keynes Council has published specific guidance on the preparation of surface water drainage strategies (see below). This provides information on the level of detail we require depending on the type of planning application. The document should be used by all developers and their consultants who wish to submit an application in Milton Keynes.

Reviews of surface water strategies or flood risk assessments should be requested via our formal pre-application advice service, where a planning officer will provide their opinion and guidance on the likely outcome of your application.

Sustainable Drainage Systems (SuDS)

Sustainable Drainage Systems (SuDS) mimic natural drainage to manage surface water run-off from a development. SuDS allow for the collection, storage and treatment of surface water in order to reduce flood risk caused by development. SuDS generally replace traditional underground, piped drainage systems. The aim of SuDS is to keep water on the surface as much as possible. They can be integrated into both rural and urban developments.

Benefits of SuDS

  • provide the potential to re-connect societies with water, providing benefits for amenity, health and well-being
  • SuDS can provide new natural habitats, connecting nature and wildlife with urban environments
  • keeping water on the surface allows any problems to be identified and managed quickly. Management of SuDS features can generally be cheaper, less time consuming and more straight-forwards than conventional drainage systems

Strategic Flood Risk and Planning Documents

The following documents have been prepared by the LLFA.

  • strategic flood risk assessment 2015
  • local flood risk management strategy 2016
  • surface water management plan
  • water cycle study

Strategic Flood Risk Assessment (SFRA)

The Milton Keynes Strategic Flood Risk Assessment Level 1 2015 has been produced in partnership with other Local Risk Management Authorities and partner organisations including the Environment Agency, Bedford Group of Internal Drainage Boards, Anglian Water, The Canal and River Trust and the Milton Keynes Parks Trust, all of whom provided technical advice and data to assist.

The SFRA is an evidence-based document to assist in the preparation of the Site Allocations Plan and Plan:MK. It collected existing data on all sources of flooding and mapped this information comprehensively, also providing suggested objectives to be considered and utilised in preparing planning policy.

The SFRA should also be considered in the Development Management process. 

The main document including appendices can be viewed at: Milton Keynes Level 1 Strategic Flood Risk Assessment (April 2015) (PDF, 18.9MB)

You can also view the appendices containing all mapped data independently by using the following links:

  • Milton Keynes Level 1 Strategic Flood Risk Assessment (April 2015) Appendix B (PDF, 4.8MB)
  • Milton Keynes Level 1 Strategic Flood Risk Assessment (April 2015) Appendix C (PDF, 6.2MB)
  • Milton Keynes Level 1 Strategic Flood Risk Assessment (April 2015) Appendix D (PDF, 6.5MB)

It should be noted that whilst the maps presented here were produced using the most up-to-date information at the time of production, new information and mapping often becomes available.  It is therefore recommended that when preparing an application for development, as well as utilising the SFRA maps, the Environment Agency's "Flood Map for Planning (Rivers and Sea)" and "Updated Flood Map for Surface Water" should also be consulted.

Local Flood Risk Management Strategy

The Milton Keynes Local Flood Risk Management Strategy (LFRMS) was adopted in March 2016.

The adopted LFRMS can be viewed at:

  • Milton Keynes Local Flood Risk Management Strategy (2016) (PDF, 16.6MB)

A summary document of the LFRMS, and associated documents can be viewed via the following links:

  • Milton Keynes Local Flood Risk Management Strategy: Strategic Environmental Assessment, Environmental Report (February 2016) (PDF, 10.5MB)
  • Milton Keynes Draft LFRMS Consultation Response document (PDF, 86KB)
  • Milton Keynes LFRMS Summary Document (PDF, 1.2MB)
  • Cabinet 14 March 2016

What is the Local Flood Risk Management Strategy?

The Flood and Water Management Act (2010), gives unitary and county councils responsibilities for leading and co-ordinating the management of local flood risk, in their role as Lead Local Flood Authority. This includes a statutory duty to develop, maintain, apply and monitor a strategy for the management of local flood risk. To this end, Milton Keynes Council in partnership with consultants AECOM and other local flood risk management authorities and partners; have prepared the Draft Milton Keynes LFRMS.

The LFRMS sets out the Council's approach to managing flood risk from local sources in both the short and long term, outlining proposals for sustainable actions that will help to manage the risk in a way that delivers the greatest benefits to the residents, businesses and environment of Milton Keynes. It also outlines how Milton Keynes Council will work with others to manage all sources of flooding within the borough and neighbouring catchments. The Strategy is accompanied by an Action Plan setting out how to deliver the objectives of the Strategy over the next six years and a Strategic Environmental Assessment assessing the impacts of the Strategy on the Environment.

Hard copies of the documents were also available to view at Milton Keynes Council Civic Offices and all Milton Keynes Libraries.


Surface Water Management Plan 2016

Milton Keynes Council has, with the assistance of our partner Risk Management Authorities, prepared a Surface Water Management Plan (SWMP). The SWMP, which covers the entire administrative area of Milton Keynes, looks to understand the causes and effects of surface water flooding and establish a starting point for a long-term preferred strategy and action plan to manage surface water risk in the most cost effective way.

Through an initial risk assessment the SWMP has identified 13 critical drainage catchments (CDCs) which represent areas or catchments across the Borough at greatest risk. Further assessment was then carried out on each CDC to look at potential measures for alleviating the surface water flood risk and options appraisals were prepared to outline the preferred site-specific, and borough wide, measures which are most viable. Utilising this information, a long-term action plan has then been established to outline the actions required to implement the preferred options for each CDC.

The final report and its associated appendices can be viewed at the following links:

  • Milton Keynes Surface Water Management Plan Report (PDF, 11.5MB)
  • Milton Keynes SWMP Appendix A (Figures & Maps) (PDF, 36.7MB)
  • Milton Keynes SWMP Appendix B (Critical Drainage Catchment Maps) (PDF, 54.5MB)
  • Milton Keynes SWMP Appendix C (Options Assessment Tables) (PDF, 360KB)
  • Milton Keynes SWMP Appendix D (Combined Action Plan) (PDF, 107KB)


Water Cycle Study

As part of Plan:MK, the Council have produced Water Cycle Study (WCS).

The WCS (2018) assesses the planned future development of the Borough, as proposed in Plan:MK, with regards to water supply capacity, wastewater capacity and environmental capacity to ensure that both the water environment and water services infrastructure has the capacity to sustain the level of growth and development proposed. Any water quality issues, associated water infrastructure upgrades, and potential constraints as a result of the proposed development have been identified and reported.

The WCS then provides information at a level suitable to demonstrate that there are workable solutions to key constraints to deliver future development for all sites (committed and allocations), including recommendations on the policy required to deliver it.

The final draft version of the WCS can be viewed here: Milton Keynes Water Cycle Study (2017) (PDF, 1.7MB)

Section 19 - Flood Investigations

Under Section 19 of the Flood and Water Management Act 2010, Milton Keynes Council investigates flood incidents that meet the following threshold:

  • flooding has affected critical infrastructure for a period in excess of three hours from the onset of flooding.
  • internal flooding of a building has been experienced on more than one occasion in the last five years.
  • internal flooding of five buildings in close proximity has been experienced during one single flood incident.

 Download our Flood Investigation Protocol (PDF, 391KB)

Who are the risk management authorities?

  • the Environment Agency is responsible for managing risk from main rivers, reservoirs, estuaries and the sea.
  • Milton Keynes Council, as Lead Local Flood Authority, is responsible for managing the risk of flooding from surface water, groundwater and ordinary watercourses. Ordinary watercourses are all rivers and streams which are not designated as ‘main rivers’.
  • Milton Keynes Council also carries out flood risk management works on minor watercourses. As Lead Planning Authority we are responsible for controlling development in their area, ensuring that flood risks are effectively managed.
  • water and sewerage companies are responsible for managing the risks of flooding from drainage systems, including both their surface water only systems and combined sewer systems.
  • Highway Authorities are responsible for providing and managing highway drainage and roadside ditches, and must ensure that road projects do not increase flood risk.

Available Reports:

Independent Flood Review

After the surface water floods in Milton Keynes in May 2018 Cabinet elected to commission an Independent Flood Review. This review has been carried out by AECOM and has produced a number of recommendations for the council and its partner organisations. Acting upon these recommendations is intended to improve flood risk management, communications, and emergency response and recovery in Milton Keynes to support any future event.

We are in the process of revising our documents. Please get in touch with us if you need a copy.

The final report and appendices 

Independent Flood Review Main Report 

Annexes A-F - which contain:

  • Annex A – Detailed recommendations
  • Annex B – Stakeholder Engagement carried out as part of the review
  • Annex C - Resident Questionnaire
  • Annex D - Business questionnaire
  • Annex E - Rights and responsibilities
  • Annex F - Combined and summarised recommendations from the three section 19 Flood Investigations

Annex G (PDF, 9.1MB) which contains:

  • Maps of already proposed flood and drainage projects
  • Risk of flooding from surface water covering Stoke Goldington
  • Risk of flooding from surface water covering Newport Pagnell
  • Risk of flooding from surface water covering South and Central Milton Keynes

Annexes H-K (PDF, 1.7MB) which contain:

  • Annex H - Economic costs
  • Annex I - Asset management and maintenance
  • Annex J - MKC Highways department gully emptying reschedule
  • Annex K - Existing key actions from reviewed documents

The council’s response to the report is detailed in the 13th January Cabinet report which is available here:

  • Cabinet Report (PDF, 260KB)
  • Annex A – Progress against recommendations (XLSX, 33KB)
  • Annex B – Engagement Plan (PDF, 218KB)

Watercourse Management

The maintenance of watercourses plays a key role in managing water levels and reducing the risk of flooding. If you are planning to undertake works within a watercourse, you need permission to do so by law. It is essential that anyone who intends to carry out works in, over, under or near a watercourse, contacts the relevant flood risk management authority to obtain the necessary permissions before starting the work.

In relation to works on an ordinary watercourse:

Section 23(1) of the Land Drainage Act 1991 states

"No person shall:

  1. erect any mill dam, weir or other like obstruction to the flow of any ordinary watercourse or raise or otherwise alter any such obstruction; or
  2. erect a culvert in an ordinary watercourse, or
  3. alter a culvert in a manner that would be likely to affect the flow of an ordinary watercourse,

without the consent in writing of the drainage board concerned.”

Ordinary watercourses include every river, drain, stream, ditch, dyke, cuts, sluices, culverts, sewer (other than public sewer) and passages through which water flows that do not form part of main rivers. It is not required for water to flow at all times for it to be considered as a watercourse. The Environment Agency remains responsible for regulating activities affecting the coast and main rivers through environmental permitting.


Land Drainage Consent

When considering if the proposed works to an ordinary watercourse will require consent, you should consider whether it would affect the flow of the watercourse when the channel is full. If the answer to this is yes, then a Land Drainage Consent will be required. Consent will be required irrespective of whether works are temporary or permanent. Any form of development within 9 metres of an ordinary watercourse will also require prior approval. This includes landscaping works (fencing and tree planting) as well as any structures (e.g. development, utilities infrastructure, drainage features, outfalls etc.).

For ordinary watercourses in the Borough of Milton Keynes, outside an Internal Drainage Board area, the relevant authority is Milton Keynes Council.

To undertake works on or near to all watercourses in the Borough of Milton Keynes that are not main rivers you need to complete a Consent form for the Bedford Group of Drainage Boards (please select the form relevant to Milton Keynes Council) as they are responsible for issuing consents on behalf of Milton Keynes Council.


Landowner Riparian Responsibility

There are many other consents, permits and exemptions that you may need to apply for depending on the work that you are doing on your land. It is your responsibility to identify all the necessary permissions and licences required to maintain, repair, build or remove anything in or around a watercourse. The ‘Riparian Owner’ factsheet (PDF, 352KB) outlines your rights and responsibilities as a riparian owner.

Enforcement action could be taken against parties who carry out unapproved works or interfere with access required for maintenance of a watercourse.

Milton Keynes Council is a Lead Local Flood Authority (under the Flood and Water Management Act 2010) with a responsibility for managing the following types of flooding:

  • surface water Flooding – this includes flooding from rainfall runoff from surfaces such as roads, roofs and patios. For more information refer to the Surface Water Flood Risk Maps.
  • ordinary watercourses – this includes flooding from drains and ditches, but excludes main rivers that are managed by the Environment Agency. A map of the main rivers is available on the Environment Agency’s website
  • groundwater flooding – this includes flooding caused by heavy and sustained levels of rainfall capable of increasing the groundwater table.

What to do in a flood emergency

We have produced a handy five step guide to help you in the event of a flood emergency and what should you do.

Our main responsibilities as a LLFA include:

  • investigating and reporting on significant flood events in the borough
  • establishing and maintaining a register for all significant flood risk assets in the county
  • producing a Local Flood Risk Management Strategy to manage surface water, ordinary watercourses and groundwater flooding in partnership with other risk management authorities in the county
  • ensuring that new developments are designed and built in a sustainable manner which does not increase flood risk and which reduces flood risk whenever possible
  • consenting new work which affects the flow of ordinary watercourses
  • the power to request information relating to flooding from any organisation or individual
  • the power to designate significant flood risk assets or features, formally recording the feature as a land charge so that it cannot be removed without permission from Milton Keynes Council and can therefore continue to protect people and property from flooding
  • the power to enforce remedial works on unapproved construction work within ordinary watercourses or those not undertaking their landowner (riparian) responsibilities

If you are looking to report a flooding issue please use our Report blocked drainage or waterways form