Ruislip – Park Wood and Pinn Meadows Flood Partnership

Closes 22 May 2021

Opened 23 May 2019


Updated: 15 February 2021

Key updates


Coronavirus is affecting us all, presenting significant challenges and demanding adaptive ways of working. The situation is constantly developing and changing and it is essential that we observe and comply with the UK Government’s restrictions.

For the Environment Agency, this means that we are not currently holding face-to-face public consultation events as we would normally do. In light of this, we are setting up an engagement portal – Engagement HQ – and will post more details once it is up and running. This will contain further detail about what’s happening in your local area and how to get involved.

We hope to launch this in March and our next update will introduce this engagement portal, and explain how we will be using it to engage with you on the project in the coming months.

Groundwater monitoring:

We have been working with Jacobs and BAM Nuttall on scoping some groundwater monitoring work. This is part of the Geotechnical activity listed below and will enable us to better understand the groundwater levels in the area.

Flooding from groundwater can happen when the level of water within the rock or soil that makes up the land surface (known as the water table) rises. The level of the water table changes with the seasons due to variations in long term rainfall. When the water table rises and reaches ground level, water starts to emerge on the surface and groundwater flooding can happen.

We are aware that this type of flooding is an issue in the Ruislip area and we need to fully understand it before we can confirm the type of options for managing flood risk that will be appropriate.

Appraisal timeline:

As we stated in our last update, the Environment Agency is now in contract with 2 delivery partners (Jacobs and BAM Nuttall) for this project. These contracts are progressing well but there have been some minor delays which are reflected in the updated key activities timeline below.

  • Appraisalthe appraisal phase of the project culminates in the identification and outline design for a preferred option and approval of the Outline Business Case (OBC). The OBC details the appraisal work on the short listed options and the selection of the preferred option to be taken through a Full Business Case (FBC) and detailed design. The OBC also provides an update on costs and benefits and a delivery plan using the HM Treasury Green Book and Five Case Model.
  • Engineeringdesigning the options in more detail to make sure that they are technically feasible and buildable.
  • Environmentbetter understanding the local environment so that we can make sure any options we propose enhance the surroundings for people and wildlife and that we minimise the project’s whole life carbon footprint.
  • Geotechnical studying ground conditions to make sure the proposed options will be suitable for the area.
  • Hydrology and hydraulic modellingcreating a simulation of the area so that we can better understand the way that water flows in times of flood, and to enable us to determine what benefit the options we propose will provide to the local community.
  • Economicsworking out the costs and benefits of the preferred options so that we know how much they will cost and the additional funding we need to find to enable the project to progress.
  • Engagement on optionswe are engaging with key community representatives throughout this project phase, but once we have more detailed options to share we will consult with other local communities and businesses.
  • Outline Business Case (OBC) Approvalthis is the final approval point for this phase of the project, and if successful allows preparations for construction of the preferred option to begin.

Option development

The responses to the consultation we held in 2018 and engagement with communities has shown us that people want to see more detail about how the options will affect them. The work we are doing now will continue to develop our understanding of how the options need to be designed to be most effective. The project team will continue to work with communities to develop these options and our new engagement portal will give us the functionality we need to be able to do this effectively during the current Coronavirus working arrangements.

The information below on the “quick wins” and natural flood management has been updated. This is work which is happening now. We will be able to provide more detail on the wider project options as part of our launch of the engagement portal in the coming months.

Quick Wins:

These are small options which were suggested by local residents and the council - to help reduce the risk of flooding in the short term, whilst the project team develops options as part of the wider project.

The council developed an initial list of quick wins in consultation with residents and the wider project team. These were prioritised depending on the reduction in flood risk they provide and the speed at which they could be implemented. The council have scoped these prioritised elements in more detail and the Environment Agency have granted a permit to undertake these works. The project is contributing £25,000 towards delivery of these quick wins in addition to the funding and resources provided by the council to deliver these works.

These quick wins will help to provide more space for water along the river and slow the flow of water to the river and help reduce some of the regular flooding experienced by communities. These works are to be undertaken early and in addition to the wider project options, which are looking at ways to manage flood risk longer term and for more extreme flood events.

Natural flood management (NFM) in Park Wood:

You can find the latest updates on Hillingdon's project to deliver NFM in Park Wood (part of Ruislip Woods SSSI and National Nature reserve) on Thames21’s website at where you can sign up to join in and help your local community. You can also find more information at

Constructing the leaky dams has commenced and will continue over the next 3 months to build a network of structures. The project has created a network of leaky dams that slow the flow from the woods towards the River Pinn (see picture below taken on the 28 January 2021). This work is fully funded. The Ruislip Woods Management Advisory group intend to continue constructing leaky dams across Park Wood in the future.

Photo of one of the leaky dams holding back water on 28 January 2021

All the information and data residents have provided on the woods and how water flows through the woods is collated by Hillingdon and Thames 21 and is provided on a regular basis to the project to help inform wider works. The council, as part of the NFM work, are modelling this area.

Alongside any NFM, an embankment will likely be required. We have taken on board feedback on initial suggestions of location, and the precise scale, location and design of this will be based on the assessment of the benefit of the NFM to the area. We will continue to work with residents and local interest groups in this area to consider the best approach for the local environment.

Once we better understand the benefits and costs of NFM, we will be able to make a decision about the best way to further reduce flood risk.

We have updated the information below, including the overall project timeline to give an overview of the current project progress. If you have any questions about any of the information in this update, or ideas for information you would like to see in future updates, then please contact the project team at


Communities in the River Pinn catchment have experienced flooding several times. According to our records, flooding has affected different parts of the catchment in 1947, 1968, 1977, 1984, 1986, 1987, 1988, 1992, 1993, 2000, 2002, 2009, 2012, 2013, 2014, 2016, 2018 and 2019.

The flooding in 2016 was the most severe in this area in recent memory. The photographs below show the impact this flooding had on some of the local communities. According to Environment Agency records, flooding affected as many as 50 properties in June 2016 but many more are at risk in case of a bigger flood event.

Photos above show flooding in Brook Drive and Park Avenue in 2016.

As recently as 1 October 2019, communities have experienced flooding in this area. The photographs below show the impact that this flooding had in Brook Drive and on Pinn Meadows.

Photos above show flooding in Brook Drive and on Pinn Meadows on 1 October 2019

Project overview

The project team, which consists of the Environment Agency, the London Borough of Hillingdon, local community representatives and Thames Water are working together with the Environment Agency’s delivery partners to understand the causes of flooding in the Ruislip area and to identify the best solutions to reduce the risk in the future.

Ruislip - Park Wood and Pinn Meadows, for this purpose, is defined as the area shown by the image below. It includes Park Wood to the north, Kings College Playing Fields, Pinn Meadows and the communities affected by flooding in the local area.

Project objectives

  • Better understand the risk of flooding in the Ruislip – Park Wood and Pinn Meadows project area
  • Collaborative with others to develop flood reduction proposals which maximise benefits for people and the environment
  • Work with local communities to help them understand what actions they can take to be more prepared for flooding
  • Work with our partners to secure additional funding from other sources to help us deliver viable projects
  • Provide an online engagement platform to ensure stakeholders are effectively engaged throughout the pandemic

How you can help

  • Tell us how you have been impacted by the River Pinn flooding
  • Tell us about your local knowledge of the environment and flooding
  • Report flooding to Hillingdon Council, and sewer flooding to Thames Water (links at the bottom of this page)
  • Let us know if you have any questions or are part of a community group that would like to work with us
  • Champion the projects locally
  • Help us identify additional sources of funding

Please understand that these proposals will not eliminate the risk of flooding altogether, only reduce it.

In addition, we will design the options to ensure that we do not increase flood risk to communities in other areas. When building flood defences there is a legal requirement that they cannot increase the flood risk of communities either upstream or downstream, and if an increase in risk is identified, it must be mitigated. 

Work to date

Work on this project up until 2019 was focused on drawing together what we know about the flooding and how it happens, from different sources to identify potential options for managing the risk. This included looking at previous studies and gathering knowledge about the flooding issues. We have gathered information from Environment Agency records, communities, the council and Thames Water.

We also improved our understanding of the area as a whole through both consultation and engagement with communities. We now appreciate better what local people think is important about the area and the importance of local sites like Park Wood, both locally and nationally.

The “River Pinn Initial Assessment Report”, which summarises the work completed before our consultation in March 2018, is available as a PDF at the bottom of the 'River Pinn project information page' here. The summary of our March 2018 consultation is also available to download here. Please note that the costs included in this report are an indication only and will be revised to make sure they are realistic as we develop the options in more detail. This report was the start of the process, identifying options for the River Pinn catchment as a whole. We are now refining the options for the Ruislip area.

Project timeline:

Below you can see an updated timeline for the overall project.

Ruislip – Park Wood and Pinn Meadows project timeline – January 2021

Working with communities

Since March 2018, when we carried out our formal consultation on our option ideas, we have been keeping communities up-to-date through these webpage updates and meeting with local community groups. There are two flood action groups in the area, representing their local communities on the project team. These are:

  • North Ruislip Flood Action Group, covering the area to the north of the River Pinn, including Broadwood Avenue, Park Avenue and Park Wood
  • Evelyn Avenue and Brook Drive Flood Action Group, covering the area to the south of the River Pinn including Brook Drive, Evelyn Avenue and Brook Close

We are also actively engaging with the Ruislip Residents’ Association (RRA) and Ruislip Woods Management Advisory Group (RWMAG) to make sure that these groups understand the project and can take the latest information back to the communities that they represent.

Since June 2019, representatives from these groups have been a formal part of the project team structure and attend monthly progress meetings. This approach makes sure that the relevant local people are involved in any decisions taken, understand the project progress better and keep the communities they represent fully informed. These meetings will allow the project team to consider local community requirements in any options to manage flood risk.

This approach will supplement, not replace, the updates to this webpage. We will also continue to carry out wider engagement with communities to make sure that everyone who is potentially affected by the options to manage flood risk has access to the latest information.

In September 2019, we published an article in the Ruislip Town Crier to help us get information about the project out to a wider audience. This is available as a downloadable PDF here.

We will be building on these relationships in the coming months and will be using these networks to make sure that information is circulated to the wider community. The Environment Agency’s Lucy Allard attended the Ruislip Resident’s Association AGM on 26 September 2019 to provide an update on our work to manage flood risk in the Ruislip area.

If you would like to become part of one of the flood action groups listed above, or would like to get in touch with them, please contact the following:

Brook Drive, Evelyn Avenue and Brook Close flood action group:

North Ruislip flood action group (Broadwood Avenue, Park Avenue and Park Woods):

What happens next?

We are entering an exciting phase for the project and we hope to soon have updated options to share with local communities. This has taken longer than we hoped, but later in 2020 we will be able to confirm when consultation on these options will be able to take place, and what format this will take.

In the meantime if you have any questions about the project, please email the project team:

The project team will also continue to work with communities and other partners to secure funding for this project. It is currently partly funded by central government, but there is still a need to find more funding, for example from organisations and businesses that will benefit. We can only progress to the point where we are ready to undertake work on the ground if we have secured full funding.

Over the next few months, you may notice Environment Agency staff and consultants visiting the area around the River Pinn in Ruislip. They will be gathering specific information about the river and the surrounding environment. As outlined above, there will also be some contractors on site putting in some groundwater monitoring. We are unable to confirm when the dates for all these visits will be, however, the project team will continue to organise specific joint site visits with members of the public and our consultants at key points during the project (subject to coronavirus restrictions).

Reporting Flooding

After an event, where there has been significant flooding (internal property flooding) the councils have a duty to undertake a Flood Investigation so please report issues to them.

For Hillingdon you can find more information at or contact them on

They will ask if you are happy to share the data you provide with the Environment Agency and other partner organisations in order that we can better understand the flooding issues.

It is also important, if you have been flooded from a public sewer to complete Thames Water's sewer flooding questionnaire on their website here and return it to them at the address on the form.

Flood insurance

The insurance industry launched the Flood Re scheme in April 2016 to help households in flood risk areas to find affordable home insurance.

Flood Re is a joint initiative between the Government and insurers. Its aim is to make the flood cover part of household insurance policies more affordable.

More information on how this works is available on the Flood Re website:

Thank you for visiting our project information page. For any comments or feedback, or if you would like to be kept updated please email our dedicated project email address to be added to our mailing list:

We will be updating the information on our website more regularly throughout this appraisal stage. Our next webpage update will be in March 2021.

Visit our website here to find out more about what you can do to reduce the impact of flooding on you and your property.

Find out about your rights and responsibilities of owning a watercourse here.

If you have been flooded from a public sewer, please complete Thames Water's sewer flooding questionnaire on their website here and return it to them at the address on the form.

If you'd like to be kept updated, please complete this form here.


  • Recreational and commercial river users
  • Members of the public with an interest in the river, the species and conservation
  • Businesses
  • Charities
  • Statutory organisations
  • Members of the public
  • Elected representatives, including MPs
  • Local councils
  • Environment Agency customers
  • Local authorities
  • District and parish councils
  • Environmental bodies
  • Land owners
  • RFCCs
  • Water companies
  • Members of the public
  • Community groups
  • Flood action groups
  • Members of the public
  • Community groups
  • Members of the public


  • Flood management
  • Water resources
  • Habitats and wildlife