Working with others – Adur and Ouse catchment

We have worked with a wide range of organisations with responsibilities for drainage, flooding and protection of the environment whilst developing our DWMP.  The organisations we worked with in the Adur and Ouse River Basin Catchment include:

  • West Sussex County Council
  • East Sussex County Council
  • Mid Sussex District Council
  • Adur and Worthing Councils
  • Brighton and Hove City Council
  • Crawley Borough Council
  • Horsham District Council
  • Lewes District Council
  • Wealden District Council   
  • The Environment Agency
  • Natural England
  • South Downs National Park Authority
  • The South Downs National Park Authority
  • The Adur and Ouse Catchment Partnership and member organisations including:
    • The Ouse and Adur Rivers Trust
    • The Sussex Wildlife Trust
    • The Woodland Trust
    • The Royal Society for the Protection of Birds
    • Inland Fisheries and Conservation Authority
    • Rural Sussex
  • South East Water


Working together to co-create the DWMP is important. Our drainage and wastewater systems are often inter-connected with the systems managed and operated by others and affect the natural environments within the catchment.

A wide range of issues and concerns have been raised and discussed throughout the development of the DWMP for the Adur and Ouse. These include:

  • It is challenging to find areas to implement SuDS in historic built up areas such as Brighton although there is potential to retrofit in parks and public areas and should be encouraged to address rain runoff issues. For example, raingardens are being installed in the Carden Avenue area.
  • Groundwater levels are high and cause both infiltration contributing to hydraulic overload and exfiltration of sewage into the groundwater protection zones. Private sewers are likely to be contributing to the issues. Wastewater systems need to be constructed to higher design standards to ensure resilience to high groundwater levels.   
  • There are clusters of flooding but generally these are quite widespread across whole area. Investigations are needed to understand whether hydraulic overload can be tackled at source in the upper catchments in the Downs as well as through separating rain runoff from the foul system. Highways authorities should be encouraged to incorporate attenuation tanks for the highway runoff.
  • Storm overflows are operating within permits but coastal areas and high quality bathing waters are critical to the local visitor economy. The impact of storm overflows and the volume of runoff in the sewers needs to be addressed by working with highways and the Council to find solutions.
  • Tide locking of outfalls can be an issue in some parts of the river basin catchment (RBC). This can affect capacity through siltation of the pipes
  • Blockages are common in built up areas. Smart technologies should be deployed to identify and proactively clear blocks before they create flooding issues as well as continuing with targeted customer behaviour change campaigns.
  • A review of the ‘Right to Connect’ policy for rural areas would be very valuable and it could be used to influence government policy.
  • There are numerous environmentally designated sites in the RBC . The impact of discharges that are hydraulically connected to designated Habitat sites  must be reviewed once the sites have been condition assessed by Natural England.

We are progressing these issues through the development of the DWMP as set out in our investment needs [link] for the Adur and Ouse. Further, we commit to working with others to co-develop and co-deliver schemes that meet multi-organisational objectives and which benefit the environment, our customers and communities.

We developed and ran a series of activities between 2020 and 2022 as we prepared our DWMP for the Adur and Ouse. The dates and purpose of the various webinars, workshops, meetings on individual wastewater systems and interim consultation were as follows:

The dates and purpose of the webinars and meetings



Regional webinar / River Basin Workshop / system meeting


25 Aug 20


Regional Webinar

What is a DWMP? Background and purpose

03 Sep 20

Regional Webinar

24 Sep 20

Adur and Ouse

Discuss the Risk Based Catchment Screening and Planning Objectives

16 Dec 20

Regional Webinar


Disseminate the BRAVA results for the National Planning Objectives

07 Jan 21

Regional Webinar


Jan – Mar 21

Meetings with West Sussex County Council, NE and EA


Develop the BRAVA methodologies for NN, GES, Surface Water, Groundwater & Bathing and Shellfish Waters. 

23 Mar 21


Regional Webinar

Disseminate the BRAVA results for the additional Planning Objectives included in our DWMP

31 Mar 21


Regional Webinar

11 May 21

Adur and Ouse

To explore the risks and potential investment options

August – October 21

41 wastewater catchment meetings covering 61 systems

To agree generic investment options

03 August 21


East Worthing

To discuss an appropriate investment strategy for each wastewater system, identify the options to manage and reduce the risks.

01 Sep 21


09 Sep 21

Peacehaven Brighton

16 Sep 21

Newhaven East

Sep – Oct 21

Interim consultation

To gain feedback on the SEA Scoping Report, the DWMP Processes and engagement and the  emerging plans for each RBC

01 Dec 21

Regional Webinar

Water industry funding

06 Dec 21

Regional Webinar

20 Jan 22

Regional Webinar

EA partnership funding

15 Mar 22


Adur and Ouse

To discuss and agree in principle the Investment needs

The regionally based webinars presented and discussed issues and information relevant across the whole or our operating region. You can view the presentations used in the webinars on our Who we’re working with page.

The presentations we discussed at the Adur and Ouse workshops are below:


Workshop 1
Held in September 2020, participants discussed the findings of the risk based catchment screening and proposed additional planning objectives for the DWMP. Workshop slides.


Workshop 2
Held in May 2021, participants:

  1. discussed the results from the BRAVA risk assessments and the proposed investment strategy for the wastewater catchments within the River Basin
  2. identified the generic options that should be explored to address the identified risks, and
  3. discussed which wastewater catchments to progress through the Options Development and Appraisal stage of the DWMP. Workshop slides.


Workshop 3
Held in March 2022, we reviewed and discussed the draft investment programme for the River Basin Catchment. This included the types of investment, priorities and timing for investment needs and the wider opportunities arising from the proposed investment in terms of partnership projects and catchment wide solutions providing multiple benefits. Workshop slides.

You can view the findings from our interim consultation.

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