Portsmouth, United Kingdom
City population: 514053
Duration: unknown – 2015
Implementation status: Completed
Scale: Micro-scale: District/neighbourhood level
Project area: unknown
Type of area: Other
Last updated: November 2021

Following a severe storm in 2000 that overwhelmed the sewage system of Portsmouth along with its main Wastewater Pump Station, causing major flooding in the city with the destruction of private and public properties, prevention of such events become a key priority (5). The Portsmouth Flood Alleviation Scheme aims to relieve the pressure on the sewage system in wet weathers by diverting the accumulated surface water flows away from the combined sewer networks and discharge them into the harbours around the island (5). The Scheme consists of several measures across the city, among others the creation of a new open watercourse channel across the Great Salterns Golf Course diverting surface water directly into Great Salterns Lake (5). This measure of the scheme is a solution that separates surface water to provide resilience, boost flood protection and benefit the environment with the minimum of new infrastructure (1).

New Open Channel at Great Salterns
Source: http://ftp2.ciwem.org/2014/delete3/2014-05/UDG7_Portsmouth%20Flood%20Alleviation%20Scheme_Presentation%20by%20R%20Taggart.pdf

Overview

Nature-based solution

  • Green areas for water management
  • Swales and filter strips

Key challenges

  • Climate action for adaptation, resilience and mitigation (SDG 13)
  • Climate change adaptation
  • Water management (SDG 6)
  • Flood protection
  • Stormwater and rainfall management and storage
  • Coastal resilience and marine protection (SDG 14)
  • Coastal protection / hazard mitigation

Focus

Creation of semi-natural blue areas

Project objectives

1. Divert surface water Quatremaine Road Catchment area from the Eastern Interceptor Sewer into the o Great Salterns Lake (5) 2. Complement and increase the surface water catchment capacity of the existing Great Salterns Drain with a new open watercourse channel across the golf course (5) 3. Reduce the risk of flooding of the golf course and the surrounding area in case of severe rainfall (5)

Implementation activities

- Creation of swales and channels sympathetic to the features of the golf course. (1)

Climate-focused activities

Climate change adaptation:

  • Protect coastal and freshwater ecosystems to prevent coastal erosion and pollution
  • Implement sustainable urban drainage infrastructure (e.g. to make space for water)

Main beneficiaries

  • Local government/Municipality
  • Citizens or community groups

Governance

Management set-up

  • Co-governance with government and non-government actors

Type of initiating organisation

  • Local government/municipality

Participatory approaches/ community involvement

  • Dissemination of information and education
  • Consultation (e.g. workshop, surveys, community meetings, town halls)

Details on the roles of the organisations involved in the project

The technical input was from MWH UK Ltd. as a part of the 4Delivery Consortium working for Southern Water (SW), Portsmouth City Council and the Environment Agency. (1)

Project implemented in response to ...

... an EU policy or strategy? Unknown
... a national policy or strategy? Yes (National Flood and Coastal Erosion Risk Management Strategy (NFCERM) and The Flood and Water Management Act 2010 (4))
... a local policy or strategy? Yes ( Portsmouth City Council’s Flood Risk Strategy (4))

Financing

Total cost

Unknown

Source(s) of funding

  • Public national budget

Type of funding

  • Earmarked public budget

Non-financial contribution

Unknown

Impacts and Monitoring

Environmental impacts

  • Climate change
  • Strengthened capacity to address climate hazards/natural disasters
  • Water management and blue areas
  • Increased protection against flooding
  • Improved stormwater management

Economic impacts

  • Unknown

Socio-cultural impacts

  • Unknown

Type of reported impacts

Achieved impacts

Presence of formal monitoring system

Unknown

Presence of indicators used in reporting

No evidence in public records

Presence of monitoring/ evaluation reports

No evidence in public records

Availability of a web-based monitoring tool

No evidence in public records

References

1. The Environment. (2016). Protecting Portsmouth. Website not available
2. Coterill T. (2017). Portsmouth £44m flood defences will protect thousands. Johnston Publishing Ltd. Accessed on November 12, 2020, Source link
3. McTaggart, R. (2015). Portsmouth Flood Alleviation Scheme. Accessed on November 12, 2020, Source link
4. Portsmouth City Council. nd. Local flood risk management strategy. Accessed on November 12, 2020, Source link
5. McTaggart, R. (n.d). Separating Portsmouth’s Sewerage System. 4Delivery. Accessed on November 12, 2020, Source link