The South Acton Estate currently includes around 1800 dwellings in generally poor condition. Buildings on the estate rise many storeys higher than surrounding development with tower blocks surrounded by green space.
There are a significant number of mature Category A trees on site and the estate surrounds a hub of three primary schools and additional well-used community buildings.
The site is in the Environment Agency Flood Zone 1, i.e. at low risk of fluvial flooding, and features shallow secondary A and secondary undifferentiated aquifers in sand/gravel overlaying London Clay.
The main areas of risk identified for the site are building overheating and surface water runoff flooding.
The adaptation strategy is being developed on two levels:
- input has been provided during the development of the outline masterplan planning submission
- building modelling is being carried out to provide guidance for the detailed design of the individual development phases.
Further project details
1. What approach did you take in assessing risks and identifying adaptation measures to mitigate the risks?
Based on the headline impacts for London from UKCP09 we carried out an initial qualitative risk assessment using a likelihood vs. consequence matrix. This assessment found overheating (at masterplan and building level) and surface water flooding to be the main risks for the site.
Modelling was carried out with the aim to quantify the cooling benefit of integrating green and blue infrastructure at masterplan level. The aim was to compare the cost and benefit of different measures.
Modelling is being carried out on a house and a flat to quantify the cooling benefit of different measures (e.g. shutters, ventilation, thermal mass). The aim is to compare the cost and benefit of different measures and determine at what stage in the lifetime of the building the design measures would have to be integrated in the design.
Other areas, such as water consumption and materials resilience are considered important to ensure adaptability to climate change, however were not considered to require detailed modelling. In these cases qualitative guidance was provided during the development of the masterplan. Guidance will also be provided for the detailed design of future phases of the masterplan.
2. How have you communicated the risks and recommendations with your client? What methods worked well?
During the development of the masterplan two workshops were held with the design team to discuss the climate risks and potential design solutions to be integrated into the masterplan.
As the teams for the detailed design of the masterplan phases are yet to be appointed, the intention is to use the building scale analysis being carried out at present to produce a guidance document applicable to the Acton Gardens masterplan. The guidance is expected to include priority lists and checklists to guide the design teams in giving due consideration to adaptive measures during the design process.
The workshops were effective to discuss opportunities and constraints with the design team.
3. What tools have you used to assess overheating and flood risks?
- ENVI-met modelling was used to assess green infrastructure benefits at masterplan scale.
- IES modelling with Prometheus future weather tapes (based on UKCP09) was used to model overheating risk at building scale.
4. What has the client agreed to implement as a result of your adaptation work?
The work is still in progress. A strategy is evolving as part of the masterplanning and building typology development.
5. What were the major challenges so far in doing this adaptation work?
- Progressing the adaptation strategy at a suitable pace to provide input into the masterplan design.
- Finding an effective way of applying the impacts of masterplan level measures to the building level modelling (in relation to urban heat island effect and overheating).
- Fnding ways of using the climate projections available to model future surface water runoff risk.
6. What advice would you give others undertaking adaptation strategies?
Start thinking about adaptation at masterplanning stage, considering passive measures such as road and building orientation at early stages.
The time required for modelling of adaptive measures should be included in the design programme and take place at concept design stage.