Water sensitive design

Does the public realm manage water sustainably to minimise flooding, and promote passive irrigation?

The Ebbsfleet Implementation Framework identifies that the public realm will be shaped by following water sensitive urban design principles. The objective is to integrate water cycle management into the public realm through sustainable urban drainage systems (SuDS) to slow surface water runoff, to expand water storage capacity, to prevent water pollution, to create an added layer of flood resilience, and to add recreational value. The following principles should be integrated across the various public realm typologies to create a connected system that adds both visual interest and biodiversity to Ebbsfleet Garden City.

Recommendations:

1. Fit system to Topographic & Hydrologic Conditions

Ebbsfleet is characterised by a distinct topography, hydrologic conditions and catchment areas. Utilising the designer’s site analysis, the public realm should be designed following water sensitive urban design principles that build from the site’s existing conditions.

2. An Integrated Approach

Sustainable surface water management works best when it is implemented across various public realm typologies rather than in isolation. The goal is to develop a connected surface water management system that functions at a neighbourhood scale to collectively slow runoff and expand surface water storage capacity.

3. Use SuDs to Create Public Realm Value

Sustainable urban drainage systems (SuDS) should be designed to create recreational value and visual amenities. Distinctive SuDS features such as wetlands and rain gardens should be designed to enhance the recreational value of the parks and SuDS should be used to add value through its integration in street verges or use as gateway focal points.

4. Slow Surface Water Runoff to Prevent Flooding

Utilising swales, retention areas, rain gardens, and tree planting the public realm should be designed to slow surface water runoff and create an added layer of resilience against flooding. Using the recommended integrated design approach, SuDS should expand storage capacity and clean surface water runoff.

5. Rain Gardens & Planting for Water Fluctuation

Retention areas should be complemented by a planting strategy that can adapt to varying levels of water inundation and provide a qualitative landscape both in times of drought and seasonal periods of rain. Ideally, retention areas should take the form of rain gardens and use the provided planting guidance for rain gardens.

6. Plant to Enhance Local Biodiversity

Sustainable urban drainage systems (SuDS) and the proposed water bodies should be designed to enhance local biodiversity. This should be accomplished through the use of natural edges along water bodies, the use of native vegetation within rain gardens, the use of SuDS features to create connected landscape corridors.