Successful Criteria for Public Open Spaces
The Context Appraisal process makes it unnecessary to require an arbitrary amount of green space for every home or for every development, as planning policies requiring this rarely take into account the extent of existing green space already serving an area. The result can be an ‘oversupply’ of green areas that are underused and which place pressure on the already overstretched ground maintenance budgets of local authorities. The requirement therefore is to provide green space that meets the needs of the new community and, if necessary, contributes to the improvement of the surrounding facilities.
If there is ample green space already within the vicinity of the site, no additional provision may be needed. However, where green space is provided it must be of a very high quality and should be:
- part of a wider network, connected internally and to its surroundings;
- overlooked by building frontages;
- well-maintained and appropriately managed, designed to support management aver a long-period of use;
- accessible to all;
- of high biodiversity value;
- of varied character and functionality to meet identified needs;
- able to offer opportunities for multifunctional activity for all;
- secure and safe;
- sufficiently well-designed and well-equipped as to become a destination – larger public spaces may be appropriate to support with facilities such as toilets an café’s to encourage people to spend more time in the open spaces;
- well-connected to walking and cycle routes;
- connected to smart infrastructure to encourage flexible use of the space for all ages and for a variety of activities;
- provisioned with seating and resting spots;
- legible to all users, with clear wayfinding; and
- provisioned with shelter and shade.
Every development is expected to make a positive contribution to the public space system through the provision of quality streets, green space or both, tested against the previously mentioned criteria. Green Space Strategies produced by Local Authorities will provide information on the wider green space provision and needs within an administrative area. However, the strategies are unlikely to include all public space, such as urban squares and landscaped streets, and all urban developments should therefore consider how the public space network at the smallest scale can link effectively with the public space network at the more strategic scale – from doorstep to countryside.
The local public space system should be mapped at a neighbourhood level within the Context Appraisal. In discussion with the Local Authority, the need for additional green space, its type and location, can be set against the baseline green assets previously identified. Every urban development should provide or contribute to public space and biodiversity and most should incorporate green space, linked as well as possible to the surrounding system.
Pocket parks, for instance, can be very small spaces knitted into the built fabric of a town that provide places for sitting and socialising; they can be particularly important for the ageing population and those with dementia. When such spaces are positioned close to the home, they are more likely to be used and can contribute to social inclusion and positive health impacts. They may be predominantly hard-paved, are usually too small for ball games and may include public art installations, which can aid in wayfinding. Small areas of grass can be difficult to maintain and should be avoided but, where appropriate, carefully chosen native planting can be used instead. The materials used should be suitable for use by all ages and levels of physical and mental ability, while planting should seek to stimulate a range of senses. The maintenance and adoption of pocket parks needs to be established and agreed with all relevant stakeholders. Such small-scale spaces often offer the greatest opportunity to integrate smart infrastructure and digital technology, making them more accessible and worth visiting for all members of the community. Examples of this include recycling or waste management points, open-access wi-fi networks, smart street furniture or innovative play infrastructure.
The quality of public space relies on a number of factors including:
- Security and safety
- Street trees
- Construction standards
- Public art
It is important to recognise that quality can only be achieved by adopting the same co-ordinated approach to design and detailing within the public realm as is required for the design of the enclosing buildings. All public space should be designed to be accessible: schemes should not provide segregated provision for less mobile members of the community, or those with physical or mental conditions.
Designing new spaces within a development provides a special opportunity to combine a consideration of these elements with a close attention to detail.
Understanding the power of scale within an urban context is vital. It can be used to create a sense of drama or visual intimacy or it can reflect the functional or symbolic importance of a place. It can be almost imperceptible or it can be striking – and it is these contrasts that help to define the character of a town.
Generally, the scale of a space ought to reflect its importance in relation to the area as a whole. Large-scale enclosed spaces must have a substantial civic meaning for them to make sense, and it is unlikely that many places in Essex will have more than one such space, usually at their centre. More common is the hierarchy of smaller-scale spaces that make up the spatial system – but even here, the same rule on symbolic importance applies. A mixed-use street, for example, needs to be wider and scaled to its functional commercial role. The space should be scaled to accommodate a greater robustness for user demands, as should the enclosing buildings.
In the same way, the scale of residential streets ought to mirror their place within the spatial system hierarchy. However, it is also important to ensure that these spaces are able to function without undue inconvenience or conflict arising between users; for example, they must be easily accessible by service vehicles.
A pedestrian-scaled environment relies upon achieving, in part, a degree of spatial enclosure that feels comfortable. The general ideal is for the width of a space to be equal to or less than the height of the enclosing buildings.
In practice, this can be difficult to achieve for lower density development, but it should become increasingly possible as densities and building heights increase. Higher densities therefore offer the potential to design spaces that are more dynamic and visually captivating than are typically found in lower density suburbs.
The enclosure and width of spaces will, of course, vary according to their function. The proposals found elsewhere in this guide for new street types and car parking provide the designer with a great deal of flexibility; it remains important, however, to keep a clear distinction between public and private space.
For example, it is possible to create a 14m-wide street (measured between building frontages) that combines on-street parking, a 6m-wide carriageway and 2.5m-wide pavements to each side. The height-to-width ratio for such a street containing four-storey buildings would be approximately 1:1.
Very narrow pedestrian spaces that link more important routes can add drama to the urban environment, but their design will need to take account of access for emergency vehicles.
Hard landscaping materials need to be aesthetically pleasing, structurally robust, with good weathering characteristics and simple maintenance requirements. These materials should be imaginatively applied so as to make places attractive, and sufficiently detailed that the surfaces are not easily damaged. It is therefore vital to assess the suitability of materials for the intended purpose before they are approved for use.
In the case of footways, materials must be able to withstand occasional vehicle traffic; in most cases, a footway should be able to withstand the axle loads of commercial servicing vehicles (approx. 8200kg = 1 standard axle).
Different surface materials can be used to sub-divide large areas of hard surfacing so as to create different spatial effects or to define routes and areas of different use. However, incidental changes in material or colour to identify land ownership or responsibility for maintenance are not acceptable.
Generally, the highest quality materials (such as granite setts and yorkstone paving) should be reserved for locations of special significance. For example, urban or neighbourhood centres and squares which are designed to attract people in large numbers should ‘show off’ their civic importance through the use of more expensive materials. Elsewhere, a limited and subtle palette of materials, sizes, shades and textures should be used as a backdrop to street activity and architecture. At the same time, there are opportunities for innovation in terms of the materials used in the public realm – for example, smart technology integrated into the public space can allow for the collection of energy generated through pedestrian footfall on hard landscaping; this can then be returned to the local power grid. The Highway Authority needs to be consulted and must approve all matters relating to existing and proposed highways, including materials. Commuted sums will be sought for the use of materials that require more costly maintenance.
The provision and type of ground surfaces should be considered from the outset of any new development, and an approach taken that enables the development to strike an appropriate balance between meeting the needs of all users over its lifetime, without the need for adaptation in the future, and addressing the technical requirements and future maintenance of highways.
Consideration needs to be given to the colours, patterns and types of surface used for ground cover. A varied mix of colours can be confusing for people affected by certain health conditions, including dementia, where black and/or dark colours can be viewed as holes, trip hazards or barriers. On a related note, a variety of patterns can create the illusion that there is no clear route to follow, and result in disorientation and anxiety.
Consideration should also be given to the potential for conflict between the provision of tactile surfaces designed for the blind or partially sighted, and the implications of such surfaces on accessibility for less mobile people, who may be using wheelchairs, mobility scooters or walking aids.
As a general rule, the quality of the design of public space is more important than the quality of the materials used. A well-designed scheme would not necessarily be compromised by the employment of simple, inexpensive materials, whereas a poorly designed scheme does not become successful through the use of expensive materials. It is therefore more cost-effective to engage competent design teams for public space than to rely upon the specification of elaborate paving.
Treatment of Ground Surface
The ground surface is one of the enclosing planes of any space. It can therefore be treated in such a way as to complement or contrast with the character of the space and its enclosing planes. It may have a greater or lesser proportion of hard paving to soft planting, and it may be designed in a more formal or less formal manner.
For example, a wider space may have a higher proportion of soft or planted surface area, as otherwise the space would be dominated by a monotonously large expanse of paving. A tighter, more enclosed space may be hard-paved without creating the same negative effect.
A continuity of materials between paving and the elevations of buildings will give a strongly unified effect to a space. Where there is opportunity within a development, flexibility should be integrated into the design of existing hard landscaped areas, such as on-street parking and parking courts, so that such spaces can be converted into parklets or small green spaces should the space no longer be deemed necessary for vehicles in future. This is particularly important in urban, built-up areas where the amount of available green space can be limited.
The quality of the public realm can be badly impacted by poor attention to detailing, both in terms of aesthetic appearance and functional accessibility. Where this occurs, it is often because there has been a failure to apply some of the basic requirements of good design, such as working in close collaboration with other design disciplines and utility companies. It can also be a result of inadequate on-site supervision of contractors.
Detailing should be considered as an integral part of public space design, to include:
- Junctions between materials, kerbs and crossings and changes in direction of paving
- Location and orientation of manhole and access covers
- Columns, poles and ground fixings and the design of paving around them
- Integration and pattern of tactile paving
- Tree pits, root barriers and irrigation
- Combining and grouping of signs and street furniture
- Location and design of drainage gullies and grilles, where technically possible
- Design of falls
- Road markings
- Paving textures
Underground ducting for utilities and services should be incorporated into new highway construction wherever possible. Refer to the ‘Streets and Roads’ section of this guide for more information on ducting and services provision.
Ducting has many long-term benefits, including reduced maintenance costs and increased longevity of highways. It is best applied to new developments as and when services are branched off from the main utility supply line. Where streets are not adopted by the Highway Authority, easements should be put in place to allow for access by third parties for works and repairs.
Routes and the futureproofing of services should be planned early in the design process, so that manholes and access cover locations can be co-ordinated with surface finishes and aligned with block paving. Where alignment is not possible, round covers should be used.
Where legal adoption or ownership boundaries need to be marked on the ground, the preferred option is the use of small metal studs. These studs can be of any non-ferrous metal fixed at 1m intervals to the relevant hard surface. The maintenance of such boundary indicators will be the responsibility of the developer, landowner or management company. The paving material should always be continuous between building or garden front and the road kerb.
The preferred method for introducing tactile paving into the footway for the benefit of the visually-impaired is a blistered surface that replicates the surrounding paving material, laying pattern and colour – avoiding random, patchwork footways. Alternatively, milled granite studs can be incorporated into the paving.
It is important that, for large development projects brought forward by a number of different developers or in regeneration areas where the entire network is to be upgraded, the design of streets and the choice of materials are consistent and logical across the entire area. In these circumstances, continuity in design and material use is essential.
A level of consistency can be achieved by adopting design codes for the public realm developed in conjunction with an area Master Plan. Special consideration should be given to the transition between a new area of public realm and the existing public space network.
Consideration needs to be given to how the existing landscape relates to that of the proposed development allowing a better transition between the new development and existing areas.
Page updated: 9/02/2018