Principles and layout guidance

Principles of green infrastructure design within highway

  1. Planting and associated infrastructure should be designed with an understanding of the local context and constraints, including the character and heritage of an area, adjacent buildings and spaces, the topography and views, vistas/ landmarks within and outside of the development site. Consideration should be given to local tree planting initiatives such as the National Forest.
  2. Existing trees and landscaping should be retained wherever possible and suitably protected during construction activity in accordance with the British Standard ‘BS5837:2012 Trees in relation to design, demolition and construction - Recommendations’.
  3. Trees, shrubs and hedgerows must be planted with sufficient space for them to reach maturity without the requirement for onerous maintenance intervention. Verges must be a minimum of 2m in width where they are to accommodate tree, shrub or hedge planting. 
  4. The focus should be on the quality of design and delivery rather than quantity – one well planted tree is hugely preferable to 100 poorly planned and planted that either die or become a significant maintenance burden. 
  5. Roads can create barriers to the movement of wildlife. Consideration should be given to creating designs that facilitate the navigation of highway. For example, poorly designed lighting can be a barrier removing the permeability of landscape for some species such as bats.
  6. An appropriate design must be developed and agreed with the council at the earliest design stage. The design must show the planting specification for all planting including hedges, shrubs, trees and herbaceous stock. The information provided will include the source of stock (i.e. from reputable nurseries with appropriate bio-security measures in place), numbers, planting locations, size, species, method of planting, preparation of planting beds and pits and a comprehensive after care program for an approved period of time.  This will help to avoid future maintenance issues, particularly regarding the integrity of the adjacent carriageway, footway and neighbouring buildings. 
  7. The design should be considerate of potential existing and future issues relating to underground services. 
  8. Careful consideration must be given to the design of landscaping to ensure that areas are not perceived to be impacting on personal safety or creating spaces for crime to take place. (See Principle 6 – Supporting Inclusive Highway)

Early Engagement and Preparation

Landscaping proposals should be prepared at the pre-planning application stage so the council can consider their suitability in good time and so the utility providers (for example, gas, water, cable TV) can be consulted over the proposals. Alongside the adherence to British Standards, early engagement (preferably at the pre planning stage) with the appropriate officers at the council and the local planning authority about green infrastructure proposals is critical. Planning authorities are unlikely to favour developments that lack quality design and layout. 

Additional Guidance including the Value of Trees Toolkit

The use of professional tools such as the Value of Trees toolkit and Trees and Design Action Group guidance should also be adopted during the design process.  Agreement of the design principles at an early stage will help reduce the risk of delay to technical approval and minimise future maintenance issues. The use of the value of trees toolkit will result in a discount to the commuted sum attracted for the future maintenance of trees within highway. 

Adopting Green Infrastructure

The council will usually adopt well-designed and planted landscaping on verges and other highway-related land providing that a commuted sum is paid to cover its long-term maintenance. The council will not adopt hedges that form a boundary with privately owned land. Other public space such as children’s play areas and recreation grounds are adopted at the discretion of the public authorities such as district and parish councils.

Need further information?
Contact
Development Approvals