Havant Road, Horndean: Total Engineering Support for a Major Housing Development

8 11 2017

Havant Road Horndean

Havant Road, Horndean, Hants: an excellent example of the total Highways and Drainage support package that The Stilwell Partnership provide for a major housing development.

From the Planning Application, to Approval, to Construction Drawings and Specification;

The Detailed Highway Design incorporates recommendations from the Transportation Assessment into a Section 278 agreement with the Local Highway Authority.

Site General

The Drainage Strategy provides a Sustainable Drainage (SuDS) solution, resolves surface water flooding from the highway drainage, includes bio retention systems for pollution control, and diverts a pumped mains foul sewer.

Footbridge

The project sheet has a drop down “accordion” format enabling the reader to get an overview of the development and select more detail on each of the specific stages:

  • Planning 1           Transportation Assessment and Travel Plan
  • Planning 2           Drainage Strategy and Flood Risk Assessment
  • Detailed Design: Planning conditions and Reserved Matters
  • Detailed Drawing and Construction Specification

The Horndean project sheet is now live on our website

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Drainage Strategy for Business Park prevents pollution from Fire-fighting event

7 11 2017

Toulouse Plant Limited proposed redevelopment of a 5,600m2 brownfield site at Littlebrook Business Park, north of Dartford.  The proposal comprised a materials recycling building, installation of weighbridges, offices, and ancillary buildings.  Their architects, March Design, submitted a Consultation to Dartford Borough and Kent County Councils.

The Stilwell Partnership were appointed to carry out a Flood Risk Assessment and develop a Drainage Strategy to submit with the Consultation.  The final Drainage arrangement had to prevent potential sources of pollution entering the groundwater, not just from normal operations, but to include catastrophic events such as a serious fire on the site.

Littlebrook Business park Schematic Drainage Layout

A Drainage Strategy considers all the many interrelated flooding and drainage issues associated with a development: Highway and Land drainage, Groundwater and Watercourses, Foul Water drainage, Surface Water drainage and Sustainable Drainage (SuDS).

The Environment Agency mapping service indicated the site is over a Minor Aquifer and is adjacent to a Ground Water Source Protection Zone.  Treatment measures would be included in the drainage network as appropriate to ensure that potential sources of pollution are prevented from entering the groundwater.

The Drainage Strategy considered the SuDS hierarchy and the best option was selected based on the underlying geology.  In this case, based on MicroDrainage calculations, buried attenuation tanks were proposed to take run-off from intensive rainfall events.  The tanks would gradually empty at a controlled rate into an existing private surface water sewer.

On site gradients and crossfalls were developed to accommodate the complex drainage arrangements.  Rainwater run-off from the roof areas would pass through a catchpit to trap the sediment content.  Surface water run-off from the parking/weighbridge area would pass through a bypass oil separator to remove pollutants and debris.

The Environment Agency requested that surface water run-off from the main yard passes through a full retention separator, to remove the potentially high silt content and debris with large sediment particles from the run-off, before discharging to the main foul water sewer.

Vehicle wash down effluent would be expected to contain high levels of pollutants. A specialised vehicle wash catchpit and full retention separator would be provided to treat the effluent before discharging to the main foul water sewer.

The Flood Risk Assessment revealed that the site is presently protected by existing off-site Environment Agency flood alleviation measures and is therefore categorised as within Flood Zone 3 (Defended)

The site is not expected to be subject to flooding provided those flood defences remain intact.  The report considered a breach of the flood defences and recommended additional flood protection (flood gates and doors) to the office and ancillary buildings, equivalent to the defence breach level plus climate change provision.  These additional measures would provide adequate time for any occupants to evacuate the site safely.

At a late stage in the process, Kent County Council raised the question of protecting the surface water drainage system in the event of a fire.  They required measures to be included that would prevent pollution bypassing the interceptors and washing into the sustainable drainage system.

It was proposed that in the event of a fire, shut-off valves would isolate the yard areas from the surface water drainage systems.  These areas have been “dished” to increase their standing water capacity.  Following a fire event, the client would use a temporary pump system to over-pump the fire water into the foul sewer before opening the shut off valves to their normal position.

In September 2017, Kent County Council accepted this proposal and lifted their objection to the development proceeding.

The Stilwell Partnership also produced a Transport Statement and Travel Plan for this proposed development.





Transportation helps Warfield Park Homes win Planning Appeal

4 10 2017

The Stilwell Partnership were pleased to be able to make a key Transportation contribution towards the success of this Appeal by Warfield Park Homes of Bracknell.

A Planning Application locating up to 82 mobile homes on their adjoining land, with suitable alternative green space (SANG), and informal open space, together with access improvements, landscape and diversity measures had been refused by Bracknell Forest Borough Council.

Warfield Park Homes appealed and on 27 September 2017, the Planning Inspector published the decision.  The Appeal was allowed and planning permission granted subject to conditions and a section 106 agreement.

One of the main issues considered by the Inspector was whether the proposed development would be in a sustainable location in respect of proximity to everyday services and facilities.

Warfield Sustainability Map

Transportation issues were carefully considered by the Inspector and described at length within the decision notice.  The Inspector considered the available facilities on site and the needs of future residents to leave the site for education and employment.

The Inspector considered the Stilwell Partnership’s Transportation Assessment (TA) and Sustainability Drawing in the context of current Planning Policies.  Referring to Providing for Journeys on Foot and Manual for Streets guidance, the TA had referred to acceptable walking distances and available public transport to reach off site facilities.  The TA also included a trip analysis to indicate the likely traffic generated by the development.

The Inspector concluded that “Whilst not well-connected, neither would (the site) be in a completely unsustainable location with no choice of transport mode or give rise to greatly increased car travel. In these respects, it would be consistent with the development plan.

The Stilwell Partnership were pleased to be part of the Project Team providing Transportation, Drainage and Sustainable Energy input to the proposed development.

The Inspector also considered the effect of the proposed development on the character and appearance of the countryside and commented “whilst the proposed development would encroach into the countryside, being similar in form and appearance to the existing development at Warfield Park, it would not be unduly incongruous or uncharacteristic”, and that “The biodiversity improvements over the remainder, and considerably larger part, of the appeal site would enhance its character.

The Project Team was led by GVA on behalf of Warfield Park Homes and included Woolf Bond Planning Consultants; HDA Enviro, Landscaping and Ecology; and legal services by Tozers Solicitors and 39 Essex Chambers.

 

 

 





The Jockey Club promotes Sustainable Travel for Cheltenham Racecourse

16 08 2017

Cheltham Racecourse New Stand

Stilwell Partnership are pleased to be appointed Travel Plan Coordinator by the Jockey Club for the prestigious Cheltenham Racecourse improvement.

The Jockey Club’s sustainability policy has ambitious targets for reducing energy, increasing the proportion of recycled waste, and minimising the impact of their business on the environment.

Their £45m investment for the new grandstand at Cheltenham Racecourse included the implementation of a Travel Plan.  The Travel Plan promotes alternative sustainable forms of transport for racegoers and staff travelling to and from the site.  Monitored and reviewed over a 10-year period by the Travel Plan Coordinator, the Plan sets challenging targets.  The aim is to reduce traffic congestion and delays, reduce CO2 and NOx emissions from vehicle exhausts and improve air quality.

As Travel Plan Coordinator, the Stilwell Partnership are responsible for the Plan’s performance, periodically reviewing the use of public transport, cycling, and walking to reach the site.  We would also be responsible for identifying further measure to improve uptake.  Results will be analysed and shared with the County Council Highway Authority, who are responsible for overseeing progress.

Advance publicity will provide a range of sustainable transport options so that visitors and staff can travel safely and efficiently to and from the course.  Options will include walking & cycling routes, public transport, and car sharing.  The location of car charging points for electric vehicles will also be provided.

Around 300,000 visitors attend the annual 4-day National Hunt festival in March.  In addition, an increasing number of visitors attend other popular race meetings throughout the year.  Outside these periods there is frequent use of the course facilities for conferences and exhibitions.

Implementing a Travel Plan at Cheltenham Racecourse provides valuable data that can used to further improve the uptake of sustainable transport elsewhere.  Successful techniques learned here may be introduced at other racecourses or sporting events around the country.

Go to our website project sheet





Derbyshire Development Wins Planning

12 07 2017

The Stilwell Partnership were pleased to help their long-standing client, Tapton Estates, win Outline Planning Approval for the proposed development of Derwentside Industrial Park, Belper, Derbyshire.

Amber Valley Borough Council unanimously approved the Application on 11 July 2017.

The scheme comprised the demolition and clearance of existing industrial buildings and re-use of the 6-ha site for 136 residential units.  The proposals also included access improvements and associated works.

Belper Tapton Master Plan

The Stilwell Partnership, with colleagues from the Patrick Parsons Group, put together a comprehensive package of technical assessments addressing many of the contentious issues and potential financial challenges facing development of the site:

The Transportation Assessment addressed potential future Traffic Impact and the long-term sustainability of the site.

The Travel Plan Framework provided an overall strategy to encourage sustainable transport measures; to increase walking, cycling, use of public transport and encourage more efficient car-use.

The Geo-Environmental Assessment examined the geotechnical issues on the site including ground conditions, potential contamination, and the building foundation requirements.

The Utility Constraints Assessment ensured there was adequate service capacity for future development without major investment in utility diversions.

The Flood Risk Assessment and Drainage Strategy confirmed that there was minimal flood risk on the site and that a foul and surface water drainage system was feasible within the capacity of local network.

The Noise Assessment considered the impact of noise from nearby roads and suggested mitigation measures that could be incorporated into future development.

On this proposed development, the Stilwell Partnership worked closely with the other project team members; David Lock Architects, FPCR Environment and Design Ltd and Rigby and Co, Commercial Property Agents.

If you would like to know more about these individual reports, or how we can deliver a successful one-stop package of services for your development, please phone our office on 0333 700 401 or email us

 





Nick Stilwell, Stilwell Partnership’s founder, celebrates 25th anniversary

24 05 2017

In May 2017, Nick Stilwell of the Stilwell Partnership celebrated 25 years in business. The Surrey based practice of consulting engineers has always “punched above its weight”, and over the years has made a major contribution to the disciplines of road safety, transportation, and highway engineering.

NJS Profile pic

Stilwell’s first client proposed a major development on a site in Holmethorpe. The site was locked within a triangle of busy rail lines with highway poor access.  Substantial infrastructure improvements, including a new rail bridge, were required to open the site for much needed housing.

To reduce the construction costs and potentially improve the viability of the development, the Stilwell practice introduced the traditionally risk-averse British Railways to a popular Swedish technique of rapid rail bridge construction.  This bridge construction technique has subsequently been adopted and widely used for many new rail bridges throughout the UK.

The Holmethorpe project was to play a substantial part in the growth and development of the practice.  For the next 20 years, the company progressed the project from Public Inquiry to Planning Consent and then through detailed design and construction, to completion.

Also in the 1990s, the District and Boroughs of Surrey had responsibility for the traffic management, road safety and highway engineering.  To improve efficiency, the Stilwell practice offered to take on their staff and provide a shared engineering resource for these Authorities.  This successful arrangement provided essential engineering services to several Boroughs including Surrey Heath, Elmbridge and also Surrey County Council.

meadows (1)

In this role, the practice wrestled with the worsening problem of traffic congestion and delays at busy or complicated roundabouts.  The conventional approach of building yet more roads or larger junctions was not a sustainable solution.  Therefore, the practice looked at new ways of reducing congestion by guiding motorists through the junction, quickly and safely, from the approach to their exit.

Experimenting with white lining and surfacing, the practice developed the Spiral road markings technique.  Initially trialled at Camberley’s Meadows interchange in 1995, the technique was so successful it was adopted as good design practice by the Department of Transport.

Spiral road markings continue to be used throughout the UK to reduce traffic congestion and improve road safety.  Many road junctions constructed today could not operate efficiently without that pioneering work by the Stilwell practice.

West wales airport

Responding to the requirements of public and private sector clients, the practice offered an increasing number of civil and municipal engineering services.

The practice was appointed civil engineer for the design and supervision of West Wales Airport improvement.  Part funded by the Welsh Parliament, this prepared the airport to become a centre of excellence for the development and operation of Unmanned Aerial Vehicles, (Drones).

In the summer of 2007, areas of the UK were subjected to the worst flooding for many years.  The Stilwell Partnership produced a strategy for Cheltenham, Gloucestershire, an area severely hit by the floods.  Using CAD systems, historic flood information from different agencies was combined to reveal weak spots in the surface water drainage network.

The practice continues to advise local authorities, developers, and parish councils on the potential impact of Flood Risk and flood alleviation measures.

Camera 2 FINAL

Most recently, the practice played a key role designing the highway junction infrastructure for the award-winning Pont Briwet road rail bridge in North Wales.

The Stilwell Partnership continues to make a significant contribution to Road Safety.  Nick Stilwell is a member of the Parliamentary Advisory group on Transport Safety, and the Association of Road Safety Officers.  In 2009, the Association presented the practice with the “Award for Outstanding Contribution”.

The Stilwell Partnership continues to promote good practice by sponsoring the Southern Region of the Institute of Highway Engineers.  In addition, Stilwell Road Safety, a not-for-profit venture, aspires to introduce a culture of Road safety from early school days throughout childhood and older to combat the increasing number of road deaths in the 17-25 age bracket.

The practice has been involved in many high profile and prestigious private and public projects over this 25-year history, and looks forward to meeting the challenges of the future.  In 2016, the Stilwell Partnership merged with a like-minded group of practices, the Patrick Parsons Group.





Construction & Environmental Management Plans

5 04 2017

Construction Management Plans (CMP) are increasingly required by Local Authorities as a condition of the Development’s Planning Consent.  CMP aim to reduce the impact of the construction operations on the local area.

Following many traffic road accidents involving construction traffic, these Plans also aim to identify potential hazards and identify appropriate road safety measures.

The Stilwell Partnership’s experience in Traffic Management, Road Safety and Highway Engineering has proved particularly applicable to the production of CMPs.

In London, a Construction Logistics Plan (CLP) is required. A CLP should improve the safety, efficiency and reliability of deliveries to that location.  It should also identify unnecessary journeys, and deliveries that could be made by more sustainable transport modes, to help reduce congestion and minimise the environmental impact of freight activity.  Particular emphasis is placed on road safety.

  • Oakforest Properties Limited had Planning Permission in the London Borough of Barnet, for four 2-storey family dwellings together with the formation of hardstanding to provide 5 car parking spaces. Existing buildings on the site were to be demolished. Planning Conditions were satisfied by our CLP in July 2016.
  • This small urban residential development for a private client in Paradise Street, Cambridge, satisfied Planning Conditions in February 2017 with our CMP which included additional consideration of Dust Management,
  • Our CMP produced for a 3 ha Solar Farm near Titchfield, Fareham, for Jardin Smith International and their Planning Consultant WSP Planning and Architecture of Reigate, successfully obtain Planning Consent in March 2017.

In each case, we carried out an assessment of the volume of traffic and types of vehicle.  Using Autotrack to model the vehicle swept paths, we checked the manoeuvrability of the construction traffic to negotiate the site access.

For larger sites, we identify suitable access routes for construction traffic from all directions.

App C TSP-LFH-P3025-02 – CMP Proposed Route

A major part of the Construction Management Plan concentrates on road safety of the other road users around the access and along the directed routes.  Highway sightlines and road conditions are assessed along the main access routes to determine what measures can be introduced to minimise the road safety risks to other road users.

Our full methodology to prepare a CMP including a Dust Management Plan considers the following:

  • The Site and Surroundings
  • The General Construction Strategy and Logistics
  • Site Waste Minimisation Measures & Dust Generation
  • Construction Management and Site Controls
  • Vehicle Types Required and Delivery Procedures
  • Mitigation Measures for Construction Traffic
  • Security and Health & Safety
  • Details of Any Hoardings
  • Materials and Plant Storage
  • Implementation and Monitoring
  • Pedestrian and Cyclist Safety
  • Consultation with Residents, Neighbours and Office Users

We have the experience to efficiently produce an effective Construction Management Plan, to the satisfaction of the Local Authority, and practical needs of the Contractor.