Progress for White Cottage Development

23 11 2017

The Stilwell Partnership were pleased to have the opportunity to work with BCI Studio architects on the White Cottage development project for AMCO homes in Woking.  The development is now under construction.

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Our Drainage Strategy identified a solution to deal with the foul and surface water from the site.  The foul water would be drained by gravity into the nearby public sewer.

The site has no history of flooding and our drainage solution would have to ensure that there was no increased risk of surface water flooding from the development.  Discharge into an adjacent drainage ditch was permitted but at a restricted “greenfield” rate.

The Drainage Strategy considered the SuDS hierarchy and selected the best option based on a geotechnical investigation of the local ground conditions.

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Using MicroDrainage calculations, infiltration through the porous paving into the ground was utilised to take surface water run-off.

Our contribution ensured that the development can be satisfactorily drained and not increase the likelihood of flooding from intensive rainfall events.

Follow the link and find out more about our Drainage Consulting and Flood Risk Management services and EIGHT things you need to know about Flood Risk Assessments

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Other consultants involved with the project were Darren Evans and Associates, Energy & Sustainability Consultants, REC Environmental Consultancy and SMB Town Planning.

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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.

 

 

 





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.

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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.

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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.

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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.

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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.





Building For Schools: Resolving Highways & Traffic Issues

23 03 2017

We have added a new section to our website describing our specialist contribution to the Building for Schools Programme and our continuing efforts to improve Road Safety around schools.

The Stilwell Partnership have successfully supported many School Building projects throughout London and the South East.  Considering issues of road safety, traffic congestion and parking, we identify safe and sustainable access arrangements for pupils, parents, and staff.

Resolving Highways and Traffic issues may be the key to a successful Planning Consent.  Our contribution can smooth the project’s progress from initial Concept, through the Planning process, and onto successful Completion.

School Expansion

To help St Joseph Catholic Primary School achieve Planning Permission for their expansion in Ealing, our Transportation Assessment evaluated the traffic generation and car parking associated with the development.  We produced a School Travel Plan recommending sustainable transport measures to minimise the impact on the local road network.

Claremont Fan Court School in Esher, planned a new sports hall.  In addition to assessing the traffic impact we produced an engineering design solution for improvements to the access road, new car park and “section 278” improvements to the adjoining public highway.  To help implement their planned expansion we designed alterations to the site drainage network and carried out a Flood Risk Assessment.

Traffic and Parking Problems

Hart District Council in Hampshire was concerned with the continuing traffic and parking problems around a number of schools and the resulting impact on road safety.  We undertook site studies and proposed a range of traffic management measures to improve road safety in the area.

Stilwell Road Safety for Schools

The Stilwell Partnership has been innovating and pioneering road safety solutions for over 20 years.  Our not for profit social enterprise srsCULTUREforSchools aims to instil a lifetime of road safety culture to our children by improving attitudes towards the safety of self and others and encouraging safe behaviour in the road environment.

Other Successful Schools Project references

Ark Blacklands Primary Fleet Primary School
Ilford & Kingston Primary Grayswood C of E Infant School, Haslemere
St Blasius Academy Shanklin St Bartholomew’s School, Haslemere
Clandon C of E Primary Tweseldown School, Church Crookham
Yateley Primary The Charter School
Cheam High School The Royal Junior School
West Byfleet Infant School St Dunstan’s Primary School




Challenging Housing Development in Horley Gets Planning Consent

6 01 2017

Despite setbacks during the Planning process, perseverance pays off.  At the end of May 2014, WSP Architecture & Planning of Reigate submitted a Planning Application for a development of up to 46 high quality dwellings in Horley, Surrey. The development was to be located on land at the rear of an existing cul-de-sac, requiring highway access between existing houses.

The Stilwell Partnership were appointed to provide the following specialist engineering services for the Planning Application:

A Flood Risk Assessment & Drainage Strategy.  Developed in full consultation with the local drainage officer, the strategy ensured that the site complied with policy for restricting and attenuating surface water run-off, and reduced the risk of flooding in the wider area.  This was achieved through tactical spatial planning and widening of watercourses to provide additional flood plain storage in the west of the site, an area subject to historic flooding.

A Transportation Assessment and additional Highway design services.  The Transportation Assessment reported that the site was in a sustainable location with good links to public transport, shops, and employment opportunities.  The highway design proposed a 5.5m width carriageway with 1.8m wide footways on either side from the cul-de-sac to serve the new residential properties.  This also included improvements to the lane, a small roundabout and other sightline enhancements.

The Stilwell Partnership reports and design proposals addressing Flood Risk, Drainage and Transportation were accepted by the Local Authority without comment.  Despite this, in July 2015, Reigate & Banstead Borough Council rejected the Planning Application referring to Planning Policy issues.

An Appeal was submitted in January 2016, heard in October, and in November, perhaps about 3 years after the development was first conceived, the Planning Inspector allowed the Appeal.

The Stilwell Partnership are pleased to be associated with this successful outcome.

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