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.

TWC_view03_02

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.

TWC_view02_4

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

TWC_View01

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

Advertisements




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.





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