The Parson’s North project will redevelop an underused parcel of land with a paved podium and underground car park in a great location in Westminster, into a 20-storey residential block with a garden courtyard and spaces for shops. The site is located on the Edgware Rd in Maida Vale.
Our brief was to scope and obtain a detailed unexploded ordnance report, review the previous desktop studies and site investigation reports and provide a current phase 1 contaminated land desktop study with conceptual model, risk assessments and recommendations.
Photograph by kind permission of David Miller Architects and Photon Studios
The proposed development site is located on the side of the valley adjacent to a shaft and engine house for a former copper mine that worked between 1817 and 1874 producing almost 25,000 tons of copper ore. This site has also been used as a telephone exchange and radio hut during the war as well as a private workshop and printers.
It was an interesting challenge to attempt to offer pragmatic cost effective options for safe development for residential use. With risk of contamination and possibility of ground instability the structural integrity of the mine shaft, the surrounding wall and the nearby chimney all to be considered it certainly makes for an interesting project.
Our brief commenced with a phase 1 desktop study and continued through to the phase 4 verification report.
Elevated levels of hydrocarbons were found in one location, the affected soil was removed and testing undertaken around the perimeter of the excavation prior to refilling with clean material. In other areas the contaminants could be left in place and capped with clean soil in order to reduce the risks to an acceptable level.
During the course of the works an unsightly scrap yard was transformed into a very desirable development comprising four substantial detached dwellings.
The photos show the site before and after.
The proposed development for this vacant site was to comprise a two bedroom residential dwelling with associates parking and soft landscape.
Whilst doing a phase 1 desktop study we found a site nearby was used as a sewage treatment plant from around 1901 until 1950. The site was then used as a landfill between 1950 and 1970.
Prior to the Landfill site, now Jarman Fields, being redeveloped to its current commercial and leisure use a number of ground investigations were performed to assess the potential for landfill gas and land contamination issues. The investigations identified some elevated levels of landfill gas from the decomposition of fill materials, including domestic refuse.
A study of old survey plans shows a steep sided natural valley originally ran across the eastern side of the site in a north east to south west direction. From about 1950 this valley was gradually filled in with domestic refuse and builder’s rubble when the site was used for landfill tipping. This work ceased around 1970 when the valley was completely filled leaving a steep embankment across the SW of the site. No records of materials tipped have been discovered.
As a result of our investigation a specialist was engaged and gas protection measures were designed and installed.
Dunwich, also known as the lost city of England, was once a large international seaport and the medieval capital of East Anglia. The Doomsday book of 1086 records the population as 3000 however large storms in 1286 and 1347 destroyed a large portion of the town. After centuries of coastal erosion all that is left of this once bustling port is a small village.
Go Contaminated Land Solutions were asked to investigate potential contamination of the site due to flooding with sewage contaminated water.
Due to a combination of a tidal surge, high winds and heavy rainfall the site had flooded, and flood waters had entered the house. The floodwater had been contaminated by sewage from the local sewage pumping station, which is only a few meters from the property.
Some soil samples were taken from the front and rear gardens. A water sample was taken from the pond. One soil sample was selected for testing for e-coli as an indicator of sewage contamination. The test results did not detect any colony forming units.
Complete a Phase 1 Environmental Report to assess the risks to sensitive receptors both on and off-site due to soil and groundwater contamination as a result of the proposed development.
The proposed development is for a detached dwelling with a conservatory, a private garden and a detached garage, together with the associated gravel access drive and hard standing areas. The remainder of the site has areas of lawn and soft landscaping. Access to the property is gained via a dedicated entrance from Main Street. The Allerston Beck ran along the west boundary, this was an obvious sensitive potential receptor for any contamination on site. Gas monitoring, or installation of gas protection, was recommended due to the nearby brick field and clay pit.
Our brief was to undertake a phase 1 environmental report.
The proposals comprise the demolition two end of terrace properties and construction of a residential development of 37 dwellings
comprising four one bedroom units, twelve two bedroom units, thirteen three bedroom units and eight four plus bedroom units with associated car and cycle parking and landscaping.
The site use at the time of the walk over was partly residential and partly commercial, mainly vehicle repairs and spraying and some areas with abandoned cars.
The report concluded that it was likely some superficial contamination would be found and gave appropriate recommendations .
During the course of the walk over Japanese Knotweed was identified, enabling timely action to be taken to eradicate this invasive species.
This was a development comprising a single detached dwelling. The site had been developed previously for residential use.
Demolition of the former dwelling had been completed, the original garage was still standing, to be demolished at a later stage.
The draft phase 1 report was issued ten working days after receipt of instruction and the final report two working days later on receipt of final comments.
This mixed residential and commercial development comprised the conversion of a number of existing farm buildings. Staddlestone Barn and Long Barn were converted to form two dwellings and the Hayloft Barn was converted to form office accommodation. Associated landscaping and parking was provided, open “cart shed” garaging was erected and site entrances reconfigured.
Because of the past usage and proposed residential use a phase one environmental report and site walk over were undertaken. The potential for some site contamination was confirmed and an area of potentially contaminated fill material was also identified during the site walk over.
An intrusive phase two investigation was therefore commissioned comprising general sampling across the site and targeted sampling of the “fill” material. Contamination of the fill material was confirmed and a simple remediation strategy in the form of a barrier between the material and site users was developed and implemented.
One of the general samples from a proposed garden area showed elevated levels of lead.
In order to avoid unnecessary soil removal further testing was undertaken in this area for lead.
None of the additional samples had elevated lead and it was concluded that the one isolated exceedance of soil guideline criteria did not constitute a significant risk to human health and therefore no remediation was required.
Our brief was to provide a phase 1 environmental report and a flood risk assessment.
The site comprises the former British Legion building with its small service yards along Arklow Road. The site is in close proximity to a railway viaduct with immediate context made up of public open space, industrial and residential usage.
The development comprisec 26 apartments distributed over a block ranging from four to five storeys and including 348m² ground floor commercial floorspace. Associated with these are amenity roof terraces and balconies, together with car parking and cycle storage.
The Flood Risk Assessment found that the site lies within the flood plain of the River Thames but benefits from flood defences. There is a residual risk of flooding at the site due to the possibility of either over topping or a breach of the River Thames defences. In the FRA it was demonstrated that there was no significant risk posed to public health and safety by the proposed development.
There were concerns about possible contamination of the site by hydrocarbons from the adjacent vehicle repair workshop.
In order to comply with the tight timescale we:
dug trial pits,
installed boreholes with gas monitors,
collected and tested contamination samples
and issued our report less than one week after receipt of instruction.
This scheme involved the development of 58 units of one and two bedroom flats with the provision of two disabled units, all timber frame construction. Thirty-one of the units are for shared ownership with the balance being for affordable general needs housing.
Demolition of the public house which had occupied the site had been undertaken and a spoil bund placed around the site perimeter, subsequently fly tipping had occurred.
A review of the original site investigation showed that there was contamination of the site with heavy metals and polycyclic aromatic hydrocarbons. An initial site visit identified the presence of asbestos fragments and also Japanese Knotweed.
Testing was undertaken across the site to determine the extent of soil contamination and thereby minimise the amount of material removed to landfill. A thorough survey of Japanese Knotweed on site was undertaken, it was established that this was located in the spoil bund and the contaminated stretches were identified and removed to landfill, timescales did not permit on site treatment. Verification testing was undertaken and after sampling the imported topsoil a concluding verification report was prepared confirming the suitability of the site for the proposed use.
The scheme was handed over on 24 July 2006 and subsequently won ‘Housing Project of the Year’ by Builder and Engineering Magazine.