In this Issue:
The Warewithal : Housing shortage, PI Insurance, office refurbishment
Focus: FWRA for piling in Hampshire
Case Study : The importance of DQRA's
Other News : Local Careers Fair and end of year
With Brexit looming, who knows what the effects will be on the British economy. The Guardian in Nov 18 highlighted that in 2017-18 there were 1.25million families on the waiting list but only 6,463 homes were built. What seems to be the case is that the demand for housing in the UK will remain regardless of the outcome of Brexit.
Fast tracking sustainable developments via a "presumption in favour" is at the heart of the National Planning Policy Framework, but we are yet to see this put into practice. Brownfield land could be argued to be the most sustainable supply of land for redevelopment and therefore a simple solution to the housing crisis could be to fast-track brownfield development schemes through the planning process. Sustainability Appraisals could be submitted with planning applications to provide the justifications for a development to be fast-tracked through planning.
We have recently renewed our PI insurance and were taken aback by the 3x increase in our premium, which apparently is largely due to the Grenfell disaster and having less underwriters in the market. We took the decision to keep our level of cover the same, but things are tightening up on reassignments and limits of liability offered.
This autumn we updated the downstairs portion of our building, creating a new kitchen, two new office rooms and a new stores which has definitely improved the workspace. Pop in when passing and see if you can locate yourself on our map of Tring on the kitchen wall.
Focus - FWRA for piling in Hampshire
WDE have recently assisted in the remediation of a former industrial site in Hampshire which has enabled the Client to reappraise their foundation design, thus saving a significant amount of money.
The contamination was previously located predominantly within made ground sitting above a layer of clay which was acting as an impermeable barrier preventing downward migration of contamination into the Principal Chalk Aquifer. The site is situated within a Source Protection Zone 1 so it was essential, whilst contamination was still present, that no additional pathways into the aquifer were created which enable contamination of the groundwater resources.
Remedial actions included the excavation and treatment of ~1,500m3 of hydrocarbon impacted materials, followed by onsite treatment via windrows/biopiles.
Prior to remedial action, the Client had designed a complex and expensive shallow foundation design comprising rafts, assuming that piles would not be acceptable. Following the removal of the contamination, WDE proposed that piled foundation could now be considered and prepared a Foundation Works Risk Assessment (FWRA). The various stakeholders reviewed and commented on the FWRA and agreement in principle has now been achieved for piled foundations, subject to additional investigations and monitoring being completed.
|Case Study - The importance of DQRA's
In late 2018, WDE were asked to investigate a site in the Chilterns which had previously made up part of a wider Paper Mill. The site was situated on a Principal Aquifer of Chalk with a river distance of ~100m. Following completion of the site investigation, limited elevated non-volatile contaminants were identified within the made ground and Total Petroleum Hydrocarbons (TPH) were encountered within the groundwater onsite which were elevated above the published target values. From the observations onsite and laboratory results it was evident that there was not any gross contamination onsite, but further assessment was recommended in the form of a Detailed Quantitative Risk Assessment (DQRA).
By completing a DQRA we are able to generate site specific criteria values, based on actual site information, rather than having to utilise published conservative criteria. The risks to controlled water were assessed using the Environment Agency’s Remedial Target Methodology (RTM), following which the calculated remedial targets were demonstrated to be higher than site concentrations. WDE were therefore able to justify that there was no requirement for any remedial works onsite associated with the groundwater and that pathway control measures would be adequate for the protection of human health from the elevated non volatile contaminants in the shallow made ground.
It is important to remember the importance of deriving site specific criteria which could end up saving money on a project in the long term by removing an element of conservatism built into Generic quantitative risk assessment. At WDE we complete DQRA as standard within our Remedial Strategy Reports.
WDE are out in the local community this January supporting Tring School's Career Fair, providing students, parents and teachers with an insight into what we do and possible careers in earth sciences. The Geography teacher (Jennah Alder) took a big interest in the soil cores we brought along (see below) and a big thanks goes to her for organising the event.
We stayed local for our own festive celebrations and the close of the calendar year. Tring has much to offer and we were spoilt with different venues for cocktails, gin experience, and fine dining.