Eight pink toilets buried in a garden in Sevenoaks and unexploded German bombs in London were two unexpected graphic images emerging from the talks and discussions at the annual CIRIA Contaminated Land Conference, where efficiency was a key theme, going hand in hand with the changing times.
Also discussed was the right to choose one's career pathway; more of that later.
Doug Laidler of Halcrow kicked off a very workmanlike, down to earth conference this year with the issue of data integrity about sites and how to manage the information. Laidler put forward the concept of a site log, including a decision record along with lines of evidence.
Issues included the sheer volume of information - slicing and dicing of data in line with submissions and managing dynamic data, as well as the question of who accesses the data.
Common problems include inadequate spatial information, poor storage and categorisation. Laidler said that much could be learned from how data is handled on nuclear sites and from the Safegrounds project. All this was set against a background of rising insurance claims and increasing demands on the skill levels of brownfield staff.
CLEA Framework reports
Ian Martin, land contamination policy advisor at the Environment Agency, outlined the changes to the updated CLEA framework reports. He said March 2009 was the date set for a new group of reports.
He said the TOX Guidance report updates and replaces CLR9 and said health criteria values as levels of minimal or tolerable risk to health from long term human exposure to chemicals in soil.
Outlining the difference between threshold Health Criteria Values and non-threshold HCVs, he said that the CLEA report replaces CLR10 and reconsiders generic land use scenarios and default assumptions and updates the data sets and model algorithms used in the CLEA model based on scientific literature.
Changes to generic land uses were highlighted, including: no residential without plant uptake; homegrown produce based on general population, default building type; small terraced house. With allotments children are the critical receptors and under commercial, the default building type is a three-storey office block (built before 1970).
Generic data sets have been extensively revised. Eight soil types have been defined from the UK soil LANDIS database. Height, weight, skin, inhalation and consumption rates have been revised from existing authorised sources, and nine building types have been based on the Building Research Establishment's review.
Soil ingestion is no longer under probabilistic distribution. There are revised air dispersion factors for dust, and vapour intrusion guidance includes revised caveats on use and interpretation.
In the Q&A session, Martin quite rightly asserted when questioned from anti-private sector practitioner Bill Baker about changes to and lack of Environment Agency personnel: "What I want to do with my career is up to me."
Flooding and brownfield
In the workshop session on brownfield sites and flooding, Ian Walton of Bureau Veritas outlined the new guidance to go with PPS 25.
Following recent flooding incidents, flooding has become a real planning issue and a constraint to regeneration. Walton said that flood risk assessments related to the EA's flood maps only relate to fluvial and tidal flooding.
Under the Sequential Test, flood risk is assessed in stages against different criteria, such as Regional Spatial Strategy and Local Development Documents, but Walton said the LDD process is two to three years away and very few strategic flood risk assessments have been prepared.
So it is down to the applicant to prove, via adopted local plans, that there are no reasonably alternative sites at lower risk of flooding.
So the danger is spending money, time and resources, only to have the Sequential Test fail, which will happen if reasonable alternative sites are found.
Although brownfield and regeneration sites are an exception to the Sequential Test, the site in question must provide wider community benefits that outweigh flood risks and not increase the risk of flooding to others.
Walton showed an animation of a 26 hour, two tide flood breach in Erith to illustrate breaching. Noticeable was how variable the soakaway was, with the second tide exacerbating areas where the first tide flood water hadn't cleared.
Walton concluded, given the constraints over defences, hydraulic modelling may pay for itself by removing or reducing site constraints (although a danger is it could make them worse).
In the discussion, Jonathan Atkinson of the EA pointed out that remediation and flooding increasingly go hand in hand and could end up in conflict, citing an example where the remediation costs of an important regeneration project were rejected by EA flood defence personnel.
Atkinson pointed out the dangers of contaminants working loose if flooding was allowed to occur. Walton said that the Water Framework Directive would alter flood work radically, with its requisite water quality standards.
Green communities
Green space offered a chance for the community to get involved in owning and deciding the shape of common land, was one conclusion from the green space workshop. Thoughts turned to examples in the Thames Gateway
Improving decision making under Part 2A was a packed workshop session, involving Rob Ivens of Mole Valley Borough Council, Richard Brinkworth of Leap Environmental and Steve Moreby from Gloucester City Council.
An example of a Part 2A site was presented and participants had to decide what depth and level of grid sampling to pursue. Costs varied but the optimum came in around the low twenties, while the group with an EA representative, involving a very thorough analysis, came in just under £60,000.
Moreby outlined the process of determining six sites at Alney Island - an area with a significant industrial past and one prone to flooding. He undertook widespread unbiased sampling with density based on current land use zones.
He stressed that determinations were made on a ‘lines of evidence' basis, with no total reliance on any one factor. And Moreby added that the approach was dependant on the site and that statistics were a powerful tool, but no panacea, or substitute for critical thinking.
Talk bombs
In the afternoon session there were a couple of presentations on CIRIA Research projects. In the Unexploded Ordnance (CIRIA RP732) talk, of note was that 10% of German bombs failed to function as intended; and that once UXO is encountered, delays on site of up to a week can occur.
And the VOCs Handbook: Investigating, assessing and managing risks from inhalation of VOCs at land affected by contamination (CIRIA RP766) is set to be published this month.
Perhaps giving clues to the future in these credit crunched times, the invasive species workshop group pronounced there was a mystique about knotweed, but there is more time to deal with the problem and come up with longer term, no-rush solutions.
Paul Mathers of WRAP opened another possible door to the future when he took us though some innovative projects mixing compost with existing soil. Perhaps the most interesting was mixing paper pellets with colliery spoil. Mathers said that paper is a good moisture absorber, and works well with a layer of compost thinly applied to the top.
Mathers implied that the reach of the project is increasing from erosion control and pollution attenuation to creating meadowlands, sustainable urban drainage, and even green roofs. There may be a lot of vacant land banks to deal with - in the short term at least.
Pictures: WRAP and Fotolia
