Produce a phase 1 environmental desk top study for a site at Corby 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 client requested that in addition trial pits be excavated throughout the site to allow a visual inspection to determine the depth and nature of made ground as much of the site had been filled.
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.
The proposal was for a solar PV park in this seemingly idyllic, secluded valley in south Wales.
The reason for our brief to prepare an environmental risk assessment was the many metres depth of pulverised fly ash, which is hidden by little more than the lush green grass, and the potential for this to reach the nearby river.
The source of the pfa was a nearby power plant, now closed, which had used the valley as a place to dispose of this unwanted by product of power generation.
In some areas where the grass cover was thin there was evidence of surface run-off carrying the pfa down the valley. The impact and effectiveness of the drainage needed to be assessed. Some evidence of settlement was noted, would the construction cause any additional settlement. The possible impact of fly-tipping needed to be assessed.
The potential for impact on the local environment and specifically the river needed to be assessed both for the construction phase and during the subsequent operational phase.