Monthly Archives: March 2014

Contaminated Land Site Investigation – Newton Abbot

Southwest Environmental had previously carried out a Phase 1 Contaminated Land Desktop Study for a site in the Teign Valley. The site had been extensively worked as mine over the last 100 years or so, before being developed for residential use, probably around 40 years ago.

Soil sampling was undertaken using hand dug trial pits across the site, with a total of 10 sampling locations. Gas monitoring wells were also installed under the proposed extension foot print, ground water was close to the surface.

Sub soils conditions were varied, bedrock was encountered in the first 1 meter below ground level in some holes, whilst other were fill.

Plan Annotated During Field Work

We are awaiting results from the labs but there were no odorous materials detected during the ground investigation.

Site Investigation Devon

Phase 1 Desktop Study – Plymouth

Acting on instruction from a developer in Plymouth, Southwest Environmental produced a phase 1 desktop study report for a planning application.

The site was on the city outskirts and had enjoyed an agricultural history. It was not foreseen that the land could be unduly contaminated and so its was recomedned that the site contamination assessment be arrested at this first phase.

An agricultural past with no buildings on site will nearly always mean low risk of harm resulting from site occupiers, although of course each site has to be assessed on an individual basis.

 Desktop Study Plymouth

Attenuation Tank Design – Surrey

Following on from planning level reporting resulting in the conditioning of various surface water management requirements. Southwest Environmental are finalising design of surface water management system for a site in Surrey.

Design of attenuation tank in line with SUDs manual – Outflow requirements are negotiated with local sewer provider Thames Water, and tank capacity is adjusted to minimise capital outlay for developer.

Application is made to Thames Water for Sewer Connection. 

Note: The size of a surface water attenuation tank is based on the peak inflow rates from the site  (the run-off coefficient is taken it to account when calculating this), and the maximum outflow rate. For example a 5 litre per second outflow rate would require an attenuation tank size of 20 cubic meters, whilst a 10 litre per second out flow would require an 8 cubic meter attenuation tank.

As well as the attenuation tank design, a maintenance plan was submitted for it continued upkeep.