BRE 365 Soak-Away Report – Brinkworth, Chippenham

Leave a Reply

BRE 365 Soak-Away Report – Brinkworth, Chippenham

On site geology is the Oxford Clay Formation. Which is described as:
“Silicate-mudstone, grey, generally smooth to slightly silty, with sporadic beds of argillaceous limestone nodules.”
BGS Borehole 398037 which is situated to the south west of site shows considerable thicknesses of Clay, extended to the base of the borehole at 44.81 mBGL.
BGS describe the Oxford clay formation as being blocky and fissile in certain areas, so there is potential the clay in to pervious (support of flow through fissures) in certain localities.
Trial pits showed varying thicknesses of made ground resting over the Oxford Clay. 
Site works comprised of 2no. trial pits with soak away tests conducted in each on. The positioning of these pits were sited in anticipation of a fairly large soak away being required. Clay typically being assumed to have a low infiltration rate.
Holes were dug using an excavator, with care being taken to keep the side vertical. This is important so as to be able to deduce an accurate volume, and pit internal surface area. 
The location of the pits can be viewed on the location plan in Appendix 1. Dimensions of the trial pits were chosen so as to representative of the final soak-away. Trial pit dimensions can be seen on the Trial Pit Log sheets in Appendix 3.
Calculations show that based on a 1 in 10 year rainfall event, allowing for a 20% increase in rainfall events owing to climate change, that a trench or pit soak-aways could provide adequate infiltration drainage for surface water from the proposed development. Results from Trial Pit 1 are adopted as a worst case scenario.
Detailed Calculations – To BRE 365

BS9530 –  Logging of Trial Pits

Geotechnical Investigation Belluton near Bristol

Leave a Reply

Geotechnical Investigation Belluton near Bristol 

In support of some road stabilisation work SWEL have carried out a geotechnical investigation at Belluton near Bristol.

Despite tight access, drilling works started in a timely fashion, with recovered of some excellent core samples. Holes were advanced to a depth of 15 meters, with dynamic sampling in soils and weathered rocks, and coring in rock proper.

Dynamic Samples from Ground Level in c. 3 Meters Depth

Core Samples from Weathered Rock Head

Close Up of  Core Fragment

SPT results and disturbed samples from Soils. 

The investigation is to provide data for a cutting for road widening. The rock seems very competent, but soil nails are proposed for further strengthening. Samples were tested for aggressive ground characteristics, and a variety of classification and strength tests.

Geotechnical Investigation Bristol

Sustainability Statement – Lyppiatt Road, Bristol

Leave a Reply

Sustainability Statement – Lyppiatt Road, Bristol

Acting Upon instructions from a property developer in Bristol SWEL have assembled a sustainability statement for a multi the residential development win commercial grounds floor use. The development incorporates large areas of south facing glazing and as such specific concerns were raised by Bristol City council regarding overheating potential mitigating measures such as

Overhanging shading were stipulated as possible future upgrades these future upgrades were included within plans with space left for them to be added as a future date when and if some overheating becomes a problem.

Bristol City council have recently started to require detailed energy Modeling at the planning stage SWELconducted a whole building energy model for the development which allows for the presentation of building energy demand and the subsequent : savings achieved through efficiency and renewable energy measures.

Sustainability Energy Statement Bristol

Desktop Study – Chittening, Bristol

Leave a Reply

Desktop Study – Chittening, Bristol

Acting on instruction from a property managment company SWEL have produced a desktop study for a property in  Chittening, Bristol.

The property lease was to be aquired by a company and as good practice they were keen to establisg risk from ground contamination in a qualified manner.

SWEL have visited site, photgraphed the building internally and externally, we then use up to date environmental data from the Bristol area and mapping to draw qualified conclusions with regards to ground quality on site.

In this instance we felt that although the build could have had a number of uses, that risk to future users was low owing to broken exposure pathways, and the nature of the intended use.

Desktop Study Bristol

Sustainability Statement – Lyppiatt Rd, Bristol BS5 9HP, UK

Leave a Reply

Sustainability Statement – Lyppiatt Rd, Bristol BS5 9HP, UK

Acting on instruction of a property developer SWEL have produced a Sustainability Statement for a site in   Lyppiatt Rd, Bristol. The site is a mixed use development incorporating residential and commercial spaces.

The project has a highly fragmented roof, and options were explored to perhaps use combined heat and power in order to provide emissions savings in line with BCC Policy BCS 14, which requires that a carbon reduction of 20% is achieved beyond building regulations.

Other Bristol City Council Sustainability Policies include:

BCS13: Climate Change – Requires development to both mitigate and adapt to climate change.

BCS14: Sustainable Energy – Provides criteria for assessing new renewable energy schemes, with a presumption In favor of large‐scale renewable energy installations.

Requires new development to minimise its energy requirements and then incorporate an element of renewable energy to reduce its CO2 emissions by a further 20%. Supports the delivery of a district heating network in Bristol.

BCS15: Sustainable Design and Construction – Requires all developments to engage with issues around sustainable design and construction.

As with London Sustainability Statements, Bristol City Council also require that the energy hierarchy is followed :

  1. Be Lean
  2. Be Clean
  3. Be Green

Site Waste Management Plan – Enfield London N13, UK

Leave a Reply

Site Waste Management Plan – Enfield London N13, UK

Southwest Environmental Limited were commissioned to undertake a site waste management plan for a site in Enfield London N13.

The project was or considerable scale with numerous residential units built on a brown field site. The report amongst other chapters considers the following:

2.1         Demolition Waste
2.1.1 Demolition Wastes
2.2         Excavation Wastes
2.2.1 Excavation Waste Types Forecast
2.2.2 Excavation Waste Quantities Forecast
2.3         Construction Wastes
2.3.1 Construction Waste Types Forecast
2.3.2 Construction Waste Quantities Forecast

The Waste Hierarchy 

The report follows the waste hierarchy and aims to minimize disposal to landfill. During the construction phase the SIte Waste Management plan makes recommendations as to good working practice that can reduce wastes. Suggestion such as:


“The design should be coordinated to avoid excess cutting and jointing of materials. Off-cuts create waste, where possible designed to standardized material dimensions. This would also apply to bespoke structural elements such as form work, where repetition of measurements should be encouraged where possible.”

Are included within the Site Waste Management Plan. 

Flood Risk Assessment – Merton

Leave a Reply
Flood Risk Assessment – Merton

SWEl have recently prepared a Flood Risk Assessment for an interesting proposed development in Merton (New Maldon).

The development sees the retention of a existing building for conversion under PD rights, and the creation of e neighbouring residential unit.

Below images show various mapping used in the compilation of the report.

Flood Extent Mapping in Merton
Modelled flood data was obtained and used in describing the site as low risk. 

Model Nodes used in 2D Models
Both 1D and 2D flood modelling data was used, the nearest water course was the Beverly Brook. 

A Considerate Design improves Planning Success
The Flood Risk Assessment also considers surface water run-off, thankfully the development was considerately designed with large areas of soft landscaping. 

Flood Risk

Odour Management Plan – Sussex

Leave a Reply

Odour Management Plan – Sussex

Southwest Environmental Limited have recently prepared an Odour Management Plan for a Nail Bar in Crawley, Sussex. The salon type establishment was sited within a busy shopping precinct. Our client had been requested by his local council to provide an odour management plan.

We were asked to prepare this document on a 3 working day turn around which we were just about able to do. We referenced industry codes of practices and focussed on the main causes of odour such as vapours and dust.

The odour management plan is a working document, and we aim to write such a report as simply as possible, with useful forms and survey checklists included for easy reference.

Odour Management Sussex

Expert Planning Objection – London

Leave a Reply

Expert Planning Objection – London


Southwest Environmental Limited (Environmental Consultants) were contacted by a residents group, who were trying to contest an application for a school in their neighbourhood. The residents group were concerned about the extra traffic generated by the proposed development and also as to whether the site was indeed suite for the intended use. 

An expert planning objection was prepared by Southwest Environmental we were requested that we limit our comments to those relating to air quality, although we would have happily commented on daylighting, traffic, or noise in this instance. 

The proposed school was situated on a busy junction, which has been subject to monitoring, for nitrogen dioxide. Nitrogen dioxide has been shown to have chronic effects on the health of adults and children alike, although at present the is a great deal of uncertainty regarding safe exposure levels. 



To that end the European Union has set targets of 40ugm3 as an annual mean, and the site exceeds these values. There are have been various studies[1] that point to unsatisfactory air quality in the area, yet reports submitted in support of planning appear to show that this is not the case thus indicating a discrepancy.

In 2014 The European Commission launched legal proceedings against the UK for failing to deal with air pollution. The EU reasoning behind case this was that levels of nitrogen dioxide, mainly from diesel engines, are “excessive” in many British cities. The Commission noted in its written statement at the time that nitrogen dioxide gas can lead to major respiratory illnesses and premature deaths.



It is important to note that there is no safe level set for exposure to nitrogen dioxide. Nitrogen dioxide is converted to nitric acid in the lungs, and this can exacerbate illnesses such as asthma, and other respiratory conditions. Studies[1] note the clear “associations between NO2 and respiratory problems among children”.

Odour Impact Assessment for Anaerobic Digestion (AD) Plant – Devon

Leave a Reply

Odour Impact Assessment for Anaerobic Digestion (AD) Plant

Acting on instruction from a client based in the greater London area, SWEL are to prepare an Odour Impact Assessment for a Anaerobic Digestion (AD) Plant in Devon.

The Anaerobic Digestion Plant  is to use agricultural feed stock in to produce gas, and ultimalty genrate electrcial energy vis the use of gas engines to feed in to the grid.

As solar and wind capacity increases  and base load capacity decreases, the UK must fill the gap. Anaerobic Digestion Plants offer the possibility of storing gas produced, and generating power when it is needed.

Odour Modelling

The odur impact assessment was conducted using odor concentrations derived from secondary sources, in the most part peer review scientific papers. These values were then used in a model to derive am odour concentration at near by receptors.

The model used was aeromod, which is the preferred modelling system used in the UK and USA. In fact the model was produced in the USA, by their equivalent of the Environment Agency the EPA.

The model works, by caluclating dispersion, and also “averaging” out plume concentrations based on wind directions. There are various parameters that can be changed, in cluding atmopshric stibility etc.

Owing to the comparatively low odor emissions from the proposed agricultural feed stock the odour impacts are very low.

SWEL can conduct Odour Impact Assessments on a quick turnaround and also offer odour modelling services, to air quality professionals.