A housing development on the steeply sloping land above the River Irwell near Bury New Road faced unexpected ground loss during excavation. The contractor had stripped topsoil without first modelling erosion paths, and within two weeks a shallow gully had formed along the drainage line. That is when our team was called in. We ran a full soil erosion analysis across the site, mapping surface runoff zones and measuring the shear strength of the exposed glacial till. The results allowed the design team to regrade the slope, install a cut-off drain, and avoid a potentially costly slip failure. For similar sites in Manchester, pairing erosion analysis with permeability field testing helps predict how rain events will behave on clay-rich soils before any earthworks begin.
Pairing erosion analysis with RUSLE modelling on Manchester's glacial till can reduce topsoil loss by up to 40% during the construction phase.
Scope of work in Manchester
Critical ground factors in Manchester
Eurocode 7 (EN 1997-1:2004) requires that geotechnical design considers the effects of water, and in Manchester that means accounting for surface erosion. The city's dense urban fabric means runoff from one site can affect neighbouring basements, highways, or public sewers. If the erosion analysis is skipped or done superficially, fines from the local planning authority can halt construction for weeks. More critically, unchecked erosion can undercut shallow foundations or expose buried services, leading to structural damage. Our analysis follows BS 6031:2009 for earthworks and includes a sediment control plan that complies with the Greater Manchester Combined Authority's drainage guidance.
This service complements our laboratory testing work for a complete project analysis.
Our services
We offer two complementary services tailored to erosion-prone sites in Manchester.
Quantitative Erosion Risk Assessment
Using the RUSLE model and on-site soil sampling, we produce a spatial erosion risk map for your plot. The report includes C-factor recommendations for temporary and permanent cover, plus a sediment yield estimate in tonnes per hectare per year.
Erosion Control Design & Monitoring
We design silt fences, sediment basins, and diversion drains specific to Manchester's clay soils. Our team installs erosion pins and collects repeat survey data to track actual soil loss during the construction phase.
Quick answers
How much does a soil erosion analysis cost for a typical residential plot in Manchester?
For a standard 0.5–1 hectare residential site, the cost ranges between £620 and £2,020 depending on the number of sample points, the complexity of the slope, and whether sediment control design is included. The final quote is provided after a brief site walkover.
What is the difference between RUSLE and the Morgan–Morgan–Finney model for UK soils?
RUSLE is more widely used in the UK for planning-level assessments because it requires fewer input parameters and has a larger calibration dataset for temperate climates. The Morgan–Morgan–Finney model is better suited to tropical or high-intensity rainfall regimes. For Manchester's moderate rainfall, RUSLE gives reliable predictions when combined with local soil erodibility data.
Do I need an erosion analysis if my site is flat and already grassed?
Yes, even flat sites in Manchester can experience sheet erosion during heavy rain if the topsoil is disturbed or if the grass cover is temporarily removed. The analysis helps you demonstrate compliance with the local planning authority's SuDS requirements and avoids unexpected sediment runoff that could affect nearby watercourses.