Geoforte provided a stream embankment remediation solution for major housing developer Persimmon Homes at Alder Stream, Five Oak Green Tonbridge. This project proved challenging on many levels with special consideration being given to environmental issues on site and downstream, limited accessibility and working space between the stream bank and the existing property development.
This ecologically sensitive project involved careful planning as a balance had to be struck with providing an earth retention solution which was suitably robust to prevent further erosion and failure of the existing bank whilst giving due consideration to all environmental issues. A full topographic survey of the stream area was carried out with supplementary SI in the form of window sampling to determine existing the soil properties. This allowed for a design solution specifically tailored to the segment of the stream being remediated.
Detailed design led to a hybrid solution which utilized ground anchors with a gabion mattress stone filled face. This allowed for minimal excavation and disturbance to the natural habitat while providing a structural solution within the existing site constraints.
The construction was undertaken using temporary scaffolding within the stream with excavation and muck away done manually. Care was taken to minimize the potential spill of excavated soil into the stream with silt traps placed downstream as a precautionary measure.
No mechanized equipment was used along the stream bank due to limited accessibility and the possibility of damaging the already fragile banks on the opposite side of our works.
Top soil was used to re-grade the slope above the gabions in order to encourage the re-growth of indigenous vegetation over the top edge of the mattress .This will allow for the blending in of the gabion face with the natural vegetation.
The work was completed without any damage to the environment and the original stream width was maintained and widened slightly in some areas to maintain uniformity which was verified by an as built survey upon completing of the works.
