Location: Chipping Sodbury, South Gloucestershire
Area size: 4,000m²
Product: Verydol Biotic Earth / Winter-Active Grass Seed
To protect the railway infrastructure and surround local property the Chipping Sodbury flood alleviation scheme involved the creation of a new attenuation lagoon using an innovative self-healing clay liner made from bentonite.
Able to naturally swell and shrink, the bentonite geomembrane however requires established vegetation to help reinforce it and offer protection during prolonged dry periods.
As the clay liner lacked no organic matter or nutrients, it made it difficult to establish the longterm vegetation required to hold the bentonite liner together and stop it from potentially failing.
With the high risk of erosion to the slopes, grass was needed as soon as installation of the geomembrane was complete but because to the time of year the necessary seeding works were outside the traditional sowing season otherwise the surface would be left exposed.
Having the two challenges of poor soil and the need for grass establishment during winter we took a two prong approach in delivering a cost effective solution for our client.
First was creating habitable growing conditions that would support new vegetation. By proposing Verdyol BioticEarth not only would the biotic soil treatment add the required organic matter but also nutrients, mycorrhizal fungi, beneficial bacteria and natural growth stimulants to help the inert soil come alive and allow the new grass to thrive.
Secondly we recommended the use of our ‘Winter Active’ seed mix. Our unique amenity grass seed mixture offers the best possible chance of achieving germination and establishment during cooler periods (in this case December) due to its ability to germinate at ground temperatures as low as 5º centigrade.
Within a few weeks of hydroseeding germination of the specialist ‘Winter Active’ seed was clear to see and already protecting the sides of the lagoon from erosion by helping to slow the velocity of rainwater runoff down the slopes and also forming a dense root mass to hold the wet clay liner together.