CLAY CORE BUNDS AT TATTENHALL
At the Tattenhall site, we utilized a natural flood defence technique called the Clay Core Bund, which involved constructing a barrier out of clay in a shallow U-shape with pipes embedded at varying levels. This method created a pool of water that was gradually released, dramatically reducing the water flow. Depending on the expected amount of water, the size of the bunds can be adjusted.
To implement these natural flood management measures, we built three Clay Core Bunds, each with controlled outlet pipes positioned at different levels to prevent water from overflowing. We utilized about 200 tonnes of locally sourced clay to build up the bunds, and covered the top layer with soil, providing a base for sowing grass seed. To encourage grass growth on the bunds, we laid a layer of seed impregnated erosion mats. The crest of the bunds was intentionally designed with low spots to allow for overtopping.
Apart from building the bunds, we also cleared a nearby brook that had become filled with silt over the years. We installed a controlled deflection barrier across the brook, which directed water onto the fields and into the Clay Core Bunds during storm conditions.
In order to preserve the entrance to the field and prevent our road vehicles from getting stuck, we used TuffTraks to create a causeway for deliveries of materials and machinery
Overall, we believe the implementation of the Clay Core Bunds and the deflection barrier at Tattenhall is a prime example of how natural flood management can be used to prevent potential flood damage. By utilizing locally sourced materials and carefully planning and constructing these structures, we were able to provide a reliable defence against flooding in this landscape. The project also took into account the preservation of the field entrance, while providing a convenient causeway for materials and vehicles. We are confident that these measures will continue to provide effective flood defence for years to come.