Situated 3 miles from Chesterfield, Grassmoor Country Park sits at the northern end of the Five Pits Trail and has become a much-loved public amenity space boasting a wide variety of wildlife. Along the park borders runs the Calow Brook, ending its journey into the River Rother. For years flooding in the area had been a regular occurrence and an opportunity had arisen to create a scheme that would reduce pressure on the river network, whilst improving other aspects of the park.
As part of a multi-beneficial scheme known as ‘Slow the flow to the Calow’, a new and innovative flood management project was developed with Don Catchment Rivers Trust in association with the Friends of Grassmoor Country Park. The scheme aims to create natural flood management, enhance biodiversity, improve hydrogeomorphology and create opportunities for the local community.
Funded by the Environment Agency and the National Lottery Heritage Fund, Ebsford developed a scheme to slow the flow of water running off areas of the park into the Calow Book during heavy rainfall. The works will also increase the availability of water within the landscape during times of drought, and reintroduce vital wetland habitats back into the landscape, providing vital lifelines for wildlife and plant life.
The works took place across four main areas: Main field, East Field, North Field, and Amphitheatre. After obtaining the correct planning permissions, Ebsford began works on the first phase, re-landscaping areas of the park into shallow temporary ponds, earth embankments and ponds, to make the most of the topography of the site and its ability to temporarily hold back water so that it drains into the brook at a slower rate than previously. This phase also included scraping and lowering the ground to avoid flooding in the same areas on site and using the excavated material to create compacted earth bunds. The bunds were designed specifically for each site to help divert, hold, and transport water around the site, using a 9t excavator to form and compact the soil creating a homogeneous structure. In addition to this, sections also required the installation of a flow spillway, culvert and headwall installation improving conveyance along with a stone apron on the downward side of the bund, reducing the impacts of erosion in high flows.
Another element of the project was the installation of leaky log dams in the North and East Field, the purpose of this was to create an overspill structure where in high flows the water will back up and spill into the newly created wetland areas to provide natural flood management. For the excess water, a surplus channel was created and a French drain for the water to slowly filter back. Minor tree enabling works were carried out for the supply of woody debris, before using an excavator to grade the brooks banks and install the logs into the banks.
Some of the newly created features will be dry most of the year and only fill up during heavy rainfall, draining again over a few days or so while others will stay wetter for longer creating more permanent wetland habitat. Soils were kept and replaced to allow the meadows to grow back and have also been sown with more seed that will introduce a greater variety of plants into the meadows, including those that can better cope with wetter conditions.
The local community were pleased with the results, with many local residents volunteering their time to work with Ebsford reseeding the parks meadows, helping to maintain and improve the diversity of plant species found at Grassmoor Country Park. Volunteers are also undertaking vegetation surveys to monitor the positive changes as a result of the project. The works will have a huge and lasting impact on both local residents and the environment, improving habitat for wildlife, enhancing biodiversity and creating natural flood management.
