Knutsford Playing Fields are owned by Watford Borough Council, located on the River Colne, and bordered by land owned by Affinity Water on the adjacent bank. It is a popular location for local residents, containing a rugby field, playground, outdoor Green Gym space, plus a viewing platform over the River Colne. This section of the river is designated as a Local Wildlife Site 84/014 for Flowing waters (rivers and streams); species.

Previous site issues:  

• Disconnection with the natural floodplain

• A lack of flow diversity, which impacts sedimentation transportation and deposition

• A lack of sunshine which negatively impacts floral biodiversity

• Presence of non-native invasive species and water quality issues

 
Improvements:
 

• A combination of berms and flow deflectors were implemented which have improved the habitat diversity and increase species that can now thrive in the river.

• Flow diversity is vital for a healthy river, as faster water increases scouring of the river bed, which in turn cleans the gravel of sediment. It also oxygenates the water, creating an ideal spawning ground for aquatic creatures. In contrast, slower flows enable sediment to be deposited for other species to thrive. See below image.

• The lack of sunshine over the river corridor was addressed through small tree works, aiming at creating a 60:40 ratio of sunshine and shade. A balance of tree cover is important, as shaded areas help to maintain in-channel oxygen levels and temperatures, especially during times of low flow in the heat of the summer. Sunlit spots are the perfect places for aquatic and riparian floral species to thrive, acting as a buffer protecting the bank erosion and providing food for fauna. 

 
Planned works:

• The ground underneath Knutsford Playing Fields is a historic landfill which is preventing the river connecting with its natural floodplain, exacerbated by steep river banks. However, an exciting opportunity was identified during the design process, redirect the river through Affinity Water land. This will allow us to reconnect the river with its natural floodplain, whilst simultaneously addressing the water quality and flood alleviation. It will also provide us with the opportunity to introduce a reed bed, a rate habitat in the Hertfordshire area. 

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Here are some images of our fantastic volunteers adding the berms and flow deflectors during the works: