The River Burn is a chalk stream which flows through a low-lying catchment and discharges into the salt marshes of Holkam National Nature Reserve. The River is classified by the Environment Agency as a Highly Modified Waterbody, a designation which recognises the long history of modifications to the Burn over several centuries. The upper Burn is a winterbourne, which means that some headwater sections dry out naturally as the level of underlying chalk aquifer drops. However, there is debate about the degree to which flows in the sections above Burnham Thorpe are affected by abstraction. Substantial flow joins the Burn at Burnham Thorpe from a system of springs surrounded by sedge beds.
Below this point the remaining 2.5 km of the river has reliable flows, and has not dried out in the last 50 years for which data is available. The majority of the course of the river has been altered by diverting it into straightened sections. Impoundments reduce the potential for fish movement and migration along the river.
For a more detailed description of the river, and for a description of the wildlife problems and suggested solutions please download a Catchment Plan from this page, or please contact us to request a hard copy.