The Upper River Witham and its tributary streams drain a ca. 573 km2 catchment area, with more than 165 km of waterway. The River Witham itself rises west of South Witham and flows more than 65 km northwards through Colsterworth, Great Ponton, Grantham, Long Bennington, Bassingham and North Hykeham. For the purpose of these plans the lower river Witham is defined as starting at Stamp End Lock in Lincoln and finishing at Grand Sluice in Boston which is the extent of the Witham before it becomes tidal. The lower Witham catchment has seven separate sub catchments, two of which are below the tidal limit. For the basis of this plans we are focusing on the main river Witham and up to the first structure on each of the sub catchments that join above Grand Sluice.
The EU Water Framework Directive (WFD) provides an approach to investigate, plan and deliver a better water environment, based on biological, chemical and physical assessment indicators. The Environment Agency (EA) has assessed the ecological status (or health) of all water bodies in England and Wales based on fish, macrophytes (plants), diatoms (algae), invertebrates (insects), on chemical factors such as phosphate and dissolved oxygen levels, and on stream flow and channel morphology.
The WFD assessments have been used to assign every river water body to one of five ecological status classes: high, good, moderate, poor, or bad. A river in its pristine, or un- disturbed, natural condition would be classified as being High Ecological Status. The various elements of the WFD classification procedure are explained in the report and a failure in any one of these elements results in the failure of a water body to achieve the target classification of Good Ecological Status.
The plans below discuss the current WFD status of the Witham and how taking a catchment approach the status of each section can be improved.
© 2019 Lincolshire Rivers Trust