Gaywood River

Overview

Where is the Gaywood River located?

The Gaywood River is a short river, just 13km (8 miles) in length. It is an ordinary watercourse in North-West Norfolk, managed by King’s Lynn Internal Drainage Board (IDB). It rises from springs near Derby Fen before flowing westwards into the historic port of King’s Lynn, where it discharges into the Great Ouse (and subsequently into The Wash). Much of the river today has been channelled into a series of deep, straight drains, with some underground sections in urban King’s Lynn.

The Gaywood River is an example of a chalk stream, although heavily modified. The river does not exhibit chalk stream features downstream of the old railway line (Bawsey). Upstream of this point the chalk stream features are fantastic in sections. This lower section is a perched section with shrunken peat on both true left- and right-hand banks.

There are also protected areas in the upper reaches of the catchment. These include 4 Sites of Specific Scientific Interest (SSSI) and 18 County Wildlife Sites (CWS). The SSSIs are Bawsey, Grimston Warren Pit and Leziate, Sugar & Derby Fens and Roydon Common. The latter is just outside King’s Lynn and is a designated Ramsar site, National Nature Reserve as well as falling within a Special Area of Conservation.

Blue dot signifies location of the river

What is the Water Framework Directive (WFD) status for Gaywood River?

We monitor the water quality of the Gaywood River to assess it against the standards set out in the Water Framework Directive. These standards allow the river to be classified as having High, Good, Moderate, Poor or Bad ecological status. High means the conditions are largely undisturbed. Monitoring takes into account the populations of macroinvertebrates present, the levels of dissolved oxygen, phosphate and ammonia in the water, and the pH of the river.

The Water Framework Directive (WFD) standard may be affected by hydromorphic harm. Hydromorphic harm considers the physical characteristics of a waterbody; namely the shape, sinuosity and form of a river as made up by the banks and bed and any adverse impact that could affect this (disregarding pollution).

The current overall ecological status of the Gaywood River is Good and is Good for physico-chemical quality elements (data collected from the 2022 Anglian River Basin District River Basin Management Plan).

When do we sample and what have we found out?

We conduct regular water quality sampling of the Gaywood River both upstream of the town (at Leziate) and within the town (off Gaywood Road). Since December 2020 we have installed a sonde upstream of the town to continually monitor the water for certain water quality parameters. The sonde is a multi-parameter water quality monitor, which reports real-time data on temperature, pH value, turbidity, conductivity, ammonium, and dissolved oxygen. The findings of recent sampling and monitoring of this watercourse show we have no evidence that the physical-chemical elements in this waterbody are having a detrimental effect on its flora and fauna populations.

Have there been pollution incidents on the Gaywood River?

We are dealing with issues of groundwater intrusion/surface water flooding in Grimston (upper reaches of the catchment) due to overflowing manholes resulting in discharges to a tributary of the Gaywood River. We are holding meetings with Anglian Water to discuss options and steps moving forward regarding the groundwater and sewer issues in this area.

We know investigations take time and responsibilities are complex. Solutions may be costly and technically challenging and will need to be collaborative. But we do expect solutions to reduce the leakage and avoid the need for discharge. We continue to record incidents on our National Incident Reporting System (NIRS) that could impact the environment and class these under our Common Incident Classification Scheme.

Some of the water quality issues on the Gaywood are caused by natural ochre production from the local geology (Peats). Ochre is formed through oxidation of iron rich water when it comes into contact with the air or through bacterial action. It forms a fine mud/silt which can coat the plants and riverbeds.

We have previously identified a potential source of pollution to the Gaywood and the case is under investigation. We are now considering our response to this pollution in line with our Enforcement & Sanctions Policy.

You can read updates on pollution incidents using the hyperlinks at the bottom of the page.