A new report about our local river was published this month (February 2023), London Lea Catchment - Water Quality Monitoring and Community Recommendations, that makes interesting reading for anyone wanting to find out about what’s been happening to its quality and management. A ‘catchment’ is the area from which water drains into the river and includes surrounding land and tributaries.

The report draws on data gathered during 2021 to 2022 from several initiatives in the catchment, including citizen science projects such as outfall safaris to learn about what is emptying into the Lea and its tributaries, water blitzes in spring and autumn last year – these are events when water samples are collected in multiple points in the catchment on one day, within a short period of time,  and river fly monitoring to check what’s living there. Sondes have also been used - these are measuring devices kept under the water to collect and transmit data. All this allows for a lot of detail.

The main sources of pollution are also reviewed: these vary according to location, with the more rural areas affected more by agricultural run-off, the more urban areas by road run-off and all affected by sewage pollution and misconnections.

What I found very interesting is where it looks at the impacts of various nature-based interventions, by checking sampling up- and downstream from them, and seeing what type is having what effect. The types of intervention include floating reedbeds, reforestation, changing river morphology, such as the restoration of Turkey Brook at Albany Park to free it from the concrete channel to have bends, wetlands and lots of other habitat features, and the beaver enclosure.

If you’re interested in taking part in work to understand and improve the quality of the Lea, keep an eye on our events page: there are several activities coming up over the next couple of months or so.