Coston’s brook safari.

Coston’s brook is a tributary of the river Brent, joining it at the south west corner of the park (red arrow on 19th Century map of the area).

Yesterday a group of  intrepid explorers ventured up stream for about 200m from its confluence with the Brent to explore it habitats. The report of this trip (below) was written and sent to me by John Staples.

And a word of caution: these walks are not for novices, you need good equipment and have previous experience of walking such river beds!

1. Top section of CB in Perivale park nearest outfall is heavily silted, we suspect due to sediment backing up behind weir – channel also lacks natural meanders and gravel beds, sewage fungus is present.
2. could be improved with flow deflectors (permission from E.A would need to be sought alongside funding). The
   Yeading Brook Projects Plan 2015 Crane Valley Project. Thames Water Funding.
3. Reeds are present in areas where light levels are suitable – increased shading is a significant issue, management of bankside vegetation removal of Himalayan balsam and coppicing willows will support healthy light levels allowing additional reed development and or planting ‘Reedbeds are great natural filters, removing pollutants whilst oxygenating the water… important habitats for wildlife, birds, invertebrates and mammals… Reedbeds oxygenate…benefits aquatic life such as fish. During severe pollution incidents, the oxygen in the river decreases rapidly. Reedbeds are a refuge to escape such incidents…reedbeds tackle pollution in water by converting toxic ammonia into nitrate, which is less harmful’
   www.thames21.org.uk/project-reedbed-2/
   Coir Flora Mats submerged just in time! And next Event – Thames21
   Coir Rolls – Salix Products (salixrw.com)
4. maintaining foot access to river bank will enable us to continue to treat Giant hogweed.
5. Lower section (below weir) has some good natural features largely created by bankside willows naturally creating blockages and meanders, suggest leave much of this.
6. Task options – set achievable targets such as – remove all HB on this section of the brook, retain healthy light levels on % of channel
7. These can be done by a combination of ranger and volunteer tasks – tba

Even from the banks of the stream where I restricted my own walk to, you see the park from an entirely different perspective. Indeed it is difficult to imagine you are in a london park at all –  a true safari.