Kingston University Biodiversity Action Group

24/25-02-2014 : Volunteers stake-out the River Hogsmill!

The poor weather of late magically (and thankfully!) relented to allow volunteers to enter the Hogsmill River and begin our biggest volunteer project to date - to renaturalise the River Hogsmill at our Knights Park campus.

Having a laugh in the River - who said hard work wasn't fun?!

The stretch of River at our Knights Park campus has in the past, like many urban rivers, been heavily engineered to reduce flood risk and allow development. It is currently overly-wide and flanked by a bare concrete wall - all factors which limit the ecological potential of the River. Together with the South East Rivers Trust and the Environment Agency we have been working hard to conceive a plan to improve the habitat provision along this stretch while maintaining flood protection, and now the time has finally come to put our plans into action!

We had an impressive response to this project, mustering 17 and 13 volunteers on Monday and Tuesday respectively, from a pool of University staff, students, local residents, and interest groups such as the Thames Anglers' Conservancy. We even attracted a student from Nottingham University!

Although eager to get going, it took quite a while to get all geared up, but with the tasks ahead it was time well spent to ensure we stayed (reasonably!) dry and in one piece. A selection of manual tools such as post knockers, drills, and hammers, and materials including posts, staples, straps and high tensile wire were needed for this transformation - which it is hoped in a few years time will look completely natural.

Gearing up, the team collect tools having donned their waders
Photo: O. Lafci
Seasonal tree works by the Royal Borough of Kingston Council provided the much needed structural timber for our plans. Many of the trees have been coppiced - a traditional woodland management technique which keeps the tree alive and produces useful wood products through cyclical harvesting - so we should see them regenerating on the riverbank before long.

The lengths of timber were used as deflectors to the River's flow, so, having rolled them to the water's edge, volunteers teamed up with lifting straps to maneouvre the wood into the correct position. Thorough monitoring of the River's flow at this stretch has been carried out by KU students and this helped inform where the deflectors should go. We attempted to achieve as low a profile as possible above the water to avoid accumulation of litter and debris on the woody structures. This part of the plan aimed to encourage a more meandering river form and the natural river processes that create a range of aquatic habitats such as scouring out deep pools to act as fish nurseries. Some of the willow limbs used will regrow in the water, providing additional habitat diversity beneficial to emerging aquatic insects. Currently the Hogsmill River at the Knights Park campus offers little variety of habitat which limits the biodiversity it can support.

Vital equipment - these lifting straps helped us to carry the tree limbs
Securing the straps, Toby Hull from the South East Rivers Trust directs the action
It is unsafe to keep logs by the riverbank as habitat piles as there is a risk of it falling into the water and causing blockages downstream, so much of the surplus timber produced has been reused in habitat piles at Middle Mill Halls of Residence, St John's primary school and the Hogsmill Community Garden. A forthcoming handmade furniture workshop at KU will make use of two logs and another will be turned into a creative masterpiece by a KU art student. Some of the thinner, bendier willow branches will be used for sculpture by the School and community garden too so very little is wasted.

Paul, Elliot and John take the lead carrying this tree limb upstream
Photo: O. Lafci
Heave Ho!! The boys drag it into position

Once in place, the tree limbs had to be secured. This called for some serious muscle power as chestnut stakes were driven in either side of the tree limbs into the riverbed using post knockers. The resonating 'dong' that sounded with every hit was, together with the smooth and apparent effortlessness of the teamwork to shift the timber, in some ways reminiscent of ancient times when huge numbers of workers pulled together to build large viking ships or the like!
Knocking in the posts to secure the timber sure gave us all a good workout!
We were always going to get with this project weren't we?! Adam hammers home one of the chestnut stakes in the water.
Photo: O. Lafci
As a backup, we also anchored the tree limbs to the existing riverbank with heavy duty wire rope to prevent them floating away in the highly unlikely scenario that all our other handywork fails under very high flows.

Drilling through the timber to thread the anchoring wire rope through.
All this hard work was rewarded with a tasty lunch each day. We were fortunate enough to be hosted by the Stanley Picker gallery on the Tuesday and thoroughly enjoyed hearing about the coconut milling history of the site and the current exhibition influenced by the River. Perhaps one day, the work we are doing now will inspire future artists and new masterpieces will grace the gallery's walls!

The obligatory group shot! Deservedly proud faces all round!
Photo: O. Lafci
In our two days on site, volunteers managed to secure 5 tree limbs into the riverbed and already the river dynamics have changed, so huge thanks go out to everyone who helped out! But there is more to come ... on March 15th, 16th and 17th we will focus on the concrete wall and install a framework of more woody debris and create banks of gravel to narrow the river and start building the natural-looking riverbanks that have been missing all this time. Tasks will include lots more staking of chestnut posts, pinning brash to the posts, and wheelbarrowing gravel into the river. As you can imagine this will take a great deal of effort and we need all hands on deck for this second phase! Please register to join us for this transformational weekend.

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