South East Rivers Trust

Hogsmill River Restoration at Kingston University


Phase 2: Wetland Creation (15th, 16th & 17th March)

The weather continued to behave itself on the days and weeks approaching the main push of the works at Kingston University’s Knights Park Campus. This resulted in river levels dropping to safe working conditions and water clarity being high. If this was not enough, for the entirety of the three day weekend we were absolutely blessed with the most stunning weather to the extent that sun cream was required and several bronzed and slightly pink faces were seen. With 40 tonnes of gravel, 250 chestnut stakes and a last minute delivery of 200 hazel faggots (bundles of brash wood) all ready on site, what was really needed was an enthusiastic and willing group of volunteers to convert these somewhat imposing piles of raw materials into a new river bank/wetland. And boy, were we impressed!

my faggots
Two hundred brash faggots arrive…
my gravel
40 tonnes of gravel…
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and 250 posts.

 

Photo courtesy of D. Hargreaves 

On all three days of the event we were joined by masses of helpers all positively oozing with eagerness to get the job done. In total over the three day weekend, 101 volunteers (with several repeat attendances) got stuck into driving stake after stake into the river bed, moving all the faggots into position, wheeling wheelbarrow after wheelbarrow of gravel along the river’s edge and creating a web of hundreds of metres of wire to secure it all together. That rather brief summary of events does little justice for the huge amounts of effort, sweat and hard graft that went into it. The saving grace was having Ben from Aquamaintain loading the wheelbarrows with an excavator.

To back up a little, the purpose of the event was to narrow and add sinuosity to the excessively widened stretch of straight river whilst providing some much needed habitat in the process. The plan was this, to create a shallow, wetland berm set at low flow conditions water height which would in-turn be planted with a diverse range of marginal wetland plants. The berm was created with a combination of installing  a wide strip of densely matted brash on the channel side and backfilling the void space between that and the base of the vertical wall with gravel. The gravel will then be planted with a mixture of yellow flag iris, sedge, and bur reed whilst the brash will see a mix of watercress, fools watercress, forget me not, water mint and marsh marigold. Over time, sediment being transported down the river will steadily drop out in the slack water created among the brash, accelerated by the raft of vegetation that establishes. In turn, more sediment will accumulate, consolidating the berm further and allowing the plants in the gravel to encroach out whilst being joined by additional stow-away species derived from the natural seed bank further upstream.

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The brash bundles are moved to the river…

Photo courtesy of D. Hargreaves 

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positioned…

Photo courtesy of D. Hargreaves

IMG_6019
7848-HOGSMILL_RIVER-ESTATES-Ezzidin_Alwan-WEB and wired into position.

Photo courtesy: Ezzidin Alwan, Web & Multimedia Team, Kingston University

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Post..

Photo courtesy of D. Hargreaves

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after post…

Photo courtesy of D. Hargreaves

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after post are driven into the river bed.

Photo courtesy of D. Hargreaves

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wheelabroows loaded up
With the wheelbarrows loaded with a bit of mechanical assistance…

Photo courtesy: M. McLellan

start of the procession
the wheelbarrow procession begins…

Photo courtesy: M. McLellan

wheelbarrow procession
and periodically stops…

Photo courtesy: M. McLellan

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before the big heave ho.

Photo courtesy: Ezzidin Alwan, Web & Multimedia Team, Kingston University

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The finishing touches are made.

Photo courtesy: Ezzidin Alwan, Web & Multimedia Team, Kingston University

my brash line
The brash that will fill with silt and have plants establish in it.
my back fill
The gravel backfill which will be planted up too.

Being set at low flow water levels, in high flows and flood conditions, the whole structure will rapidly become drowned out and will not increase the risk of flooding. With the hard work of all involved, there was even a little time to spare on the last afternoon to undertake a cleanup. It really is amazing, in a rather depressing kind of way, that when you start to look for rubbish how much there is, either buried among the trees or lying on the river bed. A large Heras fence was extracted from the river, a sun roof, large television set and of course, there was the obligatory shopping trolley.

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Time to give the river a bit of a tidy.
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And the obligatory trolley!

Photos courtesy: Ezzidin Alwan, Web & Multimedia Team, Kingston University

A huge thanks to all involved!
A huge thanks to all involved!

Photos courtesy: Ezzidin Alwan, Web & Multimedia Team, Kingston University

To read Rachel Burgess’s account of the event please click here.

When we were planning this event we were aiming BIG and I had concerns whether I had bitten off more than we could chew. Thankfully we had a fantastic turnout and it is thanks to everyone involved that this monumental task was completed and to such great effect.

Once again a HUGE thanks goes out to all involved Nick, Helen S, Ben, Jacob, Chris, Kyle, Helen R, Iaroseowa, Rebecca, David, Fiona, Derryn, Bill, Gareth, Gloria, Illana, Bea, Aisling, Orla, Ella, Millie, Kat, Paul, Joe, Sam, Bruce, James, Suzanne, Steven, Ruth, Mike, Ben, Sally, Alex, Claire, Evie, Theo, Gideon, Patrick, Liam, James B, Erica, Elliot, Simon, Dave, Angelique, Ann, Jean, Charles, James, Jelmer, Mark M, Mark W, Gilly, Rebecca, David H, James H

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