Tag Archives: Royal Parks

Richmond Park restoration: update two years on

It has now been two years since the river restoration work on the Beverley Brook through Richmond Park was completed. This time has allowed the two restored stretches with a cumulative length of 600 metres to adjust and naturalise in response to the changes which were made. The original blogs describing the works can be read in the links below.

http://www.southeastriverstrust.org/delivery-to-the-beverley-brook-in-richmond-park-phase-1/

http://www.southeastriverstrust.org/tree-planting-in-richmond-park/

http://www.southeastriverstrust.org/planting-on-the-beverley-brook/

A key principle behind the restoration was to reinstate natural processes back to the river by providing energy and diversity which in turn would allow it to ‘self-heal’. The river now has the opportunity to scour and erode the bed which consequently creates in-channel features such as pools, riffles and bars which were almost completely lacking before. The uniform sandy bed has been displaced to expose the rich gravels below, providing much improved conditions for invertebrates and fish spawning.

The bed now undulates ranging from ankle deep riffles to waist deep pools. There is now a huge array of flow types and with it a myriad of habitats. For the first time in decades the Beverley Brook is audible as the flows pass over, under and through the Large Woody Material and as it babbles over the riffles.

Large Woody Material narrowing the channel and kicking the flow around

With all this scour and erosion, sediment is being deposited in areas of slack water, such as on the inside of meanders and among the vast quantities of brash that was installed. This is working to such great effect that the brash in many locations is no longer perceivably brash. So much sediment and seeds have been deposited that these now appear to be natural banks which stabilise and help to narrow the channel to the dimensions that the Brook should naturally have. In turn, the vegetation that is establishing collects more silt, and so the channel continues to evolve and diversify.

A brash- berm on the left naturalising with a diverse mix of marginal plant species

The regraded banks and low lying berms are vegetating now that the erected fence keeps the deer and their intensive grazing habits out. Marginal and terrestrial plants are starting to thrive, providing previously absent habitats. The grass really is greener on the other side of the fence.

Follow up macrophyte, invertebrate and fish surveys will take place next summer. By then these communities will have had time to adjust enabling us to make an informed and scientific assessment of the biological impacts of the work. Until we get the results back, anecdotally we have observed significant changes. As previously described, the plant communities are noticeably diverse and extensive. Fish which were previously almost completely absent from the downstream stretch are now abundant with large shoals of dace, chub and stone loach being very apparent.

A picture describes a thousand words so I will keep the blog to a succinct length (for me anyway) with a selection of before and after shots to demonstrate the points raised above. We will keep you posted when we get the results of the follow up surveys.

Before; over-wide, straight, sandy bed and bland with few marginal plants…

and after two years later!!!

Before

Two years on.

Before

Two years on

Before

Two years on

 

A sandy bottom and over-wide channel

Two years on, gravel with marginal plants

An attractive functioning river returns to Richmond Park

A new, exciting project to improve water quality on the Beverley Brook

So you know that the roads can be pretty dirty. You see the direct effects of it on your car when you think it’s probably time to give it a clean. The dirt on the roads is also really well illustrated when it snows and soon the pure white snow changes to black slush. But where does all of this dirt come from?

You see trucks and lorries leaking oil and busses belching out thick clouds of exhaust fumes when pulling away from traffic lights. You see gulley pots full of litter, cigarette butts and sand that has run off the nearest building site. Or the paint that is dripped out of vans or has been poured into the curb. You walk along the street dodging ‘dog eggs’ which litter the pavement. Then in winter the roads get spread with grit and salt during cold snaps.

You may consider of all of these things as unsightly or unpleasant when on the roads, but within a short period of time and with a bit of rain, all of these substances are washed away and are out of sight and out of mind. But where does it disappear to?

The answer: often the nearest watercourse.

The initial runoff, known as the ‘first flush’, runs black especially in urban areas. In turn with many other outfalls also discharging the entire river turns black.

First flush on the River Wandle, South East Rivers Trust

So what is in this run-off?

Basically it consists of a nasty cocktail containing pieces of the road surface, tyres, brake pads and other material from engine parts from regular wear. Throw into the mix some fuel, gear oil, grease, brake fluid and antifreeze. Then for good measure add some pesticides, fertilisers, plant detritus, some illicit dumping of substances, inputs from misconnected drains and in winter de-icing grit and salt.

Unsurprisingly road runoff can be detrimental to the receiving watercourse, whose impacts on riverine ecology can be acute or chronic. The sediment smothers gravels vital for invertebrates and fish. The turbid water reduces light penetration so plant communities suffer due to limited photosynthesis. Furthermore, the sediment blocks the feeding mechanisms of filter feeders and gills of other aquatic organisms.

The Poly Aromatic Hydrocarbons (PAHs) (oils) and heavy metals are both known to be toxic to aquatic fauna. High concentrations of heavy metals associated with the ‘first flush’ can ‘shock’ aquatic environments as the water is polluted with levels several times higher the normal concentration. Multiple studies have shown that heavy metals can also cause long term impacts as they bio-accumulate within the food chain.

So what can we do?

It is well known that these contaminants freely bind to sediment. It therefore follows that if the sediment is removed, so too will many of the contaminants. This is the plan to protect the Beverley Brook in Richmond Park.

The Project

The Rivers Trust and WWF are managing three water management projects in the Thames and South East River Basins, for the benefit of both people and wildlife. The wider initiative is funded by the Coca-Cola Foundation and contributes to Coca-Cola’s promise to safely return the full amount of water used in finished beverages and their production to communities and nature by 2020 – an ongoing commitment as they managed to reach this goal five years ahead of target. Globally Coca-Cola works in over 2000 communities and supports more than 248 community water partnership projects in over 71 countries – this being one of them.

A schematic of how a Downstream Defender works

We are delighted to announce that the South East Rivers Trust is delivering one of these three projects which will see a large (and I mean very large) silt trap, known as a Downstream Defender® supplied by Hydro International, installed onto a surface water drain. The drain currently carries run-off from the incredibly urban surrounding catchment directly into the Beverley Brook. The Downstream Defender will trap a large portion of the sediment and associated contaminants, preventing them from reaching the Beverley Brook. Intermittently the trap will be emptied with a gulley sucker and the toxic sludge removed to landfill. Consequently, the health of the river will improve making it a better place for both wildlife and people.

Last Tuesday we launched this collaborative project with the arrival of the Downstream Defender to Richmond Park. We’d like to thank our funders, the Coca-Cola Foundation, as well as all our partners including WWF, The Rivers Trust, the Environment Agency, The Royal Parks, the Friends of Richmond Park and Thames Water. Also a big thank you to Hydro International for supplying the Downstream Defender and for their much appreciated contributions to the launch event. Thank you to all the guys at Kenward Groundworks; Tony, Matt, Dave, Mark and Woody for all your efforts with installing the chamber. And finally thanks to John Sutton from Clearwater Photography for taking photograph of the launch and project.

Partners with the Downstream Defender Silt Trap

 

Celebrating the launch of the project with partners and volunteers

Photos: John Sutton, Clearwater Photography

 

River Restoration in Richmond Park

Richmond ParkWe’ve started our latest restoration project in Richmond Park, working to enhance the Beverley Brook in partnership with The Royal Parks, The Environment Agency, the Friends of Richmond Park and the Beverley Brook Catchment Partnership.

Richmond Park is well known for its deer and its nationally important terrestrial habitats, e.g. acid grassland. Given this high status you would be forgiven for thinking that the river was also in good shape.  However, it’s actually not and its wildlife is relatively impoverished.

About 14% of the length of the Beverley Brook runs through the Richmond Park and so restoring the river through the park, presents an excellent opportunity to make a real difference to the whole river ecosystem.

Why is restoration needed?

The Beverley Brook, like many of London’s rivers, has been heavily modified in the past leaving a highly uniform river channel lacking in habitat diversity. The river channel has been over-widened and in places deepened along most of its length with all natural woody material and instream features being routinely removed from the channel for decades. Due to these reasons there is little variation in flow and depth and subsequently there is little habitat diversity for fish and aquatic invertebrates.

RP Before 2In addition to this the banks are very steep and the river is incised (if you stand on the top of the bank the river is quite a long way down!) and the banks have been subject to increased erosion due to the intense grazing of deer. The deer enjoy eating the succulent river bank plants. This means there is little vegetation left and there are no root structures to hold the soil on the river bank in place and so it washes into the river.  You may have seen a sandy bottom on the river bed: this isn’t actually what it’s meant to look like and is a result of the soil washing in and smothering the natural gravels on the river bed. This is a problem for the river ecosystem as many of the plants and animals that would naturally live in the Beverley Brook need the gravelly river bed habitats to survive.

SiltyBed           SteepBank

A natural river system has the ability to self-regulate but when it becomes modified, the processes can get out of kilter and we may need to intervene to kick start them again.  All of the modifications to the Beverley Brook have left the river with little power, taking away the opportunity for the channel to naturally fix itself with geomorphological processes.

RP Before 1What we are doing

A large river restoration project in the Park has been developed and funded in partnership with the South East Rivers Trust, the Royal Parks, the Friends of Richmond Park, the Environment Agency and the Beverley Brook Catchment Partnership. The aim of this project is to naturalise 600 m of the Beverley Brook through the park using a number of simple restoration techniques. These include:

  • Adding Large Woody Material to increase flow variation and provide a greater complexity of habitats for aquatic wildlife.
  • Re-profiling the incised and steep banks to enhance marginal habitats.
  • Narrowing and remeandering the channel to create a diversity of different flow patterns and produce marginal wetland berms.
  • Erecting fencing and river gates to temporarily exclude the deer to allow the banks to stabilise and for vegetation to recover.
  • Creating slower flowing areas as refuge for animals during the high flows which are typical of urban rivers such as the Beverley Brook. This is particularly important to help fish establish and not be washed downstream (and possibly right out of the river) in heavy rains.
  • Address the contaminated road run-off input into the river from the A3 by creating a siltation pond and wetland to trap and clean the silt from the road.

So it is going to be a busy couple of months on site and we are all excited about the results this project will bring!

You can read more about the project and how Richmond Park access will be affected during works on the Royal Parks website here.

RichmondGrid