Giving nature a hand – using woody debris to restore Essex rivers…

Our local geomorphologist and all-round river channel guru Trev Bond has been working with our Essex Ops team to give nature a hand along the River Crouch at Wickford.  The idea is to use carefully selected and installed parts of trees (woody debris) to replicate branches from trees falling into the river, influencing the flow of water and rebuilding natural features.  Unlike loose branches, these pieces of debris are firmly secured so they cannot come adrift and cause flooding problems elsewhere.  Flow velocity increases, silt is removed, gravels are exposed and habitat is created.

In this video Trev talks through what we are doing, how we do it and why…

For those who cannot view the video, here are some photos…

Some woody debris salvaged from within the Memorial Park.

Some woody debris salvaged from within the Memorial Park.

Digging a trench to secure the woody debris.

Digging a trench to secure the woody debris.

Woody debris securely installed in the bank of the river.

Woody debris securely installed in the bank of the river.

We want to return to the same spot in the future to document the effect of the features we have created.  We have had great feedback from local residents using the Memorial Park, not only of the work itself but also because we have opened up access to the River Crouch.  We hope to work with Basildon Council to undertake further improvements in the future.

Matt

Rain, restoration & renewal – an inspiring visit to Mayes Brook…

I really value the opportunity to learn more about projects that improve our rivers for the benefit of wildlife and the local community.  It is even better when I get to visit the site and speak to those involved.  I can really get a feel for how things have been achieved and the positive impact that has been made.  I am also keen to bring ideas back to Essex and make improvements here too.  That is how I ended up at Mayesbrook Park between Barking and Dagenham on a wet May day…

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It was a wet morning in Dagenham!

Mayes Brook, like many of our urban rivers, had become rather unloved.  Increasingly polluted from road run-off, misconnections and sewer overflows. It was hidden away in a concrete channel, behind tall fencing and isolated from the park and the community.  Out of sight, out of mind.  The park itself had become increasingly known for anti-social behaviour rather than being a space for people to enjoy.  Something had to change.

The Mayesbrook Park project is a great partnership between London Borough of Barking and Dagenham, the Environment Agency, the Mayor of London, Thames Rivers Restoration Trust, RSA, Natural England, London Wildlife Trust, and the SITA Trust.  The aim was to bring the brook back into the park and make it a valued feature, as well as reducing flood risk by creating an expanded flood plain and boosting ecology by creating new habitat.  By achieving these aims, hopefully the use of the park should increase and anti-social behaviour reduce.  Click on the image below to open a pdf leaflet summarising the project to date.

Click the image to open the pdf leaflet on Mayesbrook Park

Click the image to open the pdf leaflet on Mayesbrook Park

The benefit of seeing the park and Mayes Brook on a rainy day was that we could really see the scheme in action.  One area (shown below), that really impressed me, was where the old channel had been replaced by a wonderful, meandering and gently banked landscape.  Fantastic for flood storage, ecology and safe access.  This is something we could replicate at several location across Essex and changes the character of a park from a large, flat green field to something really alive.  Brilliant!

The narrow concrete lined channel has been replaced by a meandering, gently sloping channel and flood plain.

The narrow concrete lined channel has been replaced by a meandering, gently sloping channel and flood plain.

 

Another view of the more natural area created from the concrete lined channel.

Another view of the more natural area created from the concrete lined channel.

It was also great to see simple sustainable drainage (SuDS) techniques being used for the surface and roof drainage from the impressive new sports centre nearby.  Water was held in a series of fenced, grassy pond areas to reduce the rate of run-off and reduce pollutants heading to Mayes Brook.  These were working really well on the day of my visit.

One of the "SuDS ponds" to attenuate and treat roof water from the SportHouse building.

One of the “SuDS ponds” to attenuate and treat roof water from the SportHouse building.

Another view of one of the "SuDS ponds" in action.

Another view of one of the “SuDS ponds” in action.

In other parts of the park where space was restricted the fencing was removed from Mayes Brook, the concrete channel liner taken away and one of the banks reprofiled to increase capacity and habitat.  This was a huge improvement in itself and at least brought the brook out from its isolated hiding place.

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Where space was an issue, removing concrete channel and some regrading was done.

The other distinct part of the project was the nature reserve at the upstream end of the park.  This stretch of Mayes Brook had been reprofiled and improved, but was fenced off to allow wildlife to have a quiet haven.  Although public access is important, this provided a good compromise and allowed different species to flourish.

The fenced nature reserve area at the upstream end of the park.

The fenced nature reserve area at the upstream end of the park.

All this work to get Mayes Brook to be a part of the park and local community has been really successful.  By raising awareness of the importance of our rivers and streams we start to care more about pollution and misconnected drainage that would otherwise not seem as much of a problem.  The momentum we can build with these projects is staggering.

The most exciting thing about my visit to Mayesbrook Park was that I could straight away think of locations in Essex where we could adopt at least one of the techniques or approaches above.  Anywhere a brook or river flows through a park or other open space, we could do something positive.  The scale of improvement will depend on what the stretch of water needs, local support, partners, funding and willing volunteers.

Matt

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Love Your River – now I have the jumper to prove it!

Matt Butcher:

Matt says: This work looks fantastic and I would love to use it to help engage people with Essex rivers. Great stuff!

Originally posted on Communicating Landscape Futures:

#LoveYourRiver

The back of my new jumper! You can also see my twitter handle @happy_mapper on the sleeve

The PhD Visioning Catchment Futures is now on its final case study, three years after I started the PhD in January 2011 I have finished two case studies (#1 Augmented Reality & #2 Stiffkey catchment planning). The work to date has been presented across four different conferences over three years (3 in the UK (GISRUK2012. GISRUK2013, RRC2014 and 1 in Zurich DLA2014), the VesAR #AR work has won a prize for scientific excellence. I’ve been using twitter as @happy_mapper with the hashtag #loveyourriver. I’ve talked to a lot of people too, since January 2012 I have run around 25 sessions with the public in four river catchments (Gaywood, Stiffkey, Wensum, Yare) to collect information about how people engage with technology. After the last conference I was asked for a summary of the case studies and if…

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The Essex Rivers Hub keeps things rolling…

It seems a long while ago now that I worked on the concept of the Essex Rivers Hub web site with my colleague Regan and the guys at Essex Wildlife Trust.  When I thought of that name for the site it was one of those rare “Eureka!” moments, but at the time none of us knew just how much potential there was with this new venture.

Since the launch it has developed into a great resource to enable people to find out more about rivers near them, learn about the issues being faced and ideas for how to solve them.  It is evolving all the time, but I am proud to have been a part of those early stages.  Regan will shortly be leaving us for pastures new, but her contribution to improving Essex rivers will be long appreciated.

The Essex Rivers Hub site is a great place to explore...

The Essex Rivers Hub site is a great place to explore…

The Essex Rivers Hub  has also been adopted as the brand for the Combined Essex Catchment Partnership.  This can only be a good thing, as “Combined Essex” (the official name of the catchment) does not really mean a lot to most people.  We need to take every opportunity to keep things simple, break down barriers and get people involved.  Having a clear identity is a great start.

I attended a recent session with a small group of Essex Rivers Hub partners where we shaped the format of the catchment plan and discussed when it will be produced.  We  also looked at how we engage with more people to raise awareness and get them involved on the ground.

One output from this session (to be agreed by the wider partnership) is that we will use the Essex Rivers Hub site as the core of our plan.  This is interactive, flexible and easily updated.  It should mean the plan does not sit gathering dust as it is already out there for others to see and get involved with.

As for engagement, the plan is for three workshops this autumn around Essex to look at the issues and opportunities for our rivers.  We want to raise the profile of the Essex Rivers Hub (web site and partnership), encourage people to think of where their goals align or overlap and to translate the talking into action.

As with all new partnerships, the Essex Rivers Hub will take a little time to build momentum but I really feel we are heading in the right direction to make lasting improvements to Essex rivers.  Exciting times!

Matt

Its good to be shady…

Shade from trees is really important to keep rivers healthy for a wide range of wildlife. We are looking at areas across Essex where we can make an improvement.

The benefits of shade
Stretches of river without shading from trees can be several degrees warmer in the summer than those with tree cover. Over the coming decades summer river temperatures will rise further, causing a real threat to species including trout that thrive in cool water. Limiting sunlight on the water surface also controls the level of weed growth that can be detrimental to having a balanced ecosystem, and less weed can mean reduced flood risk without potentially harmful weed-cutting operations. Locating suitable sites for tree planting and doing it now will help to protect our rivers from future climate change.

Trees also provide great habitat along the river corridor, and when branches break off and fall into the water they can change the flow and provide shelter for many species. In the right place, trees can be the answer to many problems we face.

Where did all the trees go?
In a lot of places, rivers have been deepened, widened and straightened to drain land and prevent flooding. This often included removing trees along the river bank. We now have a much better understanding of how rivers work than we did generations ago, and we have the opportunity to look at the whole catchment. Rather than looking in individual locations and trying to “dispose” of the water downstream and ultimately out to sea, we aim to manage entire catchments to slow down the run-off and hold water in certain areas. This should mean less flooding, less severe impacts during dry periods and better habitat. There will always be a place for flood defences and dredging, but there is also a place for trees and wetlands.

A modified, straightened river channel with very little tree shading.

A modified, straightened river channel with very little tree shading.

A restored river channel with good tree shade. Geat habitat.

A restored river channel with good tree shade. Great habitat.

How do we know where to focus with tree planting?
We have worked with Essex Wildlife Trust to carry out walkover surveys of some Essex rivers (see HERE for more info) and we have some great information  on shading, land use etc as a result.  More recently we have been given a great dataset by our Geomatics guys showing comparative shading in all our catchments.  This gives us a powerful tool to focus our efforts, but how does it work?

The science bit
It is all thanks to LIDAR (LIght Detection And Ranging) technology used to generate detailed flood maps across the country.  The equipment is installed in aircraft and lasers are used to measure the distance from the aircraft and the ground surface, producing highly accurate 3D models.  This allows us to refine flood maps, improve flood warnings and to give advice for planning new development that could be at risk from flooding.

Our Geomatics team use light aircfraft equiped with LIDAR kit

Our Geomatics team use light aircfraft equiped with LIDAR kit

 

Inside the aircraft, some of the clever kit that helps to manage flooding and improve habitat.

Some of the clever kit that helps to manage flooding and improve habitat.

The two main types of LIDAR outputs are the Digital Surface Model (DSM) and Digital Terrain Model (DTM). The DSM includes surface objects such as buildings, vegetation etc and the DTM has these removed to show the “bare earth” ground level. We can remove just the buildings from the DSM to leave us with a model showing vegetation, compare it with the “bare earth” DTM, factor in the average solar energy for the area and create relative shade maps. Very clever, complex work but the outputs are easy to understand and very visual.

Example of a Digital Surface Model (DSM) for Cymbeline Meadows, showing all surface features.

Example of a Digital Surface Model (DSM) at Cymbeline Meadows, showing all surface features.

A Digital Terrain Model (DTM) of Cymbeline Meadows, showing the "bare earth" ground level.

Example of a Digital Terrain Model (DTM) at Cymbeline Meadows, showing the “bare earth” ground level.

An Essex example
I recently met with Paul from the Essex & Suffolk Rivers Trust to discuss what work we may be able to do with Colchester Borough Council along the River Colne at Cymbeline Meadows, Colchester. I consulted the Geomatics LIDAR data and it clearly showed a comparative lack of shade through the parkland. This means that for relatively little money and working with volunteers we can plant trees alongside the river and make a big habitat improvement over time.

Click on the image to open a pdf map you can print or save.

Click on the image to open a pdf map you can print or save.

I took a lunchtime wander along some of the “red areas” on the map.  The good news is that the science works and the shade map was spot on.  Also where there are trees by the river, there is a good source of woody debris as well as shade.  The bad news is the distinct lack of trees on the south bank as can be seen on the second photograph below.

Where there are trees, some branches are in the channel creating the woody debris of the future. Perfect!

Where there are trees, some branches are in the channel creating the woody debris of the future. Perfect!

A visit to Cymbeline Meadows confirms a lack of tree shading, especially on the far (south) bank.

The lack of tree shading on the far (south) bank at Cymbeline Meadows is something we can address.

What next for Cymbeline Meadows?
We have used our LIDAR data and local knowledge to find an area lacking in shade, confirmed that it does need some love and attention so now we need to do something.  We will be working alongside the Essex & Suffolk Rivers Trust and Colchester Borough Council, pulling together a plan to increase the shading of the river channel as well as any other affordable modifications that can be put in place with the help of local volunteers.

Watch this space as the project takes shape!

Matt

Prevention is better than cure…

When it comes to our health and wellbeing, most of us accept that prevention is better than cure. Whether it is leading a healthy lifestyle with plenty of exercise or minimising risk in what we do, there is a lot to be said for reducing our reliance on health services. It means we can get on with our lives for more of the time without intervention and it saves a lot of money that can be spent elsewhere. There will always be a need for ambulances, hospitals and other services when things DO go wrong, but anything we can do to help ourselves is better for us and reduces the pressure on valuable resources.

It is a similar story for flooding, where prevention is also better than cure. We cannot stop it from raining, but how we manage rainfall is vitally important. By looking at the catchment as a whole we can make a real difference. We can influence how long the water is retained on land and in ditches high up in the headwaters of our rivers, ensuring its journey downstream takes longer with a lower “peak” flow. We should even be able to phase differtent tributaries to stagger the flow into the main river, further smoothing out peaks and reducing flood risk. If done appropriately, working with nature, we can boost ecology and make our rivers healthier as well as needing less hard engineered flood defences that can be very expensive.

There was a recent article on the BBC News that shows some of the options for working with nature to reduce flood risk: Link to BBC article

One of the main areas we can make a real difference is with Rural Sustainable Drainage Systems, as I covered in a previous post. There are so many simple things to do, including slowing water in ditches using willow or other structures, creating scrapes at the bottom of fields to hold back the run-off etc. Also simply doing less work clearing and deepening ditches can make a big difference. The more one land owner does to drain his or her land, the more potential there is for flooding to be caused further dowstream.

A willow structure in a farm ditch, used to hold up high flows and reduce flood risk further downstream.

A willow structure in a farm ditch, used to hold up high flows and reduce flood risk further downstream.

This is a piece of large woody debris that has been positioned in the river channel.  This debris can create great habitat as well as holding back peak flows to reduce downstream flood risk..

This is a piece of large woody debris that has been positioned in the river channel. This debris can create great habitat as well as holding back peak flows to reduce downstream flood risk..

There will always be a need for flood defences for vulnerable communities in the same way we will always need health services, but with a catchment-based approach to working more closely with nature we will need to build less. We can reduce flood risk, reduce costs and enhance our rivers and landscape for people and wildlife.

My aim is to ensure that when we work with local communities in Essex to reduce flood risk that we consider these lower impact, more strategic options across a much wider area. I am also working with partners such as Essex Wildlife Trust, Essex & Suffolk Rivers Trust and Catchment Partnerships to help them to make a real difference. We need to think more laterally, I am passionate about moving this from a discussion into action.

There are a number of projects in development, and a lot more that needs to be done to really build momentum. You can check out the latest info at the Essex Rivers Hub and submit your ideas there too. Are you a land owner along one of our rivers who would like to work with us? We want to hear from you please.

Matt

How wood in rivers affects flood risk

Matt Butcher:

Matt says: Another fantastic blog post from Simon Dixon. We are getting to grips with how to play tunes on the flow to reduce downstream peaks, and this is fundamental to blending cost-effective flood risk management with good ecology.

Originally posted on The River Management Blog:

Look upstream at a logjamOne of the key objectives of my PhD research at University of Southampton was to try and assess how changing volumes of wood in rivers affects the likelihood and magnitude of flooding. The amount of wood in rivers can increase for various reasons, such as artificial insertion in the river for river restoration, river managers choosing to cease clearing natural deadwood from channels, or the growth/restoration of streamside (riparian) forests. We know that if wood is put into a river then flood water moves slower through/around it, and thus for a short distance downstream flood water will have a longer “travel time”. What no-one has done before is look at the effects upon flooding at a distant downstream location (such as a town) of changing the speed water moves through a small sections of the river catchment upstream of it.

My research in this area was sponsored by the Environment…

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