Managing Water Magazine Autumn 2105 by Relbon Limited

The on-line magazine for the water management industry

and its environment

Autumn 2015

Flow control structure on the River Wansbeck as part of the completed Morpeth flood protection scheme.

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Contents FLOOD RISK

New Chief Executive for the Environment Agency

2015 Flood Expo set for record attendance

Investment in temporary flood barrier capability

New Chief Executive for the Environment Agency

Honorary degree awarded for contribution to flood risk management Pilot scheme launched to help communities obtain flood protection funding New guidelines for flood protection experts

Environment Agency carry out exercises to test flood response £6m tidal gauge will help to forcast flooding

£26m Morpeth flood scheme officially opened

Flood Expo ready for record attendance

STORMWATER & SuDS

SuDS – Time for Celebrations?

£4.28 million Flood Defences Go Underground, Overground in London Parks

Collaborative Approach For Supermarket Development

Sustainable SuDS Treatment for Aberdeen International Business Park

RIVER RESTORATION & MANAGEMENT

Morpeth flood scheme officially opens

8 9

10 11

15 16

18 - 19 20 - 21

UK’s largest Silt Pusher launched

23 - 24

Sensitive bridge design

CW announce new electrical and mechanical engineering services Natural engineering creates safe havens for white-clawed crayfish Four new eel passes on the Bedford Ouse

DIRECTORY

30 - 32

To advertise in Managing Water or list your company on FADS,

A first in effective surface water management

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Contact

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Published by: Relbon Ltd, Company Reg 07488993 Relbon House, 3, Lake Way, Huntingdon, Cambs, PE29 6SU, UK, admin@relbon.co.uk

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Flood Risk

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Sir James Bevan appointed as the new Environment Agency Chief Executive

Sir James has had a long career in government and will leave his current role as the UK’s High Commissioner to India to take up the role of chief executive on 30 November. Sir Philip Dilley, chairman of the Environment Agency, said:

I am delighted that Sir James Bevan will be joining the Environment Agency as its chief executive later this year. Sir James will lead the organisation with passion, energy and a clear commitment to continue the great work it does to protect and improve the environment and make it a better place for people and wildlife. Sir James said:

One of the biggest challenges of our time is protecting the environment and promoting growth. We need to do both, and I look forward to playing my part in that. The Environment Agency is a great organisation which makes a great contribution to our country. It will be an honour and a privilege to lead it.

David Rooke, the Environment Agency’s current executive director for flood risk management, will act as chief executive until Sir James takes up his new role. Former chief executive Paul Leinster left his role on 25 September after 17 years at the Environment Agency. Career

Sir James was educated at Sussex University.

In 1982 he joined the British Diplomatic Service iwhere he served in Kinshasa, Brussels, Paris, and Washington, as well as various posts in the Foreign and Commonwealth Office. He was a Visiting Fellow at the Weatherhead Center for International Affairs at Harvard (2006–07) and the Chief Operating Officer of the FCO (2007–11). He has been High Commissioner to India since 2011, James Bevan was appointed CMG in 2006 and knighted KCMG in 2012.

Investment in temporary flood barrier capability The Environment Agency is seeking to improve its incident response capability by increasing its stock of temporary flood defences which will be stored at a network of depots distributed around England. These defences may be used in a variety of flooding incidents and will form an essential part of flood incident response.

The contract for the supply of barriers will be in two parts, both for temporary barriers that consist of metal frames with impermeable membranes or sections spanning between them.

The first is the supply of between 5km to 15km of temporary flood barriers, with a minimum barrier height of 1.0m and the second is the supply of up to 3km of temporary flood barriers with a minimum barrier height of 1.8m.

The quantity purchased will depend on available budgets.

Temporary Flood Barriers are deployed by the Environment Agency as a short-term measure against flooding from main rivers where: • the location for their use and the time available to deploy them in normal conditions are suitable; • there is support from the local authority, partner organisations and the community; • they are technically and economically viable;

• they are not used as a long term alternative to permanent schemes

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FLOOD EXPO

THE WORLD’S LEADING FLOOD EXHIBITION AND CONFERENCE

SPEAKERS INCLUDE

IN PAR PARTNERSHIP P ARTNERSHIP WITH

THE MUST-ATTEND EVENT FOR FLOOD PROFESSIONALS

JOHN CURTIN Director of Incident Management & Resilience at the Environment Agency

LIVE PANEL DEBATES 150 INNOVATIVE SUPPLIERS 80 CPD ACCREDITED SEMINARS

JAMES HEAPPEY MP for the Wells Constituency and Flood Advisor to Cabinet

LIVE DEMOS ON THE THAMES CASE STUDIES FROM AROUND THE WORLD FLOOD TECH THEATRE ENVIRONMENT AGENCY SEMINAR THEATRE SEARCH & RESCUE NETWORKING AREA

MARY DHONAU OBE Mary Queen of Floods

AN INCREDIBLE LINE-UP OF SPEAKERS

14 &15 OCTOBER

BRENDAN MCCAFFERTY CEO of Flood Re

FREE TO REGISTER

WWW.THEFLOODEXPO.CO.UK

OR CALL 08000 686970

MAJOR NICK FRANCIS Emergency Construction Expert from the Royal Engineers

Flood Risk & Drainage

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2015 Flood Expo set for record attendance PRYSM Group is absolutely delighted to announce Flood Expo – the world’s largest event dedicated to presenting solutions to widespread flooding problems – will return to ExCeL on the 14th and 15th of October, 2015. This event, winner of the 2015 Exhibition News Awards’ Show Rising Star, is concentrated on both solving any problems you face and providing solutions with the purpose of highlighting the new and cost-effective ways of preventing and managing flooding. Amongst this year’s outstanding selection of speakers are James Heappey, MP for Wells constituency; ‘The Queen of Floods’, Mary Dhonau OBE; and John Curtin, Director of Incident Management & Resilience at the Environment Agency. Event Director Jon Greenslade, says: “We’re absolutely thrilled by the scale of which the show has reached. As the premier show for providing the ground-breaking innovation and latest strategic thinking in flood defence and prevention, our exhibition is looking better than ever to continuing its fantastic commitment to the flood industry’.

Who else will be there? 2,500 business owners, decision makers, property and land owners will be present across both days of the show, providing an unparalleled level of networking opportunities.

What’s going on? There will be a total of 80 seminars delivered by the foremost experts in the field, 150 exhibitors showcasing cutting-edge products and services, live demonstrations, masterclasses, and live debates.

As well as all this, the Flood Expo has two halls dedicated to networking - the Search and Rescue Organisation Networking Area, a zone specifically designed for search and rescue professionals working in emergency services or voluntary organisations, and the Environment Agency Networking Area, which is specially designed to provide a chance to learn more about the Agency’s commitment to the protection and enhancement of the environment and their partnership with the Flood Forecasting Centre and the Met Office.

How do you get to go?

Flood Expo is absolutely free to attend. To find out more information on everything that’s happening at the show, simply visit www.thefloodexpo.co.uk.

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Honorary degree awarded for contribution to flood risk management

Flood Risk & Drainage

Flood campaigner, Mary Dhonau OBE, recognised for her contribution towards flood risk management

Mary Dhonau OBE HonRICS, chief executive of the Know Your Flood Risk campaign, has been presented with an Honorary Degree of Honorary Doctor of Science from the University of West England (UWE) at a ceremony held in Bristol Cathedral. The Honorary Degrees Committee from the university selected Mary in recognition of the contributions she has made in the field of flood risk management across the country, for the past 15 years. Mary, who has been flooded herself on many occasions, has extensive experience in supporting and advising the victims of flooding during their recovery. She has championed promotion of individual flood protection and resilience and is a passionate advocate of empowering communities to recognise and take responsibility for minimising their collective flood risk.

Professor Lindsey McEwen, Professor of Environmental Management in the Department of Geography and Environmental Management at UWE, was one of the nominators of Mary at the university. Professor McEwen said: “I direct the Centre for Floods, Communities and Resilience, and also have significant experience in community engagement related to flooding. In these roles, I have observed Mary’s unstinting passion for raising flood risk awareness, in supporting communities before, during and after a flood event occurs, and in promoting flood preparedness. She regularly represents the ‘voice of the flooded’ and it is her enduring drive towards supporting these communities that led me to nominate Mary for the Honorary Degree, which she greatly deserves.”

As well as Chief Executive of the ‘Know Your Flood Risk’ campaign, Mary is the Chair of the Flood Protection Group for the Property Care Association and a member of the Regional Flood and Coastal committee for Anglian Northern. She also runs a consultancy (MD Associates) specialising in raising awareness of flood risk, how to militate against it and recover from it.

Mary, who has become affectionately known by many as ‘Mary Queen of Floods’ said: “To receive an honorary doctorate from the University of West England is just marvellous. Since suffering the appalling consequences of being flooded myself, and on more than one occasion, I have made it my personal mission in life to raise the awareness of flood risk. It is something I am hugely passionate about and so to be recognised by the UWE in this way in tribute to my work is very humbling.” Mary was awarded an OBE for services to the environment in the Queen’s Birthday Honours list in 2009. In December 2014, she was then awarded Honorary RICS (HonRICS) status, in recognition of her high profile in standing-up for the public’s interest regarding flooding. Mary was also given the ‘Voice of the Customer ‘award and the CII Public Interest Awards 2015

The Know Your Flood Risk Campaign’s mission is to raise awareness of the risk of flooding from all sources. It is a one of the UK’s leading online sources for helping people find out the flood risk related to their current or future homes.

For more information, visit www.knowyourfloodrisk.co.uk, www.marydhonau.co.uk or follow the Know Your Flood Risk campaign on Twitter or via Facebook. 8

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Flood Risk & Drainage

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Pilot scheme launched to help communities obtain flood protection funding

Six rural areas are to receive a share of a halfa-million pound fund making it easier for them to apply for flood protection, The ‘Pathfinder Projects’ pilot schemes will look at cutting red tape and costs for small communities at risk of flooding across the country. Each pilot will support local authorities in developing innovative ways to apply for funding, combining smaller projects into larger and more effective flood risk management packages for each area. Floods Minister Rory Stewart said:

We are investing in flood protection across the country at record levels, with an unprecedented six-year commitment of £2.3 billion to better protect an additional 300,000 homes by 2021.

These pilots will make it easier for local authorities to apply for flood protection funding so they can better protect people’s homes and businesses. Our rural and small communities will also have the opportunity to play a key role in developing these schemes. The local authorities receiving funding to investigate and assess options are: Northamptonshire County Council Addressing flood risks in parts of Daventry, Helmdon, Grimscote, Cogenhoe, Quinton, Grendon and Grafton Underwood.

Buckinghamshire County Council Addressing surface and ground water risks in four locations in Buckinghamshire and will support projects in Bishopstone, Saunderton/Bradenham, Hughenden Valley and Monks Risborough.

Kirklees County Council Addressing a range of surface water risks for communities within Honley, Moldgreen, Huddersdfield and Kirkburton.

Warwickshire County Council Developing and assessing a package of flood risk management measures for groups of properties in small communities in Warwickshire.

Hampshire County Council Addressing a combination of ground, surface and river flood risks in the county. The project will explore possible solutions for communities near Andover, in Vernhan Dean, Upton, Hurstbourne Tarrant, Stoke and St Mary Bourne.

Lancashire County Council Addressing largely surface water and ordinary water course flood risks The communities being considered are within Whitworth, Stackstead, Strongstry, Rawtenstall and Cloughfold (all in Rossendale) and Ewood Bridge.

The Trials

Once these trials have taken place, local authorities will report on their findings and will then have the opportunity to apply for funding from the Government’s £2.3bn six year flood defence programme. The results from these trials will be shared with other local authorities and allow them to use similar approaches when developing schemes which benefit small communities.

The Pathfinder scheme enables communities at significant or greater risk of flooding to work with key partners, including local authorities, to develop innovative local solutions that: • enhance flood risk management and preparedness in ways which quantifiably improve the community’s overall resilience; • demonstrably improve the community’s financial resilience in relation to flooding; and • deliver sustained improvements which have the potential to be applied in other areas.

Please visit 2010 to 2015 government policy: flooding and coastal change for further information on the schemes.

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Flood Risk & Drainage

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New Code of Practice guidelines for flood protection experts The NEW guidelines on flood protection are set to be unveiled at a world-leading event for industry professionals. The Code of Practice for the Flood Protection of Buildings will be launched at Flood Expo 2015 – at ExCel, London on October 14 and 15.

The document, developed by the Property Care Association (PCA) Flood Protection Group, aims to provide a concise and thorough guide to the subject based on current best practice. Steve Hodgson, chief executive of the national trade body said:

“The Code of Practice will provide guidelines that set the principles and standards to which our members work. “It recognises the need for any professional involved in the protection of buildings at risk of flood to understand the physical, financial and, very importantly, the emotional impact on property owners.

“One of our key aims is to drive up standards within the industry and we believe the new Code of Practice will

be an essential part of that.”

Contractors and manufacturers affiliated to the PCA must already measure up to strict criteria and standards in areas including technical competence, financial probity, training and customer service. But Mr Hodgson believes the Code of Practice will further underline the professional credentials of the organisation’s members. He added:

“We’re keen to increase consumer confidence and become a reference point for legislators, community groups, insurers and home owners.

“By establishing the Flood Protection Group last year and now launching a new Code of Practice, we believe we’re making great strides towards those goals.”

Mary Dhonau OBE, chair of the PCA Flood Protection Group and chief executive of the ‘Know Your Flood Risk’ campaign, believes the new guidelines are essential. She said:

“With the increase in the number of devastating floods expected to rise due to climate change and

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homeowners being expected to protect their own homes, it’s vital that the PCA Flood Protection Group raises the bar within the industry and expects a high level of professionalism from its members. “Consumers will then have assurance that our members will provide an excellent service when it comes to making their homes more resilient to flooding.”

Both Mr Hodgson and Ms Dhonau will be speaking at the Flood Expo – the largest event of its kind in the world. The two-day event will feature 80 expert-led seminars highlighting new, cost-effective ways to prevent and manage floods.

The show, delivered in partnership with the Environment Agency and now CPD accredited, will also include live demonstrations with more than 150 industry-leading suppliers displaying the latest flood prevention solutions. For more about the PCA, go to www.property-care.org

Flood Risk & Drainage

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Operation ‘Obex’

The Environment Agency carry out exercises to test flood response The Environment Agency has carried out an operation to test its emergency response to flooding at six locations around the country. The tests were carried out on Thursday 17th September by 240 EA staff and Floods Minister Rory Stewart. The exercise included the constructing of temporary barriers, testing pumps and manning incident rooms in a scenario based on the severe flooding of winter 2013/14, the wettest winter in 250 years. John Curtin, Director of Incident Management, at the Environment Agency said:

Temporary defences can be extremely effective in protecting people and properties against the devastating effects of flooding. We’re really pleased that the Minister could take part in today’s exercise, which was a great example of how these defences can be put into action when flooding hits.

Although temporary defences can reduce the risk of flooding they may not be able to stop all floods. We still urge the public to take action to protect themselves and their property. They can sign up to the Environment Agency’s flood warning service by calling 0345 988 1188.

I also know we can go further. That’s why this Government is investing in flood protection at record levels, with an unprecedented six-year commitment of £2.3 billion for new and improved defences to better protect an additional 300,000 homes.

Thanks to improved flood mapping and forecasting techniques, temporary defences were successfully used during the winter 13/14 floods to protect many communities across the country alongside traditional flood risk schemes which protected more than 1.4 million properties.

The Environment Agency is now exploring the use of temporary defences in 65 locations around the country where long-term solutions to flooding are still being investigated. Temporary defences are used to block flood water before it reaches a property and can be transported to where they are most needed during a flood.

Temporary flood barriers were also tested in Romsey, Canterbury and Rye as part of Exercise ‘Obex’ – the Latin name for ‘barrier’. The barriers can be used as an interim solution in communities at risk of flooding.

One of the locations where more than 200m of temporary barriers were tested was Guildford, where Floods Minister Rory Stewart was involved in their construction along Mary Street, which can be vulnerable from flooding from the nearby River Wey.

Floods Minister Rory Stewart said:

Today’s exercise is an excellent example of how the Environment Agency is taking action to better protect homes from flooding in Guildford and across the country.

With the EA’s innovation in technology through improved flood mapping and forecasting, robust temporary defences, pumps and highly effective staff – our response to flooding should be stronger than ever.

Environment Agency staff and Minister Rory Stewart assemble a temporary barrier in Guildford

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Flood Risk & Drainage

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CONSULTANCY

£6m tidal gauge will help to forcast flooding

A new tidal gauge installed in The Wash, Lincolnshire, will help the Environment Agency measure tides, predict flooding and assess the impact of climate change more accurately.

It completes a national network of 44 gauges that record information about sea levels to provide more accurate forecasts. The instrument is on a platform measuring approximately 2 meters across and 11 meters above sea level. It’s located 4km offshore in The Wash close to the port of Sutton Bridge, Lincolnshire. As well as collecting data for the Environment Agency, the gauge’s information on tide levels will also be used by the harbor authority to help boats navigate through The Wash.

Meteorological equipment onboard will measure wind speed and direction, and air pressure and temperature, and the Eastern Fisheries and Conservation Association (EFCA) also has equipment on the platform to measure the water’s quality and salinity.

DESIGN. ENVIRONMENT. SUSTAINABILITY. Hydro International’s leading consultancy is founded on over 30 years of experience in water engineering design and implementation, with our clients served by an expert team. Our services include: • Flood Risk Management. • Flood Risk Assessments (FRA). • Site Development Design. • Sustainable Drainage (SuDS). • Water Pollution Management (WPM). • Sustainable Water Management (SWiM).

Plus, the gauge will be used by the MoD as a static marker of the end of their testing range, where previously they had used floating buoys.

Claire Rose, flood and coastal risk management team leader at the Environment Agency, said:

This new gauge has a practical benefit for local communities as the information it gathers on sea levels will help us predict tidal surges and therefore improve our flood warning service.

It’s a nationally important project, too, as it fills in the last gap in the UK’s monitoring network to give us the best picture of tidal conditions across the country.

The gauge will prove invaluable throughout its 60-year lifetime by transmitting other important scientific data to a range of partner organisations.

The £6m project was funded through Defra’s flood defence Grant In Aid scheme and was completed in May. 12

For further information call 01275 337966 or visit www.hydro-consultancy.com

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Flood Risk & Drainage

£26m Morpeth flood scheme officially opened

The Morpeth flood scheme was officially opened on the 24th August and will protect residents by storing millions of gallons of flood water upstream - one of the largest projects of its kind built by the Environment Agency.

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Photos creditrd to the Environment Agency

The Morpeth flood scheme will benefit more than 1,000 homes and businesses in the town and is the largest flood protection project completed in the North East. The upstream reservoir on the town’s Mitford Estate works by storing up to 1.4 million cubic metres of water when river levels are high – enough to fill more than 560 Olympicsized swimming pools. In September 2008, severe and prolonged rainfall caused 1,000 properties in the town to be flooded and forced hundreds of people to evacuate.

The scheme has also created 17 hectares of new habitat for local wildlife. 3,500 endangered white-clawed crayfish have been relocated upstream of the River Wansbeck – one of the last places in the UK where the native species has a stronghold. Construction has allowed for ‘refuges’ and continued habitat to ensure the crayfish will continue to thrive. The project has been jointly delivered with Northumberland County Council, which provided £12 million in funding – one of the largest partnership contributions the Environment Agency has secured.

Sir Phillip Dilley, Environment Agency chairman, said:

“With one in six people at risk of flooding in England, flood schemes like Morpeth have a key role to play in protecting people and property, and provide a valuable boost to the local economy. Creating large-scale habitat is also vital to ensuring the survival of the country’s endangered species such as white clawed crayfish.

“The success of this scheme is down to the way it has been developed in collaboration with others. In particular, the funding from Northumberland County Council is among the largest contributions received under the partnership funding regime.

“We are making record levels of investment, spending £2.3 billion over the next six years to reduce flood risk to more than 300,000 properties in England, and successful partnerships like this, with local authorities and business, will be key.”

Construction work on the scheme began in 2013 and has included a new flood wall and embankment along the riverside, over 368m long, including three new flood gates. Repairs and improvements to existing defences have also been carried out, with efforts to ensure that the look of the defences fit with the history and character of the town.

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SuDS & Surface Water Management

Stormwater & SuDS

Alex Stephenson,

www.managingwater.co.uk

Alex has 40 years experience in stormwater drainage design and related issues. As well as being the UK Stormwater Director with Hydro International he is also Chairman of the British Water SuDS focus group. He is ideally situated to keep you up to date with the industry changes and legislation.

We are at a turning point for surface water management in the UK. For the first time, we have planning regulations in place in England that ‘expect’ SuDS to be built on new development. So, we should be celebrating, shouldn’t we? Except that, it’s not the outcome that many people expected. As I explored in my last column, 10 years of wrangling over legislation to make SuDS compulsory may be over, but there is still much to be done. The revised CIRIA 697 SuDS Manual soon to be published will be an important milestone in providing national guidelines.

I believe it’s essential that we do not lose sight of our goals for more sustainable flood risk management and especially for surface water control and treatment.

Overcoming the continuing barriers demands a focus on implementing SuDS that are pragmatic, deliverable, and whose performance can be predicted and managed in the long term. We must continue to fight the battles and win the war for effective surface water flood risk policy and practice.

Adequate measures to support ownership and maintenance of SuDS schemes have still not been fully addressed with arrangements being decided on a case by case basis – leaving the danger that plans could be shelved if no agreement is reached.

It really should be possible to predict and monitor how all SuDS components will control water quality and quantity over their lifetime and set out clear schedules to maintain that performance. This is the only way to be sure that owners, public or private, will commit to looking after them. Engineered solutions can play a huge role in this – working alongside

SuDS – Time for Celebrations?

above-ground features where appropriate – because they provide a maintenance framework from the manufacturer.

In particular, it must be accepted in policy making that effective surface water management will never be achieved simply by regulating new development. There has to be much more focus on retrofitting to attenuate stormwater flows above ground and in public sewers, as well as ensuring polluted runoff is effectively treated. As recognised in the Committee’s recommendations, the role of the Water Companies is essential in delivering this.

Climate Change is going to make keeping pace with flooding risks extremely difficult, even if spending on defences continues at ‘optimal’ levels over many years. That’s not my assessment, but that of the Government’s own advisors in the 2015 Progress Report to Parliament from the Committee on Climate Change. The Committee warns that current policy is inadequate to address the 100,000s of properties projected to face high levels of flood risk in future. New development will make matters worse and increased urban infill and impermeable surfaces are likely to bring more surface water flood risk, the report says.

The Committee is clear that the changes made to the planning system in April to encourage SuDS in new development in England “fail to address the fundamental barriers to the uptake of SuDS highlighted in the Pitt Review”. Failure to remove a developer’s automatic right to connect to the public sewers leaves a significant barrier in the way of progress. The recommendations of the Government’s own advisors should not be ignored.

Contact Alex by:email: alex.stephenson@hydro-international.co.uk Telephone: 01275 878371

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Stormwater & SuDS

£4.28 million Flood Defences Go Underground, Overground in London Parks A £4.28m award-winning flood defence project in Southwark, South London, is combining above and below-ground temporary flood storage to create a pioneering solution at two sensitive and historic parks.

The project, led by Southwark Council, is designed to provide much-needed protection for Herne Hill and Dulwich, an area prone to flooding as a result of being in a low-lying catchment of the culverted Effra River – one of London’s so-called lost rivers. The design involves the construction of above- and below-ground temporary flood storage to capture overland flow during periods of heavy rainfall. Above ground, a mixture of natural earth bunding and dwarfbrick retaining-wall structures are being constructed in the Dulwich, while at Belair Park a combination of earth bund and detention basin control peak surface water flows. However, a key element of the flood defences is underground geocellular block storage from Hydro International to provide a solution that is sensitive to the needs of the park locations.

The innovative scheme won the 2015 Environment Agency (EA) award for Partnership Project Excellence for its integrated partnership working and community

engagement. Community groups had initially objected to flood relief measures involving the use of overground pond storage in the Grade II listed park areas. Engineer Mouchel’s sensitive design proposed using Hydro International’s Stormcell® and Stormbloc® modular block storage systems. “The public concern over retaining the parks’ appearance was very strong,” says Mouchel Project Engineer James Armitage. “Even though they realised the flooding problem, they did not want to lose significant areas of the parks to large ponds and swales.” By specifying attenuation tanks using Hydro’s Stormcell® and Stormbloc® modular block geocellular storage systems, several different concerns were satisfied. The block systems are load-bearing and could be landscaped back to their original grassed appearance and significant money and time was saved during installation with less heavy plant on site. Due to the modular block format, each tank is only one metre in depth, which limited the amount of excavation required. Wrapped in geotextiles, the tanks are covered with topsoil to a minimum depth of 0.5 metres, which means they are effectively invisible.

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After flushing

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Stormwater & SuDS The area has been vulnerable to flooding for a century. Overland surface water flow from the hilly surrounding topography and large open fields coupled with extensive hard surfaces such as roads, car parks and other structures, combine with the impervious underlying London Clay to create a flood risk. Events in 1984, 2004 and 2007 badly affected Dulwich Park, Belair Park, Dulwich Sports Ground and Herne Hill Velodrome as well as the centre of Herne Hill itself. To combat these risks, the Dulwich and Herne Hill flood alleviation project started in December 2012 as a partnership project between Southwark Council and Thames Water Utilities Ltd (TWUL) supported by the Environment Agency. Southwark Council’s design consultant (Mouchel) undertook the design while Thames Water’s Contractor (Morrison-Galliford Try joint venture) constructed the scheme. Construction started in June 2014 and was substantially completed in December 2014 and officially launched in May this year. The underground storage tanks are designed to provide 1 in 10 year storm protection, and the overland storage one in 75 years storms.

In Dulwich Park two tanks each measuring 31.2 m x 36 m x 1.04 m provide over 2,300 m3 of storage using Stormcell® modular blocks and at the Dulwich Sports ground in Belair Park a Stormbloc® tank provides 2,025 m3. The main part of this tank is situated under the sports pitch and shaped so that the Stormbloc® Inspect access chambers are outside the pitch limits. Discharge for all three tanks is to the storm sewer system.

Low landscaped bunds and dwarf retaining walls have also been constructed to guide surface flow with filter drainage along the bottom of the slopes, while retaining the natural appearance required. In Belair Park where the residents were keen on improved biodiversity, a small attenuation pond has also been retained in addition to a small wetland area.

Apart from the filter drainage there was no need for further water quality treatment; the Stormcell® design uses a unique self-cleansing flow system to eliminate silt accumulation

and, at Dulwich Park where the setup is slightly different, it was decided to use Stormbloc® as it has a simple inspection and jetting access facility.

For more information about the Stormcell®, Stormbloc® and other stormwater and wastewater management products please call 01275 337977, email enquiries@hydro-int.com or visit www.hydro-int.com.

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Stormwater & SuDS

Collaborative Approach For Supermarket Development

ACO Water Management

A collaboration between Leicester City Council, Asda, ISG and ACO Water Management has enabled a first in sustainable urban drainage within a supermarket development. The integrated drainage solution combines proprietary and vegetative systems to achieve effective surface water management, whilst introducing a level of biodiversity never attained before on a retail development. The project had strict planning guidelines that required two swale inlets to be incorporated onto the site. Working within these guidelines, Asda’s site feasibility team and ACO worked closely with Chryse Tinsley, the council’s landscape architect, to move away from the more common permeable paving solution, towards a cost-effective engineered system integrating vegetative elements and proprietary products - that effectively manages stormwater on or near the surface.

Sustainable Drainage Systems (SuDS)

SuDS is based on an underlying philosophy designed to counter the evident problems of urbanisation and climate change – where it is becoming increasingly untenable to discharge to an aged, over capacity, centralised sewer treatment infrastructure or to groundwater or water course. Supermarkets present large, often impermeable areas that shed water to discharge downstream. As such, they are rainwater intensive. In addition, the pollutants introduced from run-off through vehicle operation can have an adverse ecological impact.

SuDS present methodologies and tools to re-examine how surface water run-off is managed – controlling it at site level and effectively decentralising and decoupling any negative components of run-off (volume, rate or quality) from receiving waters and managing on the surface, using natural vegetative and manufactured features and products in combination with modelling, engineering, design and creativity that benefits flora, fauna and those who live nearby. 18

Surface water management for Asda

The car park gradient was set at 1:60 – falling away from the building towards a site boundary positioned swale feature. ACO Qmax, a high capacity slot drainage system was installed over an approximate 90m length, serving a catchment of over 4000m2. Specified with shallow drainage inverts of 225mm Ø, the system enables a treatment train to be employed, where surface run-off cascades through a number of treatment components en-route to eventual outfall.

Surface water treatment

The first treatment stage comprises a shallow sub-surface granular stone media, to facilitate filtration and biodegradation as well as usefully slowing the flow of runoff.

Filter treatment

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Stormwater & SuDS

With this feature allowing ‘on surface’ car parking, it’s crucial that the aggregate is protected from sediments that might otherwise blind the media. For this, two components are employed for evaluation: a filter device installed in the Qmax outlet chambers, designed to filter particulates over 0.5mm; and polystyrene filled sacks that sit in the gully, providing adsorbent properties to which particulates bind.

Water is further converged via four manhole chambers, two of which also serve roof and service yard areas. Three manholes subsequently deliver water to the receiving swale. This necessitated a shallow invert design throughout; making use of the surface gradient of 1:60 in combination with specifically designed shallow channel outlets with an invert of just 700mm – to achieve a usefully high termination in the swale.

The Swales

The ACO SuDS Swale Inlet unit links the proprietary conveyance drainage systems to the swale, and serves to dissipate some of the flow energy. The aesthetically pleasing solution is manufactured from Vienite, ACO's high strength sustainable material that offers greater durability. The inlet detail also cuts installation time. The swale itself receives run-off from roof, the west car park, east car park, service yard, PFS and access road and is the final conveyance stage to outfall. Chryse Tinsley worked closely with main contractor ISG to ensure the swale was constructed with appropriate contours. The result is a clear meandering pathway for the runoff.

High performance surface water treatment plant

The site’s petrol filling station is drained via a conventional oil separator to a detention basin to the north of the main swale. To further treat the potentially high pollution load, a high performance surface water treatment plant was installed. The ACO CPPMS system effectively removes the majority of sediments including smaller fractions of less than 100µm, and also treats dissolved metals such as copper and zinc. The CPPMS uses proprietary filters to remove and contain pollutants providing a point source for maintenance. Chryse Tinsley, landscape architect for Leicester City Council said,

“Once developed, the planting regime will provide further opportunities for wildlife and biodiversity. Planting is expected to flourish over the next 12 months and for those using the store – the natural features created will provide ambiance and natural habitat. For nearby domestic premises the trees, plants and water also provide a natural dividing line – quelling noise, whilst also providing a natural visual buffer.”

Conclusion

Martin Fairley, research director at ACO, worked closely with Asda to design the scheme.

“The scheme design exploits fully the drainage gradient on site and by combining, in sequence, shallow outlet inverts with granular sub-bases, filter strips, separators, detention basins and swales, a treatment train has been devised with many potential benefits. Water quality will improve through filtration, biodegradation, separation and exposure to sunlight.”

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Aberdeen International Aberdeen’s new International Park, built next to the City’s Business Park Gets Sustainable Business International Airport, is delivering a best-practice Sustainable Drainage (SuDS) scheme using filtration and SuDS Treatment with Hydro’s bioretention technologies from Hydro International to meet strict planning Pollution Control Technology and pollutant removal criteria. A wide-variety of SuDS components have been included for the 31,000 m2 first phase of the development to meet the level of treatment required by the Scottish Environmental Protection Agency (SEPA) to help protect the water quality of the River Dee, a wellknown salmon river.

To meet stringent planning requirements, consultants Mott MacDonald selected Hydro International’s unique Up-Flo™ filtration units and Hydro BioCell™ biofiltration units for key parts of the site.

“SEPA required two levels of pollution control in the drainage treatment train

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Stormwater & SuDS for some areas of the site,” explains project engineer Nick Watson of Mott MacDonald. “The six Hydro BioCell™ units are installed in a landscaped courtyard garden around three linked four-storey commercial blocks. There is also a two-storey 1,197 space car park and runoff from its draining surface is treated via four Up-Flo™ Filters in concrete manholes. “Space constraints meant that finding small footprint solutions that could achieve high treatment levels was limited. There are some occasions where the more natural engineering approach is less suitable due to a lack of space and having an option like Up-Flo™ can be useful,” continues Nick Watson.

The Hydro Up-Flo™ units will remove fine sediments, hydrocarbons and other pollutants from the car park runoff. They provide a highperformance multi-stage treatment train in a single device by combining sedimentation and screening with fluidised-bed filtration technology. The Hydro BioCell™ is a biofiltration device that looks like a normal tree or shrub planted through a grate. Underneath, a pre-cast concrete chamber contains a layer of enhanced mulch and a soil filter medium to deliver high levels of surface water treatment before the water is discharged into the drainage system.

The flush profile of the Hydro BioCell™ grate, with its tree-planting feature, is used to treat general pollutants in the runoff from the courtyard, which covers about 0.3 hectares. The runoff is also passed through filter trenches to provide the two levels of treatment required by SEPA.

into the Green Burn, via which water eventually ends up in the River Dee. The 16.2 hectare site Aberdeen International Business Park being constructed by Bowmer and Kirkland for Abstract (Cornwall) Ltd is strategically located on the principal link road between the Airport and the Aberdeen Western Perimeter Route /A96 and will provide well-located facilities with high-standards of office accommodation for the international business community in Aberdeen.

The topography of the area is fairly flat with a small local watercourse rerouted to facilitate site development. The mixed drainage scheme for the development also includes a variety of SuDS measures including filter strips, permeable pavement, filter trenches and soakaways and an attenuation tank under the car park to meet SEPA’s requirements. The runoff discharges www.fadsdirectory.com

As well as office, restaurant and leisure facilities, future plans include hotel accommodation. In keeping with Aberdeen Airport’s strong oil industry connections with other North Sea bordering countries, Phase 1 has been leased to a leading Norway investment provider Aker Solutions, for whom the Abstract Group of Companies is developing the site.

River & Wetland Management

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River & Wetland Management

New Silt Pusher is the UK’s largest ADC (East Anglia) Ltd has gone back to Holland to purchase their second silt pusher boat – the C86S to compliment the smaller C86XS which is already operational in the UK.

The Conver C86S silt pusher was originally developed to work in the larger canals and watercourses in mainland Europe. This machine, like the smaller C86XS is particularly useful in situations where traditional methods cannot be used. With the new restrictions being enforced regarding working from the embankments, these machines really come into their own.

“Besides watercourses, its perfect for cleaning silt from Lakes and wide stretches of open watercourses” explains Michael Reeve, General Operations Director of ADC. “There is no need to drain the lake or remove the fish stocks as they survive quite happily around the De-silting operation. We Monitor oxygen levels continually as we work and suspend operations to allow water to reoxygenate if required”.

The C86S Silt pusher helps maintain vegetation growth in and alongside watercourses, provides ecologically sensitive dredging and is non evasive to the Environment it is working in. In view of its low environmental impact, the silt pusher can be used in a much larger period of time, with almost all year round working capabilities. Trees, bushes and reed beds do not have to be removed therefore not disturbing the resident nesting birds.

The C86s has a maximum working width of up to 8.2m, although this is dependant on the amount of silt being removed at any one time. With a working blade depth of up to 2.2m it is able to work with 1m of water above the blade giving a total depth of 3.2m. The C86s is more than capable of moving 300m³ in any one day. ADC held a working demonstration at Lindsey Marsh Drainage Board’s Thorpe Culvert pumping station. This event was attended by members from Environment Agency, British Waterways, Canal and River Trust and local Internal Drainage Boards.

ADC was contracted to remove an estimated 1500 tonnes of silt that had accumulated in the stretch of watercourse adjacent to the pumping station. The area was inaccessible to an excavator and the silt levels were such that the pump could not drain down the catchment area. This had been an ongoing problem for the Drainage Board and ADC gave them the answer. By pushing the silt to an area where access was possible for a board excavator to remove the silt and store it in a Bunded area on the adjacent bank. The vessel has a sturdy steel hull propelled by twin screws which are powered by a 31kw diesel engine. The power required for the operational works comes from 2 on board auto spool winches giving a forward pull of 5000kg and a reverse pull of 2500kg. With the winch capacity of 260m of cable on board, the silt pusher can reach most areas.

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watercourse, but also the de-watering of the dredgings. We would pump the silt into our roll on/roll off de-watering skips which allows fast de-watering” says Steve Paige, Managing Director of ADC. “Processing approximately 40m³ an hour, reductions of 50% in waste can be achieved. The de-watered dredgings are then transported to a waste disposal facility. The dried out silt (‘cake’) often goes into a recycling facility therefore avoiding any landfill charges.

Apart from pushing, the C86s has a digging scraper blade mounted on the rear of the hull. This is extremely useful when cleaning areas of watercourses with limited access i.e. under trees or stop ends of ditches and profiling banks.

ADC have used this application to remove solid silt/sand banks from tidal rivers that are to large and solid for the silt pusher to use its front pusher blades.

“Environmentally this ticks all the right boxes, 50% less loads, less carbon emissions, improving the company and the client’s carbon footprint”.

Based in the Fens on the Norfolk, Cambridgeshire, Lincolnshire borders, ADC (East Anglia) Ltd has now grown into a National company, supplying not only the silt pusher, but all of the specialist services and knowledge to

ADC chose the C86S due to its efficiency, durability and ease of use. Mike Reeve said “The Conver team in Holland were most helpful in making sure that our requirements and specifications were met and delivered on time”. “Typically the types of works we are contracted for involve not only the removal of the silt from the

a wide range satisfied customers. left to right, Chrisof Pett, Mastenbroeks, Mike Reeve, Steve Paige, ADC

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CW announce new electrical and mechanical engineering services

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CW Engineers of King’s Lynn is now part of a group with its own electrical division re-branded CW Group. Managing Director Nick Watling explains.

“There is more to CW Group than weedscreen cleaners”,

“CW Group has put collaboration, innovation and transformation at the heart of its culture, to support their customers locally and nationally with high quality engineering solutions with proactive service. “Engineering with national coverage is supplied via our 8 specialised departments at regional sites to give the customer, the value of local relationships and provide them with design, electrical, mechanical, engineering and manufacturing products & services to the highest industry standards.

“Whether it’s new structural steel work for a new factory or processing equipment to produce your product, CW Group can cater for your needs”. Andy Spooner has been appointed Operations Director, bringing a wealth of Electrical engineering expertise.

“NICEIC certified, we provide electrical services to diverse sectors. Our electrical services range from design, specification, procurement, installation, inspection & testing, commissioning & maintenance. “The CW Group’s experienced and skilled mechanical engineers can realise all mechanical engineering

projects for equipment, pipework installations, fabrication & structural steelwork.

“Specialising in machine removal, relocation and installation, we can undertake mechanical installations projects ranging from installation of a simple conveyor to a full manufacturing & process line. To complement our electrical engineering services, we are able to provide a one-stop solution via our in-house mechanical engineering services”.

Your partner in water management and flood control

The CW Group Hamlin Way, Hardwick Narrows, King’s Lynn, Norfolk PE30 4NG T: 01553 775565 E: info@cw-engineering.co.uk www.cw-grp.co.uk

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Where practical meets historical Sensitive bridge design by Lattenbury Services

Timber clad bridge, Hard Water Mill, Wollaston Lattenbury Services Limited has gained a reputation for bridge designs that compliment sensitive locations. A recent example is the replacement bridge at Hard Water Mill, Wollaston, Northants. The company was approached by the Environment Agency to provide a full design and installation service regarding a replacement bridge in keeping with the historic mill buildings.

Measuring 8.5m by 3m, the new structure is built on steel beams clad in hardwood timber for 20 years or more duty.

The bridge has been upgraded to handle 3 ton loads for access to a neighbouring sluice and weir. Abutments were also replaced. Installation impact was minimised by the deployment of ground matting which protected the grassed areas around the site.

For further details please contact Chris Wisson on 01480 830224 or visit www.lattenburyservices.co.uk

Specialists in bridge replacement, bank protection and fencing.

Talk to Lattenbury Services about your next waterside project: bridges, board walks, fishing platforms etc. Besides a full design service we have access to machinerryy and equipment suited to the job in hand. See our website for projects and testimonials. Godmanchester . Huntingdon . Cambs . PE28 9PA . Tel: 01480 830 224 . lattenburysevices.co.uk www.fadsdirectory.com

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Natural engineering creates safe havens for white-clawed crayfish

A safe haven for a protected native species has been created using natural engineering techniques.

The Environment Agency and Yorkshire Wildlife Trust have worked in partnership to stabilise the banks of a stream in Leeds and build refuges for the native whiteclawed crayfish, using willow spiling.

Ian Marshall, biodiversity officer at the Environment Agency said:

The stream has suffered from excessive siltation which has impacted on fish and rare invertebrate communities living in it. However, by working closely with our partners to tackle erosion in a sustainable way, we have given the area the opportunity to improve for wildlife whilst remaining a popular destination for the public. This work also helps us achieve our targets under the Water Framework Directive and pave the way for future partnership working across Yorkshire. Elspeth Robinson, project assistant at the Yorkshire Wildlife Trust said:

Willow spiling protects banks from erosion.

The area has an established population of native whiteclawed crayfish, but was identified as in need of possible habitat improvement because there were many eroded banks with very little vegetation or suitable areas for the crayfish to burrow into.

Eroding riverbanks can cause problems for crayfish habitats because the eroded sediment can cause siltation and pollution of the stream blocking potential refuges for the crayfish and altering the quality of the water. A bank that is eroding is also unstable and unsuitable habitat for crayfish as it will not give adequate protection against fast flowing water.

Up to 100 metres of willow spiling and bundling has been built along the stream. The technique used for the willow spiling involves weaving willow between stakes on the bank to form a strong willow wall. Live willow was used so that it will root and grow creating a strong hedge that protects the bank from further erosion and provide habitat for crayfish. 28

I worked with several groups of fantastic volunteers over the course of two weeks to install the willow habitat along the beck. The willow has now started to sprout and is establishing along the banks, providing stability against erosion and brilliant habitat for the crayfish. We have much more willow spiling and bundling planned for other streams around Leeds to help secure our populations of native white-clawed crayfish.

White clawed crayfish have been significantly threatened in this country by the invasion of the non-native American signal crayfish, and crayfish plague.

Native white-clawed crayfish have no natural defence against the plague. Once the fungal disease has become established, an entire population can be wiped out in just a week. The Environment Agency and its partners are working to establish safe havens on other streams to help protect the species. White-clawed crayfish are Britainâ&#x20AC;&#x2122;s only native freshwater crayfish. They are protected under Schedule 5 of the Wildlife & Countryside Act 1981. It is an offence to intentionally take white-clawed crayfish from the wild.

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Four new eel passes on the Bedford Ouse

4 new eel passes have been installed by the Environment Agency on the Bedford Ouse to help eels migrate to the upper parts of the river. Eel stocks have been identified as â&#x20AC;&#x2DC;critically lowâ&#x20AC;&#x2122; in Europe and installation of these new passes should help more of them to get past structures in the Bedford Ouse and on upstream.

Juvenile eels (Leptocephali) start their fantastic journey in the deep waters near the Bermuda triangle, travelling into Europe, with some coming into the English Channel and through the Wash into the Great Ouse and its tributaries. They finally go further upstream to complete the freshwater stage of their lifecycle, which can last up to 60 years. James Dyke Environment Agency Fisheries Officer said:

â&#x20AC;&#x153;Getting past structures, such as the St Ives sluice is key for survival of the eels and will make a real difference to their ability to travel further upstream to complete their lifecycle.

With numbers currently so low, they need all the help they

can get if weâ&#x20AC;&#x2122;re going to keep this fascinating species in our rivers.â&#x20AC;?

Work was carried out over 2 years, after the structures between St Ives and Houghton were identified as â&#x20AC;&#x2DC;high priorityâ&#x20AC;&#x2122; barriers to eel migration. Eels were listed in year 2007 as a critically endangered species, with eel regulations requiring passes to be installed so their migration is not blocked by structures in rivers.

The Environment Agency has a key role in ensuring that the biodiversity of our watercourses is enhanced and fish stocks are managed for the benefit of wildlife and people. The organisation has a responsibility to clean up rivers; however everyone has a part to play to help make our water and land more natural and sustainable for people and wildlife.

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