Groundwater problems are causing disputes with local councils

Groundwater Flooding in Hampshire & Land Subsidence in Berkshire

May 29th 2015

Large puddle in Hampshire village creates dispute over responsibilities

Two disputes have broken out with local authorities over problems caused by groundwater issues. In the first case, residents in the village of New Cheriton on the South Downs have been concerned about a large puddle on the main road that goes through the village. The puddle ices up in the winter and causes problems for motorists and pedestrians. It appeared a year ago shortly after the road was resurfaced.

Chair of Kilmeston Parish Council, Michael Curtis, said the cause of the problem is a pond 500 yards down the road, which has been accumulating silt over the years and needs dredging. The pond is the source of the River Itchen. Dredging the pond would increase its capacity to hold groundwater, Michael Curtis said. His diagnosis was confirmed by Southern Water, but a spokesperson for the water company said that groundwater flooding was not their responsibility. Speaking to the Hampshire Chronicle, the spokesperson said: “The authority with responsibility for developing strategies to deal with groundwater flooding is Hampshire County Council – not the water company – so on this occasion we cannot help further.”

However, a spokesperson from Hampshire County Council said that the source of the problem was a natural spring which drains onto the road. The spokesperson explained that the spring gives out a small but persistent flow of water. The recent resurfacing work was carried out to manage the problem by directing the water away from the centre and to the side of the road. The Council said that following recent concerns “engineers will be visiting the site again to see if anything else can be done to improve drainage along the side of the road.” For the full story see the Hampshire Chronicle.

Local council in Berkshire is forced to publish report on land subsidence

In a second dispute, Newbury Town Council has been forced to publish a hydrogeological report into the causes of land subsidence in Victoria Park. The subsidence caused cracks to appear in playing fields and sports courts and damaged boundary walls and nearby properties. The report, which was commissioned by Newbury Town Council five years ago, was only published following a Freedom of Information request from a Newbury resident.

The report says that building works by a contractor, which gave rise to a lowering of groundwater levels, is the most likely explanation for the subsidence. The Freedom of Information request went to an appeal in 2013, following the Council’s refusal to publish the report on the grounds that it could jeopardise ongoing negotiations with the contractor.

According to the Newbury Weekly News, the report concludes that “the extent of dewatering of the site, along with inadequate mitigation measures, make this the most likely explanation for the majority of the lowering of groundwater levels and the ground disturbance seen within Victoria Park during 2010.” For the full story, see the Newbury Weekly News.

Acknowledgement

Photograph: The South Downs Way near Ditchling Beacon © Copyright Marathon and licensed for reuse under this Creative Commons Licence. Some parts of the UK are more prone to groundwater flooding due to the geology of the surrounding area, such as the predominantly chalk structure of the South Downs.

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European Geosciences Union General Assembly 2015

Advances in the science of flood forecasting

May 28th 2015

The European Geosciences Union held its General Assembly in Austria last month. The European Geosciences Union (EGU) is a non-profit international union of scientists with over 12,500 members from all over the world. The EGU is dedicated to the pursuit of excellence in geoscience, planetary science and space science, and its annual General Assembly is the largest geoscience event in Europe, attracting over 11,000 scientists from countries across the globe. The sessions cover a wide range of topics, including volcanology, planetary exploration, the Earth’s internal structure, atmosphere and climate, energy and resources, and advances in hydrology and hydrogeology.

This year’s event included an interactive session on hydro-meteorological science research and its applications, convened by the Scottish Environment Protection Agency (SEPA) in collaboration with institutes from the Netherlands and Slovakia. The session was designed to demonstrate how to bridge the gap between science and practice in operational forecasting for different natural hazards. SEPA’s presentation focused on the operational forecasting of urban flooding, using as an example its innovative early warning system of flood forecasting which was set up in Glasgow for the opening of the 2014 Commonwealth Games. See our news item “Forecasting Flood Risk from Surface Water Flooding” for more information on the system.

SEPA says that early warning systems are the result of progress in the science of forecasting: “In recent years opportunities have arisen in flood forecast modelling bringing together meteorological and hydrological forecasts, and ensemble forecasting with real-time control.” As well as using meteorological and hydrological advances in its forecasting service, SEPA is also developing “citizen science” and will be launching a new initiative later this year which will enable members of the public to report incidents of flooding. The reports will be published on a dedicated website – see the SEPA magazine for more information.

Last year the Met Office announced it was investing £97 million in a new high-performance supercomputer which will make significant improvements to the accuracy and timeliness of flood forecasting – see our news item “Met Office invests £97m in high-performance supercomputer” for the details.

Meteorological and hydrological forecasts have also been enhanced by the use of satellite data. For news items on this topic, see for instance:

For information on the 2015 General Assembly of the European Geosciences Union, see “EGU 2015”

Flood Risk Management in Scotland – SEPA Consultation

SEPA sets out seven-year timetable for the delivery of flood risk management plans across Scotland

May 27th 2015

Next week sees the deadline for responses to SEPA’s consultation on how flood risk is managed in Scotland. SEPA (the Scottish Environment Protection Agency) has described the consultation as “the most comprehensive assessment of flood risk and its impacts ever compiled in Scotland.” The consultation documents provide details of the most sustainable set of actions to help tackle flooding in areas identified as being at greatest risk across Scotland. They also provide information on those areas where the most benefits are to be gained by taking action. The deadline for comments is Tuesday 2nd June.

SEPA says that the consultation has been produced by SEPA in partnership with local authorities, following guidelines set out in the Flood Risk Management (Scotland) Act 2009. The guidelines encourage a coordinated approach to the planning of flood risk management and more partnership working between public bodies that have responsibilities for raising awareness of flood risk in Scotland. Those bodies include SEPA, Scottish Water, the Forestry Commission Scotland, the National Park authorities and local authorities.

For the purposes of managing flood risk, Scotland has been divided into 14 Local Plan Districts. These geographical areas are designated by Scottish Ministers on the recommendations of SEPA, and each Local Plan District has a Lead Local Flood Authority agreed by all the local authorities represented in that district.

SEPA has set out a seven-year timetable for the delivery of flood risk management plans across Scotland. Following feedback from the consultation, SEPA plans to publish a flood risk management strategy for each of the Local Plan Districts in December 2015. The strategies will confirm the immediate priorities for flood risk management and set out the future direction for each Lead Local Flood Authority. The lead authorities will coordinate the production of a Local Flood Risk Management Plan and will publish delivery plans in June 2016. The delivery plans will set out how actions to manage flood risk will be coordinated, funded and delivered between 2016 and 2022.

Scotland’s Minister for the Environment, Climate Change and Land Reform, Dr Aileen McLeod, has described the consultation as “another important milestone in the implementation of the Flood Risk Management (Scotland) Act 2009.”

For more information on the consultation, see “Flood Risk Management Scotland”.

Retrofitting sustainable drainage systems into urban areas

New software tool assesses feasibility of sustainable drainage systems for existing developments

May 26th 2015

Defra and the Technology Strategy Board have funded the development of a tool to assess the feasibility of retrofitting sustainable drainage systems (SuDS) into urban areas. Sustainable drainage systems are an established method of reducing the impact of new developments on the risk of surface water flooding and on the amount of water entering our sewers. They do this by encouraging rain water to infiltrate the soil as closely as possible to where it falls. New legislation is now in place to stimulate the delivery of sustainable drainage systems for new developments, but there are no coherent plans for retrofitting SuDS into existing developments. (See our news item “Government responds to SuDS consultation” for the changes to SuDS legislation, which came into effect last month.)

This new software tool incorporates research into the constraints and effectiveness of a range of SuDS techniques and looks at the characteristics of a developed area using nationally available data on land use, flood risk, geology, environmental constraints and pollution. The result is a set of interactive maps together with information on the relative feasibility of retrofitting SuDS to various parts of the selected area. The output helps to focus attention on the most promising parts where SuDS could be implemented.

The software tool was developed by Royal HaskoningDHV and piloted using data for the Royal Borough of Kensington & Chelsea. The results of the pilot study were presented to the annual conference of CIWEM last month (CIWEM is the Chartered Institution of Water and Environment Management). For more information, see Defra’s research and development website.

Acknowledgement

Photo from Wikimedia Commons shows the construction of a swale. Sustainable drainage systems use a variety of techniques, one of which is artificial swales or bioswales. Swales are designed to manage rainwater run-off by spreading it along an elevation contour line and facilitating its infiltration into the soil.

Forthcoming CIWEM Events 2015

On the agenda: flood risk management, shale gas, and drinking water quality

May 25th 2015

The future of flood and coastal erosion risk management

CIWEM’s Rivers and Coastal Group is holding its AGM next month. The event will be followed by a day of presentations on the future of flood and coastal erosion risk management. The presentations will be focused on an “aspirational look into the future” and will include speakers from the Environment Agency, Network Rail, the National Trust, the National Flood Forum, water utilities and local authorities.

The morning session will concentrate on presenting a vision for the future, with speakers providing answers to questions such as how can we best adapt to the challenges of climate change, how best to prioritise, what might we be doing differently in twenty years’ time, and what do we need to do to get there. The afternoon session will present a vision of the future from a social perspective, looking at how our aspirations might be put into practice by developing future-proofed design solutions.

The AGM and spring conference will be held at the CIWEM headquarters in London on June 4th. For more information, see the CIWEM Events Calendar.

Shale gas and integrated water management

CIWEM is holding a one-day conference on the perceived risks of shale gas extraction to the environment and the management of such risks. CIWEM says that the use of water in hydraulic fracturing to unlock natural gas trapped in shale formations generally presents greater environmental challenges than conventional methods of gas extraction and is still perceived as a highly controversial process by many: “It is therefore essential there is informed understanding among stakeholders using clear scientific evidence, transparency, and consistent messages of this highly contentious issue.” The keynote speech will be delivered by Lord Chris Smith of the Shale Gas Task Force and the speakers will also discuss the management of extractive waste and integrated water management. Other topics to be discussed include:

  • Regulatory procedures for managing risks to groundwater and surface water
  • Baseline monitoring
  • Disclosure and transparency
  • Well integrity
  • The Environment Agency’s BAT (Best Available Techniques) initiative
  • Waste water treatment
  • Case studies from the USA

The event will be held at the University of London on the 7th July. For more information, see the CIWEM website.

Developments in drinking water quality, treatment and distribution

CIWEM is also holding a seminar in November on drinking water which will look at developments in water quality, treatment and distribution. CIWEM says that water companies strive to produce drinking water that meets quality standards whilst using the most cost-effective methods. However, water companies face an ever-more complex challenge as new drinking water contaminants are continually being discovered and new technologies and processes are developed. It is therefore crucial that water companies keep up with the latest technical information and are aware of emerging water quality issues: “The aim of this technical seminar, which was last held in 2010, will be to share new information and experiences on topics relating to drinking water treatment, emerging contaminants, and water distribution.”

The seminar is due to be held on 18th November. For more information, see the CIWEM website.

Note

CIWEM is the the Chartered Institution of Water and Environmental Management, an independent professional body whose aim is to advance the science and practice of water and environmental management for the public benefit.

Groundwater and London Basements

Planners need expert advice when dealing with basement excavations, says geoscientist

Hampstead’s geology gives rise to groundwater flood risk

May 22nd 2015

A civil engineer has spoken about the problems of basement excavations in Hampstead. The number of basement excavations in London has soared in recent years, due to rising property costs and London’s housing shortage. As we reported in a previous news item, householders seeking more space have found a basement conversion can be cheaper than moving house. However, basement conversions have created a lot of neighbour disputes because of the noise and disruption. There is also the potential risk of groundwater flooding.

Michael Eldred is a geotechnical engineer who provides expert advice to householders wanting to build new basements in North London, and most of the cases he deals with are concerned with flood risk assessments and people’s worries about groundwater flooding. He has expressed his concern that town planners and structural engineers, though they can be competent in building, are not always experts on what goes on underground, and this can have an impact on the building of new basements. The absence of detail is a frequent cause of difficulties in planning and risk assessments, he said, and it is vital that proper research be completed before digging begins.

Mr Eldred voiced his concerns in a presentation to the Heath and Hampstead Society which was reported in the Camden New Journal. He explained that the problems of basement excavations in Hampstead are a consequence of the area’s geological structure. Hampstead sits on a layer of bagshot sand, he said:

“Starting deep below ground, there is a layer of London clay, which used to be a seabed. When the ground lifted up and the sea disappeared, other materials were compacted down. It formed a layer known as the claygate beds, which is a bit more porous. On top of that comes the bagshot sand. Water flows down through it and percolates down and forms springs. It is this groundwater that can affect basements. You have to investigate not only the condition of the ground in your house, but all matters relating to the flow of water through it, such as the history of the area and what was there before it was built on. We look at old maps and use satellite data to get a detailed idea.”

Acknowledgement

Photo: “North London Sprawl” by Oxyman via Wikimedia Commons, licensed for reuse under this Creative Commons Licence.

Work begins on next stage of reducing groundwater flood risk in Hampshire village

Underground pipe will transport large volumes of groundwater from the South Downs

May 21st 2015

Work is due to start at the end of this month on Phase 2 of a flood alleviation scheme for the village of Hambledon in Hampshire. The village was affected by groundwater flooding earlier last year and last summer Hampshire County Council approved a £3.9 million scheme to reduce flood risk.

Phase 1 of the scheme started last autumn and included the clearing of gullies, drainage channels and local ditches. Phase 2 of the scheme was unveiled at a public exhibition in the village last month. It involves the construction of an underground pipe beneath the main road through the village. The pipe is designed to transport large volumes of groundwater from the South Downs and away from the village. Phase 2 of the scheme will also provide new flood water culverts together with road resurfacing and re-shaping to keep any flood water away from houses and within the kerbs. The work is expected to take a year to complete.

As we reported in a previous news item, residents in the village were concerned over rising groundwater levels last November and met with planners from Hampshire County Council to discuss the situation and to develop an action plan. The residents were particularly concerned over the lack of accredited community safety officers but the Council said it had created a pool of emergency response workers who can be called on day or night should the need arise.

For further information on the scheme, see the Hampshire County Council website. The latest developments were also reported in Portsmouth News.

Acknowledgement

Photograph: Hambledon High Street leading towards the Parish Church © Copyright Anonymous 4452 and licensed for reuse under this Creative Commons Licence.