Is engineering a way out of the flooding?

Houses should be redesigned, roads raised and tidal lagoons built that generate energy to reduce the impact of flooding in the UK, according to a panel of senior engineers and academics, reported in the Guardian.

Flooding in Shepperton, Surrey, on 16 February 2014. Photo credit: Jim Crossley

Flooding in Shepperton, Surrey, on 16 February 2014. Photo credit: Jim Crossley

In light of the UK’s wettest winter on record and recent flooding in large parts of southern England, the panel gathered at a briefing in London organised by the Science Media Centre and Royal Academy of Engineering to talk about what engineering can (and can’t) do to prevent and reduce the impact of flooding in the UK.

“In some senses we’re still in a mode of ‘discovery by disaster’,” said Professor Jim Hall, Professor of Climate and Environmental Risks and Director of the Environmental Change Institute at Oxford University. “With the exception of rail infrastructure, critical national infrastructure has come through this latest set of floods pretty well, but adapting to changing climate risk is still very much a work in progress.”

Experts questioned the £4 million government plan to dredge two rivers in Somerset, suggesting that this project will have only ‘marginal’ effects on future flooding. Commenting in an article in the Independent, Jim Hall said “dredging can and does increase the cross-sectional area of a channel which means that under certain conditions the channel will drain faster but in places like the Somerset levels it also allows the tide to come in faster and in other conditions it can propagate water downstream to other locations faster.”

Press coverage

UK floods: raise roads and redesign houses, engineers say
The Guardian online, Jessica Aldred, 25/02/2014

Government’s £4m fund to dredge rivers in Somerset could only have ‘marginal’ effects on future flooding, experts warn
The Independent, 25/02/2014, Steve Connor

Raise Britain’s roads to prevent flooding chaos
The Telegraph online, 24/02/2014, Sarah Knapton

Environment Agency vows to minimise flood risk
ITV News online, 25/02/2014

Agency vows to minimise flood risk
Belfast Telegraph, 25/02/2014

Answer to flooding lies in the soil

Professor John Boardman, Emeritus Fellow in Geomorphology and Land Degradation at the Environmental Change Institute, writes a letter to the Guardian highlighting the unjoined up thinking in the regulation around soil runoff and erosion for farmers.

Water shortages could disrupt Britain’s electricity supply

The Guardian reports on a team of academics from Oxford and Newcastle who say nuclear and gas-fired power stations could be forced to shut down during future droughts.

The electricity sector uses large quantities of water for cooling processes in thermoelectric power stations, accounting for around half of all water abstractions in England and Wales. As water resources come under increasing pressures from growing populations and climate change, shortages could have serious impacts on the country’s electricity production, warns a new study co-authored by Professor Jim Hall, Director of the Environmental Change Institute, Oxford University.

“The high dependency on water in electricity generation means there is a real possibility that in just a few decades some power stations may be forced to decrease production or shut down if there are water shortages”, said Ed Byers in the Guardian article, a researcher at Newcastle University and lead author of the study.

The research, published in the journal Global Environmental Change, assesses the water demand of the government’s proposed energy ‘pathways’ to 2050. While some pathways present opportunities to both reduce water dependency and carbon emissions, others increase the dependence on water resources. For example, using fossil fuels with high levels of carbon capture and storage (CCS) could increase freshwater consumption by up to 70%.

The research shows that up to the 2030s, water use performance improves for all pathways, in line with rapid decarbonisation. This is achieved as renewable energy production expands while older coal, gas and nuclear plants are decommissioned and new and more affordable nuclear and carbon capture-equipped generation begins to take shape.

In the 2030s the water security of the UK could be in the balance as the water intensity of the different pathways diverges, warn the researchers. Coal and gas plants would be forced to shut down if they do not adopt CCS, yet if CCS and nuclear power are deployed on wider scales, water intensity will rapidly increase. Developers could be forced to choose between using limited freshwater supplies or increasing abstraction from tidal and sea water, both of which could be problematic for the environment.

The energy pathway with the highest level of renewables uses the least freshwater. Hybrid or air cooling comes at a slightly high cost and more emissions, but minimises water consumption and therefore could reduce dependency on scarce resources.

Read the Guardian article


Byers, E.A., Hall, J.W. and Amezaga, J.M. (2014) Electricity generation and cooling water use: UK pathways to 2050. Global Environmental Change. DOI:

Action needed to reduce nitrogen and phosphorus pollution in the Thames

In a podcast on the NERC Planet Earth website, Paul Whitehead from Oxford University and Mark Barnett from the Environment Agency comment on the pollution challenge of the river Thames. They explain why the river will fail to meet European Union standards unless action is taken by farmers to reduce fertiliser use and water companies cut the amount of phosphorus being discharged by sewage works.

“Nitrogen and phosphorus come from a range of different sources,” said Paul Whitehead, Professor of Water Science at the School of Geography and the Environment. For example, phosphorus comes through sewage works, from the soap we use in everyday in dishwashers and washing machines, as well as from agricultural and rural diffuse sources.

“They create eutrophic conditions in the river, where you get excessive blooms of algae and growth of unwanted plants” explained Paul. “It is possible to kill a river, meaning the oxygen levels in the river are reduced down to zero and fish and macroinvertebrates can’t survive.”

Mark Barnett, Catchment Coordinator for the Environment Agency said that although a lot of work has been done over the last few decades to reduce nitrates and phosphates, there is still quite a long way to go to meet European Union targets.

Climate change could have significant impacts on river pollution in the future as the distribution of rainfall changes, with more rainfall predicted in the winter and reduced rainfall and river flows in the summer. “This means that in the summer there will be less dilution of pollutants coming into the river system, so that could raise phosphorus levels, and in winter more nitrogen and phosphorus could be flushed out of the catchment into the river system,” warned Paul Whitehead.

Building riparian buffer strips is one measure that could be taken to cut down pollution levels – these are zones of land next to the stream channel which effectively act as a filter for the sediments and nutrients found in water running off the fields. There are also technologies available for removing phosphorus at sewage treatment works, enabling it to be recycled and sold back to farmers rather ending up in the river.

“I’m reasonably confident that things will improve” said Paul Whitehead. “They’ve improved massively over the last 50 years in the Thames so I’m sure that will continue. Technology is improving the whole time, the water companies are quite keen to actually extract phosphorus and sell it back to the farmers, it’s potentially a source of money for them and at the same time farmers want to use less and less fertiliser because it is more expensive.”

Listen to the Planet Earth podcast

Research highlight: Women in India becoming more influential in irrigation

Women in Northern India are playing an increasingly important role in irrigation, a traditionally male-dominated activity, according to new research published in the journal World Development. This is improving female engagement in formal politics more broadly, says Alexandra Girard, author of the study.

Irrigation canals in Northern India are critical for local livelihoods, but they are also important for forming cultural norms and building social support within communities and between villages. These canals are governed by deeply embedded gender traditions, a reflection of the overall decision-making system in the community. Traditionally only men in the village make formal decisions regarding the canals or participate in their repair and construction. Women are informal actors: they channel demands and complaints through informal means, such as talking to their male relatives.

However, in recent years, women have come to play a more influential role in irrigation, a result of several gender-inclusive policies. First, some canals have had their management decentralised to formal local government institutions. These local governments are composed of 33-50% female members, as required by the 1992 Reservation Law. Second, the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA), a poverty alleviation scheme aimed at investing labour surplus into the construction of durable rural assets such as irrigation, must target a minimum of 33% of women. In practice, almost half of MGNREGA beneficiaries are women. Together, these gender inclusive policies are legitimising women as both formal decision-makers and labour force in irrigation.

The research examined how women’s new legitimacy in the traditionally male domain of irrigation affects their involvement in other formal political processes in their community, and in particular their participation in formal village meetings. Factors linked to the formalisation of women’s role were examined, as well as factors from the private domain (for example, age, education, household background). The survey consisted of 593 female canal users in rural areas in the Palampur region, Himachal Pradesh, as well as interviews with 37 local government members (male and female), and over 10 other irrigation stakeholders.

The results reinforce many existing findings on the link between women’s engagement in formal politics and their personal background (for example, older women are more likely to engage in village meetings). Most importantly, the study reached several novel conclusions on the positive outcomes of formally including women in male dominated activities such as irrigation, for female engagement in formal politics. Formally creating political responsibility and economic opportunities for women in irrigation increases their visibility and mobility, and introduces them to a world of political procedures, administration, and the politicising notions of rights and benefits, which in turn favour women’s engagement and participation in other formal politics processes in the community.

Alexandra M. Girard is a recently graduated DPhil student at Oxford University.


Girard, A.M. (2014) Stepping into formal politics: women’s engagement in formal political processes in irrigation in rural India. World Development, 57: 1-18.