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Perspective

Water Catchment Management: Looking at the Big Picture

Water Catchment Management: Looking at the Big Picture

When it comes to water catchment management, the UK water industry has traditionally managed different aspects of its domain with different people and techniques. Partly prompted by the Water Framework Directive (WFD) and partly by individual challenges, some utilities are looking at wider issues and their effects on the business as a whole.

Black & Veatch originally approached this issue from the energy efficiency angle. We reported potential energy efficiency gains of up to 15 percent through conventional means and were looking for the balance of the 80 percent-plus savings target. Digging into more detail gave decreasing returns. The place to look was upwards, away from treatment works, towards the upper parts of the catchment. An ideal would be to manage the catchment to:

  • Control raw water quality into abstraction points to minimise treatment;
  • Control run-off and drainage to minimise storm peaks, flooding and pollution.

This would reduce energy and chemical demand on both the clean and wastewater side, as well as make most efficient use of existing assets and reduce risks. There are greater gains than just energy efficiency.

Natural and Man-Made Tones

Geography tells us that civilisation needs certain natural assets to thrive, and history tells us that if we ignore their limitations we can expect to struggle. We need to appreciate there are alternatives to building our way out of trouble and consider them in a balanced portfolio of responses. Some hard engineering solutions favoured in the past may have contributed to the challenges we now face.

We have sufficient knowledge about how our environment responds to natural and man-made changes to be able to predict the consequences of development. However, we still need to put all the discrete bits of ecological knowledge together to paint a more complete picture of the interdependencies. We need a stable environment to provide consistent raw drinking water and to avoid flooding. These two goals will help us mitigate against, and adapt to, climate change effects.

However, we have many competing demands on our crowded land in the UK, and most activities will have an impact on water resources. This makes consistent planning vital. These areas illustrate the wide variety of stakeholders who will need to be committed to ensure a realistic and complete coverage of any water catchment; and the problems we face in effectively prioritising its natural and man-made components.

For instance, we could build around the edges of flood plains until they become so fragmented that they don’t function. We could then build in those flood plains until they don’t exist, perhaps with publically funded flood defence infrastructure. But the flooding and other consequences, including insurance costs, should be balanced against the development gains and born by the same people for that solution to be economically equitable.

Perhaps we can then assess proposed development in environmental as well as social and economic terms, and establish the hierarchy of requirements for sustainable development. Until then, the Environment Agency warnings that most of South East England is water stressed will go unheeded.

Finding Collaborative Advantages

Most water utilities liaise with a wide variety of stakeholders already, and some have taken action. For example, it is cost-effective to help a farmer put a bund and proper drainage around cattle facilities to avoid the risk of polluting a local reservoir. Other point sources of pollution such as metaldehydes, used to control slugs, and some other pesticides can be similarly tackled. Flexibility is essential as business models can change, both for water companies and land owners. If relationships can be established, mutual help is possible and pollution events can be avoided.

However, some problems are bigger. Three water companies have part of the Peak District in their water catchments, and management of peat moorland is critical. Acid rain affects the elasticity of sphagnum moss and its ability to bind peat when it shrinks in hot weather. Keeping it moist avoids the spectre of large chunks of desiccated peat being washed down rivers.
 
We can surely find a more ecologically friendly way of retaining water than importing large gabions of rock. Until we review the economics of intensive grazing, however, this is much better than doing nothing. Certainly the partnerships built to reach current solutions are good indicators of what can be achieved – examples of collaborative advantage where the benefits are greater than any individual organisation could have achieved on its own.

Using our Knowledge Wisely

We have most of the knowledge required to manage our water catchments and reap the rewards of a wide angle view. For example, we know:

  • If we dose chemicals into one part of the water cycle, they will come back and reap negative consequences elsewhere in the cycle.
  • If a river or aquifer becomes sufficiently polluted to require membrane treatment or reverse osmosis, the energy required for treatment will rise significantly.
  • Nitrates and phosphates – vital for growing our food – are becoming scarce, but can be harvested by wastewater treatment processes.
  • If we can design a system to absorb peak flows, we can significantly reduce the size of wastewater infrastructure and in some cases adopt “no-build” solutions.
  • Heat island and cumulative run-off issues are exacerbated by built up areas, and we recognise the benefits of SUDs and other urban landscape features. Can we afford the insurance premiums if we delete these from the project scope?
  • Bio-diverse eco-systems are more resilient to intrusion, damage and climatic changes; soils with more humus have better resilience to heavy rainfall and dust storms.
  • Single crop farming or forestry has risks, and the stages of planting and harvesting need proper management.
  • The benefits are evident of separating surface and foul sewerage to avoid polluting desirable rainwater with human waste, but are these issues covered in the planning legislation?

At present most of these issues are evaluated by separate people and, because the industry has a financial regulator, most higher level decisions are based on economics. We have started to put a monetary value on some aspects of our environment (e.g. urban street trees[2]), but these come way down the development priority list.

Developing Multi-Disciplined Leadership

Techniques we need to develop could include nurturing the people who chair stakeholder meetings effectively, since this is where decisions could be made across discipline, profession, social and governmental boundaries. To arrive at acceptable solutions and gain majority commitment on a small scale may be relatively straightforward if the combination of skills can generate sensible ideas.

For larger issues, perhaps on major developments, this will obviously be more contentious, since large-scale finance will probably be involved. For these situations, new thinking is required to avoid overloading a catchment with inheritance issues.

Decisions depend upon quality data, and in some areas, this is fragmented or unavailable. Raw data is rarely suitable for decision making, so incumbent experts need to evaluate and review data impartially so it can be peer-reviewed and understood by people in other professions.

Utilizing All Resources

By thinking outside present boxes, we should be able to make best use of all resources at the water and associated industries’ disposal. By widening the debate, we involve more stakeholders. This will raise difficulties, but most of these will include solving the problems we know about. We will need to focus on three main areas:

  • Agriculture, including abstraction balancing, pollutant run-off and catchment partnering;
  • Landscape scale water management, including peak rainfall flood alleviation, raw water quality influence and catchment partnering;
  • Built environment, including run-off management, buildings and car parks, flood alleviation with SUDs, and development planning conditions.

Catchment partnering will be necessary because water companies don’t own much of their catchments. They will need to influence other land owners to fulfil their statuary obligations. Similarly, water companies will need to influence development planning in order to avoid or alleviate water supply, wastewater removal and potential flooding issues. The present planning system tends to treat water as a commodity, but this ignores natural realities until late in the process.

It’s not just the engineering, economic and immediate social issues that will need to be considered. Our current development philosophy is influenced greatly by the fallacy that clean water in limitless quantities should be available to all as a human right. The fact is, if your population pollutes, misuses or outgrows your water resources, you will pay the price.

It is not nature’s duty to supply a limitless human population with clean water. Nor is it engineers’ duty to take up where nature leaves off with treatment using ever-rising amounts of chemicals and energy. It is a responsibility of humans to manage the balance, and that includes our own numbers.

If we take up the challenge of catchment management at the scale that the UK water resource demands, these issues will fall into perspective.

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