The South East, much of the Midlands and parts of southeast Yorkshire have suffered significant drought as a result of two years of significantly low rainfall. Recent wet weather has eased the issue, but groundwater levels remain at dangerously low levels in parts of the country.
Drought status has been lifted in some areas, but we must not become complacent. In fact, we should seize upon the recent easing as a period of grace in which to take stock and consider what approach would best protect our water supplies. After all, regional water stress looks set to be part of our long-term future.
MWH has worked in water-challenged countries around the world and believes there is a lot the UK can learn from them. Let’s look at some approaches.
Bulk transfer. The bulk transfer of water from the North West to the South East via a national grid is often discussed (see feature, page 20). However, the infrastructure expenditure required could be significant, so initially we favour more local solutions. For example, Wessex Water plans to invest £100 million in a project to facilitate bulk transfer of water across its region and also with the water-only companies of Hampshire and Bristol.
The management of such water grids and an understanding of the capability and capacity of bulk transfers will increase water resilience. In the future this will be further facilitated by smart grid approaches.
Smart grid. Moving towards a smart grid and a predictive approach to both water production and water networks asset management would in the long term reduce water leakage and other wastage – not to mention reduce actual production costs and increase operating efficiency.
Take water production, for example. Minimising wastage in water production through smart source water selection, treatment benchmarking and optimisation should be a priority. Treating some surface waters and nitrate-laden borehole water can result in high wastage of up to 10 per cent. This approach could also be used for key water users to minimise their losses and usage.
Public education and incentivisation. This proved very successful in the recent drought in Australia, where per capita consumption figures significantly decreased. However, the savings were there for the taking because Australians were high water users. Domestic consumers were using 300 litres a day, compared with around 160 litres in the UK. This aside, the results were achieved through a multiple-media public outreach campaign. In parallel each major water company had a very visible demand management programme.
In Sydney, constant visibility of the region’s water supplies is available through the Sydney Water websites. This creates a feeling of “we’re in it together” – a highly prominent sentiment and one that was maintained during the height of the drought.
However, lessons from Australia show that during periods of perceived water bounty, old habits return quickly, and can deepen if the perception that reactionary investment during drought has resulted in greater availability of freshwater. This experience has been termed “bounceback” in Australia. Unpopular and arguably knee-jerk investment in desalination, combined with the end of a long drought, flooding, and some dams now over-spilling, has resulted in an upswing in per capita consumption. This now has to be combated to prevent a return to previous profligate water usage levels.
Water footprinting. This is new to the UK and follows similar principles to that of carbon footprinting. Essentially, the amount of water used in the production of equipment or construction of infrastructure is calculated to understand the water footprint. Water companies, being major water users, need to start to consider their overall water footprint and the means to manage and reduce it. Once we in the water industry understand the process, we can expand this thinking into wider commercial areas to proliferate the potential benefits.
Use wastewater. Pumping treated wastewater into rivers to increase environmental flows has the potential to increase abstraction possibilities. Clearly, though, this needs to be considered against the long-term operational cost and the relative cost of other water security measures, as well as understanding the implications to public and aquatic health.
More straightforward is the reuse of recycled effluent for agriculture and commercial horticulture. We must look to semi-arid countries to support the case for this approach, and Spain has experiences we can draw upon – particularly in agriculture, where recycled effluent is commonly used. Right across the world, effluent recycling for irrigation purposes is widely practised with the concept further expanding to the use of “sewer mining” to extract, treat and return wastewater from nearby sewers for commercial building use or local irrigation.
A water company could take the lead on this. Just imagine the great PR, as well as the potential for cost and carbon savings, if one of our major water company head offices took the initiative and made use of sewer mining for its water needs.
Rainwater storage. The storage of rainwater needs to be maximised. Traditionally this has been through reservoirs, although a number of water companies are now looking to use aquifer storage and recharge (ASR) as an alternative. ASR was developed in the US, mainly in California and Florida. UK water companies are already looking at knowledge transfer to remove the development phase and reduce the time needed to implement the approach. We also have significant network storage capacity for storm water. If this was handled appropriately, it could provide an additional source of water and make use of infrastructure already available.
Long-term water resilience in the UK is likely to require a combination of the above approaches. The main problem is what to implement first and which will offer the most resilience and the lowest long-term cost. This question was posed in the Australian drought and gave rise to the integrated water management approach. This is risk and prioritisation based and allowed councils and water companies to look at the investment sensitivities.
The approach is applicable to the UK water industry and should be used in conjunction with water resource management plans. This would allow water companies to plan their short and long-term strategic investment on drought and at the same time increase the efficiency of water production and water delivery.
Richard Ratcliff is water sector director and Ajay Nair product line leader for MWH in Europe and Africa, specialising in water and wastewater
This article first appeared in Utility Week’s print edition of 6 July 2012.
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