Review of challenges for implementing water resources planning frameworks and asset management strategies to deliver sustainable water in the UK by 2050

Abstract

Many of today’s water utility managers face multiple challenges to guarantee their optimal service such as i) population growth, with a consequent requested expansion of distribution networks to cope with; (ii) limited economic resources, essential to finance the timely replacement and maintenance of existing assets; and (iii) climate change, with more heavily polluted waters. The way an organization manages its assets determines its success in addressing these challenges.

Asset management for water utilities is more complex than for most other sectors because of the number, variety, age, condition, location of assets, the magnitude of asset investment, the difficulty of inspecting and maintaining buried assets.

This paper provides an overview of the challenges affecting specific water sectors (water abstraction, water supply, water management and water regulations), identifying areas that require improvements and referring to case studies that could ameliorate the ways that water assets are managed including uncertainties and risks.

Keywords: Asset Management, Climate Change, Urbanisation, Strategic Plans, Sustainability, Frameworks

Introduction – Challenges

Water asset management frameworks are commonly used by the UK water industry to increase asset performance, decrease asset outage times, reduce maintenance costs, boost profit, as well as deliver customer service that aligns to local priorities (Faiz and Edirisinghe, 2009); (Federation of Canadian Municipalities and National Research Council, 2005; Institution of Civil Engineers, 2013).  However, long term planning and asset management decision making is currently impacted by a range of factors. For example the UK population has grown from 52.3 million in 1960 to 64.4 million in 2014 (Office for National Statistics, 2017). Forecast’s suggest that the UK will have one of the largest populations in Europe by 2047 (Statistical Bulletin, 2016) and will continue to increase by 2086 (Figure 1, UK Climate Change Risk Assessment 2017). In addition per capita water consumption in the UK has grown by an average of one per cent per year since 1930 (Water, 2012). Water scarcity is now considered a serious future problem in the UK, especially in the South East and East of England.

Asset and waste resource management in the UK is also impacted by climate change which is likely to lead to progressively unpredictable weather patterns, causing less certainty over river flows and rainfall (Roach et al., 2014). Global Climate Models (GCMs) have failed to adequately simulate observed precipitation patterns under historic emissions (Kundzewicz et al., 2008; Blöschl and Montanari, 2010) and therefore offer limited assistance to water managers that seek to predict future drought characteristics. The climate change adaptation agenda has focused new attention on uncertainty and presented the water resources community with a range of probabilistic climate information, fostering new dialogue around the tenancy of deterministic metrics in contemporary water resources planning (Milly et al., 2008; Salas et al., 2013; Turner 2014).

Figure 1 – Projected population increase for low (left) and high (right) scenarios, by local authority area (UK Climate Change Risk Assessment 2017: Projections of future flood risk, Main Report).

Water companies and utilities in the UK are required to produce Water Resource Management Plans (WRMPs) every five years that outline their future strategies for maintaining a secure water supply to meet anticipated demand levels and adheres to detailed planning guidance set out by the Environment Agency (Water , 2012). However attracting infrastructure investment from the private sector is becoming more challenging due to the perceived risks and long pay back periods (Rodriguez et al., 2012). Hall et al. (2012) and Hall and Borgomeo (2013) have advocated a risk-based planning framework informed by a probabilistic approach to water resources system assessment. A recent UKWIR study found that ‘numerous scientific papers illustrate components of such a risk-based framework although none address the practical challenges that would be faced by the water companies’ (UKWIR, 2012). Whilst previous contributions have developed the application of probabilistic climate projections to natural stream flows (e.g. New et al., 2007; Manning et al., 2009) and water resources system models (e.g. Lopez et al., 2009). UKWIR (2012) now note a need to advance practical methodologies for: characterising supply and demand uncertainties; linking the probabilistic outputs of (e.g.) the UK Climate Impacts Programme to water resource system models; estimating probabilities of supply-demand deficits; and optimising water resources system design by weighing investment costs against benefits in terms of reduced risk (Turner et al., 2016). These intentions reflect a sector-wide ambition to develop risk-based planning methods for dealing with climate change and hydrological uncertainty (Kundzewicz et al., 2008; Brown & Baroang, 2011; Salas et al., 2013).

This paper provides a state of the art review of i) the implications that future challenges such as climate change and urbanisation will have on the management of assets in the water sector and ii) the strategical actions to tackle these problems based on some of the eleven big questions defined by UK Water Industry Research (UKWIR) (UKWIR 2017). The Stream project Coordinated by Cranfield University and including Imperial College London and the universities of Sheffield, Newcastle, and Exeter has produced eight journal papers (Goodwin 2015, Turner 2014a, Turner 2014b, Turner 2015, Turner 2016, Ward 2012, Ward 2014a, Ward 2014b), one conference papers (Turner 2013) and four theses tackling these challenges and producing some solutions for the future (Turner 2014, Hillas 2014, Ward 2015,  Holmes  2015) and outcomes are included within this review paper.

1.      How do we halve our abstractions by 2050?

In the UK, most of the abstracted water comes from rivers, groundwater and reservoirs. Collectively, 60 billion litres of water are taken out of the environment every day (OFWAT, 2011). The Environment Agency manages water abstraction in England and Wales. One of the Environment Agency’s aims is that sustainable abstraction can provide “enough good quality water for people, agriculture, commerce and industry, and an improved water-related environment” (OFWAT, 2011). Hence, abstraction levels can be seen as a delicate balance between maintaining security of supply and maintaining sufficient streamflows to protect ecological function in natural water bodies. This balance comes under strain in times of drought. Historically, the Water Resources Act 1963 introduced a formal system for licensing abstractions from surface waters and groundwater (Environment Agency, 2016). Allocated volumes were based on amounts that had previously been abstracted and abstraction equipment capacity. Licences had no time limits – and few restrictions in times of low flow. The Water Resources Act 1991 consolidated successive legislation such as the Water Resources Acts of 1963, 1968 and 1971 and the Water Act of 1989 (Turner, 2014). Increased environmental awareness, combined with concerns about the effect of the 1995-96 drought, led to a review of water abstraction management, which included the determination of ‘hands-off’ lake and river levels to particularly limiting or avoiding the impacts of abstractions during times of low flows. Many of the additional resulting recommendations were accommodated within the Water Act 2003. The main changes made to abstraction licensing in the 2003 Act included the following.

• Greater focus on efficient and sustainable water use;
• A requirement that all new abstraction licenses have a start and end date (time limited);
• Mechanisms to help license trading, for example removing the need to specify on a license where the water will be used;
• The introduction of different license types: temporary, transfer and full licenses;
• Deregulation of approximately 20,000 licensed abstractions of less than 20m³ /d;
• Changes to who the licensing system should regulate. Some previously exempt abstractions, for example canal transfers, trickle irrigation and dewatering of excavations, will need to be licensed as soon as the regulations come into force. Under the current abstraction licensing system there are more than 20,000 abstraction licenses in England. They permit access to about 130,000 Ml/d of water from surface, groundwater and tidal sources (ABSTAT 2008).

Current understanding of the likely impact of climate change on water resources in England is based on the latest UK Climate Projections 2009 (UKCP09). The effect of projected changes in rainfall and evaporation mean that natural river flows during the summer may decrease by the 2050s almost everywhere across England, with little change in average annual rainfall. Drier, warmer summers could increase seasonal soil moisture deficits. This may extend into the autumn, shortening the winter recharge season for groundwater, reducing groundwater storage and increasing vulnerability during subsequent drought.

Following this trend there is a risk that, in future, there will not be enough resources to supply homes and businesses, to grow local food, produce the goods needed or generate power. Reliable water supplies are already under pressure in parts of England and Wales. Population growth and lifestyle changes will make the situation worse. For licences with restrictions, the amount of time that an abstractor would be able to take water in an average year could decrease. This period of restriction would be likely to occur during the driest months of the year, which, particularly in the case of summer-only licences such as for spray irrigation, is when the abstraction is most required. Even abstractors with no licence restrictions may start to see some effects as flows and levels reduce − water may simply not be available for them to abstract. This could have a major impact on some abstractors and their businesses. For example, it could mean water companies and their customers need to make tough decisions about their use of water. The companies will need to maintain security of supply, whilst the use of improved hydrological forecasting models may increase available water without significant extra investment (Asfaw et al., 2016).  Instead of reducing demand, cutting waste or changing the way they use their networks, which may be more cost-effective, Ashaw et al., 2016, provided an example of a conceptual rainfall-runoff model using a Markov chain Monte Carlo (MCMC) technique entitled Differential Evolution Adaptive Metropolis (DREAM) (Vrugt et al., 2009) on a case study catchment in the UK, demonstrating that uncertainties related to climate change in the future, such as drought, could be better managed by refining current reservoir operational rules to minimize the impact on meeting demands and the water environment. Unfortunately, where new insights are available, the industry may lack the tools to use them effectively to inform investment planning decisions (Turner, 2014). Hence, more tools similar to those presented by Ashaw et al., 2016 and Turner et al., 2016 are needed to define water resources modelling methods measuring the performance of existing knowledge and treat eventual hydrological uncertainty characteristic of each case study.

Another option to reduce abstraction by 2050 is increased routine of water re-use schemes. It has been demonstrated that suitably treated wastewater from one process is can be reused for a different beneficial purpose (i.e. a common type of recycled water is water that has been reclaimed from municipal wastewater, or sewage is reused within an industrial facility for cooling processes). There is significant potential for increased use of reuse schemes in the UK as much of the water used for non-potable purposes such as industrial applications, toilet flushing and irrigation, is unnecessarily treated to potable-water standards but despite that, it is clear that there are still a number of barriers which prevent the widespread implementation of water reuse on a truly global scale (van Rensburg, 2016). Sanz & Gawlik, (2014) reviewed and published the following obstacles as the primary contributors for concern on water reuse: (1) public perception/acceptance, (2) appropriate/standardized technical solutions; (3) monitoring/management of health considerations and risks; (4) reuse not being a part of integrated water supply strategies; (5) water pricing and business models; (6) regulatory and policy issues (lack of local/regional/global standards and best practices).

2.      How do we achieve zero interruptions to water supplies by 2050?

Every day, almost 15 billion litres of clean drinking water is pumped through a complex system of pipes to get it to where it is needed and at a pressure at which it can be used. Transferring water long distances is expensive and is energy intensive. This is one reason why there is no national grid for water like there is for electricity (OFTWAT 2008). In England and Wales, there are more than 338,000 kilometres of water supply pipes, many of which run under roads and buildings. Effective maintenance of these assets is therefore a difficult and expensive task. Water companies must balance the need to find and fix leaks while making sure roads and property are not constantly disrupted by repair work.

Additionally, water companies don’t deal only with maintenance issues but they need to ensure that water supply meets appropriately managed demand within natural environmental limits in all regions of the country and that water services are delivered at an acceptable price to the consumer.

Emerging from the principles of the Stockholm Framework, the WHO’s Guidelines for Drinking Water Quality (GDWQ) (Figure 2, WHO 2011) take an integrated approach to risk assessment and risk management to control water-related disease.

Figure 2 – WHO’s Framework for Safe Drinking-Water (adapted from WHO, 2011).

The GDWQ is a preventative management approach described by the Framework for Safe Drinking Water (FSDW) that consists of three components (Goodwin 2015): 1) establishment of health-based targets, 2) Water Safety Plans; and 3) a system of independent surveillance (WHO 2011). The FSDW is the risk management framework and the WSP is the applied risk management process. The WSP is essential to operationalising the risk management framework in a consistent and transparent way. Within the WSP component are three elements. These are: i) system assessment, ii) monitoring, and iii) management and communication and these three factors are all related to the water infrastructures that are providing drinking services.

Through a process of hazard analysis, critical control points identification, establishment of critical limits, monitoring, taking corrective actions, recordkeeping, and verification, risk managers can understand the relationship between hazard and process and thus take preventative action against threats. This approach has been adopted by the water industry and modified to accommodate elements such as risk assessment, community involvement, noncritical control points, multiple barriers (Salgot et al., 2012; Dewettinck et al., 2001, Swierc et al., 2005; Page et al., 2008). Water reuse guidelines, standards and research programmes are increasingly referring to and promoting the use of the WSP or a Water Reuse Safety Plan (WRSP) for both potable and non-potable water reuse schemes to provide zero interruptions to water supplies by 2050.

Goodwin et al., (2015) completed a review of WSP approach on the risk considerations for water reuse, the existing technological performance and water sector experience and the communication and engagement between regulators, practitioners and customers proposing modifications to existing WSP approach and its overarching risk management framework. The findings of the study conducted by Goodwin et al., (2015) highlight that a more integrated systems approach to risk management for water reuse, encapsulated within a risk management framework and operationalised through the WRSP, would help scheme managers to better anticipate potential risks and opportunities.

3.      How do we achieve zero leakage in a sustainable and zero uncontrolled discharges from sewers by 2050?

The data availability and quality of data concerning asset performance present a major barrier to the successful deployment of effective asset management techniques for any asset base (Ward et al., 2014b). To overcome this knowledge gap in the water sector, an end-to-end asset management methodologies are now being developed such as, for example, South West Water mapping 2452 km of newly transferred private sewers. Given an understanding of the asset, Ward et al., 2014a, suggested three objective functions that are used to evaluate the benefits and trade-offs of different asset rehabilitation solutions at catchment, or network, level: i) maximise asset life; ii) minimise investment cost; iii) proactively address serviceability problems. Objective function 1 considers a simplified approach to the problem of quantifying network improvement. It builds on previous work undertaken in clean water distribution planning by Halhal et al. (1997), in which the authors assumed that any length of pipe replaced in the network would provide for an improvement in overall water quality, thus allowing the total length of water mains replaced to be representative of the network’s water quality improvement.

Lack of maintenance is also a concerning factor because sewer blockages play a significant role in causing uncontrolled discharges.

Figure 3 – An example of uncontrolled discharge from sewers (© South West Water).

200,000 sewer blockages events (Figure 3) were reported on public sewers in the UK in 2008/9 (OFWAT 2009, WICS 2009, and NIUR 2009). This represents a rate of 517 blockages per 1000 kilometres of sewer per year (blockages/1000km/yr) (Hillas 2014). Across all UK water and sewerage companies, the highest rate reported was 1936 blockages/1000km/yr (Hillas 2014). Of these blockages, approximately 25% caused uncontrolled discharges from sewers, 2% generated internal flooding of properties and 23% triggered external flooding (Hillas 2014).  In order to reduce uncontrolled discharges due to blockages, sewers need to be effectively managed but this includes operational difficulties (such as problems with consistent data and problems in establishing asset ownership) that need to be overcome.

Hillas (2014) calibrated and validated a model to support decisions regarding proactive intervention on sewer maintenance. The main objective of the model proposed allows sewerage operators to identify which sewers in their network are most susceptible to suffering blockages and what factors characterise this susceptibility. Once an understanding of the factors and mechanisms (i.e. solid movement in sewers) implicated in blockage formation has been achieved, the effect of various types of proactive intervention on blockage rate can be estimated and single or multiple effective intervention can be determined. This can then allow proactive maintenance to be scheduled on an economic basis.

Uncontrolled spills from CSO’s are also a result of ageing assets that are becoming increasingly more susceptible to failure (Abraham & Gilliani, 1999). Hydroinformatic tools have been reported during the last decade to provide a support tool for the problem of optima sewerage asset management (Adey et al., 2003; Elachachi & Breysse 2007). Ward & Savic (2012) provided a unique methodology, based on work of Ugarelli & Di Federico (2010) and Ward & Savic (2011) for the optimal specification of sewer rehabilitation investment accounting for the critical risk of asset failure and applied it to a case study catchment delivered by South West Water, UK. Three objective functions were included in this strategical model: 1) structural condition improvement; 2) rehabilitation construction cost and 3) critical risk of failure. The GANetXL optimisation model used in this analysis (Savic´ et al., 2011) evaluated each of the objective functions separately. Whilst the global optimality of the solutions identified cannot be guaranteed, the model presented by Ward & Savic (2012) clearly demonstrates the ability to converge towards optimal solutions which would otherwise be over looked through manual interpretation of the data alone. Thus, given the resounding improvement over the manual specification of sewer rehabilitation strategies, coupled with the ability of the optimisation tool to use widely available condition data, this study further reinforces the need to effectively integrate such hydroinformatic tools into business-as-usual processes within the UK sewerage industry.

4.      How do we ensure that the regulatory framework incentivises efficient delivery of the right outcomes for customers and the environment?

Planning the efficient and sustainable use of water resources requires both great skill and rigorous analysis. In order to design reliable, cost-effective supply systems, planners must attempt to understand how the natural availability of water, and society’s demand for it, will change in future because yet many of the mechanisms that influence hydro-climatic extremes are poorly understood (Koutsoyiannis et al., 2009) and so robust design must somehow accommodate uncertainty.  Yet if we are to understand water resources system risk then we must acknowledge the existence of emergency provision and its influence on the problem at hand. By sizing emergency provision subjectively, water planners in England and Wales (perhaps unwittingly) impose a largely undefined assumption regarding the level of risk against which their systems are designed. They can choose to apply an emergency provision of between 15 and 45 days’ demand volume (UKWIR, 2012b), but planning guidelines fall short of mandating a demonstrated understanding of the drought probabilities these volumes protect against (1 in 100, 1 in 1000, 1 in 10,000 year…?) But because that ‘failure’ relates to a drought of undefined probability of occurrence, the whole analysis becomes ambiguous and potentially misleading. Future regulatory framework incentivises efficient delivery should include the following four objectives (Turner et al.,2016): (i) to integrate supply and demand uncertainties into the water resources modelling procedure; (ii) to predict the probabilities of meeting levels of service related to tangible consequences for customers (supply restriction), companies (e.g., operational, legal and reputational costs of supply disruption) and the environment (e.g., failure to meet compensation flow requirements); (iii) to consider impacts arising from droughts of different severity and duration; and (iv) to understand risk reduction as a goal to be weighed against the costs of system improvement. To date, the focus of policy makers has traditionally been on delivering the necessary investment to meet regulatory environmental standards and to deliver operational efficiencies. This has meant little stimulus for the industry itself to be less risk-averse in terms of adopting new technology hence changes are needed to the regulatory regime (Council for Science and Technology, 2009). These changes should include i) mechanisms to value and reward innovation through new technology, including innovative low-carbon solutions, which would in themselves create a virtuous circle by helping to stimulate the wider supply chain to develop low-carbon solutions; and ii) mechanisms to value and reward water and sewerage companies when they make the necessary longer-term investments into innovative low-carbon solutions, which would in themselves help to create a virtuous circle by stimulating the wider supply chain to develop low carbon solutions.

5.      What is the true cost of maintaining assets and how do we get this better reflected in the regulatory decision-making process?

Decision-making and planning for sewerage asset renewal/rehabilitation is a process that seeks to evaluate the condition of an asset, its risk of failure and the cost of remediation, and to understand serviceability improvements that could be achieved through different interventions. Governments can improve co-ordination across regulators and investigation e into more flexible approaches to regulation by looking to examples of good practice in other countries and in other sectors. The recent collaboration of OFWAT, the Environment Agency and DEFRA working on water rights trading is a good example of partnership working.

Typically, the objectives of a rehabilitation programme are conflicting, implying that interventions that vastly improve the structural condition or serviceability of an asset typically have high associated costs. Therefore, to permit effective planning and investment, it is important that decision-makers understand the cost–benefit trade-offs that exist between different schemes (Ward et al., 2014a).

Ward (2015) suggested how this should be considered different asset management decision- making levels: i) strategic level, driven by corporate long term views that are aimed at establishing strategic priorities; ii) tactical level, focused on delivering the best medium-term asset management policies that effectively manage risk; iii) operational level, planned and reactive interventions delivered with appropriate consideration to the impact of these actions on the strategic objectives. Ward (2015) also developed a series of decision support tools and methodologies that can improve asset management decision making for water and wastewater assets, highlighting as modelling the 25- years impact of different investment scenarios is a huge benefit to asset managers and asset owners and it provides a platform to develop a series of “what-if” scenarios that can be benchmarked against the current business policy. The additional functionality of applying an optimisation algorithm to identify the most effective business policy under basic constraints is a distinct advantage because the outputs can provide the decision maker within an informed view of what the optimal maintenance strategy should be across his/her portfolio of assets. In reality other constraints such as political or regulatory drivers might prevent the business achieving the truly optimal position. Under these circumstances, the minimum proactive renewal rate should be constrained in the model to reflect the company’s regulatory or political commitments which would prevent the optimisation algorithm selecting infeasible scenarios. A relevant example

would be the commitment from UK Water Companies to replace lead communications at the same time that their customers replace their own lead supply pipes. Therefore, the minimum proactive renewals in the model should be accounted for based on historic levels of proactive lead replacement.

Ofwat confirmed that the current system in which capital expenditure (capex) and operational expenditure (opex) accounted for separately are complex and burdensome. It has also been reported that the water industry currently exhibits a bias towards capex rather than opex (Engelhardt and Turner, 2011; OFWAT, 2011a; Utility Week, 2012). The problem with this type of bias is that utility providers are being financially incentivised to invest in capital schemes instead of more operationally related solutions, almost irrespective of which option is better suited to addressing the problem (OFWAT, 2011b). In light of the above, it is widely foreseen that the UK water industry will begin to evaluate investment on a total expenditure (totex) basis. To assist in this transition, a previously successful sewer rehabilitation optimisation model presented by Ward & Savic´, 2012 previously described has been modified. It improves on all of these limitations, while retaining the underlying principles of the original work resolving the challenge of embedding sewer network performance into the decision-making framework by means of the use of advanced geospatial information technology to quantify network performance improvements associated with different rehabilitation schemes across a catchment. A new objective function was added to the 2012 model to represent this new decision-making criterion. By introducing this new objective function, the model now considers sewer rehabilitation from a total expenditure perspective by actively promoting solutions that offer direct serviceability benefits for customers and therefore reduced operational costs for utility providers. These optimal serviceability solutions were also found to outperform the original engineering solution from a capital expenditure perspective in their own right. However, by integrating operational benefits into the decision-making process, the latest version of the model considered sewer rehabilitation from a total expenditure perspective. The advantage of this approach is that the decision-maker is directed towards rehabilitation solutions that deliver ongoing serviceability benefits to customers while also outperforming any originally developed engineering solution from a capital expenditure perspective (Ward et al., 2014).

Conclusions

A review of existing studies and regulation was completed to implement water resources planning frameworks and asset management strategies to deliver sustainable water in the UK by 2050. Based on the key findings of this research, it is possible to confirm that water companies need new ways to assess and understand multiple risks to produce effective and defensible resilience strategies and authors have identified some approaches and suggestions to be implemented in the near future.

In all the industry water sectors considered in this paper (water abstraction, water supply, water management and water regulations) it is vital that the regulators allow a degree of regulatory risk in support of developing novel and more sustainable technologies. The complexity of interactions between sectors and infrequency of events means empirical data is limited yet the potential impacts are large and regulators and the industry need to work as partners to deliver the most sustainable and long term solutions. Long term investment and planning cycles should include i) multi objectives and ii) the uncertainties related to climate and demographic change in regular plans to obtain more resilient results. Manage and deliver sustainable water should be considered as a continuous journey rather than a final destination. Flexibility is a key factor and regular new approaches and innovations should be incorporated into management plans and delivery techniques to guarantee a continuous and successful progress for each community.

 

Funding

This research was funded by EPSRC through the grant with the reference EP/G037094/1EP.

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