The key characteristics of a good indicator are: (1) easy to access, (2) easy to understand, (3) timely and relevant, (4) reliable and consistent, (5) credible, transparent and accurate, and (6) developed with the end-user in mind (Norman et al. 2010). The choice of indicators is per definition subjective. There are many options for other indicators and a variety of methods to quantify them. However, the selected questions and indicators provide for a good overview of the key sustainability issues in UWCS.
From a methodological point of view, there are options to improve the way the assessments have been made. The scores of the cities are dependent on data availability and quality. This is a major issue. In fact, the baseline assessment of the cities has shown that the choice of the indicators is partly driven by the availability, quality and comparability of the input data. In a couple of cases no local information could be provided, and assessments were based on regional or national information (Van Leeuwen et al. 2012; Van Leeuwen and Chandy 2013). In some cases there was no information at all and expert judgment scores or best professional “guesstimates” have been provided. For instance, the water security, environmental quality and public participation (VPI) data have been obtained from regional or national data sources. Depending on the size of the country and regional differences in e.g. precipitation, soil type, pollution and governance, the use of these regional/national data may lead to errors in the assessment of the local situation.
In the discussions with the stakeholders in cities it became obvious that priorities based on an assessment following the City Blueprint approach are viewed differently as priorities are set in their local political, economic and social contexts. As the City Blueprint assessment is only a baseline assessment (Philip et al. 2011) and can, and very often should, be followed by more refined analysis of particular aspects of UWCS, a pragmatic decision was taken not to attribute different weights to the indicators at this preliminary assessment stage. Every indicator has thus received the same weight, resulting in a BCI with a theoretical minimum of 0 and maximum of 10.
The use of national or regional information on environmental quality as used in this report may lead to serious overestimations of local environmental quality as cities are often sources of pollution (Grimm et al. 2008; Bai 2007). The use of local information rather than national data on e.g. water quality in the case of Rotterdam (Van Leeuwen et al. 2012) and Dar es Salaam (Van Leeuwen and Chandy 2013) leads to much lower scores and are clear examples of this. In other words the scores as provided in the current paper on environmental quality are probably too optimistic and are underestimations of the actual environmental quality of the cities. Furthermore, many water pollutants have not been accounted for. The Environmental Performance Index (2010) uses only three parameters measuring nutrient levels (dissolved oxygen, total nitrogen, and total phosphorus) and two parameters measuring water chemistry (pH and conductivity). These parameters were selected because they cover issues of global relevance (eutrophication, nutrient pollution, acidification, and salinization) and because they are the most consistently reported. The consequence of this is that important groups of chemicals such as persistent organic pollutants (POPs), persistent bioaccumulating and toxic chemicals (PBTs), endocrine disrupters and many other groups of micro-pollutants have not been addressed at all. This may lead to a serious underestimation of the actual pollution status in cities.
Retrospectively, it would have been better to be more specific about climate change. Climate change can mean different things to different people. It may implicitly address related, but totally different issues such as: (1) concrete greenhouse gas reduction targets, (2) safety; i.e. adaptation strategies and measures against flooding, (3) water security; i.e. measures to combat water scarcity, (4) measures to increase green cover (park, trees and agricultural surfaces in urban areas) to reduce the “heat island” effects. Answers on this question have been used to score indicators 18 (climate commitments) and 19 (safety). Cities may put different priorities to these aspects.
While water is generally abundant in much of Europe, water scarcity and droughts continue to affect some areas. Water scarcity and droughts have direct impacts on citizens and economic sectors. Activities with high water demand, such as irrigated agriculture, industrial production and the use of cooling water, are heavily affected by water scarcity. The current indicators do not optimally address the complexities of water scarcity (Hoekstra et al. 2012). Further information on water scarcity for Europe is provided by the Water Exploitation Index (WEI) as presented by the EEA (2010).
The Strength and Limitations of the City Blueprint
The City Blueprint is a baseline assessment and quick scan for the sustainability of the UWCS. Early involvement of stakeholders is important (Van Leeuwen 2007; Van Leeuwen and Chandy 2013). The City Blueprint method and process is proposed as first step of gaining a better understanding of UWCS and the challenges ahead (Philip et al. 2011). This has been accomplished. The inherent limitations are that the baseline assessment does not cover all aspects of the UWCS. Some aspects of UWCS are addressed very generally. The assessment is also a snapshot. It is a picture and, therefore, does not address long-term trends in UWCS stress and adaptations. In other words, the assessment is static and not dynamic. In discussions with the cities of Oslo, Athens and Dar es Salaam, the representatives explained that more drinking water needs to be provided in the very near future (Rozos and Makropoulos 2013; Van Leeuwen and Chandy 2013). For instance, in the city of Dar es Salaam in Tanzania the population is expected to double in size in the next decade! These trends are not captured in the City Blueprint. Furthermore, the current political situation in Greece precludes long-term planning and investment strategies in UWCS and is so uncertain that, in contrast with the global trend (Fig. 1) people are leaving the city of Athens and move to rural areas. This actually leads to a decrease in the number of city inhabitants. Finally, drinking water consumption in Algarve is very high (146 m3 per person per year). This may be explained by the high influx of tourists, whereas the calculation for drinking water consumption is based on the registered population. All these observations need to be included in the city reports. When these limitations are taken into account, the City Blueprint provides stakeholders with a basic insight in the current status of the sustainability of their UWCS. It enables them to internally reflect upon the current status in terms of possible consequences for future UWCS management, to share the results with other UWCS stakeholders, and to discuss potential improvements.
Towards Implementation of Best Practices
The fastest route to failure in the transition towards sustainable cities would be to sit and wait for e.g. the ultimate technological breakthroughs in water technology. This is not recommended. There is a need for a two-stage approach. The first challenge is to start the discussion with all stakeholders, to enhance public participation and to translate the baseline assessments into actions to improve the UWCS of cities based on currently available technologies (Fig. 5; Makropoulos and Butler 2010). This is an enormous challenge. However, climate change, population growth and changes in consumption patterns are projected to further increase water shortages. Improving cities on the basis of current technologies will most likely be insufficient to cope with these trends and challenges ahead. Therefore, the second challenge is to continue technological research to further improve the sustainability of UWCS. This baseline survey of UWCS can be used for a variety of purposes to:
Aid in the evaluation and compare outcomes with other cities.
Translate knowledge and educate.
Raise/improve awareness (particularly in communicating with the public).
Enable informed decision-making, i.e. to identify priorities and budgets (planning).
Refine parts of the assessment, with tailor-made in-depth studies and advanced models, if necessary.
Stimulate the exchange of best practices for UWCS (UNEP 2008; De Graaf et al. 2007a,b).
Although there are clear differences among the UWCS of the cities in this report, the most important conclusion from this study is that cities can learn from each other. The learning potential would theoretically allow an increase in the range of BCI scores from 3.31 (Kilamba Kiaxi) and 7.72 (Hamburg) to 9.70 (Fig. 5), based on current technologies. This result can be used in the transitions of UWCS in cities as described by Brown et al. (2009). It is important to realize that the implementation of “best practices” for some of these indicators–such as the water scarcity related indicators (1–3) is easier said than done. Water scarcity is not only determined by human behavior, but also by large-scale climatic, geological and hydrological processes. On the other hand, almost all indicators can be influenced directly at the level of the city.
Hundreds of millions of people in urban areas across the world will be affected by climate change. The vulnerability of human settlements will increase through rising sea levels, inland floods, frequent and stronger tropical cyclones, and periods of increased heat and the spread of diseases. Climate change may worsen the access to basic urban services and the quality of life in cities. Most affected are the urban poor–the slum dwellers in developing countries (UN-Habitat 2010). This probably also holds for Europe, where climate change is projected to increase water shortages, particularly in the Mediterranean region (EEA 2012). These megatrends pose urgent challenges in cities (Fig. 1; Engel et al. 2011). One of the follow-up actions in the context of UWCS would be to develop a simple tool for the estimation of the costs and benefits of measures to improve UWCS. Another priority would be to refocus the plans of the European Commission regarding the Blueprint to Safeguard Europe’s Water with more focus on cities. Cities should become part of the solution.
The fastest way to meet the global water challenges is not another policy document, but active and timely information exchange. This can be stimulated by more transparent communication, more focus on public awareness as well as on implementation of available technologies (Fig. 5). Examples are the creation of a Blue City website where cities can display their best practices regarding UWCS, a Blue Friend Label for industries and their products contributing to cost-effective improvements in UWCS, and an annual Blue City Award for the best performing city. By enabling this, sustainable development will take place, cities will start to learn from each other, and civil society and the private sector can play their role (European green city index 2009). Recently, this City Blueprint proposal on governance has been prioritized by the European Commission in the context of the European Innovation Partnership on Water (European Commission 2013).