Vous consultezThe spread of sustainable urban drainage systems for managing urban stormwater: A multi-level perspective analysis

AuteursCéline Patouillard du même auteur

EVS-ITUS (UMR 5600), Université de Lyon, INSA de Lyon, celine.patouillard@insa-lyon.fr

Joëlle Forest du même auteur

EVS-ITUS (UMR 5600), Université de Lyon, INSA de Lyon, joelle.forest@insa-lyon.fr

Following the Brundtland Commission in 1987 (United Nation, 1987), numerous reports have condemned the impact of human activities on the environment, with the result that “sustainable development” has become a major issue for society.[1] [1] The authors thank the two reviewers for their interest for...
suite The move towards creating more sustainable cities, as described in the New Charter of Athens (ECTP, 2003), is a clear reflection of these concerns.

2 In fact, for the last two decades cities have been a focal point in the debate over the environmental impacts of human activities. In Europe, the challenges facing contemporary urban development were first comprehensively addressed by the Aalborg Charter, which was adopted at the first European Conference on Sustainable Cities and Towns in 1994. These challenges are also tackled by Agenda 21, the United Nations program of action (United Nations, 1993), which has been implemented by major conurbations and metropolises around the world. Agenda 21 covers the construction of alternative urban environments that optimize their exchanges with and limit their impacts on the natural environment.

3 The production and operation of alternative urban technical systems does not appear to pose “technical” problems to the actors involved in urban development.[2] [2] We use the term “technical systems” to refer both to...
suite Alternative techniques (also referred to as “low-impact techniques”, “eco-techniques”, “ecological techniques” or “eco-technologies”) have been available for over 30 years in numerous domains, including decentralized renewable-energy production (photovoltaic panels, wind turbines, etc.), low-impact techniques for managing parks and gardens (elimination of chemical pesticides and fertilizers, use of less fragile species requiring less maintenance, etc.) and alternative water management techniques (swales, storage basins, wetland wastewater treatment based on the infiltration and evapotranspiration of water).

4 The present article examines this final category of alternative techniques, focusing on urban stormwater management systems, which are designed to avoid the problems rainwater runoff can cause in urban environments, such as erosion of urban surfaces, floods, traffic disruption, and disruption to urban activities in general. More precisely, the barriers of uptake of innovation for sustainability in urban stormwater management systems are discussed.

5 Widespread recognition of the drawbacks of conventional sewerage networks, especially with respect to their impacts on the environment, has been accompanied by the development of “alternative techniques” that overcome many of these drawbacks. Although these alternatives are often presented as preferable solutions, they are struggling to gain widespread acceptance. This situation is even more paradoxical given that these alternative techniques respect the precepts of sustainable development. So, why are they not being more widely adopted? Why have they been used merely to complement existing networks rather than to replace them? Is this state of affairs likely to be temporary or permanent?

6 The present article explores possible answers to these questions through a case study on the history of French stormwater management and at the driving forces behind the choice of management systems. Reviewing the history of French urban stormwater management systems (section one) can reveal two important points. First, alternative stormwater management techniques appeared as responses to other issues, such as the cost of urban development and the need for flood prevention, long before the environment became such a high profile political issue. Hence, environmental protection, and more specifically, sustainable cities are relatively recent arguments in favour of alternative techniques. Second, despite the positive contribution they can make to urban environments, the use of alternative techniques remains marginal.
The history of stormwater management leads to the question of the mechanisms and driving forces behind the competition between different technologies (section two). Although sewerage systems appear to be a classic example of a lock-in situation (Arthur, 1988), the origins of the lock-in have yet to be identified. To do this we use Geels’ (2005) multi-level perspective to examine the factors affecting the adoption of alternative management stormwater techniques. Our analysis showed that the main brakes on progress originate in the socio-technical regime.

Evolution of urban stormwater management systems from the 19th century to the present

7 From the earliest times, urban stormwater management systems have had to reconcile the prevention of rain-related risks with the constraints imposed by urban environments and activities. The sewerage networks we know today, which are distant cousins of Roman sewers,[3] [3] They were based on the same principles as the natural hydrological...
suite came to be the accepted wastewater management solution in the second half of the 19th century and gradually became the dominant design (section 1). In recent decades, recognition of the limits of these networks has opened the way for the development of alternative stormwater management techniques (section 2).

Establishment of the sewerage network as a dominant design

8 After the fall of the Roman Empire, mediaeval towns did not maintain the sewer systems built by the Romans, allowing them to become dilapidated. As a result, they fell into disuse and were not rediscovered and reused, most notably in Paris, until the cleanliness, or rather the insalubrity, of the streets became a major problem.[4] [4] As early as 1350, decrees were pronounced forcing citizens...
suite However, it was only in the 19th century, with the industrial revolution, that the building of sewers accelerated and spread under the aegis of the public authorities. In fact, the building of sewer networks was part of a more general urban transformation strategy aimed at bringing “order” to the towns that grew out of the industrial revolution (Dupuy, Knaebel, 1982, pp. 16-23). Thus the rise of the sewerage system was triggered for a large part by the major changes of the European societies in the 19th century.

9 Industrialization gave rise to highly segregated towns with huge contrasts between the working class districts and the affluent areas inhabited by the burgeoning middle classes. The insalubrious conditions of the poor neighborhoods, often denounced by contemporary town planners (Choay, 1965, p. 13), exacerbated, or even triggered, the epidemics that were rife throughout Europe. Doctors, whose knowledge was increasing rapidly at this time, observed a phenomenon of contamination via “miasmas”, or “entities” that arose from stagnant water and infected the air.[5] [5] Later work by microbiologists would disprove these hypotheses...
suite These observations were taken up by several categories of people, including the public authorities, the bourgeoisie, town planners and doctors, all of who recognized the need to “clean up” towns. The remedy was found in ensuring the continuous flow of sewage so it did not stagnate, and preventing sewage coming into contact with the air.[6] [6] Just as a body is kept healthy by the circulation of the...
suite Concretely, cleaning up towns involved supplying clean water to wash the streets, and collecting and evacuating runoff water (which had been “dirtied” by contact with the street) and the waste it carried. Here we can see that the sewerage system cannot be described only as a technical system, but must be referred to as socio-technical system. Indeed many stakeholders, with different backgrounds and aims, have influenced its principles and developments.

10 Building of the sewers in France, which began in Paris in 1830, serves as a case study. First one sewer at a time was built, then systematically following the drawing up of a sewer master plan in 1854.[7] [7] This work was part of the great transformation that Haussmann...
suite This was an ambitious plan in which the tunnels provided conduits for other utilities (gas, electricity), as well as pipes for clean and dirty waters. The tunnels were large enough for people to be able to enter them to clean the sewers. At this time, the public authorities assumed responsibility for new urban utilities, and new professions appeared, notably that of sewerman, to clean the sewers, and sewerage engineer, to design them.

11 The creation of a blueprint for sewer systems in 1854 gave this blueprint design an initial advantage in the adoption of a sewerage network, which subsequently became the dominant design in urban stormwater management systems. Indeed, many of France’s major provincial cities quickly followed Paris’s example, with Lyon and Bordeaux building sewerage networks in the 1850s and 1860s. In contrast, Marseille and several smaller cities did not follow suit until the 1880s and 1890s. At the same time, council departments were set up to design and manage these sewerage networks.
In addition to evacuating stormwater, these networks were gradually adapted to fulfill new functions, most notably the evacuation of wastewater from public buildings (hospitals, administrative buildings), and then from private homes, which were generating increasing amounts of sewage as more and more houses had drinking water on tap. This functional modification had technical consequences, as the sewage being evacuated from buildings did not have the same composition, frequency or volume as surface water runoff. In addition, recognition of the health consequences of microbial activity led to the need to treat the sewage. Thus, sewerage networks gradually began to integrate systems to reduce the pollution load, mostly in the form of water treatment plants downstream of the network (see Figure 1).[8] [8] Following the failure of sewage spreading techniques, first...
suite These facilities were subject to numerous negotiations over the financial contributions to be made by local authorities, the government and national organizations such as the French Waterways Authority (for example, for the city of Lyon, see Scherrer, 1992).

Figure 1 - Scheme of a combined sewer drainage system, adapted from Dutang and Beaumont (1990)

12 This functional change was paralleled by an organizational change. It was observed that the “all-to-the-sewer” policy brought in new actors and excluded some of the original players, because a system that was originally intended for managing stormwater and street cleaning, that is to say, the public domain, became a system for all citizens. At first reticent about this intrusion by the public authorities into their private property, which forced them to connect to the sewerage network, property owners soon appreciated the comfort provided by the new system. In addition, the trade of evacuating organic waste and turning it into fertilizer for farmers disappeared (Barles, 2005),[9] [9] Poorly structured, their resistance was not strong enough...
suite while the role of sewermen and, especially, of sewerage engineers increased. Sewerage engineers, who formed a large, highly structured body based on the schools where they were trained, most notably the “Ponts et Chaussées”, whose expertise was recognized in a context characterized by a new division of labor.

13 Advances in hydraulic and mechanical engineering led to the replacement of dendritic, gravity networks by mechanized networks, in which valves and pumps were used to overcome natural slopes and to direct flows in the chosen direction. Engineers also saw that sewers could be self-cleaning; all that was needed was for the flow to be periodically strong enough to unstick any deposits. With self-cleaning, it was no longer necessary for people to enter the sewer system to clean it, which reduced maintenance costs and meant sewers could be smaller, thereby reducing construction costs.[10] [10] On the other hand, this requires more precise sizing of...
suite In addition, the all-to-the-sewer approach modified the role of the town’s authorities by increasing their control over urban activities (now, they alone were in control of sanitation).
This is another example of the close intertwining of technical and social parameters that form the sewerage system. New stakeholders – the public – got interested to the new drainage network thus inducing transformation in the technical system. The technicians that were made responsible for the system became experts, which resulted advances in knowledge. In return, the technical system was modified – the engineers would say ‘improved’. However, this system was soon to meet its own limits.

Limitations of conventional sewerage networks and the emergence of alternative techniques

14 The French Government’s desire to build sewerage networks in all major conurbations, and then in every town, was generally welcomed by local authorities, especially given the subsidies available to help finance sewerage systems. These subsidies were awarded following a scheme’s approval by the relevant government departments, as stipulated under the law, at a time when France’s administration was very centralized. However, with no standardized framework to refer to, it was difficult to check the large number of projects that were put forward. Given the political stakes involved, this led to tensions between local authorities and central government.

15 Rules for the construction of sewerage networks were finally imposed in 1949, with the publication of a ministerial circular that remained in force for 30 years (Ministère de la reconstruction et de l’urbanisme, 1949). However, this circular was frequently criticized, even by the relevant government departments (Dupuy, Knaebel, 1982, p. 36), due to the difficulty in adapting to local needs a standard solution based on the geographical layout of 19th Century Paris.

16 In addition to differences in geographical layout, the acceleration of urban development meant that sewerage networks had to fulfill the needs of ever-larger cities: the larger the city, the greater the volume of sewage and stormwater to be collected.[11] [11] In 1851, 25% of France’s population was classified as...
suite In dendritic networks, where flows converge, the spatial and temporal concentration of stormwater during heavy rain events can saturate the network and cause flooding,[12] [12] For example, at the beginning of the 20th Century in Lyon...
suite or even lead to untreated sewage and pollution being discharged into the receiving body of water. In addition, with the institution of sewerage management as a public service, the principle of equality meant every citizen had to be provided with an equivalent service. Hence, it became necessary to find an alternative solution to the sewerage network that would allow cities to grow and ensure the maintenance of an equitable public service.

17 The first proposal involved abandoning the all-to-the-sewer principle. Other countries, most notably the United States, use two separate networks to manage urban wastewater (see Figure 2). Under the separate sewer principle, one network collects stormwater and a second network collects all other sewage. The advantages of this system are related to the differences in flow rates between the two types of wastewater (larger, more unpredictable and more variable flow rates for stormwater) and to the presumed difference in water quality. As stormwater was considered to be clean enough to be discharged directly into watercourses, stormwater networks could be shorter, more precisely dimensioned and, therefore, cheaper. This solution has been generally applied in France since the 1970s;[13] [13] Today, the total length of France’s sewerage network is...
suite however, one of its advantages was lost when more detailed analyses, carried out in the 1980s, showed that stormwater contains high enough levels of pollution to damage the receiving water body. In fact, stormwater washes pollutants out of the atmosphere and picks up heavy metals and hydrocarbons (from construction materials and vehicles), and organic and chemical wastes (from urban activities in public spaces), as it runs over urban surfaces.

Figure 2 - Scheme of a separate-sewers drainage system, adapted from Dutang and Beaumont (1990)

18 Other stormwater management techniques (called “alternative techniques”)[14] [14] Under this designation, “alternative techniques” are...
suite have been tested, including swales and ditches (see Figure 3), trenches and pits, storage basins and infiltration basins. Derived from ancestral agricultural drainage techniques, these systems are designed to avoid the concentration effect produced by sewerage networks, and thereby reduce the risk of flooding, either by delaying rainfall input (temporary storage) or by encouraging rainwater to percolate into the ground as close as possible to where it falls. In addition to infiltration, systems may facilitate water storage and water uptake and evapotranspiration by plants.

Figure 3 - Picture of a swale in Lyon, Porte des Alpes

19 Alternative techniques were first used in large-scale developments, in order to reduce costs. In general, they were applied to two types of projects. One was the large building of American-style subdivisions with unfenced housing that were created in the Greater Paris area from 1965, where alternative techniques were used on the initiative of private developers. The other was for the building of New Towns, which began in the early 1970s. In this case, in order to introduce alternative stormwater management techniques the public bodies responsible for building new towns benefited from virgin areas were they could design everything, from the general plan to the buildings, including streets, parks, and sewers (see Figure 4).[15] [15] Although they had to find ways of getting round official...
suite These two types of development, very peculiar in that one stakeholder controlled everything, occurred during a period of economic crisis and at a time when the pressure on real estate and housing was growing rapidly (in particular around Paris). In this difficult context, developers were forced to build away from city centers and to use the most economical building methods, which included alternative stormwater management techniques.[16] [16] In fact, it is the difference in investment cost that is...
suite

Figure 4 - Principles of sustainable urban drainage systems developed in the 70’s, adapted from Plan Urbain (1985)

20 Other actors have also taken an interest in alternative techniques, most notably large local authorities, which, with the introduction of the 1966 Metropolitan Authorities Act, can take actions covering an entire conurbation. For example, in the 1970s, Bordeaux metropolitan council built storage basins between its historic city center and its new suburbs, in order to hold up stormwater flows from the suburbs and thereby protect the city center (Bordeaux Métropole, 1998).

21 These local experiences did not go unnoticed by the relevant government departments, who were forced to recognize that the 1949 circular had become obsolete. As a result, a new Technical Circular was published in 1977, incorporating the objectives of the 1964 Water Act for the protection of the receiving environment, and, most importantly, allowing greater freedom to determine local solutions, taking into account an area’s geographical characteristics. It officially sanctioned the use of the separate sewer technique, as well as the temporary storage of sewage to reduce pressure either on wastewater treatment plants – the basins used for this are referred to as “stormwater basins”– or on the separate networks, via the creation of storage basins. The new circular’s main objective was to reduce the cost of stormwater management: “the transit of runoff waters from urban areas with separate (or pseudo-separate) sewerage networks…usually results in high costs. In many cases, a better operational solution is to truncate storm peaks and store them, either outside the input area, but as close to it as possible…it will thereby be possible to considerably reduce the size of the collectors or reduce the cost of modifying streams with low evacuation capacities, and ultimately reduce expenditure.” (ministère de l’Intérieur, 1977)

22 This circular, although not diverging from very centralized solutions, was more flexible and allowed local authorities to continue experimenting with new techniques,[17] [17] Local authorities try to optimize their sewerage networks...
suite notably alternative techniques, as was done by the metropolitan authorities for Bordeaux, Lyon and Rouen, and by Seine Saint-Denis “départemental” council, who were leaders in alternative stormwater management systems in the 1990s. Apart from these few areas, the sewerage system as recommended by the 1977 Technical Circular remained the norm.
However, from this time and more particularly from the 2000s, stormwater management, like many other urban-related activities, was increasingly been influenced by the concept of sustainable development. Alternative techniques are now presented as “low-impact techniques”, and the arguments used to champion them now highlight their similarities with natural cycles. This is in stark contrast with the previous phase in which most arguments in favour of alternative techniques were based on reducing construction and network management costs, and the impact of the saturation of traditional sewerage networks. The new arguments focus on the treatment of stormwater, which has been widely researched by scientists in recent years.[18] [18] By reducing the runoff flow path, alternative techniques...
suite The natural aspect of alternative techniques is highlighted because:

23

• They improve the living environment by providing areas for leisure activities.
  
• They are seen as guaranteeing minimal impact of human activities on ecosystems. Most alternative techniques allow the restoration of physical-chemical processes between surface waters, underground waters, the biosphere and the atmosphere, which facilitates groundwater recharge and limits the effects of urban heat islands. In addition, alternative techniques are generally energy efficient, unlike networks, which use pumps to facilitate the circulation of flows.
  
• They help protect biodiversity (notably, through the development of greenbelts and bluebelts).
  

The technical limitations of traditional sewerage networks now appear to be widely accepted and the advantages of alternative techniques should provide a strong argument for the widespread use of such systems, even as far as the progressive replacement of sewerage networks.[19] [19] This long-term hypothesis does not seem to be favoured by...
suite However, despite the solidity of the arguments in favour of alternative techniques that have been built up over almost 40 years,[20] [20] Guidebooks encouraging the use of these techniques have...
suite these techniques have not yet been widely adopted by cities. In fact, they are still mostly used to complement sewerage networks, thereby allowing the development of new areas or the redevelopment of derelict sites, without overloading the existing sewerage network. Why should this be so?

Why have alternative techniques not been more widely adopted?

24 The history of urban stormwater management is a perfect illustration of a lock-in situation as defined by Arthur (1988), who showed that a technological monopoly can appear at the end of a period of competition between ‘n’ technologies due to a “self-reinforcing” mechanism based on increasing returns to adoption “What makes competition between technologies interesting is that usually technologies become more attractive –more developed, more widespread, more useful – the more they are adopted” (Arthur, 1988, p. 391). The growing awareness of the link between cleanliness and health and the creation of a blueprint for sewer systems in 1854 seem to have acted as a catalyst – or, as David (1985) put it, an accident of history – thereby creating an initial and long-lasting advantage for the sewerage network approach,[21] [21] This advantage is undoubtedly strengthened in the present...
suite even though this system is now criticized on numerous fronts. But is this situation irreversible? Are alternative techniques, despite their environmental efficiency, destined to remain ancillary additions to sewerage networks, rather than replacements for them?
In order to answer this question, we first have to identify the origin of the technological lock-in. We do this by analyzing the situation from a multi-level perspective, an approach that is widely used to examine competition processes between a dominant technology that is firmly established in a technological regime, and an emerging technology (Kemp, Rip, Shot, 2001, p. 278).

The multi-level perspective

25 To date, the multi-level perspective (MLP) framework has been used mostly to examine past technological transitions, such as the transition from piston engine aircraft to jetliners, or from horse-drawn carriages to automobiles (Geels, 2005). The MLP framework does this by distinguishing three interdependent levels: niches (micro-level), socio-technical regimes (meso-level) and landscapes (macro-level).

26 A niche is a protected space, a sort of incubator that allows radical innovations to hatch and develop. At this level: “there is little stability and much uncertainty, and actors work in different directions, exploring different trajectories” (Geels, 2005, p. 367). A socio-technical regime consists of an ensemble of routines and practices relating to all the actors in a given sector. According to Geels (2005, pp. 366-7) “… the activities of these social groups (re)produce and maintain the elements and linkages in socio-technical systems… Socio-technical regimes account for the dynamic stability of socio-technical systems, meaning that innovation still occurs but is of an incremental nature, leading to trajectories and path dependencies.”

27 The socio-technical landscape refers to aspects of the technology-exogenous environment. It encompasses features of the system that cannot be changed directly at the will of the actors, for example material infrastructure, political culture, and social values (Rotmans and Kemp, 2001).

28 Hence, the multi-level perspective regards technological transitions as being the result of interactions between the three levels. The first stage of the transition is the production of innovations within niches “in the context of existing regime and landscape developments” (Geels, 2005, p. 368). The development from this first stage is shown in Figure 5.

Figure 5 - Multi-level perspective on transitions, adapted from Geels (2005)

29 The MLP has been criticized for not paying enough attention to the way in which innovation emerges within niches, of overlooking competition between alternative solutions within niches, or even of giving a heroic image of niches.[22] [22] A number of criticisms of the MLP can be found in Smith...
suite Nevertheless, multi-level analysis allows the question of technological transitions to be examined in their material, organizational, institutional and historical dimensions, and hence to identify the origin of technological lock-ins.

The macro and micro levels: an alignment that favours the spread of alternative techniques

30 Applying the multi-level perspective analysis to urban stormwater management shows that there is pressure on the socio-technical regime from the macro and micro levels in favour of the development of alternative techniques.

31 In terms of landscape, approaches to urban development have evolved considerably as a result of the critical re-evaluation of contemporary changes to the urban environment in a context of unprecedented urban development.[23] [23] As Emelianoff (2008, p. 15) pointed out, “sustainable...
suite This is rooted in the reflection launched by the OECD in 1986 on the relations between cities and the environment, and in the diagnostic carried out by the European Green Book on the urban environment (Commission européenne, 1990), which helped set up the first group of experts on sustainable cities.

32 The importance given to the environment resulted in a number of European directives on pollution. These directives, which set down particularly strict limits for pollutants in aquatic environments, include the European Urban Waste Water Treatment Directive of 1991, which was transposed into French law by the 1992 Water Act; and the 2000 European Water Framework Directive (WFD). The WFD, which stipulated that good water status must be reached by 2015,[24] [24] This directive set ambitious objectives for the conservation...
suite was transposed into French law by the Water and Aquatic Environments Act of December 30, 2006 (LEMA) and strengthened by the Grenelle environment forum.

33 However, it was at the Aalborg Conference, in 1994, that cities took the biggest step towards recognizing their responsibility for the environment and their ability to act in favour of sustainable urban development. Numerous cities voluntarily introduced local Agenda 21s, in the wake of the action plan for the 21st century that was adopted by 173 heads of state at the Rio environment and development conference in June 1992. Chapter 28 of this action plan called on regional authorities to set up Agenda 21 programs in fields as varied as housing, air pollution, and the management of water resources and sanitation.

34 Although the landscape seemed to be favourable to the emergence and spread of alternative techniques, what was the situation at the micro level? A priori, this level played the role attributed to it by Geels, that is, the generation and development of techniques that would challenge established methods in the socio-technical system, as described in the previous section.

35 The formation of a community of actors (researchers, landscape consultants, local authorities) in the 1970s facilitated the development of alternative techniques, which were tried in several large cities with very positive results. For example, according to Bourgogne: “After 25 years of operations, compensatory solutions [alternative techniques] have proven their effectiveness, even if, here and there, a few hitches have been observed, which are currently being resolved. Globally, these techniques have fulfilled the tasks for which they were built: avoiding damaging floods downstream, and avoiding the local authorities having to make major investments to evacuate rainfall runoff from newly developed areas.” (Bourgogne, 2010)
In addition to their environmental efficiency, alternative techniques also turned out to be financially advantageous for public sanitation departments, as they do not require large-scale excavations to install pipes, always a difficult operation in urban areas (Tabuchi, 1992). However, operating costs are still subject to debate (Sibeud, 2001).

The socio-technical regime: barriers to the spread of alternative techniques

36 Although the first two levels seem to favour the emergence and spread of alternative techniques, numerous barriers at the level of the socio-technical regime are slowing this process. The first barrier results from the fact that alternative techniques are no exception to the rule that introducing new methods requires changes in behavior. This learning curve affects all the actors involved, from developers to local sanitation departments and individuals. Developers have to consider stormwater management from the earliest stages of their proposed development, in order to take into account both technical (flow directions) and esthetic aspects; sanitation departments have to consider maintenance aspects (e.g. de-icing salt that could kill plants); and individuals who, to avoid having mud in their garden, may be tempted to drain a swale on their property into the stormwater system, thereby reconstituting the network.

37 The need to learn how to use these alternative techniques requires a similar investment to “post-switching” behavior adaption, which is known to be a major consideration in decisions to adopt alternative methods. These are entry costs rather than exit costs, and can be insurmountable. As Arthur (1988, p. 404) suggests: “Where learning effects and specialized fixed costs are the source of reinforcement … repositioning the system is then difficult”.

38 The second barrier is formed by the dynamic of the transition. It is now generally agreed that the sewerage network, which is currently the dominant sewerage management method, has functional (flow rate problems leading to floods) and environmental (pollution) limitations that make it a much less attractive solution. Although this favours the development of alternative technologies, decisions to replace sewerage networks with alternative techniques are not as self-evident as they may first appear. For example, any substitution would have to be progressive (it would be impossible to instantaneously change from one system to the other for economic and practical reasons) and a partial substitution could seriously disrupt the functioning of the sewerage network.

39 Third barrier is formed by the legal constraints on stormwater management in France. Today, the whole French community shares the cost of evacuating stormwater from private land via the sewerage network, but this is not the case for alternative techniques, whose costs have to be born by the developer. Hence, even if alternative techniques are relatively inexpensive, they represent an additional cost (installation and maintenance) and they often take up valuable real estate. This raises issues about the equity of public services; why should some individuals or some developers have to pay for stormwater management on their land while simultaneously contributing to the local authority budget in the same way as other residents?
Fourth barrier, according to some authors (Berdier, Toussaint, 2007) is the spread of alternative techniques which are partly linked to choices favouring value creation for manufacturers, rather than for society. Hence, a system with very low running costs and requiring little maintenance will not be favoured by manufacturers because it would not form a resource for the organizations that are currently in charge of urban sanitation.[25] [25] This hypothesis stresses the logic of value creation, which...
suite Thus, the barriers are not linked to the presence of the increasing returns to adoption, but to the existence of the organizations that make up the socio-technical system. This hypothesis deserves further investigation. If true, it could be a substantial barrier because the manufacturers who design and operate networks are powerful national and international companies who take part in the drawing up of standards and regulations and who have large economic resources. In addition, the economic health of these companies is synonymous with employment and investment in the regions where they are based. As a result, some may consider it politically valid to ensure that the techniques chosen, as long as they provide a similar service, favour the creation of value.

Conclusion

40 The present paper examines why alternative urban stormwater management techniques have not been more widely implemented as complements to, or replacements for, classic sewerage networks.

41 Approaching this question from a multi-level perspective shows that a technological transition can be facilitated or blocked by the alignment (or non-alignment) of different levels: “if there is no external landscape pressure…then the regime remains dynamically stable and will reproduce itself. Radical niche-innovations may be present, but have little chance to break through as long as the regime is dynamically stable” (Geels, Schot, 2007, p. 406).

42 Applying the MLP to urban stormwater management systems, as shown in Figure 6, shows that the current socio-technical regime ensures a high degree of stability in the system. Hence, more detailed analyses are needed in order to understand how the system opposes the pressures in favour of the spread of alternative techniques, identified in the macro and micro levels, and why, in certain cases, these sources of inertia have been removed (because experiments and policies have been carried out).[26] [26] The interest of this project is not to point the finger...
suite In this, we fully agree with the research suggested by Smith et al. (2010), which should allow us to differentiate between different alternative techniques (competition within the niche).

Figure 6 - Multi-level perspective in urban stormwater: a synthesis. Favourable factors (in red) stemming from niches and the landscape are not sufficient – as for now

43 This work is of practical as well as theoretical interest, in that identifying factors of inertia may open the way for actions to overcome this inertia, such as the creation of a tax credit, as has been done for solar energy, or the introduction of changes to the current tax system for sanitation. A first step has been taken in this direction. A bill passed in 2006 should allow local authorities to tax stormwater management, with an exoneration for those who treat stormwater on their own land. However, this bill has not yet been signed into law, even though a second bill confirming the principle was passed in 2010. In November 2010, it was announced that the bill would be written into law in the second quarter of 2011. Would this modification be enough to overcome the regime inertia?

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Notes

[1] The authors thank the two reviewers for their interest for the present paper and their helpful comments to improve it.

[2] We use the term “technical systems” to refer both to an ensemble of objects that are manufactured to provide a service and to the organizations that the existence of these objects implies (Toussaint, Zimmermann, 2001).

[3] They were based on the same principles as the natural hydrological systems they partly replaced (gravity-driven convergence of increasingly large streams leading to the network outflow; stream, river or sea).

[4] As early as 1350, decrees were pronounced forcing citizens to clean the street in front of their home and leading to the creation of trades related to urban cleanliness (such as sewer scraper and refuse collector) but these decrees had no effect. Cleanliness was not managed on a town-wide scale and the local authorities did not take responsibility for it.

[5] Later work by microbiologists would disprove these hypotheses (Goubert, 1986).

[6] Just as a body is kept healthy by the circulation of the blood, town planners, inspired by doctors, imagined a town that is kept healthy by the continuous circulation of air and water.

[7] This work was part of the great transformation that Haussmann imposed on Paris, which included the building of wide boulevards that would allow air to circulate.

[8] Following the failure of sewage spreading techniques, first tried in the 1870s, French engineers copied the British technique of biological treatment (first wastewater treatment plant built in Achères in 1935). However, throughout the 20th century France’s treatment capacity remained insufficient for the amount of sewage produced.

[9] Poorly structured, their resistance was not strong enough to overcome Paris’s prefecture. Other trades disappeared with this growth in public urban services: water carriers, replaced by the drinking water network, and rag-and-bone men, who collected and recycled urban refuse found in the street, replaced by the city’s garbage collection department.

[10] On the other hand, this requires more precise sizing of the pipes with respect to the expected flow rate. Calculating such flow rates is far from easy (Chatzis, 1997).

[11] In 1851, 25% of France’s population was classified as urban. This figure had risen to 41% by 1901, to 56% by 1954 and to 75% by 2000 (INSEE, INED, 2006, 2010).

[12] For example, at the beginning of the 20th Century in Lyon (Scherrer, 1992), and from the 1960s in Bordeaux, Rennes and Grenoble (Dupuy, Knaebel, 1982, p. 43). Run-off floods continued to affect other towns and areas that had become highly urbanized (Nîmes in 1988, Vaison-la-Romaine in 1992, Seine-Maritime in 1998, Marseille in 2000, etc.) (Direction de la Prévention des pollutions et des risques [Department for the Prevention of Pollution and Risks], 2006)

[13] Today, the total length of France’s sewerage network is around 400,000 km, including 100,000 km of combined sewers and 300,000 km of separate sewers (consisting of 200,000 km of sewerage pipes and 100,000 km of stormwater pipes).

[14] Under this designation, “alternative techniques” are presented as alternatives to the dominant sewerage network model, whose drawbacks (too rigid, too expensive, too polluting) they promise to overcome (Azzout, 1994; Chocat, 1997).

[15] Although they had to find ways of getting round official regulations (Dupuy, Knaebel, 1982).

[16] In fact, it is the difference in investment cost that is most important: “Classic systems of buried pipes and the increase in urban development have led to a need for ever larger pipe and to sometimes intolerable costs” and “development land is increasingly difficult. Either sites that had been overlooked because of poor ground quality – rocky ground, or areas where the water table is near the surface, etc. – are made commercially attractive by urban development, or there are very few possibilities for collecting sewage in an underground network (…)” (Plan Urbain, 1985, p. 9).

[17] Local authorities try to optimize their sewerage networks via greater mechanization (with valves) combined with automatic control, achieved by computerizing the system (sensors to measure flow rates, pollutants, etc. and centralized control). In addition, a number of sophisticated management tools (decision-making tools, modeling of the system, etc.) have been developed (Scherrer, 1992).

[18] By reducing the runoff flow path, alternative techniques reduce the pollutant load. Stormwater may also be treated by decantation and by filtration via the soil and plants (Chaïb, 1997).

[19] This long-term hypothesis does not seem to be favoured by any of the stakeholders, since they see the networks as a heritage from past public investments.

[20] Guidebooks encouraging the use of these techniques have been published at regular intervals by the relevant government departments (STU, 1989; CERTU, 1998, 2008), municipal authorities (Bordeaux, Lyon, etc.), or scientists and research groups (Azzout, 1994). They all begin by lauding alternative techniques, which they regret seeing being so little used.

[21] This advantage is undoubtedly strengthened in the present case by the weakening of the hypothesis of the “contemporaneousness” of techniques (Foray, 1989).

[22] A number of criticisms of the MLP can be found in Smith et al. (2010).

[23] As Emelianoff (2008, p. 15) pointed out, “sustainable urban development practices will go as far as inverting, in western countries, the main health policies introduced in the 19th century and often pursued ever since”. Published in 1977, almost a century after the official doctrine in favour of the continuous underground flow of all types of water, France’s second Technical Circular officially recognized the validity of managing sewage in the open air and via storage in basins. This reflects an important modification in the way in which the problem of urban sanitation was viewed (Scherrer, 1992). By adding the “time” parameter, the problem became one of flow management, rather than an a-temporal problem of continuous flow evacuation. “Management of urban waters” became the preferred term, rather than sanitation, clearly indicating the rejection of the hygiene perspective.

[24] This directive set ambitious objectives for the conservation and restoration of surface (fresh and coastal) and underground waters. A good status water is a water capable of supporting rich and varied animal and plant life, a water that is exempt from toxic products and a water that is available in sufficient quantity to satisfy all uses.

[25] This hypothesis stresses the logic of value creation, which is relatively infrequently considered in the literature on technological competition.

[26] The interest of this project is not to point the finger at the socio-technical regime by conjuring up the myth of David versus Goliath (Geels, 2005) but to provide a more detailed understanding of the modalities of emergence and technological competition.

Résumé

PLAN DE L'ARTICLE

• Evolution of urban stormwater management systems from the 19th century to the present
  • Establishment of the sewerage network as a dominant design
  • Limitations of conventional sewerage networks and the emergence of alternative techniques
• Why have alternative techniques not been more widely adopted?
  • The multi-level perspective
  • The macro and micro levels: an alignment that favours the spread of alternative techniques
  • The socio-technical regime: barriers to the spread of alternative techniques
• Conclusion

POUR CITER CET ARTICLE

Céline Patouillard et Joëlle Forest « The spread of sustainable urban drainage systems for managing urban stormwater: A multi-level perspective analysis », Journal of Innovation Economics 2/2011 (n°8), p. 141-161.
URL : www.cairn.info/revue-journal-of-innovation-economics-2011-2-page-141.htm.
DOI : 10.3917/jie.008.0141.