Environmental Science & Technology Table 1. Evolving Focus of Water Resources Management As Evidenced by Federal Legislation and Regulationsa FEATURE period 1870 1908 1908 1953 1953 1991 post-1991 principal goal ﬂood protection hydropower water quality protection integrated water resources management a Source: Vermont.43 of public waters and responsibility for enforcement rests mainly with the Cantons (i.e., the 26 Swiss states), and implementation and operation and maintenance of infrastructure are generally performed at the municipal or community level. Despite this decentralization of authority and responsibility, the Swiss Federal legislation provides a useful overview for the evolution of societal goals over time (Table 1). Expanded ﬂood protection eﬀectively increased the availability of land for settle- ment and agricultural use, and hydropower development sup- ported rapid industrialization. Thus legislation in these domains may be considered as increasing the direct beneﬁts gained by Swiss society from the environment. In contrast, the focus of later legislation and regulations (corresponding to the goals “water quality protection” and “integrated water resources manage- ment” in Table 1) shifted toward environmental protection as the detrimental impacts of human activities on the environment and the need for their amelioration became apparent. ’ MOVING TARGETS: UNINTENDED CONSEQUENCES AND UNANTICIPATED DEMANDS It is clear from Table 1 that some of the activities conducted under the auspices of earlier Federal legislation (particularly related to ﬂood protection and hydropower development) led to conditions that were later considered unacceptable to society. Although some of the environmental impacts of these early measures (e.g., the loss of ﬂuvial habitat) were not the intended consequences of river channelization and dam construction, they were mostly anticipated and were considered as an acceptable consequence at the time. During the long lifetime of water infrastructure, an increasing value has been placed by society on the conservation of landscapes, biodiversity, and native species (particularly ﬁsh populations) with a consequent em- phasis on preserving and restoring aquatic habitat. These values can be considered as an unanticipated demand on the infra- structure that compromises its perceived success in the long term. Similarly, various types of measures that have been employed by society can be evaluated not only in terms of their intended goals but also in terms of their unintended conse- quences on the water environment and the unanticipated demands that they must accommodate (Table 2). ’ CONTEXT FOR PRESENT AND FUTURE MANAGE- MENT OF WATER INFRASTRUCTURE AND WATER RESOURCES Past decisions on the management of water infrastructure and water resources (as illustrated by Federal legislation and regulation key legislation and regulation 1877 Federal Law on Hydraulic Engineering (SR 710.10) 1878 Federal Law on Forests (revised1902, 1991 SR 921.0) 1916 Federal Law on the Exploitation of Hydroelectric Power (SR 721.80) 1955 Federal Law on Water Protection (revised 1971, 1991, 2010 SR 814.20) 1991 Federal Law on Fisheries (SR 923.0) 1991 Federal Law on Flood Protection (SR 721.100) 1992 Ordinance on Protection of Flood Plains (SR 451.31) 1998 Water Protection Ordinance (SR 814.201) 2001 Ordinance on Environmental Quality (SR 914.14) corresponding to the goal “integrated water resources manage- ment” in Table 1) have incorporated an increasing recognition of the complexity and interrelatedness of the systems being managed. Although existing infrastructure and long-term agree- ments (such as hydropower concessions) constrain present-day and future decisions, a pragmatic strategy of adaptation can, in many cases, accommodate evolving scientiﬁc understanding and societal expectations. Thus, for example, the problem of eutrophication of lakes in the Swiss midlands was addressed through a combination of advanced wastewater treatment, the elimination of phosphates from detergents, and improved agricultural practices (see Box). Cooperation across political boundaries, for example the formation of voluntary associations of communities to collect and treat wastewater,5 has been moti- vated by the need to overcome limited capacities or to achieve economies of scale. REVERSAL OF EUTROPHICATION IN LAKES OF THE SWISS MIDLAND: After World War II, eutrophica- tion was observed in Lake Z€urich, a large lake (volume 3.9 km3, surface area 88.66 km2, average depth 49 m) in the Swiss midland. Algal blooms were ﬁrst observed in 1949 (Figure 1, left panel) and were accompanied by a steep rise in phosphate concentrations.39 In smaller lakes, maximum phosphate concentrations were observed around 1970 (Figure 1, right panel) despite implementation of iron- based phosphate removal in wastewater treatment plants as early as 1960. Expanded wastewater treatment resulting from infrastructure subsidies in the 1970s combined with a ban on phosphate-containing detergents40,41 was successful in controlling phosphorus concentrations in many Swiss lakes that had become eutrophic42 and restoring them to mesotrophic or even oligotrophic status. It is likely that future management of water infrastructure and water resources will demand a more systematic approach to integration across sectors and adaptation to evolving boundary conditions than has been followed in the past. This is partly the consequence of demographic and historical developments that have resulted in highly altered rivers and ﬂoodplains, a dense distribution of existing infrastructure, and spatial overlap of diﬀerent impacts on aquatic ecosystems in many locations. Furthermore, an increasing awareness of the importance of ecosystem services and biodiversity has been accompanied by the recognition that aquatic systems should be considered as 113 dx.doi.org/10.1021/es202189s |Environ. Sci. Technol. 2012, 46, 112–118