Wetlands
Wetlands, including river and lake floodplains, bogs, mires, permanent and tempo- rary lakes of varying sizes, saturated or high water-content soils (such as peatlands), flowing surface waters (rivers), mangroves and estuaries, are among the most con- spicuous components of natural water infrastructure. Wetlands perform significant hydrological functions; for example, as regulators of surface water flows, including in particular flood events, and, in many cases, regulating groundwater recharge. They also perform significant roles in nutrient cycling, including recycling wastes, and in soil regulation, including influencing land formation and stability, particu- larly in estuaries and along coastal systems. “Wetlands” also includes vegetation associated with them, such as mangroves, which can contribute to wetlands ser- vices, such as coastal protection against storms and nutrient cycling.
Changing paradigms for water management
There has been a shift towards more proactive approaches to using the environ- ment as an asset to solve water problems. This centres on a better understanding of how the ecosystem functions as natural water infrastructure. Historical approaches tended to be aware that water management impacts ecosystems, but proceeded on the assumption that water use (for humans) was more important than the eco- system (environment). The values and benefits of the full suite of services provided by the ecosystem were therefore not included in decision-making. The result is an increased overall risk, with the ecosystem and its needs perceived as in conflict with human needs. In the “new paradigm”, ecosystems are managed (together with built infrastructure) to achieve a water-management goal of delivery of the full suite of required ecosystem services (including water quantity and quality), and
thereby reduce overall system risks. The ecosystem is seen not as a problem, but as a solution (Figure 2).
Figure 2: Evolving approaches to the water–ecosystem nexus
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