Urban Evolution: The Role of Water

Abstract

Abstract:The structure, function, and services of urban ecosystems evolve over time scales from seconds to centuries as Earth's population grows, infrastructure ages, and sociopolitical values alter them. In order to systematically study changes over time, the concept of "urban evolution" was proposed. It allows urban planning, management, and restoration to move beyond reactive management to predictive management based on past observations of consistent patterns. Here, we define and review a glossary of core concepts for studying urban evolution, which includes the mechanisms of urban selective pressure and urban adaptation. Urban selective pressure is an environmental or societal driver contributing to urban adaptation. Urban adaptation is the sequential process by which an urban structure, function, or services becomes more fitted to its changing environment or human choices. The role of water is vital to driving urban evolution as demonstrated by historical changes in drainage, sewage flows, hydrologic pulses, and long-term chemistry. In the current paper, we show how hydrologic traits evolve across successive generations of urban ecosystems OPEN ACCESSWater 2015, 7 4064 via shifts in selective pressures and adaptations over time. We explore multiple empirical examples including evolving: (1) urban drainage from stream burial to stormwater management; (2) sewage flows and water quality in response to wastewater treatment; (3) amplification of hydrologic pulses due to the interaction between urbanization and climate variability; and (4) salinization and alkalinization of fresh water due to human inputs and accelerated weathering. Finally, we propose a new conceptual model for the evolution of urban waters from the Industrial Revolution to the present day based on empirical trends and historical information. Ultimately, we propose that water itself is a critical driver of urban evolution that forces urban adaptation, which transforms the structure, function, and services of urban landscapes, waterways, and civilizations over time.

Nutrient Retention in Restored Streams and Rivers: A Global Review and Synthesis

“…Restoring groundwater-surface water connectivity also provides ecological benefits, amenity values, and improved erosion and siltation control. Stream restoration represents an adaptation to urban water quality issues and degradation, and is one component of urban evolution of the form and function of cities over time [87,88].…”

“…Streams and stormwater management wetlands may experience "urban succession" in biological communities and ecosystem functions following phases of construction and disturbance over time [87,88]. Several studies linked elevated nutrient uptake rates in newly restored streams to increased light availability and coarser substrate composition following construction [74,78,81].…”

Spatial and Temporal Variation in Local Stormwater Infrastructure Use and Stormwater Management Paradigms over the 20th Century

“…This suggests that spatial and temporal variation in urban stormwater infrastructure is likely more complex than current conceptual models suggest. Much of the previous research has focused on large, older cities that are more likely to have followed similar trajectories and to be subject to similar regulations and patterns of growth [20,22,26], but there is reason to believe that patterns may differ in smaller and new cities. As of the 2010 Census, 86% of urban clusters had populations of less than 50,000 and those represented 12% of the urban population and 18% of the urban land area in the United States.…”

“…Much of the urban stream and urban hydrology literature assumes that all urban systems follow the same trajectory of change from no infrastructure, to centralized storm sewer systems, to decentralized systems and the use of green infrastructure [12,17,18,20,21], leading to relatively homogenous current conditions across cities [3,22].…”

Water use in a heavily urbanized delta : scenarios and adaptation options for sectorial water use in the Pearl River Basin, China

“…The government targets to reach 60% by 2020, and if the current growth rate holds, some 1 billion people could move into one of the Chinese cities (Bai et al 2014), including those in the Pearl River Basin. The rapid urbanization will demand more and more water resources to support the expanding cities, urban populations, and all the production and services required (Kaushal et al 2015).…”