Holden Laboratory

Urban Water Environment

Figure 1:  Urban Water Environment Concept
Conceptual Elements in the Urban Water Environment
Urban Water Environment (Painting by Martha E. Holden)
Hope Drain Santa Barbara, (P.A. Holden)
Hope Drain, Santa Barbara (P.A. Holden)

Urban Water Environment (UWE) is about cities, where, worldwide, human populations are concentrated.  Cities employ, house, sustain, entertain, educate, and transport people.  In cities, there are no real boundaries between “natural” and built environments: yards and parks surround residences, manufacturing plants, and offices; these are bridged by hardscaping, and buried infrastructure (Fig. 1).  Potable water—the foundation of U.S. cities—is continuously delivered for consumption and irrigation; the byproducts are sewage and runoff, whose management profoundly affects the urban lifeblood, i.e. the resupply of healthful, potable water. This system of urban water is, however, increasingly challenged by higher water demands from greater urban populations, more complex wastewater composition, aged infrastructure, soil contamination, and a changing climate.

Research to date has substantially informed urban water quality management, although the endeavors are piecemeal, i.e. addressing either water provision or sewage or runoff or specific contaminants, etc.  Research for the future must be integrated and prioritized around a central vision for comprehensive water quality management, where individual projects inform management of the entire system.  The vision for UWE is a research program whose primary aim is to inform urban management for water quality, and whose impact is made by recruiting knowledge and approaches from all relevant disciplines, including engineering, chemistry, soil science, microbiology, ecology, hydrology, and information management. Multiple, highly-integrated, projects are towards answering questions to create impact, e.g.: 

  • What are the fates of contaminants released from aged wastewater infrastructure (i.e. sewers, and pump stations), including transport and transformation in nearby (including beneath pavement) soils, drains, and surface waters?  The impacts of answering include improving infrastructure design criteria, guiding restoration, and identifying priorities for controlling chemical and pathogen pollution.
  • What soil conditions promote multiple pollutant attenuation, and what mathematical models best describe the processes in space, and in time?  The impacts of answering include predicting contaminant migration, and allowing for managing the reactive soil environment to prevent groundwater contamination by chemicals and pathogens.
  • What contaminants persist in reclaimed water, and what are their fates and effects at their points of use, i.e. green spaces with underlying soils?  The impacts of answering include exposing reclaimed water quality, and defining treatment needs and optimal use practices.
  • What are the characteristics of nutrient cycling in urban open spaces, including soils, water, and sediments, and how are the processes affected by pollution (e.g. metals, engineered nanomaterials, and other CECs)?  The impacts of answering include predicting pollution generation (e.g. nitrate) and attenuation (e.g. denitrification) patterns within urban environments, and thus how to promote ecosystem functions for improved water quality.
  • How can geographic information systems be used to prioritize research and management of the urban water environment? The impacts of answering include revealing how multiple information sets (e.g. physical attributes, monitoring- and meta- data) can be structured and continuously refreshed to reflect current conditions.

How does urbanization affect the urban water environmentAnswering requires statistical analysis of integrated datasets across space and time, with the impacts of revealing how cities affect the urban water environment, and thus how to alter practices to improve and protect urban water quality.

UWE is conducted through the generous support of Mr. Henry (Sam) Wheeler.