Impediments and Solutions to Sustainable,Watershed-Scale Urban Stormwater Management: Lessons from Australia and the United States

In urban and suburban areas, stormwater runoff is a primary stressor on surface waters. Conventional urban stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.     

Microcosm investigations of stormwater pond sediment toxicity to embryonic and larval amphibians: variation in sensitivity among species

Stormwater ponds have become common features of modern development and often represent significant amounts of open space in urbanized areas. Although stormwater ponds may provide habitat for wildlife, factors responsible for producing variation in wildlife use of ponds have received limited attention. To investigate the role of variation in species tolerances of pollutants in structuring pond-breeding amphibian assemblages, we exposed species tolerant (Bufo americanus) and not tolerant (Rana sylvatica) of urbanization to pond sediments in laboratory microcosms. Pond microcosms had elevated sediment metal levels and chloride water concentrations. Among R. sylvatica embryos, exposure to pond sediments resulted in 100% mortality. In contrast, B. americanus embryos and larvae experienced only sublethal effects (i.e., reduced size at metamorphosis) due to pond sediment exposure. Our results suggest variation in pollutant tolerance among early developmental stages of amphibians may act in concert with terrestrial habitat availability to structure amphibian assemblages associated with stormwater ponds.     

Characterization of particulate matter for three sites in Kuwait

Many studies have shown strong associations between particulate matter (PM) levels and a variety of health outcomes, leading to changes in air quality standards in many regions, especially the United States and Europe. Kuwait, a desert country located on the Persian Gulf, has a large petroleum industry with associated industrial and urban land uses. It was marked by environmental destruction from the 1990 Iraqi invasion and subsequent oil fires. A detailed particle characterization study was conducted over 12 months in 2004-2005 at three sites simultaneously with an additional 6 months at one of the sites. Two sites were in urban areas (central and southern) and one in a remote desert location (northern). This paper reports the concentrations of particles less than 10 microm in diameter (PM10) and fine PM (PM2.5), as well as fine particle nitrate, sulfate, elemental carbon (EC), organic carbon (OC), and elements measured at the three sites. Mean annual concentrations for PM10 ranged from 66 to 93 microg/m3 across the three sites, exceeding the World Health Organization (WHO) air quality guidelines for PM10 of 20 microg/m3. The arithmetic mean PM2.5 concentrations varied from 38 and 37 microg/m3 at the central and southern sites, respectively, to 31 microg/m3 at the northern site. All sites had mean PM2.5 concentrations more than double the U.S. National Ambient Air Quality Standard (NAAQS) for PM2.5. Coarse particles comprised 50-60% of PM10. The high levels of PM10 and large fraction of coarse particles comprising PM10 are partially explained by the resuspension of dust and soil from the desert crust. However, EC, OC, and most of the elements were significantly higher at the urbanized sites, compared with the more remote northern site, indicating significant pollutant contributions from local mobile and stationary sources. The particulate levels in this study are high enough to generate substantial health impacts and present opportunities for improving public health by reducing airborne PM.     

Redesigning the FDMT Food Chain Transfer Model: Now Probabilistically Enabled and Fully Flexible

Environmental Modeling & Assessment - In Europe, the two main nuclear accident response decision support systems in use are ARGOS and JRODOS, both of which make use of the FDMT (Food Chain and...     

In search of a unifying criterion for meandering systems: examples from natural and built environments

Environmental Fluid Mechanics - Meandering of river systems has been attributed to erosion and deposition of sediments along river banks, yet a universal cause of the instability has not been...