Nancy White

Greening Development to Protect Watersheds: Does New Urbanism Make a Difference?

Abstract New urbanism has been touted as a more environmentally sustainable form of development than conventional low-density sprawl. To test this assertion, this study comparatively evaluates how well 50 matched pairs of new urban and conventional developments in the United States integrate watershed protection techniques. Findings indicate that new urban development practices offer a greener and more compact alternative to sprawl in greenfields on the suburban fringe, as they are more likely to protect and restore sensitive areas, reduce impervious cover, and incorporate best management practices. New urban developments in infill sites are more likely to incorporate impervious surface reduction techniques and restore degraded stream environments, but have equivalent levels of sensitive area protection and use of best management practices. Recommendations offer ways in which watershed protection techniques can be used to implement more environmentally sustainable development.

Tracking Salmonella Contamination in Various Watersheds and Phenotypic and Genotypic Diversity

Salmonella enterica is an important foodborne pathogen, and contamination of surface and ground water that may result from various human activities, such as animal production and urbanization, may contribute to the public health burden. The aims of this study was to determine the sources of Salmonella contamination in four different types of watersheds and to assess the relative contribution of multidrug-resistant strains. Eighty-six water samples collected from four different watershed systems, including those impacted by swine production (n = 12), residential/industrial (n = 34), crop agriculture (n = 12), and forestry (n = 28), were cultured for Salmonella and further characterized by serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis genotyping. Salmonella prevalence was high in all four watersheds: residential/industrial area (58.8%), forestry (57.1%), crop agriculture (50%), and swine production (41.7%). Majority of the Salmonella isolates (87.1%) were pansusceptible. Multidrug resistance up to eight antimicrobials (R-type: AmStTeAxChCeKmGm) was detected in water samples that originated from swine production systems only. Serovars identified included Anatum, Gaminara, and Inverness (18.3% each) and Muenchen and Newport (8.7% each), Bredeny (7.6%), and Montevideo (6.8%). Pulsed-field gel electrophoresis analysis indicated genotypic relatedness among Salmonella recovered from residential/industrial and forestry-associated watersheds (genotypic cluster types A, C, D, E, F, G, H, and J), sites with relatively close geographic proximity. Swine-production-associated isolates were distinctly different from the others (genotypic cluster types B and I), corroborating the phenotypic findings. Overall, the findings suggest that all the various watersheds, including natural forest, remain important contributors of Salmonella contamination. While swine-production-associated water samples were not found to have a disproportionately high prevalence, it was the most important reservoir of multidrug-resistant strains.

Efficiencies of temporary sediment traps on two north carolina construction sites

Sediment export from construction sites is receiving increasing scrutiny, and correspondingly the efficiencies of sediment controls are being questioned. Sediment or total suspended solids (TSS) and total phosphorus (TP) concentrations in outflow from, as well as sediment accumulation, in three temporary sediment traps located on North Carolina construction sites were monitored to assess the efficiencies of the traps. The trapping efficiency of the trap located on a Coastal Plain site (Woodsong) was 69%, while the efficiencies of two traps located on a Piedmont site (Carpenter) averaged 59%. In addition, the Carpenter trap retained 30% of the TP coming off the site, while the Woodsong trap retained 9%. Sediment size analyses of a limited number of samples indicated that the Woodsong trap retained 91%, 43%, and 21% of the sand, silt, and clay primary particles entering the trap, while the Carpenter traps retained 68%, 72%, and 40% of the sand, silt, and clay particles entering it. The turbidity of outflow samples was also measured and correlated to TSS concentrations. A relatively strong linear correlation was found for data from the Carpenter traps (r2 = 0.96), and a weaker correlation was documented for the Woodsong trap (r2 = 0.64). These data indicate that for sites with high TSS concentrations in runoff and relatively little organic matter left on the site, TSS may be computed from turbidity; however, more data is needed to confirm this assertion.

Using the AMOEBA approach to measure progress toward ecosystem sustainability within a shellfish restoration project in North Carolina

Abstract Sustainable development, a concept of concern today in the political decision-making arena, captures and combines the need for economic development and the urgency of ecosystem protection. Sustainability indicators not only describe the environmental situation and the current burden on it; they also show what environmental burden the ecosystem is able to withstand in the long-run. Sustainability indicators tell us if, and to what degree, we are making progress toward the goal of sustainable development. This paper examines the purposes and requirements of sustainability indicators, using the AMOEBA approach as its main focus. AMOEBA, in the Dutch language, stands for ‘general method of ecosystem description and assessment’. In the AMOEBA approach, quantitative and verifiable objectives are developed that allow for a quantitative description and assessment of ecosystems. The AMOEBA approach is a tool in aiding political decision makers to better understand the ecological status of an area of concern. AMOEBA is described both in general terms and with respect to its application at Jumping Run Creek shellfish restoration project in North Carolina. The project seeks to mitigate impacts to watershed hydrology due to land use changes that contribute to excessive bacterial loading and bed closure. Parameters being studied are indicators of bacterial stores, hydrologic modification and building density. An altered AMOEBA was developed which graphically presents the selected indicators and allows for an assessment of ecosystem impairments.

Runoff and Pollutant Export from a LID Subdivision in North Carolina

AbstractStorm rainfall on and runoff from a 3.35-ha low-impact development (LID) residential subdivision in the Piedmont region of North Carolina were monitored for 6+ years, which included predevelopment, during-development, and postdevelopment phases. Runoff was monitored and sampled at two stations using automated samplers. Along with residences, the drainage area to one of the stations (PC1) included an undisturbed wooded riparian buffer with level spreaders to distribute runoff, while the area to the other station (PC2) included four bioretention areas, permeable pavement, a roof runoff collection system, a detention pond, and other LID measures. Monitoring results documented that the postdevelopment, runoff to rainfall ratio, and pollutant export at both stations were significantly greater than those of the predevelopment phase, during which time the land use on the site was mature woods. The total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) export at both LID monitoring s...

Berke et al. Respond

and the control group, one would expect to find more mitigation of runoff in the higher-density subdivisions. Finding it in greenfield developments is not surprising; not finding this to be the case in infill developments is disturbing. But is the presence or absence of mitigation the appropriate dependent variable? I argue that impervious surface per gross acre and quantity of runoff are the outcomes that should be measured. Finally, my confidence in the research protocol would be greater if the authors had adopted a null hypothesis rather than an advocacy research design.