Low impact development

– The rise in population moving to urban centers and the land development to support this growth creates additional stress on natural resources, including the aquatic ones. In many countries that have made significant strides in addressing the point source pollution through massive investments in sewer collection systems and wastewater treatment plants, the quality of the receiving waters still shows signs of impairment due to diffuse pollution. In order to address these remaining challenges, especially in controlling the quality of urban storm water runoff, new approaches, closer to natural systems, are implemented. These new approaches and techniques include Low Impact Development, Green Infrastructure, Sustainable Urban Drainage Systems and Smart Growth, among others.

Community-based participation is a vital component of municipal efforts to address water quality, reduce pollution, and enhance habitat in the Salish Sea basin. At the request of Nature Conservancy and Snohomish Conservation District, a team of researchers from Edmonds Community College in Lynnwood, Washington have conducted a rapid ethnographic study of residents of the Perrinville watershed with the goal of helping the Cities of Edmonds and Lynnwood with their efforts to better manage stormwater and improve the ecology of these urban communities north of Seattle.

The results of an ethnographic analysis that included participant observation, informal interviews, and a door-to-door and online survey reveal a community eager to contribute to the efforts of their municipalities to address urgent environmental and stormwater management issues in the Perrinville basin. While most residents currently have lawns of grass, nine out of ten of them prefer the aesthetics and environmental benefits of diverse plants and flowers and are willing to contribute financially and via their own time and effort to the installation of rain gardens in public right of ways and their own yards. The residents do have some concerns about maintenance and would like a voice in placement, size, and selection of appropriate plants for rain gardens on their property. Most would need some financial incentives and technical assistance to be able to retrofit their properties or care for rain gardens in public right of ways but are willing to put some of their own money and labor into the effort. The community is clearly ready and willing to contribute to the efforts of their municipal governments to improve water quality, reduce flooding and pollution, and enhance environmental sustainability.

Urban streams and their associated riparian zones in western Washington contain important fish and wildlife habitat. This report summarizes the results of an in-stream salmon spawning survey from October 23, 2016 through December 16, 2016; wildlife surveys using tracking and camera traps from January to December 2016; and monthly water quality sampling from January through December 2016. Additionally, this report draws comparisons and contrasts with previous surveys that began in January 2012. Edmonds Community College students, staff, and volunteers conducted the surveys in Japanese and Big Gulches in response to requests from the City of Mukilteo and Snohomish County Airport.

The surveys demonstrate that small numbers of adult coho continue to return to Japanese Gulch for the fifth year in a row after the completion of a significant stream restoration project removing four major barriers to salmon migration (Murphy, et al. 2013; Murphy & Coale 2014; Murphy, et al. 2016a). For the second out of four years, coho have returned again to Big Gulch. In contrast to small and modest runs in the past three years, though, surveyors documented zero chum returning to Big Gulch in 2016. Two out of three necropsies of female coho in Japanese Gulch revealed evidence of pre-spawn mortality. One necropsy of a female coho in Big Gulch provided evidence of spawning. Data over three years indicate coho pre-spawn mortality rates of 40% for Japanese and 50% for Big Gulch. Wildlife monitoring confirmed sightings of cooper’s hawk in Japanese Gulch, previously reported by Mukilteo Wildlife Society.

Water quality data took on increased significance this year. A newly implemented macroinvertebrate survey documented caddisfly, mayfly, stonefly, scud, aquatic worm, and midge in both creeks, leech in Japanese Gulch, and blackfly in Big Gulch and resulted in a “fair” rating of the health of both streams. Chemical and bacteriological sampling found the streams to be in a habitable range for salmon with a couple of key exceptions. Surveyors observed a spike in E. coli in Big Gulch in May and June that returned to normal levels after City of Mukilteo officials identified and corrected a potential source of fecal coliform. Students documented high pH, low alkalinity, and high turbidity that coincided with the storm event that should have brought chum back to Big Gulch this year. Surveyors documented a significant flow of polystyrene beads in Japanese Gulch, a form of plastic pollution observed but not reported in the previous year. Distribution and density patterns suggest that a ruptured and submerged float in the detention pond may be the source. Corrective efforts are needed to stem the flow and clean up the beads.

This year, 141 students, staff and faculty volunteered for salmon monitoring, wildlife and/or water quality monitoring. Ten of these volunteers were returning volunteers from previous years, while 131 were new to the project. Overall, 353 students, staff and community members have contributed to this community-based service-learning project over the past five years. Participation has grown as faculty and students at Edmonds CC recognize the value of assisting local municipalities in their endeavors to restore and conserve fish and wildlife habitat. This project serves as an example of the value of community-based citizen science and service-learning in filling the monitoring and assessment gap in current salmon and steelhead restoration throughout the Pacific Northwest.

This study introduces a preliminary approach to integrating design framework with Low Impact Development (LID) technologies which promote education and awareness, and evaluates the impact of LID. The proposed framework, called a “BLUEprint” for Stormwater Infrastructure Design, serves as a three-tiered design performance measurement structure. To verify the proposed framework, three water conservation-based design projects in Texas were selected. The framework was applied to determine types of appropriate LID facilities in each project and to simulate their hypothetical performance with quantitative measurements utilizing same variables to compare efficacy of LID applications in each site. First, to develop the framework, after reviewing existing LID facilities applied in previous projects, 17 LID facilities including the green roof, bio-swale, and bio-detention pond were selected and categorized into three typologies based on hydrological functionality: capture, convey, and clean. Runoff amounts and collectable rainwater were measured according to these typologies. Second, to promote public’s awareness, each LID facility was suggested to be integrated with an innovative hierarchical way-finding system which illustrates the ratio of infiltrated water to total rainfall. Expanded social space and number of signage were correspondingly assessed to measure social benefits of LID. Finally, the vegetation palette effectiveness was evaluated based on drought tolerance and water treatment capacity relative to site conditions. In a comparison among the three projects, the hypothetical results showed that the LID facilities examined reduced runoff volume by up to 45% and could annually save about $10,000 by planting xeriscape vegetation with less water demand and reusing harvested rainwater for irrigation. This result emphasizes the significance of the integrated LID design framework and efficacy-evaluating model. The proposed framework would be an effective tool in the decision making process for holistic LID design and planning with more objective design strategies using quantitative measurements.

This study aimed to estimate the watershed runoff caused by extreme events that often
result in the flooding of urban areas. The runoff of a residential area in the city of
Guaratinguetá, São Paulo, Brazil was estimated using the Curve-Number method proposed by
USDA-NRCS. The study also investigated current land use and land cover conditions,
impermeable areas with pasture and indications of the reforestation of those areas. Maps and satellite images of Residential Riverside I Neighborhood were used to characterize the area. In addition to characterizing land use and land cover, the definition of the soil type infiltration capacity, the maximum local rainfall, and the type and quality of the drainage system were also investigated.

Several constituents discharged with urban storm water runoff have been sampled and analyzed in a residential area in Bucharest, Romania. A total of five rainfall-runoff events were monitored through grab sampling. The monitored parameters included conventional measurements, such as pH, conductivity, oil and grease, but also heavy metals, nutrients and pathogens. The analysis shows that urban storm water runoff washes of certain pollutants in concentrations above the numerical water quality standards. The attempt to determine the existence of a first flush phenomenon proved inconclusive.

Sustainability often appears as an elusive term even in renowned reports of public policy and international urban development. One reason explaining this is that the translation between the different dimensions of sustainability – the economic, the social and the environmental - cannot be simply articulated. Measuring the environmental and social costs of urbanization seems especially difficult, and this sets an epistemological tendency to prime the quantitative economy costs of urbanization, over its more qualitative social and environmental costs. As an alternative to this situation, this report uses secondary research literature to select indicators, find their magnitudes, and normalize the economic, environmental, and social costs and gains of urbanization.
The report does not only shows the impossibility to reduce these dimensions to a cohesive, integrative definition of sustainability. It also makes the case for building retrofitting projects at a large scale, which provide more working salaries and much less carbon footprint and population displacement, at an apparent lack of difference in economic costs.

The dramatic impacts of the climate change phenomenon faced by the urban communities coupled with increased urbanization trend dictate a new paradigm in managing urban storm water runoff in the wider context of Integrated Urban Water Management. To defend cities from the threat of flooding and to protect the quality of receiving waters, nature-based solutions, such as Low Impact Development, Green Infrastructure, Natural Water Retention Measures, etc., must be part of the toolbox of practices.
The creation of dedicated centers for studies, research, and specialists training, to support the implementation of these techniques, appear to be a positive approach for countries attempting to initiate the change to the new paradigm.

Stormwater runoff from urban areas is a significant source of water pollution in the United States. Many states are promoting low impact development (LID) practices, which provide a variety of direct and ancillary ecosystem services. We describe a meta-analysis designed to evaluate the property value benefits of LID practices that reduce impervious surfaces and increase vegetated areas in developments, and present an example application to a hypothetical land use scenario. From the many hedonic property valuation studies of the benefits of general open space, we identified 35 studies that valued open spaces that were similar in nature to the small, dispersed open spaces characteristic of LID. The meta-regression estimates the percent change in a home's value for an observed percent change in open space within a specific radius of a parcel, based on changes expected to result from LID approaches that increase green spaces. Our results indicate that the design and characteristics of a project affect the magnitude of benefits, and that values decline with distance. More broadly, the meta-analysis shows percent change and proximity are robust determinants of household willingness to pay for aesthetic and other services associated with local availability of small, dispersed open spaces resulting from LID, but that values for other features, including type of vegetation and recreational use may be site-specific. Policymakers and developers could draw on our synthesis of site characteristics' effects to maximize benefits from open space associated with LID.