Improved Stormwater Management Research Articles

Modelling infiltration enhancement in a tropical urban catchment for improved stormwater management

AbstractTo mitigate the impacts of impervious surfaces in urban areas, structures such as bioretention systems and permeable pavements have been installed to enhance infiltration in many countries. However, relatively little knowledge is available regarding the performance of such infiltration‐based structures in humid tropical and highly urbanized areas. This study investigates the feasibility of enhancing the infiltration of stormwater in tropical urbanized areas using Singapore as a case study. It first shows that the rainfall depth and intensity are both high, but the time interval between consecutive rainfall event is long in Singapore. It then numerically simulates single‐event local infiltration and finds that the fraction of infiltrated rainfall is actually high. It finally performs catchment‐scale simulations and finds that bioretention systems can enhance infiltration and groundwater recharge particularly during wet periods. However, local mounding of groundwater can be significant and can hinder the performance of those structures. Furthermore, with 5% of catchment area being converted to such structures, the infiltration of the entire catchment is enhanced but still not yet up to the natural level. To increase the overall effectiveness, future studies can look into bioretention systems with underdrain systems. Copyright © 2016 John Wiley & Sons, Ltd.

A tale of two rain gardens: Barriers and bridges to adaptive management of urban stormwater in Cleveland, Ohio

Green infrastructure installations such as rain gardens and bioswales are increasingly regarded as viable tools to mitigate stormwater runoff at the parcel level. The use of adaptive management to implement and monitor green infrastructure projects as experimental attempts to manage stormwater has not been adequately explored as a way to optimize green infrastructure performance or increase social and political acceptance. Efforts to improve stormwater management through green infrastructure suffer from the complexity of overlapping jurisdictional boundaries, as well as interacting social and political forces that dictate the flow, consumption, conservation and disposal of urban wastewater flows. Within this urban milieu, adaptive management—rigorous experimentation applied as policy—can inform new wastewater management techniques such as the implementation of green infrastructure projects. In this article, we present a narrative of scientists and practitioners working together to apply an adaptive management approach to green infrastructure implementation for stormwater management in Cleveland, Ohio. In Cleveland, contextual legal requirements and environmental factors created an opportunity for government researchers, stormwater managers and community organizers to engage in the development of two distinct sets of rain gardens, each borne of unique social, economic and environmental processes. In this article we analyze social and political barriers to applying adaptive management as a framework for implementing green infrastructure experiments as policy. We conclude with a series of lessons learned and a reflection on the prospects for adaptive management to facilitate green infrastructure implementation for improved stormwater management.

Urban climate and adaptation strategies

Extreme heat poses a threat to the livability and sustainability of cities, and disproportionally harms marginalized groups. The frequency of extreme heat events is expected to increase in the future as climate change exacerbates urban heat island (UHI) effects. Common UHI mitigation strategies – such as cool pavements (light‐colored surfacing or permeable pavements), cool roofs (often categorized as “white”, “blue”, or “green” roof strategies to differentiate the approaches), and increased planting of vegetation – vary in effectiveness depending on a city's baseline climate, as well as on city size and layout. Microclimate mitigation efforts must move beyond exterior site‐level strategies to consider land‐use planning at the neighborhood level and the role of passive cooling strategies for buildings. Green infrastructure offers benefits in the form of improved stormwater management, air quality, carbon sequestration, and microclimate regulation. The creation of a new utility – one akin to a public company that provides services such as electricity or water and that recognizes the multiple and overlapping environmental and social benefits of green infrastructure – may expedite implementation of such strategies.

ZIELONE DACHY JAKO ROZWIĄZANIA POPRAWIAJĄCE GOSPODARKĘ WODAMI OPADOWYMI W MIASTACH

The interest in green roof technologies is increasing due to the many tangible benefits that allow to provide. One of them is the ability to improve stormwater management in urban areas, because construction of green roofs can retain and delay in runoff . Due to the fact that the market of green roofs in Poland is relatively young, there is still a need for research to provide detailed information about green roof hydrologic performance in the national climate conditions. The objective of this study is to present the research results on retention capacity of green roofs, carried out at the Wroclaw University of Life Sciences. The results show that the possibility of water retention is considerably improved at green roofs when antecedent dry weather period lasts longer than one day and the rainfall depth does not exceed 10 mm / day.

Design of Improved Stormwater Management System for the Federal University of Technology Akure

Stormwater management is becoming a problem in many cities due to rapid urbanization and poor infrastructure. Proper drainage system conveys stormwater from the road to a suitable disposal area. FUTA is well planned with good networks of roads. However, many of them are without functioning drains. The paper presents a pragmatic approach to the design of an improved stormwater management in FUTA. The entire catchment area was divided into subcatchments that form the designated units for data collection. The result of the field work showed that over half (57.31%) of the drainage area are grass land and the paved road covered 10.96%. the unpaved road and built up area covered 10.29% and 9.76% respectively. Others areas are thick forest (7.66%) and rock area (4.02%). The design of stormwater collection systems were based on the principles of hydraulics as explained by Manning. The drain size was based on the maximum discharge from each subcatchment and the time of concentration computed with Kirpichbs formula. If this design is implemented, common flash flood and siltation along roads in FUTA will be completely eliminated. http://dx.doi.org/10.4314/njt.v33i4.7

Forest Canopy Interception Loss Across Temporal Scales: Implications for Urban Greening Initiatives

Increasing urban forest canopy coverage due to greening initiatives requires watershed managers to balance societal water practices with forest hydrological processes. One such process, canopy rainfall interception, can remove substantial portions of precipitation from catchments by simply intercepting, storing, and evaporating meteoric water. We performed a field study examining interception losses across temporal scales comparing two landscaping species of contrasting crown structures (Fagus grandifolia Ehrh., American beech, and Liriodendron tulipifera L., yellow poplar), native to the highly urbanized northeastern United States, to highlight the effect of landscape design on urban water and storm water management. Results show that landscape designs using the rougher bark texture, lower branch inclination, and thinner canopy of L. tulipifera can increase water losses during rainfall and, therefore, can be used to improve storm water management. On the other hand, the smoother bark, higher branch inclination, and deeper canopy of F. grandifolia decreased water losses, allowing greater water transfer to the surface or subsurface. Thus, interception-related water resource losses during urban forestry projects can be manipulated to benefit urban sustainability efforts if designers consider the multifaceted ramifications of planting different tree species with differing canopy structures.

Multivariate analysis for assessing the quality of stormwater from different Urban surfaces of the Patiala city, Punjab (India)

Land use modifications associated with urbanization, such as clearance of vegetation, replacement of previously pervious areas with impervious surfaces and drainage channel modifications, result in increased runoff volumes, which often create flooding hazards and increase pollutant transport. An attempt has been made in the present study to investigate stormwater quality from five different urban sub-watersheds (that differ in land use and development activities) in the city of Patiala, India. The five sub-watersheds have similar geological, topographical and climatic conditions and were chosen to minimize the effect of these characteristics on stormwater quality and quantity. Stormwater samples were collected during six storm events between April 2010 and March 2011 and analyzed for BOD5, COD, TSS, TDS, Oil and Grease, TKN, Total P, Coliforms and Heavy Metals (Zn, Cd, Ni, Pb, Fe and Cu). Results of the investigation indicate a strong correlation between land use and development activities and the resulting stormwater quality. TSS, COD and Oil and Grease were found to be major pollutants in surface runoff generated from commercial and urbanized catchments (all exceeded the surface water quality standards developed by Central Pollution Control Board, India). The water quality of the smaller residential catchment was better as compared to other catchments. Principal component analysis was investigated to identify linkages between stormwater quality and urban surface types. It was also confirmed through regression analysis that both antecedent dry period and rainfall intensity have telling influence on stormwater quality. Results obtained can provide practical information for improved stormwater management.

Comparative Assessment of Urban Drainage Systems in Different Cities Based on Substance Flow Analysis

In this paper the substance flow analysis (SFA) method was employed to map the water, COD-C, TN-N flows in urban drainage system, focusing on the pathways of contaminants to urban water environment. As case studies, four cities were selected for the comparative assessments using the statistical data of 2011.Through examining the fluxes of three sources (effluent of WWTPs, wastewater discharged without treatment, and urban storm runoff) of COD-C and TN-N emission, analysis and discussionwere made based on different units of measurements.The results showed that the load of COD-C was in the range of 16.50~80.25 kg/y/capand 131.44~227.58 t/y/km2, and TN-Nwas in the range of 1.20~5.43 kg/y/capand 9.57~23.18 t/y/km2.Taking considerations ofproportional relationship among the three origins, urban storm runoff released the majority of COD-C to receiving water, accounting more than 60% of the total. For TN-N flows, effluent of WWTPs and urban storm runoff wereidentified as the major contributors, accumulated contribution of 85%.Thus, the outcomes from these substance flow analyses, suggested that a reduction in pollution could be achieved by improvingstormwater management and upgrading emission standard of WWTPs, and proved itself as an effective tool for urban wastewater management as well.

Substance flow analysis as a tool for urban water management

Human activity results in the production of a wide range of pollutants that can enter the water cycle through stormwater or wastewater. Among others, heavy metals are still detected in high concentrations around urban areas and their impact on aquatic organisms is of major concern. In this study, we propose to use a substance flow analysis as a tool for heavy metals management in urban areas. We illustrate the approach with the case of copper in Lausanne, Switzerland. The results show that around 1,500 kg of copper enter the aquatic compartment yearly. This amount contributes to sediment enrichment, which may pose a long-term risk for benthic organisms. The major sources of copper in receiving surface water are roofs and catenaries of trolleybuses. They represent 75% of the total input of copper into the urban water system. Actions to reduce copper pollution should therefore focus on these sources. Substance flow analysis also highlights that copper enters surface water mainly during rain events, i.e., without passing through any treatment procedure. A reduction in pollution could also be achieved by improving stormwater management. In conclusion, the study showed that substance flow analysis is a very effective tool for sustainable urban water management.

Survey Says: Implications of a Public Perception Survey on Stormwater Education Programming

Abstract:Effective watershed and stormwater education and public involvement programs strive to increase awareness of watersheds and landscape connectivity and also encourage behavior changes that may be contributing to water quality and quantity problems within a targeted basin. According to new guidance from the US Environmental Protection Agency on stormwater permit improvement, regulators are looking for programs to utilize targeted issues relevant to a community to guide the development of a comprehensive outreach program. In an effort to collect information on public perception, knowledge, behaviors and willingness to get involved in improved stormwater management, a telephone survey was implemented. This manuscript presents the results of this survey and offers insight on stakeholders’ attitudes, knowledge, and behaviors related to watershed and stormwater, critical factors in the initial development of effective stormwater education and public involvement programs.

Innovation in Stormwater Management in Canada: The Way Forward

Abstract Rapid urban expansion, increased traffic, ageing infrastructure, greater climatic variability, and the need for enhanced sustainability of urban water resources pose significant challenges to conventional stormwater management. Innovative approaches are needed in order to mitigate the risk of flooding, pollution, and aquatic ecosystem degradation, and enhance beneficial uses of urban waters. To examine such approaches, a series of three regional conferences on innovative stormwater management were held in Vancouver, Calgary, and Toronto during 2007 to 2008 under the sponsorship of the Canadian Water Network (CWN) and the Canadian Mortgage and Housing Corporation (CMHC). Authors of selected conference papers providing information on innovative approaches to mitigating the risk of flooding and reducing pollution impacts at the property, neighbourhood, and watershed scales were then invited to submit journal papers, and those accepted in the review process were included in this Special Issue of the Water Quality Research Journal of Canada. An overview of the selected papers indicates that no single innovative measure is adequate under all circumstances,and a multibarrier approach is deemed to be most effective. Examples of innovations at the property level include harvesting roof runoff and reusing water, managing rainwater by infiltration in swales and into soils in bioretention areas, minimizing impervious surfaces, and using pervious pavement. At the neighbourhood level, runoff impacts are mitigated by designing roads without curbs, gutters, and drain pipes, and diverting runoff into infiltration channels, swales, and wetlands. Creating roads and parking lots with pervious pavement and draining runoff from such surfaces into infiltration basins is also discussed. Among stormwater quality source controls, potential effects of street sweeping on runoff quality enhancement were assessed. New innovations at the watershed scale include: (a) the creation of wide riparian buffer zones that can detain water, remove sediments, and mitigate nutrient export and other pollutant effects, (b) the minimization of channelization of streams and rivers, and (c) the designation of floodwater storage areas. A new water balance model that is linked to a global information system (GIS) and works at all the three scales offers the best option to conceptualize stormwater problems, and their mitigation, in urban watersheds. Finally, the aim of this Special Issue is to promote examples of successful innovative approaches to improving stormwater management in Canadian cities, hoping that other practitioners will build on this experience and bring stormwater management practice to the next higher level.

Using Individual Parcel Assessments to Improve Stormwater Management

U.S. localities facing extreme challenges in meeting unfunded surface water quality mandates are increasingly turning to decentralized stormwater management. Planners, though traditionally removed from stormwater management decision making, possess the land-use management skills to significantly contribute to this effort. This article argues that conditions are currently favorable for U.S. localities to follow the example of many German cities and consider assessing the storm-water burden created by individual land parcels (1) to support public policy that provides incentives to manage storm-water on site, (2) to inform watershed planning efforts, and (3) to increase public awareness of the connections between individual land use choices and regional environmental problems.

Effect of Substrate Depth and Planting Season on Sedum Plug Survival on Green Roofs

Abstract Green roofs, a roofing technology that entails growing plants on rooftops, provide many benefits such as improved stormwater management, energy conservation, mitigation of the urban heat island effect, increased longevity of roofing membranes, reduction in noise and air pollution, and improved aesthetics. Plants on rooftops are more susceptible to extremes in temperature and drought due to their shallow substrate and elevation above ground. Because of these unfavorable growing conditions, plant selection and season of establishment are critical. The major objective of this study was to quantify the effect of substrate depth and planting season on successful establishment of plugs of Sedum species on green roofs. Plugs of nine species of Sedum were planted in East Lansing, MI, in autumn (September 20, 2004) or spring (June 8, 2005) and then evaluated for survival on June 1, 2005, and June 1, 2006, respectively. Overall, spring planting exhibited superior survival rates (81%) compared to autumn (23%) across substrate depths. Sedum cauticola ‘Lidakense’, S. floriferum, and S. sexangulare were not affected by season of planting. Sedum cauticola barely survived at any substrate depth or planting season, whereas the latter two exhibited nearly 100% survival regardless of planting season. All other species had superior survival percentages when planted during spring.

Lot size, garden satisfaction and local park and wetland visitation

Modest increases in urban density have been achieved through decreasing lot size in developments in many Australian cities over the last 20 years. It has been hypothesised that decreasing lot size need not seriously decrease quality of life or gardening satisfaction but may result in increased use of local open space. This suggestion was investigated with matched small and larger blocks in four areas in Perth, Western Australia. All locations had access to local parks and were in the vicinity of local wetlands. It was found that small lots did not affect the interest and recreation values of gardens. They also did not affect visitation to local parks. Increased reported visitation to wetlands was reported for households on smaller lots and particularly where there were no children under the age of 14 years. Perceived environmental control appeared to be a significant factor in governing wetland visitations and had a small correlation with park visitation. The potential use of wetlands created for improved stormwater management to cater for increased demand caused by higher urban density is noted.

Field Evaluation of Permeable Pavement Systems for Improved Stormwater Management

The contribution of impervious surfaces to the disrupted runoff processes in an urban watershed is overwhelming. Nearly all the problems ultimately result from the loss of the water-retaining function of the soil in the urban landscape. Traditional solutions for storm water management have not been widely successful; in contrast, permeable pavements can be one element of a more promising alternative approach to reduce the downstream consequences of urban development. We report on a constructed experimental facility for measuring water quantity and water quality from four different permeable parking surfaces. Preliminary results demonstrate similar runoff performances of the surfaces relative to each other, and significant attenuation of runoff relative to traditional asphalt.

Microtopography, Runoff Processes, Sediment Transport, and Their Implications for Land-Use Planning in the Central Texas Hill Country: ABSTRACT

ABSTRACT The Hill Country near Austin is characterized by a stepped microtopography formed by alternating beds of hard limestone and soft marl in the Glen Rose Formation. These microlandforms control the distribution of soil, with thick residual soils (up to 10 ft deep) lying over the risers and thin transported soils (less than 1 ft deep) on the treads. Detailed field studies in the Barton Creek watershed reveal that hillslope processes are governed by these features. Infiltration rates on risers typically exceed 4 in/hr, and overland flow rarely extends beyond one tread-riser-tread sequence. Sediment transport is limited by this system, and sinks, including juniper stands, are abundant on hillslopes. Small drainage basins function as partial-area stormwater systems, with much more water and sediment held in storage than is generally thought to be so by city planners and engineers. These discoveries provide new opportunities for improved site planning and local stormwater management in areas undergoing development. Recommendations include landscape restoration, which promotes trees on high-infiltration riser soils, reducing the scale of development to fit the fabric of the microtopography, and protection of the partial-area system from grafting of additional drainage areas during development of roads and stormwater systems.