Modeling Green Infrastructure Components in a Combined Sewer Area

2013

JWMM

The causes and impacts of, and emergency responses to, the recent catastrophic flooding in northern and central Thailand, including Bangkok, are reviewed. A number of short term and long term engineering solutions have been proposed to avoid or minimize future flooding impacts. Low impact development (LID) technologies might be one reasonable, sustainable, approach to solving urban drainage and water quality problems in Bangkok, but the local urban approaches should be integrated with watershed wide planning efforts.PCSWMM was used to model single and multiple LID technologies in a case study of a peri-urban village near Bangkok as a preliminary exploration of LID benefits in terms of stormwater quantity and quality. A 2 y design storm for Thailand was used in the modeling. The design plans of LID technologies, using either CAD or Google SketchUp, were visualized through Google Earth, and were costed using local information.All LID scenarios reduced combined sewer overflow (CSO) volume, CSO pollutant loadings and the durations of surface flooding, although single rain barrels installed at all houses had a relatively small (4% to 9% reduction) impact. This may be related in part to the fact that a 2 y storm in Thailand is more similar to a 50 y or 100 y storm in northeastern North America. The combined rain barrel and bioretention cell scenarios offered the greatest control in reducing CSO discharges, but the costs may be prohibitive in Thailand at present.

Section: Introductionmentioning

confidence: 99%

Low Impact Development Modeling to Assess Localized Flood Reduction in Thailand

Chaosakul

Koottatep

2013

JWMM

“…Modeling efforts to date seem to suggest that LID technologies are less helpful in managing larger events (Gill et al 2007;Holman-Dodds et al 2003) , although an unpublished report by Drexel University for a test area in Cambria Heights, New York City, showed that LID technology performed exceedingly well in controlling runoff from superstorm Sandy and hurricane Irene. Hopefully, the data gaps are starting to change with projects described, for example, by Pitt and Voorhees (2011), although more work in tropical environments is needed.…”

Section: Localized Surface Flooding Reduction Through Increased Pumpimentioning

confidence: 99%

Application of PCSWMM to Assess Wastewater Treatment and Urban Flooding Scenarios in Phnom Penh, Cambodia: A Tool to Support Eco-City Planning

Sovann

Suthipong

et al. 2015

JWMM

Eco-city philosophy and urban sustainability have been increasingly incorporated into planning and policy making. Often, system sustainability and resilience are assessed using a simple index approach, which can be helpful in measuring changes over time or in a comparative evaluation of cities, but is less helpful in guiding specific policy and design decisions. To this end, we illustrate the application of a dynamic water resource model which can complement an index analysis. Specifically, a personal computer (PC) version of the Stormwater Management Model (PCSWMM) was used to explore different wastewater treatment and urban flood management scenarios for Phnom Penh, Cambodia. Currently wastewater in Phnom Penh is treated effectively using sustainable, naturally occurring wetlands. Urban expansion is placing increasing pressure on these wetlands and PCSWMM results showed that infilling of the largest wetland by up to 22% could have a negative impact on treatment, but the system still would function. The alternative of activated sludge treatment is shown to be costly and energy intensive. Impacts of infilling on the large peri-urban community living on the wetland and to other ecosystem services were not assessed. Increased pump capacity at the existing stations would reduce, but not eliminate, local surface flooding. More sustainable, eco-friendly low impact development technologies should be considered in addition to hard engineering to reduce surface flooding.

“…Some important gaps in our understanding remain, as, for example, there seems to be very little empirical data at a large sewershed scale, across multiple storms and seasons, to confirm performance of the technologies and models. Hopefully this is starting to change with projects such as those described by Pitt and Voorhees (2011). Furthermore, modeling efforts (e.g.…”

Section: Much Of What I Heard During the Workhop Was Directed At Howmentioning

confidence: 99%

Climate Change and Urban Hydrology: Research Needs in the Developed and Developing Worlds

2013

JWMM

Although opinion polls indicate the public continues to be uncertain about climate change, the scientific community generally has reached consensus that increasing anthropogenically-sourced greenhouse gases have contributed substantially to rising global temperature over the second half of the twentieth century. This chapter takes the position that global warming and attendant changes in the precipitation regime have started and likely will intensify over the next century and explores these issues in relation to urban hydrology research needs for both the developed and developing worlds. Most research on climate change and water resources has focused on river flooding and drought at the watershed scale, irrigation demands, and impacts due to sea level rise. Assessment of urban drainage and sanitation infrastructure impacts and resiliency under climate change scenarios have received much less attention. Urban hydrologic impacts are broadly defined in this chapter and are discussed under eight categories: i) system resiliency and adaptation; ii) storm frequency and runoff; iii) water and sediment quality; iv) health impacts; v) water use and reuse; vi) sea level rise; vii) greenhouse gas emissions; and viii) urban heat islands. Adaptation measures to improve urban hydrologic resiliency are explored, with a focus on low impact development (LID) technologies, water reuse, land use planning, green buildings, and political will. Research needs in hydrologic science and engineering include: continued improvement of General Circulation Models (GCMs), particularly in the area of spatial downscaling; the need to further link GCM outputs and stormwater/ sewer modeling efforts (for both water quantity and quality); reconsideration Climate Change and Urban Hydrology: Research Needs … of design approaches under non-stationary rainfall time series; more extensive field verification (and modeling linkages) related to LID benefits; and opportunities and technologies for water reuse and green buildings. Scientists and engineers must increase their communication with politicians and policymakers about the need to consider greater temperature and precipation variability in community planning and include full-cost accounting of hydrologic services in these discussions. A more integrated approach to green community planning and management is required and the Singaporean model offers an interesting possibility. However, we also must recognize that a "one size fits all" solution to climate change resiliency and adaptation is not possible. Exchanges regarding water resource management technologies between the developed and developing world are occuring, but must be culturally appropriate and adapted to the specific environment.