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Stormwater management (SuDS)
Published in David Butler, Christopher Digman, Christos Makropoulos, John W. Davies, Urban Drainage, 2018
David Butler, Christopher Digman, Christos Makropoulos, John W. Davies
Detention basins provide storage for stormwater with controlled outflow to the next stage of stormwater management or to a watercourse. They are effectively storage facilities formed out of the landscape. They are not intended to encourage infiltration to the ground and may be lined if infiltration is to be prevented completely. After controlled outflow has taken place the basin is commonly left dry until the next rainfall. In many cases detention basins are hardly noticed by the public as a consequence of thoughtful landscaping and choice of vegetation. They are often multifunctional, also operating as recreation areas and only filling during storms. Detention basins may be online or offline. They have relatively low pollutant removal efficiencies because of the re-erosion of previously deposited solids during filling.
Detention basin design
Published in James C. Y. Guo, Urban Flood Mitigation and Stormwater Management, 2017
A flood-control detention basin is designed to store the excess storm runoff associated with the increased watershed imperviousness. As shown in Figure 13.2, the stormwater detention storage volume is the volume difference between the inflow and outflow hydrographs. Between two adjacent storm events, the detention basin remains dry. During a major event, the operation of a flood detention basin is divided into a filling period, when the inflow rate is greater than the outflow rate, and a depletion period, when the outflow rate is greater than the inflow rate. These two distinct periods are separated by the peak outflow, which is selected based on the allowable flow release. Figure 13.2 shows that the higher the peak outflow, the lesser the storage volume. The peak outflow is an important design parameter and shall be determined according to the allowable flow released from the tributary watershed. According to the continuity principle, the total stored (detention) volume during the filling period is equal to the total released volume during the depletion period. In order to provide a large storage volume, a stormwater detention system is often blended into floodplains, depressed areas, recreational parks, and/or sport fields.
Stormwater management
Published in David Butler†, John W. Davies††, Urban Drainage, 2000
David Butler†, John W. Davies††
Detention basins provide storage for stormwater with controlled outflow to the next stage of stormwater management or to a watercourse. They are effectively storage facilities formed out of the landscape. They are not intended to encourage infiltration to the ground and may be lined if infiltration is to be prevented completely. After controlled outflow has taken place the basin is commonly left dry until the next rainfall. In many cases detention basins are hardly noticed by the public as a consequence of thoughtful landscaping and choice of vegetation. They are often multifunctional, also operating as recreation areas and only filling during storms. Detention basins may be on-line or off-line. They have relatively low pollutant removal efficiencies because of the re-erosion of previously deposited solids during filling. More information is given in The SUDS Manual (Woods-Ballard et al., 2007a).
Urban runoff quality and quantity control: a functional comparison of various types of detention basins
Published in Urban Water Journal, 2022
Kelly Proteau, Negin Binesh, Sophie Duchesne, Geneviève Pelletier, Isabelle Lavoie
Managing the quantity and quality of stormwater before discharge into receiving waterbodies or inundation of downstream areas can reduce the potential for costly repairs and the serious consequences arising from uncontrolled urban runoff (Leber 2015; O’Neill and Cairns 2016). Use of Best Management Practices (BMPs) is an effective control solution, with the construction of storage ponds (i.e. basins) at the watershed outlet being one of the most common methods (Karamouz et al. 2010; MDDEFP and MAMROT 2011; Noor et al. 2017; Binesh et al. 2019). Two variations often used for flood control and stormwater treatment are dry and wet basins, each appearing similar in design yet different in purpose. Dry basins, also known as detention basins, are designed to release captured runoff over time and remain dry between storms. Their primary function is to delay the runoff discharge into watercourses and downstream areas through an outlet located at the bottom of the basin. As a secondary function, dry basins may also provide some limited water quality benefits. Wet basins (retention ponds or wet detention basins) have an outlet structure located at a higher level and, therefore, retain a permanent pool of water. This allows for additional biological interactions and treatment of contaminants, the main process of the latter being the removal of pollutants through sedimentation, although other physicochemical and biological processes operate in parallel.
Real-time control of stormwater detention basins as an adaptation measure in mid-size cities
Published in Urban Water Journal, 2018
Karine Bilodeau, Geneviève Pelletier, Sophie Duchesne
Significant changes can occur in the characteristics of watersheds due to land development, and rainfall due to climate change, during the useful life of urban drainage infrastructure (e.g. a few decades on average for detention basins). These changes can have major impacts on runoff rates and volumes (Blair et al. 2014). That is why stormwater management systems should be designed to adapt to environmental changes and therefore ensure continued performance throughout the systems’ useful life. Adaptive measures must be integrated into a municipality’s stormwater management plan, for example best management practices (BMPs) including source, conveyance or end-of-pipe controls. The most commonly used BMPs are bio-retention systems, infiltration trenches, pervious pavement, vegetative swales and ditches, oversized pipes, and basins that are dry or wet (with a permanent water body). Detention basins, whether dry or wet, are used at the system’s end; they help reduce peak flows and control river bank erosion by gradually releasing the detained water. In most cases, the infrastructure outlet opening remains fixed; this is called static control. The discharge rate varies according to water height but is not controlled otherwise. Previous studies have shown that the performance of dry detention basins for removing suspended solids is roughly 60% at best when the control is static (Carpenter 2011; MDDELCC 2017; Rivard 2017). The dimensions of this type of basins are very large when associated with a 100-year level of service. However, their storage capacity is hardly ever used for more frequent, small rainfall events.
Risk-based analysis of a detention basin for urban runoff control
Published in Journal of Applied Water Engineering and Research, 2018
Detention basin is one type of stormwater retardation facility commonly used in urban areas for sustainable urban drainage systems. The prevalent design practice is, under a specified design frequency, to determine the storage capacity and outlet control to temporarily accommodate excessive surface runoff produced by the rainstorm. For any design storage capacity, the presence of various uncertainties implies that the detention facility cannot guarantee to serve its intended function at all times. There is a chance that randomly occurring storms could produce surface runoff with volume in excess of the design capacity, hence causing undesirable overflow. This study presents a risk-based design of detention basins by explicitly considering the trade-off between the cost of the detention basin and overflow volume. The statistical properties of overflow volume such as the mean and standard deviation are derived by considering the inherent randomness of rainstorm events and their magnitudes. The special feature of the suggested risk-based analysis framework is that no monetary damage relation with the overflow volume is used or needed. The trade-off decision considers directly the cost of the detention basin and the statistical characteristics of overflow volume. A decision criterion based on marginal cost is applied to facilitate the determination of ‘best’ design according to the designer's willingness-to-pay for one unit reduction of overflow volume.