scholarly journals Modelling the impact of retention–detention units on sewer surcharge and peak and annual runoff reduction

2015 ◽  
Vol 71 (6) ◽  
pp. 898-903 ◽  
Author(s):  
Luca Locatelli ◽  
Søren Gabriel ◽  
Ole Mark ◽  
Peter Steen Mikkelsen ◽  
Karsten Arnbjerg-Nielsen ◽  
...  
Keyword(s):  
Retention Volume ◽  
Stormwater Runoff ◽  
Annual Runoff ◽  
Reduction Peak ◽  
Peak Reduction ◽  
Small Catchment ◽  
Runoff Reduction ◽  
Impervious Area ◽  
Peak Runoff ◽  
The Impact

Stormwater management using water sensitive urban design is expected to be part of future drainage systems. This paper aims to model the combination of local retention units, such as soakaways, with subsurface detention units. Soakaways are employed to reduce (by storage and infiltration) peak and volume stormwater runoff; however, large retention volumes are required for a significant peak reduction. Peak runoff can therefore be handled by combining detention units with soakaways. This paper models the impact of retrofitting retention–detention units for an existing urbanized catchment in Denmark. The impact of retrofitting a retention–detention unit of 3.3 m3/100 m2 (volume/impervious area) was simulated for a small catchment in Copenhagen using MIKE URBAN. The retention–detention unit was shown to prevent flooding from the sewer for a 10-year rainfall event. Statistical analysis of continuous simulations covering 22 years showed that annual stormwater runoff was reduced by 68–87%, and that the retention volume was on average 53% full at the beginning of rain events. The effect of different retention–detention volume combinations was simulated, and results showed that allocating 20–40% of a soakaway volume to detention would significantly increase peak runoff reduction with a small reduction in the annual runoff.

scholarly journals Analysis of Stormwater Retention on Green Roofs / Badania Retencji Wód Opadowych Na Dachach Zielonych

2012 ◽  
Vol 38 (4) ◽  
pp. 3-13 ◽  
Author(s):  
Ewa Burszta-Adamiak
Keyword(s):  
Life Sciences ◽  
Green Roofs ◽  
Retention Capacity ◽  
Runoff Reduction ◽  
Science And Education ◽  
Peak Runoff ◽  
The Impact ◽  
Stormwater Retention ◽  
Maximum Runoff ◽  
Sewage Systems

Abstract This study presents the results of tests conducted in 2009 and 2010 on experimental sites installed on the roof of the Science and Education Building of the Wroclaw University of Environmental and Life Sciences. The aim of the analysis was to determine the retention capacity of green roofs and the runoff delays and peak runoff reduction during rainfall recorded in Wroclaw conditions. The research shows that green roofs allow to reduce the volume of runoff stormwater in comparison to conventional roofs, that they delay the runoff in time and influence the reduction of the maximum runoff intensity, and thus may limit the impact of stormwater on the stormwater drainage and combined sewage systems.

scholarly journals The economic benefits of reductions in nitrogen loads from stormwater runoff by street trees

2020 ◽  
Author(s):  
Mariana D. Baptista ◽  
Marco Amati ◽  
Tim D. Fletcher ◽  
Matthew J. Burns
Keyword(s):  
Stormwater Runoff ◽  
Canopy Cover ◽  
Annual Runoff ◽  
Urban Trees ◽  
Deciduous Trees ◽  
Street Trees ◽  
Runoff Volume ◽  
Nitrogen Loads ◽  
Tree Canopy Cover ◽  
The Impact

Abstract It is increasingly recognised that urban trees can contribute to reducing stormwater runoff by intercepting and retaining a fraction of rainfall received. What is less studied is the translation of this to reduced pollutant loads being transferred to receiving streams, rivers, and water bodies. In this paper, we assess interception of two tree species (Eucalyptus microcorys and Ulmus procera) in an urban park. This data is used in simple water balance modelling to predict the environmental and economic benefit of reducing nitrogen loads to receiving waterways as a function of reduced runoff volume resulting from rainfall interception by urban trees on public land (21% of the catchment area). We use a highly urbanized catchment in Melbourne, Australia to demonstrate the impact of an urban forest dominated by deciduous trees, evergreen trees or a mixed tree canopy cover. We found that doubling the urban canopy cover in the catchment, while keeping the current mix ratio of deciduous and evergreen trees, could reduce annual runoff volume by 30 mm (92 MLyr−1). Using the prescribed values that developers must pay the local water authority for nitrogen treatment as a condition of new development, we calculate that this would deliver a nitrogen load removal benefit of AUD$ 200/tree. If only deciduous trees are planted the annual runoff reduction would decrease to 24 mm (73 MLyr−1) and increases to 37 mm (112 MLyr−1) if only evergreen trees are planted. This study highlights both the additional benefits of public street trees and the differences in deciduous and evergreen trees which should be accounted for by policy makers.

scholarly journals Study on the Variation of Annual Runoff and Influencing Factors in Kuye River during the Past 60 Years

2018 ◽  
Vol 7 (2) ◽  
pp. 72
Author(s):  
Zhihua MA ◽  
Qiaoling GUO ◽  
Ning SU
Keyword(s):  
Human Activities ◽  
Large Scale ◽  
High Strength ◽  
Annual Runoff ◽  
Runoff Variation ◽  
Runoff Reduction ◽  
Filter Methods ◽  
Runoff Series ◽  
Concentration Degree ◽  
The Impact

In this study, observed runoff series from a hydro-station respectively named Wenjiachuan station in the Kuye river was manipulated for monthly annual variation analysis assisted by using nonuniformity coefficient and concentration degree(period).the cumulative filter methods was employed to detect the trend of inner-annual runoff. Based on meteorological and hydrological data of the Wenjiachuan hydrologic station from 1955 to 2015, the paper studied the variation tendency, the abrupt and periodic changes of annual runoff using the Mann-Kendall non-parametric test and accumulation anomaly curve. Double mass curve was used to estimate the impact of human activities and climate change on the runoff variation. The curve of seasonal runoff distribution for Wenjiachuan station appeared two peak patterns. The annual runoff declined markedly, the effect of climate on runoff decreased, the influence of human activities on runoff gradually increased the human activities are the primary factors leading to the reduction of annual runoff. In human activities, large-scale water and soil conservation measures and high-strength coal mining have produced significant effects on the annual runoff reduction in Kuye River.

scholarly journals Effectiveness of Permeable Pavements and Vegetative Swales for Developing Sponge Cities

2021 ◽  
Author(s):  
ARUNA V ◽  
Suja R ◽  
Rajalakshmi C R
Keyword(s):  
Water Management ◽  
Soil Type ◽  
Urban Areas ◽  
Low Impact Development ◽  
Storm Water ◽  
Small Catchment ◽  
Storm Water Management ◽  
Permeable Pavements ◽  
Runoff Reduction ◽  
The Impact

Abstract As communities grows, the area covered by rooftops and concreted surfaces increases. Rain water which would have infiltrated, flows across these impermeable surface carrying pollutants along the way. This causes frequent flash floods in urban areas. Effective storm water management is needed for the sustainable development of communities. In this study the runoff generation for a small catchment is quantified and the effectiveness of low impact development (LID) practices (permeable pavements (pp) & vegetative swales) in mitigating the runoff at the source itself is studied using Storm Water Management Model (SWMM). The most influential design storm and the soil type pertaining to the study area were the determining factors for evaluating the impact of LID’s. The steady flow model and Hortons’s infiltration parameters for the soil type in study area were adopted for the analysis. The permeable pavements and swales performed well in reducing the runoff but the swales were less efficient in reducing the runoff, and the runoff reduction potential of permeable pavements and swales are 4.48% and 2.05% respectively. Runoff reduction is more efficient in case of combination of permeable pavements and vegetative swales as LIDs. The percentage reduction in runoff is about 6.05% and the efficiency of the combination type LID is about 17%. The results from simulation show that the low impact development practices are efficient in mimicking the pre-development hydrologic conditions of the landscape to a great extent.

scholarly journals Evaluation of Green Roof Performance in Mitigating the Impact of Extreme Storms

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 815 ◽  
Author(s):  
Liu ◽  
Chui
Keyword(s):  
Hong Kong ◽  
Hydraulic Conductivity ◽  
Return Period ◽  
Green Roof ◽  
Design Parameters ◽  
Soil Thickness ◽  
Rainfall Characteristics ◽  
Runoff Reduction ◽  
Peak Runoff ◽  
The Impact

Green roofs are used in urban areas to mitigate the adverse effects of stormwater. Through numerical modeling, this study evaluates the impacts of design parameters on green roof hydrological performance under different rainfall characteristics. A calibrated model is run with long-term precipitation data series for three locations (Hong Kong, China; Beltsville, MD, USA; and Sidney, NY, USA). The results show that the amount of peak runoff reduction increases with the duration of the storm return period in Beltsville and Sidney; while the trend is opposite in Hong Kong. Percentage peak reduction generally shows a decreasing trend with the storm return period in three locations. For average runoff reduction, the amount of reduction increases with the storm return period, whereas the percentage reduction presents an opposite trend in all three locations. The actual values vary between the three locations due to differences in rainfall characteristics. Both peak and average runoff reduction increase with green roof thickness, but in practice, it is not cost effective or feasible to increase the thickness beyond a certain threshold. The hydraulic conductivity can then be optimized for peak runoff reduction and it is found to increase with the return period. However, hydraulic conductivity has a minimal effect on average runoff reduction. Overall, this paper studies green roof hydrological performance in response to different rainfall characteristics and provides recommendations on green roof designs related to soil thickness and hydraulic conductivity.

Impact of changing rainfall conditions on surface and groundwater resources in an experimental watershed in Greece

2013 ◽  
Vol 12 (2) ◽  
pp. 119-125
Keyword(s):  
Groundwater Resources ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Winter Rainfall ◽  
Rainfall Depth ◽  
Rainfall Volume ◽  
The Mean ◽  
Groundwater Reserves ◽  
The Impact

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.

Large-Scale Application of Biofiltration Swale Runoff Management Practices

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
William C. Lucas
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Peak Flow ◽  
Low Impact Development ◽  
Urban Runoff ◽  
Management Model ◽  
Check Dams ◽  
Runoff Reduction ◽  
Impervious Area ◽  
Hydrologic Responses

Retaining rainfall where it lands is a fundamental benefit of Low Impact Development (LID). The Delaware Urban Runoff Management Model (DURMM) was developed to address the benefits of LID design. DURMM explicitly addresses the benefits of impervious area disconnection as well as swale flow routing that responds to flow retardance changes. Biofiltration swales are an effective LID BMP for treating urban runoff. By adding check dams, the detention storage provided can also reduce peak rates. This presentation explores how the DURMM runoff reduction approach can be integrated with detention routing procedures to project runoff volume and peak flow reductions provided by BMP facilities. This approach has been applied to a 1,200 unit project on 360 hectares located in Delaware, USA. Over 5 km of biofiltration swales have been designed, many of which have stone check dams placed every 30 to 35 meters to provide detention storage. The engineering involved in the design of such facilities uses hydrologic modeling based upon TR-20 routines, as adapted by the DURMM model. The hydraulic approach includes routing of flows through the check dams. This presentation summarizes the hydrological network, presents the hydrologic responses, along with selected hydrographs to demonstrate the potential of design approach.

scholarly journals Analysis of the Behavior of Abstractions in Two Urban Micro-Basins of the City of Cuenca (Ecuador), through an Aggregate Model

2021 ◽  
Vol 13 (6) ◽  
pp. 3209
Author(s):  
Ricardo Rubio-Ramírez ◽  
Rubén Jerves-Cobo ◽  
Diego Mora-Serrano
Keyword(s):  
Stormwater Runoff ◽  
Great Sensitivity ◽  
Aggregate Model ◽  
Antecedent Soil Moisture ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Impervious Area ◽  
Process Of Urbanization ◽  
Negative Impacts ◽  
The City

Several cities in developing countries are challenging the permanent process of urbanization. This generates a great disturbance on the hydrological response of the urbanized area during rainfall events, which can cause floods. Among the disturbances that urbanized basins may suffer, it is found that variations in rain losses (hydrological abstractions) can be estimated by the named volumetric runoff coefficient (CVOL) methodology. In the present study, this methodology is used in an attempt to estimate the hydrological abstraction of two nearby urbanized basins, with different degrees of impermeability, located in the city of Cuenca in Ecuador. The data for that analysis were collected between April and May of 2017. The results obtained indicate that the micro-basin with the largest impervious area presents the higher initial hydrological losses, the higher rate of decrease in abstractions, and the higher stormwater runoff flows per unit area. In addition, the abstractions found in the two urban micro-basins show great sensitivity to the maximum rainfall intensity and do not relate to the antecedent soil moisture. These results demonstrate the importance of having higher pervious surfaces in urbanized areas because they lead to reduce negative impacts associated with increased stormwater runoff on impervious surfaces.

scholarly journals Assessing the Feasibility of a Cloud-Based, Spatially Distributed Modeling Approach for Tracking Green Stormwater Infrastructure Runoff Reductions

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 255
Author(s):  
Gary Conley ◽  
Nicole Beck ◽  
Catherine Riihimaki ◽  
Krista McDonald ◽  
Michelle Tanner
Keyword(s):  
Spatial Data ◽  
Program Effectiveness ◽  
Urban Runoff ◽  
Integrated Approach ◽  
Regulatory Compliance ◽  
Annual Runoff ◽  
Catchment Scale ◽  
Design Storm ◽  
Runoff Reduction ◽  
Green Stormwater Infrastructure

Use of green stormwater infrastructure (GSI) to mitigate urban runoff impacts has grown substantially in recent decades, but municipalities often lack an integrated approach to prioritize areas for implementation, demonstrate compelling evidence of catchment-scale improvements, and communicate stormwater program effectiveness. We present a method for quantifying runoff reduction benefits associated with distributed GSI that is designed to align with the spatial scale of information required by urban stormwater implementation. The model was driven by a probabilistic representation of rainfall events to estimate annual runoff and reductions associated with distributed GSI for various design storm levels. Raster-based calculations provide estimates on a 30-m grid, preserving unique combinations of drainage factors that drive runoff production, hydrologic storage, and infiltration benefits of GSI. The model showed strong correspondence with aggregated continuous runoff data from a set of urbanized catchments in Salinas, California, USA, over a three-year monitoring period and output sensitivity to the storm drain network inputs. Because the model runs through a web browser and the parameterization is based on readily available spatial data, it is suitable for nonmodeling experts to rapidly update GSI features, compare alternative implementation scenarios, track progress toward urban runoff reduction goals, and demonstrate regulatory compliance.

Urban hydrogeomorphology and the urban stream syndrome

2015 ◽  
Vol 40 (3) ◽  
pp. 480-492 ◽  
Author(s):  
Geoff J. Vietz ◽  
Christopher J. Walsh ◽  
Tim D. Fletcher
Keyword(s):  
Flow Regime ◽  
Stormwater Runoff ◽  
Control Measures ◽  
Urban Stream ◽  
Urban Stream Syndrome ◽  
Stream Morphology ◽  
Research Areas ◽  
Urban Catchments ◽  
Urban Stormwater Runoff ◽  
The Impact

The urban stream syndrome is an almost universal physical and ecological response of streams to catchment urbanization. Altered channel geomorphology is a primary symptom that includes channel deepening, widening and instability. While the common approach is to treat the symptoms (e.g. modifying and stabilizing the channel), many stream restoration objectives will not be achieved unless the more vexing problem, treating the cause, is addressed in some way. Research demonstrates that the dominant cause of geomorphic change in streams in urban catchments is an altered flow regime and increase in the volume of stormwater runoff. Thus, managers can choose to treat the symptoms by modifying and controlling the channel to accommodate the altered flow regime, or treat the cause by modifying the flow regime to reduce the impact on channel morphology. In both cases treatments must, at the least, explicitly consider hydrogeomorphology—the science of the linkages between various hydrologic and geomorphic processes—to have a chance of success. This paper provides a review of recent literature (2010 to early 2015) to discuss fluvial hydrogeomorphology in the management of streams subject to urbanization. We suggest that while the dominant approach is focused on combating the symptoms of catchment urbanization (that we refer to as channel reconfiguration), there is increasing interest in approaches that attempt to address the causes by using stormwater control measures at a range of scales in the catchment (e.g. flow-regime management). In many settings in the oft-constrained urban catchment, effective management of stream morphology may require multiple approaches. To conclude, we identify five research areas that could inform urban hydrogeomorphology, one of the most challenging of which is the extent to which the volume of excess urban stormwater runoff can be reduced to mitigate the impact on stream geomorphology.

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