scholarly journals A Novel Buffer Tank to Attenuate the Peak Flow of Runoff

2019 ◽  
Vol 5 (12) ◽  
pp. 2525-2534 ◽  
Author(s):  
Yinghong Qin ◽  
Zhengce Huang ◽  
Zebin Yu ◽  
Zhikui Liu ◽  
Lei Wang
Keyword(s):  
Urban Areas ◽  
Peak Flow ◽  
Heavy Rain ◽  
Green Roofs ◽  
Sewer Pipes ◽  
Rainfall Depth ◽  
Dead Storage ◽  
Buffer Tank ◽  
Edge Side ◽  
Outlet Orifice

Impermeable pavements and roofs in urban areas convert most rainfall to runoff, which is commonly discharged to local sewers pipes and finally to the nearby streams and rivers. In case of heavy rain, the peak flow of runoff usually exceeds the carrying capacity of the local sewer pipes, leading to urban flooding. Traditional facilities, such as green roofs, permeable pavements, soakaways, rainwater tanks, rain barrels, and others reduce the runoff volume in case of a small rain but fail in case of a heavy rain. Here we propose a novel rainwater buffer tank to detain runoff from the nearby sealed surfaces in case of heavy rain and then to discharge rainwater from an orifice at the tank’s bottom. We found that considering a 100m2 rooftop with 0.80 runoff coefficient and a 10cm rainfall depth for an hour, a cubic tank with internal edge side of a square of 2 m attenuates the peak flow about 45%. To reduce a desirable peak flow, the outlet orifice of the buffer tank must be optimized according to site-specific conditions. The orifice can be set at an elevation from the tank’s bottom to create a dead storage for harvesting rainwater.

scholarly journals Control of Runoff Peak Flow for Urban Flooding Mitigation

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1796
Author(s):  
Yunan Lu ◽  
Jinli Xie ◽  
Cheng Yang ◽  
Yinghong Qin
Keyword(s):  
Surface Runoff ◽  
Peak Flow ◽  
Heavy Rain ◽  
Urban Flooding ◽  
Sectional Area ◽  
Cross Sectional ◽  
Rainfall Duration ◽  
Vegetated Roofs ◽  
Buffer Tank ◽  
Outlet Orifice

Urban flooding has become a serious but not well-resolved problem during the last decades. Traditional mainstream facilities, such as vegetated roofs, permeable pavements, and others, are effective to eliminate urban flooding only in case of small rains because the water-retaining and detaining capacities of these traditional facilities are limited. Here, we propose a new buffer tank buried in soil to deal with rainwater onsite as peak-flow control for urban flooding mitigation. Experiments showed that the buffer tank intercepts the surface runoff and discharges the intercepted water through a designed outlet orifice. By properly setting the cross-sectional area of the orifice, the tank extends the drainage duration several times longer than that of the rainfall duration. It is found that the buffer tank attenuates the peak flow greater at heavier rain. At small rain (<2.5 mm), the tank is always unfilled, preserving storage spaces for detaining rainwater in case of heavy rain. The buffer tank is thus greatly helpful to mitigate the flooding problem, avoiding being saturated by small long-lasting rain.

scholarly journals Assessing the hydrologic restoration of an urbanized area via integrated distributed hydrological model

2013 ◽  
Vol 10 (4) ◽  
pp. 4099-4132 ◽  
Author(s):  
D. H. Trinh ◽  
T. F. M. Chui
Keyword(s):  
Urban Areas ◽  
Hydrological Model ◽  
Peak Flow ◽  
Green Roofs ◽  
Base Flow ◽  
Peak Discharge ◽  
Generic Model ◽  
Distributed Hydrological Model ◽  
Hydrologic Restoration ◽  
The Tropics

Abstract. Green structures (e.g. green roof and bio-retention systems) are adopted to mitigate the hydrological impacts of urbanization. However, our current understanding of the urbanization impacts are often process-specific (e.g. peak flow or storm recession), and our characterizations of green structures are often on a local scale. This study uses an integrated distributed hydrological model, Mike SHE, to evaluate the urbanization impacts on both overall water balance and water regime, and also the effectiveness of green structures at a catchment level. Three simulations are carried out for a highly urbanized catchment in the tropics, representing pre-urbanized, urbanized and restored conditions. Urbanization transforms vegetated areas into impervious surfaces, resulting in 20 and 66% reductions in infiltration and base flow respectively, and 60 to 100% increase in peak outlet discharge. Green roofs delay the peak outlet discharge by 2 h and reduce the magnitude by 50%. Bio-retention systems mitigate the peak discharge by 50% and also enhance infiltration by 30%. The combination of green roofs and bio-retention systems even reduces the peak discharge to the pre-urbanized level. The simulation results obtained are independent of field data, enabling a generic model for understanding hydrological changes during the different phases of urbanization. This will benefit catchment level planning of green structures in other urban areas.

scholarly journals Assessing the hydrologic restoration of an urbanized area via an integrated distributed hydrological model

2013 ◽  
Vol 17 (12) ◽  
pp. 4789-4801 ◽  
Author(s):  
D. H. Trinh ◽  
T. F. M. Chui
Keyword(s):  
Urban Areas ◽  
Hydrological Model ◽  
Peak Flow ◽  
Green Roofs ◽  
Base Flow ◽  
Peak Discharge ◽  
Generic Model ◽  
Distributed Hydrological Model ◽  
Hydrologic Restoration ◽  
The Tropics

Abstract. Green structures (e.g. green roof and bio-retention systems) are adopted to mitigate the hydrological impacts of urbanization. However, our current understanding of urbanization impacts are often process-specific (e.g. peak flow or storm recession), and our characterizations of green structures are often on a local scale. This study uses an integrated distributed hydrological model, Mike SHE, to evaluate the urbanization impacts on both overall water balance and water regime, and also the effectiveness of green structures at a catchment level. Three simulations are carried out for a highly urbanized catchment in the tropics, representing pre-urbanized, urbanized and restored conditions. Urbanization transforms vegetated areas into impervious surfaces, resulting in 20 and 66% reductions in infiltration and base flow respectively, and 60 to 100% increase in peak outlet discharge. Green roofs delay the peak outlet discharge by 2 h and reduce the magnitude by 50%. Bio-retention systems mitigate the peak discharge by 50% and also enhance infiltration by 30%. The combination of green roofs and bio-retention systems even reduces the peak discharge to the pre-urbanized level. The simulation results obtained are independent of field data, enabling a generic model for understanding hydrological changes during the different phases of urbanization. This will benefit catchment-level planning of green structures in other urban areas.

scholarly journals Wpływ pokrycia dachu na ilość i wielkość zawiesin w spływach deszczowych

2017 ◽  
Vol 26 (4) ◽  
pp. 457-469
Author(s):  
Ewa Burszta-Adamiak ◽  
Piotr Dragański ◽  
Karolina Urbańska
Keyword(s):  
Urban Areas ◽  
Suspended Solids ◽  
Green Roofs ◽  
Rainfall Characteristics ◽  
Low Concentrations ◽  
Rainfall Depth ◽  
Pre Treatment ◽  
Size Of Particles ◽  
Roofing Materials

Among various drainage surfaces which allow rainwater to be utilised locally, roofs are frequently chosen solution. This is because they represent a big share of all sealed surfaces in cities and discharged liquids are considered potentially clean. Scientific reports confirm that pollutants accumulate on roofs and influence the quality of discharged water. Suspended solids are the biggest group of pollutants which occur in runoffs. The selection of rainwater pre-treatment installation and further use of the water depends on the concentration of suspended solids and their particle size. This article describes results of a research concerning suspended solids discharged from roofs made of traditional materials as well as green-roofs located in urban areas. The quantity and size of particles were assessed against rainfall characteristics: rainfall depth, length of antecedent dry weather periods and season. Results of the research show diversity of concentration levels and size of suspended solids within runoffs in reference to roofing materials, rainfall characteristics and season. The highest concentrations of suspended solids in runoff from traditional roofs were observed during rainfall depth less than 5 mm, after ancedent dry weather periods more than  50 h and in winter. These parameters did not have significantly influence on the low concentrations of suspended solids in runoff from green roofs. Suspended solids particles with the size of up to 200 μm constitute the biggest share of all roof runoffs.

scholarly journals Addressing the Water–Energy–Food Nexus through Enhanced Green Roof Performance

2021 ◽  
Vol 13 (4) ◽  
pp. 1972
Author(s):  
Jeremy Wright ◽  
Jeremy Lytle ◽  
Devon Santillo ◽  
Luzalen Marcos ◽  
Kristiina Valter Mai
Keyword(s):  
Climate Change ◽  
Performance Optimization ◽  
Urban Areas ◽  
Stormwater Management ◽  
Green Roof ◽  
Green Roofs ◽  
Management Tool ◽  
Contributing Factors ◽  
Rainwater Runoff ◽  
Rain Events

Urban densification and climate change are creating a multitude of issues for cities around the globe. Contributing factors include increased impervious surfaces that result in poor stormwater management, rising urban temperatures, poor air quality, and a lack of available green space. In the context of volatile weather, there are growing concerns regarding the effects of increased intense rainfalls and how they affect highly populated areas. Green roofs are becoming a stormwater management tool, occupying a growing area of urban roof space in many developed cities. In addition to the water-centric approach to the implementation of green roofs, these systems offer a multitude of benefits across the urban water–energy–food nexus. This paper provides insight to green roof systems available that can be utilized as tools to mitigate the effects of climate change in urbanized areas. A new array of green roof testing modules is presented along with research methods employed to address current issues related to food, energy and water performance optimization. Rainwater runoff after three rain events was observed to be reduced commensurate with the presence of a blue roof retention membrane in the testbed, the growing media depth and type, as well as the productive nature of the plants in the testbed. Preliminary observations indicate that more productive green roof systems may have increasingly positive benefits across the water–energy–food nexus in dense urban areas that are vulnerable to climate disruption.

Green roof hydrologic performance and modeling: a review

2013 ◽  
Vol 69 (4) ◽  
pp. 727-738 ◽  
Author(s):  
Yanling Li ◽  
Roger W. Babcock
Keyword(s):  
Peak Flow ◽  
Green Roof ◽  
Field Measurements ◽  
Green Roofs ◽  
Economic Benefits ◽  
Design Parameters ◽  
Technical Literature ◽  
Factors Affecting ◽  
Model Soil ◽  
Runoff Volume

Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology.

Fractal tools to analyse the spatial variability of Blue Green Solutions in an urban area

2021 ◽  
Author(s):  
Gustavo Otranto-da-Silva
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Model Performance ◽  
Green Roofs ◽  
Initial State ◽  
Runoff Reduction ◽  
Build Environment ◽  
Input Variables ◽  
Neighborhood Scale ◽  
Design Options

&lt;div&gt; &lt;p&gt;&lt;span&gt;A city's response to a rainfall event depends not only on the rainfall spatial-temporal variability, but also on the spatial distribution and the initial state of its Blue Green Solutions (BGS), such as green roofs. They hold back runoff and may prove being critically important elements of blue-green build environment.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;The aim of this study was first to adapt the existing hydrological model to the urban area of Melun (France), to validate it and then to assess numerically an optimal configuration of green roofs&amp;#160;to mitigate pluvial floods for particularly vulnerable areas. &lt;/span&gt;&lt;span&gt;The main focus was put on the investigation of interactions between rainfall space-time scales and resulting hydrological response over fine scales, all being controlled by the performance assessment of BGS. &lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;This presentation will particularly illustrate how fractal &lt;/span&gt;&lt;span&gt;tools were used to:&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;- highlight the scale dependency of the input variables and its e&lt;/span&gt;&lt;span&gt;ff&lt;/span&gt;&lt;span&gt;ects on gridded model performance;&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;- explore, &lt;/span&gt;&lt;span&gt;analyse&lt;/span&gt;&lt;span&gt; and represent the influence of BGS location and configuration on the mitigation of runoff associated with short-duration, high-intensity rainfall at neighborhood scale;&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;&amp;#160;- identify the urban design options that maximize the potential for runoff reduction&lt;/span&gt;&lt;span&gt;. &lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;In overall, these &lt;/span&gt;&lt;span&gt;results may serve as a referential &lt;/span&gt;&lt;span&gt;for upscaling the optimized implementation of BGS in urban areas, by considering other urban infrastructures and their interactions.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;

scholarly journals Evaporation from (Blue-)Green Roofs: Assessing the Benefits of a Storage and Capillary Irrigation System Based on Measurements and Modeling

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1253 ◽  
Author(s):  
Dirk Cirkel ◽  
Bernard Voortman ◽  
Thijs van Veen ◽  
Ruud Bartholomeus
Keyword(s):  
Energy Balance ◽  
Urban Areas ◽  
Evaporation Rate ◽  
Climate Adaptation ◽  
Irrigation System ◽  
Green Roof ◽  
Green Roofs ◽  
C3 Plants ◽  
Rapid Decline ◽  
Air Temperatures

Worldwide cities are facing increasing temperatures due to climate change and increasing urban density. Green roofs are promoted as a climate adaptation measure to lower air temperatures and improve comfort in urban areas, especially during intensive dry and warm spells. However, there is much debate on the effectiveness of this measure, because of a lack of fundamental knowledge about evaporation from different green roof systems. In this study, we investigate the water and energy balance of different roof types on a rooftop in Amsterdam, the Netherlands. Based on lysimeter measurements and modeling, we compared the water and energy balance of a conventional green roof with blue-green roofs equipped with a novel storage and capillary irrigation system. The roofs were covered either with Sedum or by grasses and herbs. Our measurements and modeling showed that conventional green roof systems (i.e., a Sedum cover and a few centimeters of substrate) have a low evaporation rate and due to a rapid decline in available moisture, a minor cooling effect. Roofs equipped with a storage and capillary irrigation system showed a remarkably large evaporation rate for Sedum species behaving as C3 plants during hot, dry periods. Covered with grasses and herbs, the evaporation rate was even larger. Precipitation storage and capillary irrigation strongly reduced the number of days with dry-out events. Implementing these systems therefore could lead to better cooling efficiencies in cities.

scholarly journals Vegetation Cover Drives Arthropod Communities in Mediterranean/Subtropical Green Roof Habitats

2018 ◽  
Vol 10 (11) ◽  
pp. 4209 ◽  
Author(s):  
Ibrahim Salman ◽  
Leon Blaustein
Keyword(s):  
Vegetation Cover ◽  
Urban Areas ◽  
Green Roof ◽  
Structural Complexity ◽  
Green Roofs ◽  
Life Forms ◽  
Suitable Habitat ◽  
Positive Effects ◽  
Habitat Template ◽  
Arthropod Abundance

Worldwide, urban areas are expanding both in size and number, which results in a decline in habitats suitable for urban flora and fauna. The construction of urban green features, such as green roofs, may provide suitable habitat patches for many species in urban areas. On green roofs, two approaches have been used to select plants—i.e., matching similar habitat to green roofs (habitat template approach) or identifying plants with suitable traits (plant trait approach). While both approaches may result in suitable habitats for arthropods, how arthropods respond to different combinations of plants is an open question. The aim of this study was to investigate how the structural complexity of different plant forms can affect the abundance and richness of arthropods on green roofs. The experimental design crossed the presence and absence of annuals with three Sedum sediforme (Jacq.) Pau (common name: stonecrops) treatments—i.e., uniformly disrupted Sedum, clumped disrupted Sedum, and no Sedum. We hypothesized that an increased structural diversity due to the coexistence of different life forms of plants on roofs is positively related to the abundance and richness of arthropods. We found that arthropod abundance and richness were positively associated with the percent of vegetation cover and negatively associated with substrate temperature. Neither arthropod abundance nor richness was influenced by the relative moisture of substrate. We also found that arthropod abundance and richness varied by green roof setups (treatments) and by seasonality. Arthropod abundance on green roofs was the highest in treatments with annuals only, while species richness was slightly similar between treatments containing annuals but varied between sampling periods. This study suggests that adding annuals to traditional Sedum roofs has positive effects on arthropods. This finding can support the development of biodiverse cities because most extensive green roofs are inaccessible to the public and can provide undisturbed habitat for several plant and arthropod species.

scholarly journals IMPACT OF GREEN ROOF ON HEATING AND COOLING IN CONTEXT OF DIFFERENT CLIMATIC ZONES IN INDIA

2021 ◽  
pp. 436-440
Author(s):  
Ar. Ankur Bhardwaj ◽  
Dr. Shweta Chaudhary ◽  
Ar.Kirti Varandani
Keyword(s):  
Urban Areas ◽  
Green Roof ◽  
Green Roofs ◽  
Climatic Zones ◽  
Sustainable Living ◽  
Secondary Sources ◽  
Heating And Cooling ◽  
The World ◽  
Depth Study ◽  
Rainwater Runoff

The ecological, social and visual commitments that green roofs can make towards sustainable living in more intensified urban centres are generally recognized around the world. Green roof is one such sustainable methodology, utilization of which causes us in insulating the buildings and, subsequently contributing to better energy proficient execution of the same. Green roofs additionally give environment to various species, lessen the rainwater runoff and better deal with the carbon-dioxide cycle. In spite of these advantages, Green roofs are not as basic an element in India as they are in other European and American urban areas. In this paper an attempt has been made to enhance the advantages of this innovation in India. Green roofs systems looks simple in terms of setting up, but actually very complex in maintaining and achieving sustainability. In depth study of green roofs, historic background, climatic zones, impacts of green roofs on heating and cooling, benefits, problems and opportunities is done with the help of data taken from secondary sources like books, magazines and published literature (articles, journals, conference proceedings) form various e-libraries and other online platforms. KEY WORDS: Heating, Cooling, Green Roof, Sustainability)

Sign in / Sign up

Export Citation Format

Share Document