scholarly journals Rainwater storage in urban environments using green roofs

La Granja ◽  
2020 ◽  
Vol 32 (2) ◽  
pp. 54-71
Author(s):  
Nelson Andrés López Machado ◽  
Christian Gonzalo Domínguez Gonzalez ◽  
Wilmer Barreto ◽  
Néstor Méndez ◽  
Leonardo José López Machado ◽  
...  
Keyword(s):  
Peak Flow ◽  
Total Duration ◽  
Green Roofs ◽  
Urban Environments ◽  
Peak Time ◽  
Interesting Point ◽  
Soil Matrix ◽  
Bituminous Materials ◽  
Flood Zone ◽  
Runoff Hydrographs

This article discusses the use of green roofs as rainfall water storage in its soil matrix. The methodology is analytical based on mathematical models, where runoff produced in an urban area is compared with current conditions of ordinary roofs with ceramic or bituminous materials as the original scenario, against another where green roofs are used. The study area is located in the Palavecino municipality of Lara state in Venezuela, in the flood zone of Quebrada Tabure. In this research, a quantitative comparison of the direct runoff hydrographs of the proposed scenarios was used, obtaining as a main result the reduction of runoff between 60% and 80% according to the period of return. An interesting point of this research was the incorporation of the routing of hydrographs on the roofs, reducing even more the peak flow over 90%, and delaying the peak time of the generated hydrographs between 10 and 12 minutes while the total duration of the hydrographs increase more than three times.

scholarly journals Green Infrastructures in Stormwater Control and Treatment Strategies

Proceedings ◽  
2019 ◽  
Vol 48 (1) ◽  
pp. 7
Author(s):  
Bárbara Pereira ◽  
Luís Mesquita David ◽  
Ana Galvão
Keyword(s):  
Suspended Solids ◽  
Peak Flow ◽  
Water Cycle ◽  
Treatment Strategies ◽  
Green Roofs ◽  
Urban Environments ◽  
Urban Water ◽  
Flow Rates ◽  
Filter Strips ◽  
Stormwater Control

Green infrastructures can provide multiple benefits and play an important role in cities’ resilience to extreme stormwater events caused by climate change. Additionally, these techniques can contribute to the protection of transport infrastructures, averting major environmental and economical adversities. Stormwater can be treated through several processes, some processes being more effective than others for specific contaminants. A review of some of the most commonly used green infrastructures (GI) for stormwater management in urban environments was carried out, with emphasis on their efficiency in reducing peak flow rates, runoff volumes and the following pollutants: total suspended solids, heavy metals, total phosphorus and total nitrogen. The GI studied were green roofs, bioretention systems, filter strips, vegetated swales and trenches. In addition to the advantages in the urban water cycle, benefits of amenity and ecosystem services of these GI have also been identified. The discussion of the results and the comparative analysis of GI performance were carried out taking advantage of a table that summarizes the range of percentages of GI efficiency obtained in various studies for the different functions.

scholarly journals Hillslope Contribution to the Clark Instantaneous Unit Hydrograph: Application to the Seolmacheon Basin, Korea

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1707
Author(s):  
Chulsang Yoo ◽  
Huy Phuong Doan ◽  
Changhyun Jun ◽  
Wooyoung Na
Keyword(s):  
Peak Flow ◽  
Peak Time ◽  
Rainfall Runoff ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Storage Coefficient ◽  
Channel Velocity ◽  
Linear Reservoir ◽  
Mountainous Basin

In this study, the time–area curve of an ellipse is analytically derived by considering flow velocities within both channel and hillslope. The Clark IUH is also derived analytically by solving the continuity equation with the input of the derived time–area curve to the linear reservoir. The derived Clark IUH is then evaluated by application to the Seolmacheon basin, a small mountainous basin in Korea. The findings in this study are summarized as follows. (1) The time–area curve of a basin can more realistically be derived by considering both the channel and hillslope velocities. The role of the hillslope velocity can also be easily confirmed by analyzing the derived time–area curve. (2) The analytically derived Clark IUH shows the relative roles of the hillslope velocity and the storage coefficient. Under the condition that the channel velocity remains unchanged, the hillslope velocity controls the runoff peak flow and the concentration time. On the other hand, the effect of the storage coefficient can be found in the runoff peak flow and peak time, as well as in the falling limb of the runoff hydrograph. These findings are also confirmed in the analysis of rainfall–runoff events of the Seolmacheon basin. (3) The effect of the hillslope velocity varies considerably depending on the rainfall events, which is also found to be mostly dependent upon the maximum rainfall intensity.

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.

scholarly journals Dependence Between Extreme Rainfall Events and the Seasonality and Bivariate Properties of Floods. A Continuous Distributed Physically-Based Approach

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1896 ◽  
Author(s):  
Gabriel-Martin ◽  
Sordo-Ward ◽  
Garrote ◽  
García
Keyword(s):  
Peak Flow ◽  
Total Duration ◽  
Weather Generator ◽  
Return Periods ◽  
Storm Events ◽  
Stochastic Weather Generator ◽  
Rainfall Events ◽  
Annual Peak ◽  
Extreme Flood ◽  
Physically Based

This paper focuses on proposing the minimum number of storms necessary to derive the extreme flood hydrographs accurately through event-based modelling. To do so, we analyzed the results obtained by coupling a continuous stochastic weather generator (the Advanced WEather GENerator) with a continuous distributed physically-based hydrological model (the TIN-based real-time integrated basin simulator), and by simulating 5000 years of hourly flow at the basin outlet. We modelled the outflows in a basin named Peacheater Creek located in Oklahoma, USA. Afterwards, we separated the independent rainfall events within the 5000 years of hourly weather forcing, and obtained the flood event associated to each storm from the continuous hourly flow. We ranked all the rainfall events within each year according to three criteria: Total depth, maximum intensity, and total duration. Finally, we compared the flood events obtained from the continuous simulation to those considering the N highest storm events per year according to the three criteria and by focusing on four different aspects: Magnitude and recurrence of the maximum annual peak-flow and volume, seasonality of floods, dependence among maximum peak-flows and volumes, and bivariate return periods. The main results are: (a) Considering the five largest total depth storms per year generates the maximum annual peak-flow and volume, with a probability of 94% and 99%, respectively and, for return periods higher than 50 years, the probability increases to 99% in both cases; (b) considering the five largest total depth storms per year the seasonality of flood is reproduced with an error of less than 4% and (c) bivariate properties between the peak-flow and volume are preserved, with an error on the estimation of the copula fitted of less than 2%.

scholarly journals Possibility of Using Selected Rainfall-Runoff Models for Determining the Design Hydrograph in Mountainous Catchments: A Case Study in Poland

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1450 ◽  
Author(s):  
Dariusz Młyński ◽  
Andrzej Wałęga ◽  
Leszek Książek ◽  
Jacek Florek ◽  
Andrea Petroselli
Keyword(s):  
Catchment Area ◽  
Peak Flow ◽  
Rainfall Runoff ◽  
Peak Flows ◽  
Mountainous Catchment ◽  
Mountainous Catchments ◽  
Relative Errors ◽  
Runoff Hydrographs

The aim of the study was to analyze the possibility of using selected rainfall-runoff models to determine the design hydrograph and the related peak flow in a mountainous catchment. The basis for the study was the observed series of hydrometeorological data for the Grajcarek catchment area (Poland) for the years 1981–2014. The analysis was carried out in the following stages: verification of hydrometeorological data; determination of the design rainfall; and determination of runoff hydrographs with the following rainfall-runoff models: Snyder, NRCS-UH, and EBA4SUB. The conducted research allowed the conclusion that the EBA4SUB model may be an alternative to other models in determining the design hydrograph in ungauged mountainous catchments. This is evidenced by the lower values of relative errors in the estimation of peak flows with an assumed frequency for the EBA4SUB model, as compared to Snyder and NRCS-UH.

The performance of LID (low impact development) practices at different locations with an urban drainage system: a case study of Longyan, China

2015 ◽  
Vol 10 (4) ◽  
pp. 739-746 ◽  
Author(s):  
Peng Li ◽  
Jun Liu ◽  
Rui Fu ◽  
Xin Liu ◽  
Yanyan Zhou ◽  
...  
Keyword(s):  
Land Surface ◽  
Peak Flow ◽  
Low Impact Development ◽  
Drainage System ◽  
Green Roofs ◽  
Similar Degree ◽  
Rain Gardens ◽  
Runoff Generation ◽  
Permeable Pavements ◽  
Rain Barrels

Urbanization has strongly changed the condition of the land surface and therefore rainfall runoff varies greatly. Peak flood flow and flood volumes increase with runoff volume. Low Impact Development (LID) is a sustainable concept that minimizes the effects of urbanization to maintain natural hydrological function in urban cities and has therefore gained increasing attention. This paper studies the effects of low impact development measures on the reduction of runoff generation and peak runoff at different locations in Longyan, China. The study was conducted using the SWMM model (5.1.006) with a newly developed LID module. In this study, the LID module, which includes rain gardens, green roofs, permeable pavements, and rain barrels, was used to simulate different layout scenarios and different rainfall patterns. The results show that the performance of a certain LID is similar at different locations but the reduction effect on runoff and peak flow varies. Rain gardens and permeable pavements perform a similar degree of reduction under different durations, but the peak flow reduction by rain barrels and green roofs varies greatly. Further research should focus on composite LID applications in other locations, combination with the local pipe network layout, which will ensure that the implemented system will be aesthetically pleasing, economically viable, and effective for reducing runoff and peak flow.

scholarly journals Impact of Urbanization on Stormwater Runoff from a Small Urban Catchment: Gdańsk Małomiejska Basin Case Study

2014 ◽  
Vol 61 (3-4) ◽  
pp. 141-162 ◽  
Author(s):  
Borys Olechnowicz ◽  
Katarzyna Weinerowska-Bords
Keyword(s):  
Stormwater Management ◽  
Overland Flow ◽  
System Development ◽  
Drainage System ◽  
Wave Model ◽  
Green Roofs ◽  
Army Corps ◽  
Peak Time ◽  
Runoff Reduction ◽  
The Impact

AbstractThis paper deals with the impact of different forms of urbanization on the basin outflow. The influence of changes in land cover/use, drainage system development, reservoirs, and alternative ways of stormwater management (green roofs, permeable pavements) on basin runoff was presented in the case of a small urban basin in Gdansk (Poland). Seven variants of area development (in the period of 2000-2012) - three historical and four hypothetical - were analyzed. In each case, runoff calculations for three rainfall scenarios were carried out by means of the Hydrologic Modeling System designed by Hydrologic Engineering Center of the U.S. Army Corps of Engineers (HEC-HMS). The Soil Conservation Service (SCS) Curve Number (CN) method was used for calculations of effective rainfall, the kinematic wave model for those of overland flow, and the Muskingum-Cunge model for those of channel routing. The calculations indicated that urban development had resulted in increased peak discharge and runoff volume and in decreased peak time. On the other hand, a significant reduction in peak values was observed for a relatively small decrease in the normal storage level (NSL) in reservoirs or when green roofs on commercial centers were present. The study confirmed a significant increase in runoff as a result of urbanization and a considerable runoff reduction by simple alternative ways of stormwater management.

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 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 Increasing Evapotranspiration on Extensive Green Roofs by Changing Substrate Depths, Construction, and Additional Irrigation

Buildings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 173 ◽  
Author(s):  
Daniel Kaiser ◽  
Manfred Köhler ◽  
Marco Schmidt ◽  
Fiona Wolff
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Urban Environments ◽  
Normal Green ◽  
University Of Applied Sciences ◽  
Daily Evapotranspiration ◽  
Urban Heat ◽  
Cooling Effects ◽  
Cool Summer ◽  
The University

Urban environments are characterized by dense development and paved ground with reduced evapotranspiration rates. These areas store sensible and latent heat, providing the base for typical urban heat island effects. Green roof installations are one possible strategy to reintroduce evaporative surfaces into cities. If green roofs are irrigated, they can contribute to urban water management and evapotranspiration can be enhanced. As part of two research projects, lysimeter measurements were used to determine the real evapotranspiration rates on the research roof of the University of Applied Sciences in Neubrandenburg, Germany. In this paper, we address the results from 2017, a humid and cool summer, and 2018, a century summer with the highest temperatures and dryness over a long period of time, measured in Northeast Germany. The lysimeter measurements varied between the normal green roof layer (variation of extensive green roof constructions) and a special construction with an extra retention layer and damming. The results show that the average daily evapotranspiration rates can be enhanced from 3 to 5 L/m2/day under optimized conditions. A second test on a real green roof with irrigation was used to explain the cooling effects of the surface above a café building in Berlin.

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