scholarly journals Vegetation Survival in Green Roofs without Irrigation

2020 ◽  
Author(s):  
Anita Raimondi ◽  
Mariana Marchioni ◽  
Umberto Sanfilippo ◽  
Gianfranco Becciu
Keyword(s):  
Probabilistic Approach ◽  
Green Roofs ◽  
Design Parameters ◽  
Dry Period ◽  
Rainfall Events ◽  
Average Return ◽  
Growing Medium ◽  
A Chain ◽  
Proper Values ◽  
Stormwater Control

The implementation of green roofs as sustainable urban drainage systems provides benefits for stormwater control and the environment and is always more encouraged. In this paper, the estimation of the probability of vegetation survival without irrigation has been proposed as a guide to choose the proper values for the design parameters; in particular the growing medium thickness has been related to the average return interval of the water content at the end of the dry period. Moreover the study represents an improvement of the analytical probabilistic approach since a chain of consecutive rainfall events has been considered, in order to take into account the possibility that the storage capacity is not completely available at the beginning of each event because of the pre-filling from more than one previous rainfall as typically happens for green roofs. Finally, developed equations have been validated by means of their application to two case studies, respectively in northern and southern Italy.

scholarly journals Vegetation Survival in Green Roofs without Irrigation

2020 ◽  
Author(s):  
Anita Raimondi ◽  
Mariana Marchioni ◽  
Umberto Sanfilippo ◽  
Gianfranco Becciu
Keyword(s):  
Storage Capacity ◽  
Irrigation System ◽  
Probabilistic Approach ◽  
Green Roofs ◽  
Design Parameters ◽  
Urban Drainage ◽  
Rainfall Events ◽  
Peak Runoff ◽  
A Chain

The Sustainable Urban Drainage Systems on stormwater management provide benefits for sewer networks, treatment plants and environment and should be encouraged. Green roofs are part of these systems and can contribute both to delay and cut peak runoff and reduce discharged volumes. In this paper the probability of vegetation survival without irrigation has been proposed as a guide to operators on selecting vegetation and irrigation system as well as design parameters. An analytical probabilistic approach has been proposed; a chain of consecutive rainfall events has been considered to take into account the possibility that storage capacity is not completely available at the beginning of the considered event but pre-filled from previous rainfalls, as typical of green roofs. Finally, an application to a case study has been proposed to validate proposed equations.

scholarly journals Vegetation Survival in Green Roofs without Irrigation

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 136
Author(s):  
Anita Raimondi ◽  
Mariana Marchioni ◽  
Umberto Sanfilippo ◽  
Gianfranco Becciu
Keyword(s):  
Green Roofs ◽  
Medium Thickness ◽  
Rainfall Events ◽  
Continuous Simulation ◽  
Proposed Model ◽  
Growing Medium ◽  
Model Equations ◽  
Stormwater Control ◽  
Derivation Procedure ◽  
Good Agreement

The implementation of green roofs as sustainable urban drainage systems provides benefits for stormwater control and the environment and is more and more encouraged. A model for the estimation of the probability of vegetation survival without irrigation is proposed. The model, developed through a probabilistic analytical derivation procedure, can also consider the effects of chained rainfall events, without the need of continuous simulation of hydrological processes. The model equations can be useful in the design of green roofs, allowing to determine the growing medium thickness in terms of an assumed risk of vegetation withering in dry periods. The proposed model is also able to identify the optimal thickness of the growing medium, over which the survival performances can be increased only with irrigation. Model performances were tested by the application to two case studies in Italy. Comparison between the probabilities and the cumulative frequencies from a continuous simulation of water content in the growing medium shows a good agreement and provide a first confirmation of reliability.

scholarly journals Factors Affecting Runoff Retention Performance of Extensive Green Roofs

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1217 ◽  
Author(s):  
Yongwei Gong ◽  
Dingkun Yin ◽  
Xing Fang ◽  
Junqi Li
Keyword(s):  
Hydraulic Conductivity ◽  
Retention Rate ◽  
Green Roofs ◽  
Retention Performance ◽  
Dry Period ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Drainage Layer ◽  
Factors Affecting ◽  
Extensive Green Roofs

The runoff retention effectiveness of 10 extensive green roof (EGR) modules (100 mm substrate planted Sedum lineare Thunb.) were analyzed in Beijing for 22 rainfall events (2.4–46.4 mm) from 1 July to 30 September 2017. Differences between minimum inter-event dry periods, module scales, substrate hydraulic conductivity and depths, drainage layer types and rainfall characteristics were examined to study their correlation to the retention performance of EGRs. In general, EGRs with lower substrate hydraulic conductivity, deeper substrate and lower rainfall depth had higher runoff retention performance. By comparsion, no siginificant correlation was found between rainfall duration, prior dry period, average rainfall intensity, drainage layer type and EGR runoff retention rate. Analyses of variance (ANOVA) and Tukey tests supported these results. Low or moderate rainfall (<15 mm) may or may not have an effect, but heavy rainfall (>25 mm) definitely affects the EGR retention performance of the next rainfall event.

scholarly journals Performance of Green Roofs for Rainwater Control

2020 ◽  
Author(s):  
A. Raimondi ◽  
G. Becciu
Keyword(s):  
Goodness Of Fit ◽  
Probabilistic Approach ◽  
Green Roof ◽  
Green Roofs ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Climate Conditions ◽  
Average Return ◽  
Roof Design ◽  
The Given

AbstractGreen roofs can be an effective tool for sustainable urban drainage, since they reduce and retain runoff by delaying its peak. Most studies analysing the retention capacity of green roofs are usually referred to a specific place and roof condition and do not consider the possibility that the roof could be partially pre-filled from previous rainfalls at the beginning of the given event. The aim of this paper is to develop an analytical probabilistic approach to evaluate green roof performance for stormwater control in terms of runoff that could be applied for different sites and climate conditions. To this end, the possibility that the green roof retention capacity could not be completely available owing to pre-filling from previous rainfall events has been considered and equations for an optimum green roof design, relating the runoff average return interval to the water retention capacity, have been proposed. The influence of parameters affecting the runoff process has been examined in depth and a case study to test the goodness of fit of the resulting equations has been developed.

scholarly journals Probabilistic Modelling of Sustainable Urban Drainage Systems

2022 ◽  
Author(s):  
Anita Raimondi ◽  
Maria Gloria Di Chiano ◽  
Mariana Marchioni ◽  
Umberto Sanfilippo ◽  
Gianfranco Becciu
Keyword(s):  
Control Systems ◽  
Probabilistic Approach ◽  
Urban Drainage ◽  
Rainfall Events ◽  
Drainage Systems ◽  
Effective Strategies ◽  
Urban Drainage Systems ◽  
Rainwater Management ◽  
A Chain ◽  
And Control

Abstract Sustainable Urban Drainage Systems (SuDS) gatherer effective strategies and control systems for stormwater management especially in highly urbanized areas characterized by large impervious surfaces that increase runoff peak flow and volume. The main goal is to restore the natural water balance by increasing infiltration, evapotranspiration and promoting rainwater reuse. This paper proposes an analytical probabilistic approach for the modelling SuDS applicable to different structures and goals. Developed equations allow to estimate the probability of overflow and the probability of pre-filling at the end of dry periods, to evaluate the efficiency of the storage in rainwater management and its ability to empty between consecutive events. A great advantage of the proposed method is that it allows to consider a chain of rainfall events; this aspect is particularly important for control systems SuDS characterized by low outflow rates which storage capacity is often not completely available at the end of a dry period because pre-filled by previous events. Suggested formulas were tested to two cases studies in Milan and Genoa, Italy.

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.

Application of Design Axioms to Marine Design Problems

2000 ◽  
Author(s):  
Y. S. Yang ◽  
B. S. Jang ◽  
Y. S. Song ◽  
Y. S. Yeon ◽  
S. H. Do
Keyword(s):  
Structural Design ◽  
Probabilistic Approach ◽  
Design Stage ◽  
Design Parameters ◽  
Independence Axiom ◽  
Preliminary Design ◽  
Functional Requirements ◽  
Mapping Procedure ◽  
Information Axiom ◽  
The Given

Abstract The Design Axioms proposed by N. P. Suh consist of Independence Axiom and Information Axiom. The Independence Axiom assists a designer in generating good design alternatives by considering the relations between the functions and the physical product using a hierarchical mapping procedure. The Information Axiom, which is related to the probability of achieving the given functional requirements, can be used as a criterion for the selection of the best solution among the proposed alternatives in the conceptual or preliminary design stage. In the early stages of marine design, especially ship design, there exists a lot of uncertainty because of the size and complexity of a marine vehicle. The uncertainty often leads to a probabilistic approach rather than a deterministic approach. The ship designs are mostly routine design to change an existing design case a little. In this paper, the availability of the Design Axioms in this marine design field will be investigated through three examples. In the conceptual design of a thruster, the Independence Axiom will be proven to be useful in examining the independence of functional requirements at each level of the decomposition process. In main engine selection example, the Information Axiom will be used for selecting the best solution among the given alternatives by estimating their respective information contents under the uncertain and ambiguous condition. In the structural design, some difficulties arise in maintaining the independence of functional requirements in general because the number of design parameters is greater than that of functional requirements. Therefore, there is much trouble in generalizing the application of the Design Axioms for the structural design, especially for the preliminary design where the principal design parameters of a design object have to be determined after its shape fixed. This paper will try a generalized approach to the similarity-based design where it is important to select which parameters should be changed and in what order they should be changed. How to make use of the Design Axioms will be showed in a barge design example. However, a lot of research is needed for the generalized application of the Design Axioms for the structural design.

scholarly journals Probability-Based Concrete Carbonation Prediction Using On-Site Data

2020 ◽  
Vol 10 (12) ◽  
pp. 4330
Author(s):  
Hyunjun Jung ◽  
Seok-Been Im ◽  
Yun-Kyu An
Keyword(s):  
Probabilistic Approach ◽  
Concrete Structures ◽  
Design Parameters ◽  
Degree Of Hydration ◽  
Concrete Carbonation ◽  
Remaining Service Life ◽  
Long Term Performance ◽  
Term Performance ◽  
Prediction Approach

This study proposes a probability-based carbonation prediction approach for successful monitoring of deteriorating concrete structures. Over the last several decades, a number of researchers have studied the concrete carbonation prediction to estimate the long-term performance of carbonated concrete structures. Recently, probability-based durability analyses have been introduced to precisely estimate the carbonation of concrete structures. Since the carbonation of concrete structures, however, can be affected by material compositions as well as various environmental conditions, it is still a challenge to predict concrete carbonation in the field. In this study, the Fick’s first law and a Bayes’ theorem-based carbonation prediction approach is newly proposed using on-site data, which were obtained over 19 years. In particular, the effects of design parameters such as diffusion coefficient, concentration, absorption quantity of CO2, and the degree of hydration have been thoroughly considered in this study. The proposed probabilistic approach has shown a reliable prediction of concrete carbonation and remaining service life.

scholarly journals Effects of Extensive Green Roofs on Energy Performance of School Buildings in Four North American Climates

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 6 ◽  
Author(s):  
Milad Mahmoodzadeh ◽  
Phalguni Mukhopadhyaya ◽  
Caterina Valeo
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Design Parameters ◽  
Soil Thickness ◽  
Area Index ◽  
Roof Design

A comprehensive parametric analysis was conducted to evaluate the influence of the green roof design parameters on the thermal or energy performance of a secondary school building in four distinctively different climate zones in North America (i.e., Toronto, ON, Canada; Vancouver, BC, Canada; Las Vegas, NV, USA and Miami, FL, USA). Soil moisture content, soil thermal properties, leaf area index, plant height, leaf albedo, thermal insulation thickness and soil thickness were used as design variables. Optimal parameters of green roofs were found to be functionally related to meteorological conditions in each city. In terms of energy savings, the results showed that the light-weight substrate had better thermal performance for the uninsulated green roof. Additionally, the recommended soil thickness and leaf area index for all four cities were 15 cm and 5 respectively. The optimal plant height for the cooling dominated climates is 30 cm and for the heating dominated cities is 10 cm. The plant albedo had the least impact on the energy consumption while it was effective in mitigating the heat island effect. Finally, unlike the cooling load, which was largely influenced by the substrate and vegetation, the heating load was considerably affected by the thermal insulation instead of green roof design parameters.

Forecasting Manufacturing Quality and Optimizing Product Robustness Using Process Capability Data

Manufacturing ◽  
2003 ◽  
Author(s):  
Daniel Kern ◽  
Xiaoping Du ◽  
Agus Sudjianto
Keyword(s):  
Probabilistic Approach ◽  
Process Capability ◽  
Simulation Models ◽  
Design Parameters ◽  
Set Design ◽  
Manufacturing Quality ◽  
Design Engineers ◽  
Parameter Values ◽  
Manufacturing Variation

A company’s success is highly dependent on its ability to manufacture quality products. Designing products that can be manufactured to meet customer needs with an acceptable level of variation is challenging because design engineers are often unfamiliar with the company’s manufacturing capability or are unable to effectively use the capability data to improve a design. The authors present an approach to forecast the manufacturing quality of a product and optimize its robustness while it is being designed. The system comprises a database that stores process capability data and simulation models to simulate process capability data when actual, appropriate data are nonexistent. These data and tools are used with a new probabilistic approach through the inverse reliability strategy to optimize the robustness of a design by locating values of design parameters that enhance the performance of the design and are insensitive to manufacturing variation. Design engineers can use this approach to set design parameter values that will improve the functionality of the product while ensuring it can be produced with high capability. This approach is demonstrated with a design example of an engine valvetrain.

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