Modeling Hydrologic Performance of a Green Roof System with HYDRUS-2D

Li, Yanling; Babcock, Roger W.

doi:10.1061/(asce)ee.1943-7870.0000976

Cited by 44 publications

(37 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, the HYDRUS software suite (Šimů nek et al, 2008) has been widely used in the literature for the description of the hydraulic behavior of green roofs (Hilten et al, 2008;Li and Babcock, 2015;Newcomer et al, 2014;Palla et al, 2009), with excellent agreement between numerical simulations and experimental data. Newcomer et al (2014) investigated the effects of LIDs on recharge.…”

Section: Introductionmentioning

confidence: 99%

“…Simulations were run using HYDRUS-1D for a 24-h design storm to determine peak flow, retention, and detention time for runoff. Li and Babcock (2015) used HYDRUS-2D to model the hydrologic response of a pilot green roof system. The root-meansquare error deviation (RMSD) between the modeled water contents and field measurements ranged between 0.38 and 1.74%.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A comprehensive numerical analysis of the hydraulic behavior of a permeable pavement

Brunetti

Šimůnek

Piro

2016

Journal of Hydrology

120

View full text Add to dashboard Cite

a b s t r a c tThe increasing frequency of flooding events in urban catchments related to an increase in impervious surfaces highlights the inadequacy of traditional urban drainage systems. Low Impact Development (LID) techniques have proven to be a viable and effective alternative by reducing stormwater runoff and increasing the infiltration and evapotranspiration capacity of urban areas. However, the lack of adequate modeling tools represents a barrier in designing and constructing such systems. This paper investigates the suitability of a mechanistic model, HYDRUS-1D, to correctly describe the hydraulic behavior of permeable pavement installed at the University of Calabria. Two different scenarios of describing the hydraulic behavior of the permeable pavement system were analyzed: the first one uses a singleporosity model for all layers of the permeable pavement; the second one uses a dual-porosity model for the base and sub-base layers. Measured and modeled month-long hydrographs were compared using the Nash-Sutcliffe efficiency (NSE) index. A Global Sensitivity Analysis (GSA) followed by a Monte Carlo filtering highlighted the influence of the wear layer on the hydraulic behavior of the pavement and identified the ranges of parameters generating behavioral solutions. Reduced ranges were then used in the calibration procedure conducted with the metaheuristic Particle swarm optimization (PSO) algorithm for the estimation of hydraulic parameters. The best fit value for the first scenario was NSE = 0.43; for the second scenario, it was NSE = 0.81, indicating that the dual-porosity approach is more appropriate for describing the variably-saturated flow in the base and sub-base layers. Estimated parameters were validated using an independent, month-long set of measurements, resulting in NSE values of 0.43 and 0.86 for the first and second scenarios, respectively. The improvement in correspondence between measured and modeled hydrographs confirmed the reliability of the combination of GSA and PSO in dealing with highly dimensional optimization problems. Obtained results have demonstrated that PSO, due to its easiness of implementation and effectiveness, can represent a new and viable alternative to traditional optimization algorithms for the inverse estimation of unsaturated hydraulic properties. Finally, the results confirmed the suitability and the accuracy of HYDRUS-1D in correctly describing the hydraulic behavior of permeable pavements.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A comprehensive numerical analysis of the hydraulic behavior of a permeable pavement

Brunetti

Šimůnek

Piro

2016

Journal of Hydrology

120

View full text Add to dashboard Cite

show abstract

“…A pilot green roof system was installed at University of Hawaii at Manoa [16]. There were three different module depths, 10 cm, 15 cm, and 20 cm.…”

Section: Pilot Green Roof Experimental Datamentioning

confidence: 99%

“…Typical hydraulic property parameters (θr, α, and n) for perlite and other growth media can be found in the literature [17]. Values for all of these parameters were measured in the pilot green roof at the University of Hawaii and used to calibrate a HYDRUS-2D model as described elsewhere [16]. Calibration results showed that this simplified modeling approach is able to capture the general water content trend, but it does not reflect the slow increases and decreases during the irrigation events as seen in Figure 2.…”

Section: Calibration and Sensitivity Of The Simplified Modelmentioning

confidence: 99%

A Simplified Model for Modular Green Roof Hydrologic Analyses and Design

Babcock

2016

Water

Self Cite

View full text Add to dashboard Cite

Green roofs can mitigate urban rooftop stormwater runoff. However, the lack of accurate, physically-based performance assessment and design models has hindered their wide application. Most hydrologic or hydraulic models have no direct connection to the physical properties of green roof components such as media type/depth, drainage depth, etc. In an effort to assist design engineers, a simplified yet effective physically-based model was developed and calibrated with pilot data in order to provide green roof hydrologic performance curves to guide design. Precipitations with depths ranging from 0 to 40 cm and durations 30 to 1440 min were simulated for 21 green roof designs to determine the effects of common physical design parameters. Results revealed that effective capacity and transient capacity are the controlling factors for runoff volume reduction for single precipitation events. Including a water storage feature in the design increased cumulative long-term runoff reduction by an average of 23.5%, whereas increasing growth media depth yielded an average 5.3% improvement. Peak reduction and peak delay are governed by media depth and drainage opening size. Study results indicate that LEED criteria should be modified to require specific designer-controlled parameters of storage and media depth for the design storm to ensure desired performance.

show abstract

“…Metselaar (2012) used the SWAP model (van Dam et al, 2008) to simulate the one-dimensional water balance of a substrate layer on a flat roof with plants. Li and Babcock (2015) used HYDRUS-2D to model the hydrologic response of a pilot green roof system. The model was calibrated using water content measurements obtained with TDR (Time Domain Reflectometer) sensors.…”

Section: Introductionmentioning

confidence: 99%

On the use of surrogate-based modeling for the numerical analysis of Low Impact Development techniques

Brunetti

Šimůnek

Turco

et al. 2017

Journal of Hydrology

View full text Add to dashboard Cite

a b s t r a c tMechanistic models have proven to be accurate tools for the numerical analysis of the hydraulic behavior of Low Impact Development (LIDs) techniques. However, their widespread adoption has been limited by their computational cost. In this view, surrogate modeling is focused on developing and using a computationally inexpensive surrogate of the original model. While having been previously applied to various water-related and environmental modeling problems, no studies have used surrogate models for the analysis of LIDs. The aim of this research thus was to investigate the benefit of surrogate-based modeling in the numerical analysis of LIDs. The kriging technique was used to approximate the deterministic response of the widely used mechanistic model HYDRUS-2D, which was employed to simulate the variably-saturated hydraulic behavior of a contained stormwater filter. The Nash-Sutcliffe efficiency (NSE) index was used to compare the simulated and measured outflows and as the variable of interest for the construction of the response surface. The validated kriging model was first used to carry out a Global Sensitivity Analysis of the unknown soil hydraulic parameters of the filter layer, revealing that only the shape parameter a and the saturated hydraulic conductivity K s significantly affected the model response. Next, the Particle Swarm Optimization algorithm was used to estimate their values. The NSE value of 0.85 indicated a good accuracy of estimated parameters. Finally, the calibrated model was validated against an independent set of measured outflows with a NSE value of 0.8, which again corroborated the reliability of the surrogate-based optimized parameters.

show abstract

Modeling Hydrologic Performance of a Green Roof System with HYDRUS-2D

Cited by 44 publications

References 14 publications

A comprehensive numerical analysis of the hydraulic behavior of a permeable pavement

A comprehensive numerical analysis of the hydraulic behavior of a permeable pavement

A Simplified Model for Modular Green Roof Hydrologic Analyses and Design

On the use of surrogate-based modeling for the numerical analysis of Low Impact Development techniques

Contact Info

Product

Resources

About