# Modelling Pluvial Flooding in Urban Areas Coupling the Models Iber and SWMM

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Hydraulic Models

#### 2.1.1. Iber

#### 2.1.2. SWMM 5.1

#### 2.2. Linking Methodology

**n**+ 1, adjusted to the synchronization with SWMM if it was necessary, $\Delta {t}_{SWMM{\text{}}_{n+1}}$ and $\Delta {t}_{Iber\text{}CF{L}_{n+1}}$ are the SWMM and Iber time steps computed independently in both models for the step

**n**+ 1 (i.e., without considering synchronization), ${T}_{syn}$ is the time of the last synchronization, and ${{\displaystyle \sum}}_{i=1}^{n}\text{}\Delta {t}_{Ibe{r}_{i}}$ is the elapsed time of Iber.

## 3. Case Studies and Results

#### 3.1. Simplified Urban Street

#### 3.1.1. Case Study Description

#### 3.1.2. Results

#### 3.2. Full-Scale Urban Drainage Physical Model

#### 3.2.1. Case Study Description

^{2}with a sewer system and a rainfall simulator. This facility was used in previous studies [10,35,36,37] to validate urban drainage models and to measure wash-off and sediment transport in urban environments. The street consists of a concrete roadway and a concrete pavement separated by a 15-cm high curb. The roadway has 2% and 0.5% transversal and longitudinal slopes, respectively. Surface runoff is drained through two inlets and through a lateral channel that ends into a third inlet. From there, water is conveyed through the sewer system to a downstream outfall (Figure 7). The street geometry and experimental data presented in WASHTREET [38] were used to build the numerical model.

#### 3.2.2. Results

#### 3.3. Real Urban Settlement

#### 3.3.1. Case Study Description

#### 3.3.2. Results

^{3}/s). At outfall O1, there are some minor differences at some time steps, but those are not significant for practical purposes (MAE of 0.06 m

^{3}/s), and the peak discharge computed with both meshes is the same. Regarding outfall O3, the MAE increases to 0.11 m

^{3}/s, and the difference in peak discharge is around 8%. While these differences are larger than in the case of O1 and O2, they are still small for the analysis of sewer networks in real applications, where the uncertainties on input data are in general larger than those values. Moreover, it should be considered that the CPU time was 15 times larger when using the fine mesh in relation to the coarse mesh.

## 4. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 5.**Results of maximum depths at surface and photography of a manhole flooding [34] that justifies the assumption that the main returned flow to the surface occurs through the manholes.

**Figure 6.**(

**a**) Time series evolution of accumulative volumes; (

**b**) mass balance error during the simulation for the simplified urban street.

**Figure 7.**(

**a**) Physical model facility and (

**b**) measuring points in inlets, pipes and surfaces used for results validation.

**Figure 8.**Experimental and numerical profiles of discharges at inlets GP1 (

**left**) and GP2 (

**middle**) and at the outfall (

**right**).

**Figure 9.**Experimental and numerical profiles of depths in pipes at control points P1 (

**top-left**), P2 (

**top-middle**), P3 (

**top-right**) and P4 (

**bottom-left**) and in surface at control points S1 (

**bottom-middle**) and S2 (

**bottom-right**).

**Figure 10.**(

**a**) Time series evolution of accumulative volumes; (

**b**) mass balance error during the simulation for full-scale urban drainage physical model.

**Figure 12.**(

**a**) Maximum depths at surface; (

**b**) numerical hydrographs computed at outfalls for a 1 h design storm with a 25-year return period for coarse (C) and fine (F) mesh.

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**MDPI and ACS Style**

Sañudo, E.; Cea, L.; Puertas, J. Modelling Pluvial Flooding in Urban Areas Coupling the Models Iber and SWMM. *Water* **2020**, *12*, 2647.
https://doi.org/10.3390/w12092647

**AMA Style**

Sañudo E, Cea L, Puertas J. Modelling Pluvial Flooding in Urban Areas Coupling the Models Iber and SWMM. *Water*. 2020; 12(9):2647.
https://doi.org/10.3390/w12092647

**Chicago/Turabian Style**

Sañudo, Esteban, Luis Cea, and Jerónimo Puertas. 2020. "Modelling Pluvial Flooding in Urban Areas Coupling the Models Iber and SWMM" *Water* 12, no. 9: 2647.
https://doi.org/10.3390/w12092647