Towards a smart water city: A comprehensive review of applications, data requirements, and communication technologies for integrated management

This study investigates and compares several design storms for flood estimation in partially urbanized catchments. Six different design storms were considered: Euler II, alternating block method, average variability method, Huff’s curves, and uniform rainfall. Additionally, two extreme historical storms were included for comparison. A small, ungauged, partially urbanized catchment in Novigrad (Croatia) was chosen as a study area to account for the infiltration impact on the rainfall-runoff process. The performance of each design storm was assessed based on the flood modeling results, namely the water depth, water velocity, flow rate, and overall flood extent. Furthermore, several rainfall durations were considered to identify a critical scenario. The excess rainfall was computed using the Soil Conservation Service’s Curve Number method, and two-dimensional flooding simulations were performed by the HEC-RAS model. The results confirmed that the choice of the design storm and the rainfall duration has a significant impact on the flood modeling results. Overall, design storms constructed only from IDF curves overestimated flooding in comparison to historical events, whereas design storms derived from the analysis of observed temporal patterns matched or slightly underestimated the flooding results. Of the six considered design storms, the average variability method showed the closest agreement with historical storms.

https://www.mdpi.com/2073-4441/12/7/2044/pdf

Evaluation of Design Storms and Critical Rainfall Durations for Flood Prediction in Partially Urbanized Catchments

In the context of global climate change and urbanization, urban flooding is an important type of natural disaster that affects urban development, especially in China, which is experiencing rapid urbanization. In the past 10 years, urban flooding events have caused huge disaster losses in Chinese cities. This has resulted in significant negative effects on the urban infrastructure, socioeconomic systems, and urban residents, thus causing widespread concern. Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations In addition, numerical simulations provide an economical and viable means to perform these studies. This paper presents a numerical model of Xiamen Island in China. Simulations were conducted for 12 design rainstorm events with different return periods, rain patterns, and durations. The results indicate that, in the case of an equal rainfall amount, the rainfall intensity is the key factor that affects the inundated area, depth, and damages. However, the rainfall intensity is not the only determining factor; the rainfall pattern also affects the inundations. In regard to the rainfall pattern, a higher rainfall peak coefficient usually leads to severe urban inundation and damage. As a result, the lag time would be shorter, which may further exacerbate the impact of urban flood disasters. The results of this study provide insights into managing flood risks, developing urban flood prevention strategies, and designing flood prevention measures.

Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

Flooding events can produce significant disturbances in underground transport systems within urban areas and lead to economic and technical consequences, which can be worsened by variations in the occurrence of climate extremes Within the framework of the European project RESCCUE (RESilience to cope with Climate Change in Urban arEas—a multi-sectorial approach focusing on water), climate projections for the city of Barcelona manifest meaningful increases in maximum rainfall intensities for the 2100 horizon A better comprehension of these impacts and their conditions is consequently needed A hydrodynamic modelling process was carried out on Barcelona Metro Line 3, as it was identified as vulnerable to pluvial flooding events The Metro line and all its components are simulated in the urban drainage models as a system of computational link and nodes reproducing the main physical characteristics like slopes and cross-sections when embedded in the current 1D/2D hydrodynamic model of Barcelona used in the project RESCCUE This study presents a risk analysis focused on ensuring transport service continuity in flood events The results reveal that two of the 26 stations on Metro Line 3 are exposed to a high risk of flooding in current rainfall conditions, and 11 of the 26 stations on Metro Line 3 are exposed to a high risk of flooding in future rainfall conditions for a 20-year return period event, which affects Metro service in terms of increased risk This research gives insights for stakeholders and policymakers to enhance urban flood risk management, as a reasonable approach to tackle this issue for Metro systems worldwide This study provides a baseline for assessing potential flood outcomes in Metro systems and can be used to evaluate adaptation measures’ effectiveness

https://www.mdpi.com/2071-1050/12/13/5291/pdf

Flood risk assessment in an underground railway system under the impact of climate change: a case study of the Barcelona metro

This work presents a methodology for analyzing the influence of urbanization in a long-term approach on the number of floods in an urban catchment. The mathematical model presented for predicting the multiannual number of stormwater floods accounts for dynamic changes in the urban catchment in the subsequent years covered by the simulations. Logistic regression was applied to predict flooding occurring during rainfall events. The model may be applied to catchments with different characteristics. The assumed solution allows the development of early warning systems by modeling the occurrence of stormwater flooding in a studied catchment area based on the identification of the rainfall origin. To verify the simulations with a mathematical model, an innovative concept based on a hydrodynamic model is used; this concept includes the changes in the impervious area that occur during the simulation period. 

Influence of urban catchment characteristics and rainfall origins on the phenomenon of stormwater flooding: Case study

The present research develops a systematic application of a selected family of 11 well-known design storms, all of them obtained from the same rainfall data sample. Some of them are fully consistent with the intensity–duration–frequency (IDF) curves, while others are built according to typical observed patterns in the historical rainfall series. The employed data series consists on a high-resolution rainfall time series in Valencia (Spain), covering the period from 1990 to 2012. The goal of the research is the systematic comparison of these design storms, paying special attention to some relevant quantitative properties, as the maximum rainfall intensity, the total cumulative rainfall depth or the temporal pattern characterising the synthetic storm. For comparison purposes, storm duration was set to 1 h and return period equal to 25 years in all cases. The comparison is enhanced by using each of the design storms as rainfall input to a calibrated urban hydrology rainfall–runoff model, yielding to a family of hydrographs for a given neighbourhood of the city of Valencia (Spain). The discussion and conclusions derived from the present research refer to both, the comparison between design storms and the comparison of resulting hydrographs after the application of the mentioned rainfall–runoff model. Seven of the tested design storms yielded to similar overall performance, showing negligible differences in practice. Among them, only Average Variability Method (AVM) and Two Parameter Gamma function (G2P) incorporate in their definition a temporal pattern inferred from empirical patterns identified in the historical rainfall data used herein. The remaining four design storms lead to more significant discrepancies attending both to the rainfall itself and to the resulting hydrograph. Such differences are ~8% concerning estimated discharges.

A Comparison of Design Storms for Urban Drainage System Applications

The two-parameter gamma function (G2P) design storm is a recent methodology used to obtain synthetic hyetographs especially developed for urban hydrology applications. Further analytical developments on the G2P design storm are presented herein, linking the rainfall convectivity n-index with the shape parameter of the design storm. This step can provide a useful basis for future easy-to-handle rainfall inputs in the context of regional urban drainage studies. A practical application is presented herein for the case of Valencia (Spain), based on high-resolution time series of rainfall intensity. The resulting design storm captures certain internal statistics and features observed in the fine-scale rainfall intensity historical records. On the other hand, a direct, simple method is formulated to derivate the design storm from the intensity–duration–frequency (IDF) curves, making use of the analytical relationship with the n-index.

Rosario Balbastre-Soldevila

Papers

A Comparison of Design Storms for Urban Drainage System Applications

Estimation of the G2P Design Storm from a Rainfall Convectivity Index