scholarly journals Modeling Urban Flood Inundation and Recession Impacted by Manholes

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1160 ◽  
Author(s):  
Merhawi GebreEgziabher ◽  
Yonas Demissie

Urban flooding, caused by unusually intense rainfall and failure of storm water drainage, has become more frequent and severe in many cities around the world. Most of the earlier studies focused on overland flooding caused by intense rainfall, with little attention given to floods caused by failures of the drainage system. However, the drainage system contributions to flood vulnerability have increased over time as they aged and became inadequate to handle the design floods. Adaption of the drainages for such vulnerability requires a quantitative assessment of their contribution to flood levels and spatial extent during and after flooding events. Here, we couple the one-dimensional Storm Water Management Model (SWMM) to a new flood inundation and recession model (namely FIRM) to characterize the spatial extent and depth of manhole flooding and recession. The manhole overflow from the SWMM model and a fine-resolution elevation map are applied as inputs in FIRM to delineate the spatial extent and depth of flooding during and aftermath of a storm event. The model is tested for two manhole flooding events in the City of Edmonds in Washington, USA. Our two case studies show reasonable match between the observed and modeled flood spatial extents and highlight the importance of considering manholes in urban flood simulations.

2014 ◽  
Vol 2 (9) ◽  
pp. 6173-6199 ◽  
Author(s):  
L. Liu ◽  
Y. Liu ◽  
X. Wang ◽  
D. Yu ◽  
K. Liu ◽  
...  

Abstract. Flash floods have occurred frequently and severely in the urban areas of South China. An effective process-oriented urban flood inundation model becomes an urgent demand for urban storm water and emergency management. This study develops an effective and flexible cellular automaton (CA) model to simulate storm water runoff and the flood inundation process during extreme storm events. The process of infiltration, inlets discharge and flow dynamic can be simulated only with little pre-processing on commonly available basic urban geographic data. In this model, a set of gravitational diverging rules are implemented in a cellular automation (CA) model to govern the water flow in a 3 x 3 cell template of a raster layer. The model is calibrated by one storm event and validated by another in a small urban catchment in Guangzhou of Southern China. The depth of accumulated water at the catchment outlet is interpreted from street monitoring sensors and verified by on-site survey. A good level of agreement between the simulated process and the reality is reached for both storm events. The model reproduces the changing extent and depth of flooded areas at the catchment outlet with an accuracy of 4 cm in water depth. Comparisons with a physically-based 2-D model (FloodMap) results show that the model have the capability of simulating flow dynamics. The high computational efficiency of CA model can satisfy the demand of city emergency management. The encouraging results of the simulations demonstrate that the CA-based approach is capable of effectively representing the key processes associated with a storm event and reproducing the process of water accumulation at the catchment outlet for making process-considered city emergency management decisions.


2018 ◽  
Vol 44 ◽  
pp. 00129
Author(s):  
Monika Nowakowska

In the paper were made the verification of the operation of a rainwater drainage system in the residential communities of Gaj and Tarnogaj in Wrocław, carried out in the hydrodynamic model using SWMM software. There were used two criterial precipitation: Euler’s model (with a frequency of C = 3 years) and the actual precipitation (C = 5 years). The criteria of overloading the system was the specific flood volume (SFV). For both cases of precipitation load of catchment, the simulated calculations showed the occurrence of outflows from the channels. Due to the value of SFV indicator (respectively: 19 m3/ha and 42,9 m3/ha), it was found that the tested system needs modernization, therefor acceptable instantaneous water level above the maximum water impoundment were more often than 1 per 3 years, which leads to overflows from channels for residential areas more often than allowed once every 20 years.


Author(s):  
Vidyapriya V. ◽  
Ramalingam M.

Mostly populous city like Chennai is subjected to frequent flooding due to its complex nature of natural and man-made activities. From the analysis of the past records of flood events of 1943,1976,1985,2005 and 2008,it has been observed Adayar watershed is subjected to cataclysmic flooding in low-lying areas of the city and its suburbs because of inoperativeness of the local drainage system, rainfall associated with cyclonic activity, topography of the terrain, encroachments along the floodplain, hugh upstream flow discharge into the river and the highly impervious area which blocked the runoff to flow into the storm water drainage. After looking into these problems of flooding, a study have been conducted on Adayar watershed to develop a 2D hydrodynamic model for the two scenarios of existing condition of storm water drainage network and revised conditions of storm water drainage network using high resolution Lidar DEM to assess the volume of runoff with respect to time and duration on flood peaks for the two flood events of 2005 and 2015.Secondly to develop a 1D flood model to predict the river stages during peak floods using MIKE 11 for the Adayar watershed. Thirdly to integrate the coupled 1D and 2D model using MIKEFLOOD for assessing the extent of inundation in the floodplain area of Adayar river. Finally results from the integrated model have been validated and the results found satisfactory. As a part of mitigation measures, two flood mitigation measures have been adopted. One measure such as revised storm water drainage system which enhances the flood carrying capacity of the drains and results in less inundated area which solves the problem of urban flooding and second measure such as regrading the river bed which reduces the floodplain inundation around the adjacent area of the river. After adopting these measures, the river is free to flow into the sea without any blockades.


2019 ◽  
Vol 29 (4) ◽  
pp. 128-140
Author(s):  
Ireneusz Nowogoński ◽  
Ewa Ogiołda ◽  
Marcin Musielak

Abstract The article presents the current state of knowledge in the field of estimating preliminary values of storm water subcatchment calibration parameters in the case of using the Storm Water Management Model (SWMM) for building a model of storm water drainage system. The key issue is estimating the runoff width in the case of reducing the network structure and storm water catchments due to the shortening of calculation time and simplification of the model calibration process. Correction of one of the recommended literature methods has been proposed. The assessment was based on the real catchment model with single and multi-family housing. It was found possible to apply the proposed method in the case of reducing systems connected in series.


Sign in / Sign up

Export Citation Format

Share Document