Surface stormwater hazard assessment in steep urban areas. Case of the city of Mendoza, Argentina

Abstract

The current paper focusses on the hazard assessment associated with urban runoff on streets. A review of the existing criteria to evaluate such a hazard is made. Two new criteria based on theoretical analysis of the water's force acting on a static pedestrian are presented: no slipping criterion and stability to tilt criterion. According to these criteria, either a maximum depth, or a maximum velocity or some relation between depths and velocities should be fulfilled in order to guarantee the pedestrian's and driver's safety in the case of medium to large storms. A one-dimensional numerical model is used to solve the urban storm runoff within a street network. This model is applied to an urban watershed of the city of Mendoza (Argentina), obtaining the runoff values belonging to return periods of 5, 10 and 25 years. The results are evaluated bearing in mind four hazard criteria. In conclusion, the numerical model is shown to be a useful tool in relation to the application of the hazards criteria. It is also conclude that an effort should be made to determine specific hazard criteria based on experimental data.

Keywords:

• Dual drainage
• Numerical model
• Hazard assessment
• Hazard criterion
• One-dimensional modelling
• Steep streets
• Street network
• Street runoff
• Surface stormwater
• Urban drainage
• Urban hydrology
• Urban runoff

Acknowledgement

L. Nanía thankfully acknowledges the Spanish Agency of International Cooperation for their support via a 42-month scholarship and that of the Technical University of Catalonia in the whole study period. Ing. Jorge Maza from INA-CRA is thanked for the design storm data and Ing. Francisco Morandini from OSM, Mendoza is thanked for the topographic data of Mendoza.