Hydraulic modeling in Iber for flood prevention in the Tesechoacán river basin

Abstract

Watershed modelling for hydraulic analysis is necessary to estimate or have information from hydrographs to be used as basic tools for studying floods in particular times or extreme events. In the present work, a 2D hydraulic modelling was carried out in Iber with data of the Hurricane Matthew event from September 26th to October 1st, 2010, seeking to identify and quantify the areas with a high risk of flooding in the Tesechoacán river basin, and providing some proposals that could reduce the impact for future events. Results show a surface area of 29 027.24 ha was flooded with tie rods up to 7.45 m. The areas with the largest runoff surface area are cultivated pasture and agriculture, representing 80.89 % of the total area. According to the generated hazard map, 33 localities were affected, with 56.9 % classified as highly hazardous areas. Due to the little information available, the validation of the model was carried out using the spatial comparison of the margins of the floodplain obtained in Iber with a SPOT 4 image (HRVIR 1), observing good agreement between the model and the satellite image. The following measures are proposed for flood control: dredging and the construction of marginal borders. This last concept was an option to consider because it reduces up to 71 % of the impact of floods in the Tesechoacán sub-basin.