Design of a Creager Spillway to Minimize Flooding in a Micro-Basin of the Sabinal River in Tuxtla Gutiérrez, Chiapas, Mexico

Abstract

This study introduces a design proposal featuring the mitigation of flooding in the 24 de Junio micro-basin. The most flood-prone area is Street Ricardo Flores Magón. The proposed design includes a Creager spillway to minimize flooding in the “24 de Junio” micro-basin of the Sabinal River, located at the following geographical coordinates: 16˚45'47'' N latitude and 93˚05'28'' W longitude, in Tuxtla Gutiérrez, Chiapas, Mexico. The primary objective is to intercept sediment, urban debris, rocks, stones, branches, and tree pieces that are transported (by drag force or flotation) within the streamflow (Q). However, to achieve this objective, it is necessary to design a spillway capable of retaining rural and urban debris. This design must be carried out using a specific method, and therefore, a significant portion of this study will focus on the design of a Creager-type spillway using the USRB method. This transport occurs from the upper part of the micro-basin to its discharge point. The discharge point is located at the intersection of Street Ricardo Flores Magón with the elevated North bypass bridge. The General Prosecutor’s Office of the State of Chiapas is situated near the discharge point and is adjacent to Rosa del Oriente Street, in the El Bosque Neighborhood of Tuxtla Gutiérrez, which is heavily traveled by people and vehicles. If it rains heavily in SCRS, then Ricardo Flores Magón Street and the zone of the General Prosecutor’s Office of the State of Chiapas flood. For a return period (Tr) of 500 years, we estimated Q to be 25.33 m 3 /s, leading to a flow depth close to 1 meter. So, vehicles could be carried away by the force and velocity of the supercritical flow, posing a risk to individuals in the vicinity. The Creager profile spillway was designed with the USBR method, and its Creager profile is connected to a gabion base to mitigate water erosion during discharge. The upstream face of the Creager profile spillway is vertical (z = 0). The design hydraulic head is 0.54 m (H o ), with a height of 18 m (P) and a width of 35 m (L). The spillway’s maximum discharge is 25.33 m 3 /s (Qm), associated with a return period (Tr) of 500 years.