2022

MCHAP

Containing the flood: Colosio Embankment Dam

School of Architecture UNAM / Loreta Castro Reguera, José Pablo Ambrosi

Nogales, Mexico

January 2020

PRIMARY AUTHOR

School of Architecture UNAM / Loreta Castro Reguera Mancera, José Pablo Ambrosi Cortés

CONTRIBUTING AUTHOR

Juan Ansberto Cruz Gerón

CLIENT

Secretaría de Desarrollo Agrario, Territorial y Urbano

PHOTOGRAPHER

Rafael Gamo, Diana Luque

OBJECTIVE

This project emerged from our interest to work in the intersection between architecture and infrastructure, a field we have discovered to lack the attention of design professionals, such as architects and urban designers, but desperately in need of it.

In Colosio dam, we were initially asked to design a park adjacent to the water body. After understanding the prevailing hydraulic and urban conditions, we decided to intervene in the dam itself, transforming the space both, into a working infrastructure and a public and recreational space. We achieved this through three main strategies:

Structure is the guiding system of the project. Gabion solves both architecture and infrastructure, permitting the filtration of water while containing the sliding ground. Through modular elements, pedestrian terraces allow circulation around the water body. The project is designed with a limited number of construction details to simplify construction.

Geometry is used as a tool to dialogue with the context and the community: Linear geometries refer to the existing urban fabric and curves suggest the presence of water. The triangular roof serves as the element that gives relevance to the dam, making it perceptible from the main avenue. It gives scale and a facade to the entire intervention, while serving as a landmark for the community by reinterpreting the local building typology.

The program is infrastructure. The new design prevents the cyclical flooding of the area. A system of floodable platforms and the rise of the perimetral wall address this condition. These hold sport courts, gardens and playgrounds.

CONTEXT

Represo Colosio is a compacted earth embankment dam, built during the 1960’s, as a strategy to control runoff coming from the Los Adobes mountains. It is located west of Nogales in Sonora, a border town in the north of Mexico. One of the city’s pressing issues is that streets were former periodical streams, converging in downtown, also the main border checkpoint. During the rainy season,streams carry water and waste all the way to the United States.

As soon as the dam was built, informal settlements started to establish around it, counting a population of 9,027 in a 750m radius in 2020. The conditions in which these people live are precarious due to the pressing need for housing and high poverty rates. Cardboard, wood-plank and cinder block houses roofed with concrete slabs or cardboard/metal ondulated sheet constitute the typology. Additionally, several houses were built along the dam’s curtain and along the slope, becoming vulnerable to landslides and provoking the curtain’s fracturing. Moreover, waste water and other residues were poured into the dam, polluting it.

From the hydrological perspective, the dam started malfunctioning as the result of silt and lack of maintenance, and because it missed a proper spillway. Frequent urban floods occurred yearly during the rainy season, with water pouring along the southeastern streets of the dam, then moving north, making it a vulnerable area. The capacity of the dam was totally exceeded. The surrounding neighborhood lacked sanitation. The entire city perceived it as a potential disaster.

PERFORMANCE

The introduction of this project has proved to positively impact several aspects around the site, both expected and not.

In terms of water management, since its completion in January 2020, there has been no need to dredge or drain the dam despite the strong rains registered during July 2021. Runoff easily enters the water body without affecting the surrounding houses and, mainly, without interfering with mobility around the dam, permitting neighbors to circulate using the perimetral paths and cars to cross from west to east using the bridge.

Social life in the area has appeared and insecurity decreased. Sport facilities have fostered the creation of local teams and raised new activities for the inhabitants. Gabion pathways and platforms are used for pedestrian accesible mobility and recreational promenades. Artificial light at night time makes it a safe space for all ages and genders, permitting the park’s use during the entire day.

As an architectural and infrastructural typology, the Colosio dam encourages the integration of water into the urban landscape as an agent of positive change. Industrial materials and design strategies become an invitation to dialogue with the context looking forward to the future expansion and development of the area.