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Hybrid Green Corridors in Arid Northern Mexico: Design for a Balance between Ecological and Non-Motorized Mobility Networks

DOI

https://doi.org/10.7275/fabos.710

Publication Date

2016

Abstract

Urban planning in Mexico has been going through intensive updating by the hand of the recently created Municipal Planning Institutes (IMPLANES). These institutes have emerged in the XXI century as a response to the inability to implement medium to long term planning efforts derived from an urban administration model determined by three year municipal government terms with no reelection as an option. Before the emergence of IMPLANES, decisions pertaining urban infrastructure were determined by mayors trying to leverage brief periods of time in the scale of urban administration and planning. IMPLANES have spent a significant part of their efforts updating the aged and conceptually obsolete –largely based on XX century zoning practices- urban plans of medium to large cities in the country.

One of the frequent components added, as innovations, to the urban plans are green corridors and non-motorized mobility networks conceived as devices to structure what often are highly fragmented urban fabrics. Green corridors are planned on creeks, dry rivers, and rivers. Non-motorized mobility networks are planned on existing streets of various hierarchies. These 2 types of networks, are often planned as separate systems. The green corridors are associated to the production of public space/green areas and the non-motorized systems are related to mobility plans which typically include pedestrian, bicycle, and public transportation alternatives.

The separation of green corridor and non-motorized mobility systems results in plans with complete spatial coverage for non-motorized mobility. But, it also results in plans which have proven to be unrealistic towards implementation. After some years of planning there are very few bicycle lanes built today. As bicycle transportation is slowly being accepted by the population, particularly young people, public budgets continue to be sucked away by expensive traditional car-oriented infrastructure.

The intention of this paper is to propose that a hybrid network composed of integrated green corridors and non-motorized mobility can be more effective as a strategy towards implementation. While the spatial coverage might not be as extensive as the planned non-motorized networks on retrofitted streets, it is a coverage which can be targeted and centered on green corridors which, complemented by complete streets, can both deliver mobility, public space, and ecosystem services.

This paper is the result of the design exploration of hybrid networks in applied academic studios. The inquiry is led by urban studies on 4 northern Mexico cities, 3 of which were supported by design studios in collaboration with the local IMPLANES. These studios fill the gap created by the lack of educational programs in landscape architecture and urban design in Mexico; while serving as an opportunity to learn by serving communities.

The four cities were selected because of two different characteristics in their green corridor capacities: Chihuahua and Los Cabos possess networks already planned on natural drainage ways; Hermosillo and Mexicali have mostly artificial drainage ways found on irrigation and storm water management canals.

All these four cities also share 2 other critical conditions relevant to the production of hybrid corridors: these are all semi-arid and arid cities. According to their urban plans, their average rainfall rates are 262.7 millimeters for Los Cabos; 427.2 mm for Chihuahua; 348 mm for Hermosillo; and 36 mm for Mexicali. Their natural landscapes are mostly composed of grasslands and desert scrub with the presence of trees only on intermittent riparian corridors and on mountain slopes. These corridors and massifs contain spatial and environmental quality but are threatened, destroyed, or polluted by urbanization. The four cities have insufficient green areas. According to recommendations by the World Health Organization, used as indicator by their urban plans, city dwellers need 9 square meters of green areas: Los Cabos has only 4 m2 per person; Chihuahua 3.7 m2; Hermosillo 6.19 m2; and Mexicali 2.1 m2.

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