A case study
GIS and Proposal for Territorial Planning at the Malvín Brook Basin, Montevideo-Uruguay.

by Prof. Álvaro González-Gervasio and Gabriela Fernández
Department of Geography
Faculty of Sciences, Universidad de la República

Introduction.- The Malvin Brook Basin is located at the south east of Montevideo City, within a total area of 828 hectares. Nowadays about 60,000 persons inhabit the area. By 1950 the basin was occupied by idle lands, farms and stone quarries. Significative changes in the soil use took place since: middle class houses were built in the southern section of the basin, complex of buildings spread in the northern section, while shanty towns began to occupy the borders of the brook and dells, and the site of abandoned quarries. The rest of the basin is occupied by idle lands with no defined functions.

Such changes led to the progressive degradation of the area from the environmental and social point of view. In the meantime the upper and lower courses of the brook were covered and substituted by streets, and the middle course –where at present social and environmental problems concentrate- was rectified. The existence of several educational institutions and sport infrastructures, as well as the new location of the Faculty of Sciences can be considered positive elements in this context.

Activities of the Project.- 1) Delimitation of the basin (study area: 570 hectares). 2) Documentary revision. 3) Interviews to satakeholders. 4) Chemical analysis of water. 5) Survey of the state of streets and pavements. 6) Design of the GIS. 7) Elaboration of the proposal for territorial planning.

Conflicts detected.- a) Non-planified soil use. b) Pollution of organic origin due to the lack of connection to the sewage systems or to breakages in the pipes, which affecting the quality of the hydrological network. c) Growth in the volume of garbage that is classified at some of the shanty towns. Undesired material ends in the brook and dells. d) Loss of the esthetic quality of the landscape.

Main causes of the existing problems.- 1) Even though the sewage system exists, about 50% of the homes are not connected to it. b) Inadequate maintenance of the sewage system. c) Garbage disposal and transportation is irregular. d) Weak social interactions due to the difference among the groups coexisting in the area (there is not a sense of community).

Original aspects of our research.- a) Systemic approach since both socioeconomic and physical aspects of the basin and their interactions were taken into account. This is not usual in urban basins. b) New information at a detailed scale was generated. c) The past and expected (with and without planning) dynamics of the area were considered, as well as the generation of possible scenarios.

 We think that this kind of approach and methodology can be applied to similar cases existing in urban environments in the region.

Mapping of environmental risk.- The environmental risk depends on the intensity of the factor considered as a menace, and the vulnerability of the affected element. We have chosen 2 physical aspects (landform and distance to the brook), which combined with 3 socioeconomic aspects (presence or absence of sewage system, health cover and number of people per home), resulted in 3 levels of environmental risk: low, medium and high. The area bordering the creek, and those occupied by the shanty towns Aquiles Lanza and La Cantera were defined as prone to high environmental risk.

 Proposals for territorial planning.- 1) Descentralization of the activities of maintainance of the sewage system, in order to give a quick response to urgent problems (e.g. pipe breakage). The descentralization process started by the Municipality of Montevideo more than a decade ago can be a positive input to this regard. 2) Coordination of the municipal agencies devoted to environmental services. 3) Give priority to the areas considered  of “high environmental risk”, taken into account the differences existing among them.  4) Implementation of a specific plan regarding garbage production, classification and transportation.