Integrated Management of Surface and Underground Water in an Urban Environment - Aburrá Medellín River Basin

The hydrographic basin of the Aburrá-Medellín River is located on the Central Mountain Range of the Andes of Colombia; it has an extension of 1,152 km². In it, inhabits more than 4 million people. Physically the territory is characterized by the presence of steep slopes, deep and narrow water channels, high flow velocity, great transport capacity and high erosive power upon its margins. In addition, anthropogenic activities associated with urban growth and expansion generate high pressure on natural resources in this territory, especially on surface and underground water.

The main problems that generate an impact on the water resource are: inadequate use of the soil, exploitation of materials in stream beds and slopes, degradation of soils by erosive processes, sedimentation processes, inadequate disposal of solid waste and human settlements in high risk areas, deforestation of headwaters and springs, discharges of untreated wastewater treatment, unplanned use of underground waters and lack of protection of recharge zones. These circumstances highlight the existence of a poor local water culture. More than 80% of the water supply for the population is taken from external basins.

It has been fifteen years, since the environmental authorities of the region began a monitoring program for shallow water resources on the river and its main tributaries. In 2010, the operation of a hydrogeological monitoring network was put in place. In addition to these monitoring networks, there is an Early Warning System that provides ‘real time’ information about the main hydroclimatic variables in the Aburrá Valley. The regular operation of these networks generates the information that serves as an input to execute programs of geostatistical analysis and numerical modeling that allow maintaining an up-to-date diagnosis of water resources and take effective management measures that guarantee the sustainability of ecosystem functions in this fundamentally urban environment.

Today, The Aburrá Medellín river basin has enough information from which environmentally strategic areas have been identified and water resources management tools have been formulated: The Water Resources Management Plan-PORH and the Environmental Management Plan of the Aquifer.

Keywords: Hydrologic models, surface water – groundwater interaction, Hydrologic Information, environmental management.