Author(s): Jaime I. Ordoñez Dr. Eng. ; Luis A. Camacho Ph. D. ; Leonel Vega Ph. D. ; Gabriel Pinilla Ph. D.
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Keywords: Tropical Deltas; Environmental Management
Abstract: The Canal del Dique, in Colombia is a manmade canal that derives its flow from the Magdalena River and flows into the bay of Cartagena; it was built by the Spaniards in 1650, to connect the interior part of the country, through the River, with the bay of Cartagena without the perils of navigating the treacherous waters of the river mouth at Barranquilla, in the Caribbean Sea. Successive Canal improvements have increased the discharge to the Bay generating an abundant sediment inflow which has created a large depositional delta and also a cloudy plume which are considered detrimental to the bay, requiring control. This article presents the results of an investigation to evaluate the solutions proposed to reduce the sediment entrance to the channel. One option includes a sluice system and floodgates to reduce de average discharge in the main canal, together with numerous other hydraulic structures to control all flows within the complicated network of swamps, lakes and interconnecting channels whilst others prefer to maintain the discharge and preserve the natural functioning of the aquatic ecosystems, enhancing the interconnected nature of the water bodies and the pulses of water from the River-Canal system developed through years of human intervention. The article reviews the resulting environmental problems, and warns the project developers against difficult to run automatic systems that can run havoc in this critically productive tropical deltaic ecosystem. The Canal is located in northern Colombia, in the western part of the delta of the Magdalena River, near its mouth in the Caribbean Sea. The watershed area has some 4. 400 km2, bordering north and west with the Caribbean, and west with the Magdalena River, the largest in Colombia, with an average discharge of some 8, 000 cubic meters per second at the mouth. It is formed by lowlands, mangrove swamps and salt marshes of riparian vegetation, more than 215 km2 of water surfaces and wetlands of great ecological significance, and some 870 km2 of deltaic wetlands. The authors present the significant environmental factors in the different schemes as a result from the derivation water from the sediment laden Magdalena River, and the consequences of the different alternatives in the ecological balance of the ecosystems, in order to contest the feasibility of the proposed structural design. Despite the results of a comprehensive study of the Magdalena River-Canal del Dique Deltaic area, and the warnings concerning the idea of reducing the average discharge in the canal through the use of hydraulic structures of Complex operation, the Colombian government has gone ahead with the study of a massive structural solution for the Canal zone that involves as a basic principle the reduction of discharge, (“Control Activo de Descarga”) . Due to this actions, which are seen as dangerous to the environment, the authors of that study, scientists and University professors present the characteristics of the System and the risks to the environment of the proposed actions, as well as a set of more sustainable and environmentally minded schemes of much smaller cost and more assured results, to manage the sedimentation problem while maintaining the natural Environmental Quality of the ecosystems without the risks of a controlled super project, where somebody must at every step decide what part of it to conserve and what part of this extraordinary natural and touristic resource of the Caribbean Coast of Colombia, to destroy or to put at risk.
Year: 2015