Canal Del Dique Research Articles

La modelación hidrodinámica para la gestión hídrica del embalse del Guájaro, Colombia

The Guájaro Reservoir in northern Colombia is a hydrosystem that is supplied by an artificial channel (Canal del Dique) through a system of floodgates. During the last decades, has been presenting problems of excessive use, which is why, it is necessary to regulate the hydraulic structures that serve this water body, as they play an important role in managing the levels that in turn affect the water supply. The present work is carried out as a sustainability management alternative of the reservoir. A two-dimensional hydrodynamic model (EFDC Explorer) and its calibration is implemented using time series of the free surface levels, and comparing the measured velocities and those estimated by the model for two different climatic periods, to assist the operation of the Hydrosystem Canal del Dique-Guájaro Reservoir sustainability. The corresponding comparisons showed a good behavior between measured and simulated data, based on the quantitative results of Nash-Sutcliffe reliability method. It is considered that the results are quite satisfactory and allows the estimation of conditions for restoration, its use, as well as the incoming and outgoing water through hydrosystem channel-reservoir.

POLVO DE LA SEMILLA Cassia fistula COMO COAGULANTE NATURAL EN EL TRATAMIENTO DE AGUA CRUDA

Natural plant extracts have been used for water purification for many centuries. Most of these was derived from seeds, leaves, bark or sap, roots and fruits of trees and plants. In this paper, using seed powder of Cassia fistula as natural coagulant, establishing their optimal dose through “jar tests” and determining the parameters of color, turbidity, total alkalinity and total hardness, using water from the “Canal del Dique”. The optimal effective dose of coagulant is found between 15-25 mg/L, obtaining final values of turbidity and color of 6 NTU and 25 UC respectively. The pH values no major variations, as total alkalinity. The values of the parameters turbidity and color are located near the standards set by the Colombian standard to ensure the quality of water for human consumption, as well as the pH, total alkalinity and total hardness, demonstrating the potential use of this coagulant primary natural coagulant in water treatment.

Bacterias autótrofas y heterótrofas asociadas a nieve marina lodosa en arrecifes con escorrentía continental

The density of heterotrophic bacteria is greater than autotrophic in marine snow aggregates influenced by continental runoff. Four coral reef areas at different distances from the Canal del Dique served to evaluate this premise; this canal is the main source of inland resources for the coral reefs of the Nuestra Señora del Rosario archipelago in Cartagena in the Colombian Caribbean. The average density of microorganisms in marine snow aggregates was determined using epifluorescence. The results showed higher density of heterotrophic bacteria (3.63 x 104 ± 1.6 x 104 SE cells mL-1) than autotrophic (6 x 103± 1.3 x 103 SE cells mL-1), mainly in reefs near continental runoff discharges (heterotrophic bacteria density of 8.9 x 104 cells mL-1 and 3 x 104 cells mL-1 Isla Arena and Tesoro, respectively). The density of microorganisms found is typical of high-particulate organic matter areas and, therefore, could be a potential indicator of continental runoff. Future studies should focus on determining the composition of the bacterial community associated with marine snow and its potential virulence on reef organisms.

Freshwater discharge into the Caribbean Sea from the rivers of Northwestern South America (Colombia): Magnitude, variability and recent changes

The monthly averaged freshwater discharge data from ten rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analysed to quantify the magnitudes, to estimate long-term trends, and to evaluate the variability of discharge patterns. These rivers deliver ∼340.9 km3 yr−1 of freshwater to the Caribbean Sea. The largest freshwater supply is provided by the Magdalena River, with a mean discharge of 205.1 km3 yr−1 at Calamar, which is 26% of the total fluvial discharge into this basin. From 2000 to 2010, the annual streamflow of these rivers increased as high as 65%, and upward trends in statistical significance were found for the Mulatos, Canal del Dique, Magdalena, and Fundación Rivers. The concurrence of major oscillation processes and the maximum power of the 3–7 year band fluctuation defined a period of intense hydrological activity from approximately 1998–2002. The wavelet spectrum highlighted a change in the variability patterns of fluvial systems between 2000 and 2010 characterised by a shift towards a quasi-decadal process (8–12 years) domain. The Intertropical Convergence Zone (ITCZ), El Niño – Southern Oscillation (ENSO) events, and quasi-decadal climate processes are the main factors controlling the fluvial discharge variability of these fluvial systems.

Towards a systemic assessment of environmental impact (SAEI) regarding alternative hydrosedimentological management practice in the Canal del Dique, Colombia

The Canal del Dique, located on the Colombian Caribbean Coast, can be seen as an "artificial" branch of the River Magdalena. Since its inception in 1650, it has undergone a series of interventions aimed at optimising river navigation between Cartagena and the interior of the country, little consideration having been paid to institutional, economic, social and environmental impacts. This paper presents a systemic assessment of environmental impact (SAEI) methodology, based on systemic parameterisation of the environment, proposed by Vega [2011], for the strategic environmental assessment of policy, plans, programmes or large-scale projects, considering a case study of the Canal del Dique environmental rehabilitation as proposed by the Colombian government. Information arising from the framework of an inter-administrative agreement between the Universidad Nacional de Colombia and the Regional Autonomous Corporation for the Rio Grande de la Magdalena (CORMAGDALENA) was used for studying the environmental restoration of and navigation in the Canal del Dique [UN-LEH, 2008]. The authors developed and summarised SAEI regarding six alternatives for hydrosedimentological management in the canal to obtain results concerning environmental impairment or improvement regarding each factor considered, and the degree of aggressiveness or betterment involved in each alternative. Alternative 4, an enhanced version of current condition (ECC) would have produced the greatest environmental benefit (i.e. limited dredging plus optimising channel-wetland interconnection) requiring the narrowing of three straight reaches along the canal and the construction of a sluice-gate system in the Strait of Paracuica (near the town of El Recreo).

ESTIMATING FLUVIAL DISCHARGE IN THE CARIBBEAN SEABOARD OF COLOMBIA: MAGNITUDE, VARIABILITY AND EXTREME EVENTS

Monthly freshwater discharge data of ten rivers draining into the Caribbean Sea in the northern of Colombia (Caribbean alluvial plain) are analyzed. The data are used to quantify the magnitude, to estimate long-term trends, and to evaluate variability patterns of freshwater discharges into the ocean. These Colombian rivers contribute with ~340.9 km3 yr-1 of freshwater into the Caribbean Sea. The Magdalena River delivers the largest discharge, with a mean discharge at Calamar of 205.5 km3 yr-1 which represents 26% of the total fluvial discharge into this basin. From 2000 to 2010 the annual streamflow of these rivers rose up three fold. However, only the Mulatos, Canal del Dique, Magdalena, and Fundación Rivers have significant statistical upward trends. The concurrence of the major oscillation processes and the maximum power of the 3-7 year fluctuation defined a period of intense hydrological activity around 1998-2002. Wavelet spectrum analysis indicated a change in the variability patterns of fluvial systems between 2000 and 2010, characterized by a shift toward a domain of quasi-decadal processes (8-12 years). The Intertropical Convergence Zone (ITCZ), ENSO events, and quasi-decadal climate processes (e.g. sea surface temperatures over tropical North Atlantic, Pacific Decadal Oscillation) are the main factors controlling fluvial discharge variability of these fluvial systems.

Gestión del riesgo de inundaciones en Colombia

The last rainy season 2010-2011 resulted in Colombia in around 500 casualties and more than 3.6 million of victims. Although this rainfall term accounted for one of the strongest it was not an unprecedented event since for more than fifty years this phenomenon has been taking place in the same Colombian regions producing casualties and victims. This fact makes us to think about the public management by authorities regarding flooding prevention in our country. This article elaborates on this topic explaining the risk management system in case of flooding in Colombia. It shows some national figures of the main ravages brought about by the 2010 2011 rainy seasons. Finally the article analyzes two cases of study of how operational is this public policy in risk management: La Mojana and Canal del Dique regions. It was evident that the state failed in managing the risk management from flooding because despite the important investment, every year the victims, casualties and material damages are increasing steadily.

Geometría de los depósitos cuaternarios y actuales de la Bahía de Cartagena de Indias, Colombia

The description of the stratification found in the different parts of Cartagena de Indias Bay is presented by the analysis of thirteen sub-bottom transects made with a Stratabox 10 kHz sub-bottom profiler. There were zones with very hard superficial sediments that aloud little penetration in the external area off Bocagrande with layers of 10-12m of softer mud deposited over harder bases. Some deep structures are old coral reefs. Other transects present strata with steep slopes of semi-hard sediments implying old deposits handled by coastal dynamics different from the present. The southern sections show the sedimentary prism forms at the mouth of Canal del Dique in several directions.Topographic anomalies of the shelf seem to be inherited from a former coast line, controlled by structures in NNW direction that define the axes of the current bays, and for a megastructure possibly associated with Oca and Santa Marta fault systems, with an important role in the raising and evolution of the SNSM and the associate basins.

Análisis de la evolución del fondo marino y cambios en la línea de costa, en el área de influencia de la desembocadura del Canal del Dique

The sedimentary inputs from the Canal del Dique has been causing large amount of morphological changes, both in the coastline and the adjacent seabed to the mouth. By analyzing bathymetry and shorelines from several years, using geographyc information system tools, was possible to determine the erosion-sedimentation rates at the mouth, resulting in a clear sedimentation and growth of the mouth in a 4.17 m/year rate, over a period of 48 years, similarly it was found that the seabed has a strong tendency to sedimentation in the area immediately adjacent to the mouth of the channel.

Morphodynamics of the Pacific and Caribbean deltas of Colombia, South America

This paper analyzes the physical factors controlling the recent morphology of major deltas along the Pacific and Caribbean coasts of Colombia. The study considers the fluvial, coastal, and oceanographic contributions to changes in delta morphology and uses different approaches, including (1) remote sensing techniques; (2) time series analysis of river discharge, sea level, wave climate and tidal variability; (3) analysis of the relationship between monthly mean sea level anomalies near the deltas related to the El Niño Southern Oscillation (ENSO); (4) development of a database of key physical variables; (5) series of correlation calculations to examine which environmental factors control delta morphology; (6) analysis of shoreline changes for the 1986–2000 yr-period; and (7) classification of each delta system based on the relationship between water and sediment discharges and wave and tidal energies. Overall, Colombian deltas are built under destructive physical conditions. The Pacific deltas, San Juan, Mira, and Patía, are tide-influenced deltas although they exhibit definite characteristics of wave-dominated systems such as the presence of barriers and beach ridges. Also, these deltas exhibit the highest marine energy conditions of all Colombian deltas (marine power values between 9.1 and 11.6) due to the interplay of (1) moderate wave conditions as a result of the effect of swells from the SW with a significant height varying from 1.7 in the San Juan delta to 3.0 m and 3.1 m in the Mira and Patía deltas, respectively; (2) meso-tidal ranges; (3) steep subaqueous profiles; (4) low attenuation indexes of deep-water waves; and (5) strong oceanographic manifestations associated with the ENSO, causing regional sea level rises of 20–44 cm during El Niño events. The Caribbean deltas, Magdalena, Sinú and to a lesser extent, the Atrato, are wave-influenced deltas. The Magdalena, with deep and nearshore wave power values of 45 × 10 6 erg s −1 and 35 × 10 6 erg s −1, respectively, and the lowest attenuation index of deep-water waves, is the most wave-influenced delta of Colombia. Statistical relationships show that the area of Colombian deltas is best predicted from average discharge and bank-full width of river entering the delta. The number of distributary channels is explained by the marine power index and the gradient of the delta plain. The average and total width of distributary channels are largely controlled by the tidal range. Further analysis of shoreline changes indicate that the retreating behavior of the western part of the Magdalena delta has been due to anthropogenic causes, including the construction of jetties in 1936. By contrast, processes of rapid erosion in the San Juan delta have been the result of 2.6 mm yr −1 long-term relative sea level rise due to tectonic induced subsidence coupled with a eustatic rise of sea level. Overall, the other deltas are experiencing prograding phases with rates of accretion of 100 m yr −1 in the artificial delta of the Canal del Dique.

Fluvial fluxes into the Caribbean Sea and their impact on coastal ecosystems: The Magdalena River, Colombia

The Magdalena, a world-class river, in the top ten in terms of sediment load ∼ 150 MT/yr, is the largest river discharging directly into the Caribbean Sea. Data on water discharge, sediment load, and dissolved load of the Magdalena River is presented as an initial interpretation of coastal ecosystems changes in relation to water discharge and sediment load from the Magdalena. During the 1972–1998 yr-period, the Magdalena River has delivered approximately 4022 MT of sediment to the Caribbean coast. The river reflects high inter-annual variability and delivers large portions of its fluvial discharge and sediment loads in short periods of time. The analysis of annual deviations from the 27-yr mean sediment load indicates that 59% of the total sediment load variability of the Magdalena at Calamar could be attributed to flashy peak events. Further analyses of sediment load anomalies suggest that there was a high discharge period in the Magdalena River between 1985 and 1995 and another one in the Canal del Dique between 1985 and 1992. These increasing trends in sediment load coincide with the overall decline of live coral cover around the Rosario Islands, a 145 km 2 coral reef complex in the Caribbean Sea that constitutes a marine protected area. The comparison of live coral: algae ratios for the 1983–2004 yr-period, also indicates that there has been an associated increase in the percentage of algae cover (i.e., Grande Island 1983 = 5%, 2004 = 59%). Other analyses show that nearly 850 ha of seagrass existing in the Cartagena Bay in the 1930s, only 76 ha remained in 2001, which is less than 8% of the original cover. There has been a mix of multiple stressors (natural and anthropogenic; local, regional and global; temporal and chronic) affecting the coastal ecosystems in the area, but the effect of the Magdalena River runoff has been constant and very prolonged (several decades). The impacts of heavy sediment loads and freshwater discharges from the Canal del Dique to Cartagena Bay have greatly contributed to the partial disappearance of coral formations and also to a considerable reduction in abundance of seagrass beds in the bay and neighboring areas.

Patrones de la pluma turbia del canal del Dique en la bahía de Cartagena

The dispersion patterns of the turbid plume of Canal del Dique in Cartagena Bay are described through the analysis of 69 SPOT images and the results of the numerical modeling designed to detect the principal mechanisms for the formation of the turbid plume patterns from the Dique channel at the Cartagena Bay. Six different patterns of the plume were detected based on homologous selection. The implemented hydrodynamic model simulated the turbid plume and identified the hydro-meteorological conditions for each pattern.

Hydrocarbon contamination in Cartagena Bay, Colombia

This study deals with the levels of aromatic and aliphatic hydrocarbon quantification in sediments and organisms in Cartagena Bay (Colombia), 1996–1997. Sediments (14 stations) and bivalves (2 stations) were monitored at different times of the year. Areas with high values were in the north with concentrations above 100 μg/g with a maximum of 1415 μg/g. Areas with low values were located toward the south, near the outlet of the Canal del Dique and Barú Island, with values below 10 μg/g. In other areas concentrations were between 50 and 100 μg/g. A decrease in sediment concentrations of hydrocarbons has occurred since 1983, but levels in some sectors are still similar to those in polluted areas. Organisms have relatively low values (8–30 μg/g for bivalves, and 10–40 μg/g for fish).

Sedimentos en suspensión e Hidrodinámica al sureste del delta del Río Magdalena, Mar Caribe (Colombia)

The imagery obtained by SPOT HRV (High Resolution Visible) over Colombian Caribbean Coast covers the area between the Río Magdalena Delta (Barranquilla), and the Canal del Dique, located south of Cartagena. Suspended load fo Río Magdalena is studied, this river supplies most of the suspension to the Caribbean sea and strongly influences the neighbouring sea dynamics. A global view of the distribution of the suspended load and the related hydrodynamics obtained from image analysis is proposed. The turbid plume of the Río Magdalena depends upon two dynamical factors, with contrary effects: 1) the North East Trade Winds tend to curve the outer part of the plume towards the coast whereupon, 2) the Darien counter-current divides it into two branches, the one following the coast - almost as far as the delta – flows into the littoral drift waters.

Nota sobre la turbidez, circulación y erosión en la región de Cartagena (Colombia)

A photographic mosaic of a window from a image take by HVR-1 of the SPOT satellite over the Cartagena region on the 27/03/1986 is analized with a special treatment in order to observe suspended surface sediments (turbidity). The specular reflection permitted the observation of different wave patterns; the turbidity density authorised establish the influence and circulation of the Canal del Dique waters within the Cartagena Bay. Also served to detect severe erosion sectors as follows: The coast of Island and the western beaches of Manzanillo Island. Low turbidities in Ensenada de Codego suggests a natural morphological protection for the fresh waters of this inlet and probable local upwelling southeast of Tierra Bomba Island.

Platinum conditions

This paper analyzes the physical factors controlling the recent morphology of major deltas along the Pacific and Caribbean coasts of Colombia. The study considers the fluvial, coastal, and oceanographic contributions to changes in delta morphology and uses different approaches, including (1) remote sensing techniques; (2) time series analysis of river discharge, sea level, wave climate and tidal variability; (3) analysis of the relationship between monthly mean sea level anomalies near the deltas related to the El Niño Southern Oscillation (ENSO); (4) development of a database of key physical variables; (5) series of correlation calculations to examine which environmental factors control delta morphology; (6) analysis of shoreline changes for the 1986–2000 yr-period; and (7) classification of each delta system based on the relationship between water and sediment discharges and wave and tidal energies. Overall, Colombian deltas are built under destructive physical conditions. The Pacific deltas, San Juan, Mira, and Patía, are tide-influenced deltas although they exhibit definite characteristics of wave-dominated systems such as the presence of barriers and beach ridges. Also, these deltas exhibit the highest marine energy conditions of all Colombian deltas (marine power values between 9.1 and 11.6) due to the interplay of (1) moderate wave conditions as a result of the effect of swells from the SW with a significant height varying from 1.7 in the San Juan delta to 3.0 m and 3.1 m in the Mira and Patía deltas, respectively; (2) meso-tidal ranges; (3) steep subaqueous profiles; (4) low attenuation indexes of deep-water waves; and (5) strong oceanographic manifestations associated with the ENSO, causing regional sea level rises of 20–44 cm during El Niño events. The Caribbean deltas, Magdalena, Sinú and to a lesser extent, the Atrato, are wave-influenced deltas. The Magdalena, with deep and nearshore wave power values of 45 × 106 erg s−1 and 35 × 106 erg s−1, respectively, and the lowest attenuation index of deep-water waves, is the most wave-influenced delta of Colombia. Statistical relationships show that the area of Colombian deltas is best predicted from average discharge and bank-full width of river entering the delta. The number of distributary channels is explained by the marine power index and the gradient of the delta plain. The average and total width of distributary channels are largely controlled by the tidal range. Further analysis of shoreline changes indicate that the retreating behavior of the western part of the Magdalena delta has been due to anthropogenic causes, including the construction of jetties in 1936. By contrast, processes of rapid erosion in the San Juan delta have been the result of 2.6 mm yr−1 long-term relative sea level rise due to tectonic induced subsidence coupled with a eustatic rise of sea level. Overall, the other deltas are experiencing prograding phases with rates of accretion of 100 m yr−1 in the artificial delta of the Canal del Dique.