Cycle 4 (2015 Deadline)
Satellite-based estimations of river discharge into the Cartagena Bay, Caribbean Colombia: Capacity building to mitigate sources of upstream runoff and associated risks of pollution
PI: Juan D. Restrepo (firstname.lastname@example.org), Universidad EAFIT
U.S. Partner: Robert Brakenridge, University of Colorado
Project Dates: October 2015 - April 2020
|Dr. Restrepo (center) during the poster session at AGU Fall 2016 with U.S. partners Albert Kettner (left), Associate Director of the Darmouth Flood Observatory-UC and Professor James Syvitski, Director of the CSDMS at University of Colorado|
The city of Cartagena and its bay, a UNESCO World Heritage Site, have a limited capacity for water resource management, as evident in the degradation of coastal water quality. The greatest source of pollution to the bay and the adjacent Rosario Islands National Marine Park is the Dique Canal, which drains 7% of the country’s largest river, the Magdalena. During the last six decades, coastal fisheries and ecosystems (sea grasses and coral reefs, for example) have almost disappeared, and Cartagena Bay is considered one of the Caribbean Region´s “hot spots” of pollution due to human-induced stressors impacting water quality and ecosystems services. Colombia and its national public environmental institutions have not previously used near real-time satellite observing systems, but this PEER project is aimed at generating near real-time satellite river data for the region by deriving time series of streamflow and flooding extent data. The main goals include (1) estimating river discharge from the Dique Canal-Magdalena River system into Cartagena Bay by applying satellite-derived measurements; (2) relating the constructed river flow series since 1998 to identify climate variability and human impacts for the Magdalena River basin; (3) making satellite-based data available as GIS files so they can be incorporated into end-user decision-support systems; and (4) developing capacity building for implementing satellite-based river freshwater estimations in environmental decision making in Cartagena Bay.
Findings on Cartagena Bay’s pollution and its current inadequacy for recreational use and fish consumption are widely known within the scientific community. In addition, lack of reliable data on freshwater discharge flowing into the bay has limited detailed modeling and applied science on how river fluxes impact physical and chemical characteristics of coastal waters. The ambiguity of the problem means that mitigation strategies are lacking. This PEER project team aims to have a significant impact by generating a clearer and more precise foundation of knowledge on continental runoff fluxes and related marine pollution problems, which could thus inform the development of adaptive strategies at both the community and political level. The planned collaboration between the Dartmouth Flood Observatory at the University of Colorado and EAFIT University-Colombia, the latter with its current project in the region, BASIC-Cartagena (Basin Sea Interaction with Communities), will serve as a joint effort in strengthening the capacity of regional stakeholders to integrate geospatial and satellite products into development and decision making, with the final goal of improving environmental management for Cartagena Bay.
Scientific conclusions at the onset of the fourth year of the project are as follows:
(1) For Andean rivers of Colombia, characterized high rainfall rates, steep relief and limited alluvial plains, microwave satellite radiometry is a robust tool for estimating near-real-time water discharge. In this study, stream flow series during the 1998-2017 were obtained at 14 sites along the Magdalena River and its main tributary, the Cauca.
(2) Observed series of river discharge at the upper basin stations exhibited low seasonality and smaller variations in the satellite signal. In the middle and lower reaches of the Magdalena River, the accuracy of the satellite results is improved at longer time scales. Floods were well recognized by the observed series of river discharge, especially during La Niña event in 2010-2011, the strongest flooding event on record in Colombia. Six out of 14 studied stations witnessed high peak discharges during this period, with stream flow magnitudes being more accurate than the water discharge values gauged at ground-based stations.
(3) The analysis of river-floodplain connectivity, allowed the team to present the following conclusions:
• Once states of flood-connection are identified, turbid waters and disconnection, by analyzing daily MODIS images + water level, we obtained water level thresholds at different connectivity stages.
• After analyzing frequency plots or histograms of water level and DFO water discharge (Q), once the identified thresholds of water level and DFO Q were coupled, we estimated the %s of connectivity time.
• Looking at the statistics, the %s of connectivity time identified by water level and DFO Q are in agreement, in other words, are of the same magnitude! This fact means, that after taking some cautions, DFO can be used to monitor stages of connectivity in different geomorphologic patterns of the Magdalena floodplain, one a braided channel floodplain (Barbacoas lagoon) and the other an anastomosing avulsive floodplain (Momposina depression).
(4) This study is an innovative applied research generating near-real-time satellite river data for the region by deriving time series of stream flow and flooding data back to 1998.
During April -June 2019 reporting period the team convened a workshop on designing the course RIVERS OF THE AMERICAS IN THE ANTHROPOCENE. Between May 31st and June 7th 2019, the team conducted a short working session in Manaus, Brazil. Four scientists, including our PEER from DFO-UC (Dr. Albert Kettner), the partners from the LA River network, including professor Naziano Filizola (Federal University of Manaos, Brazil) and professor Andrew Wilcox (The River Center, University of Montana), and PI Juan Restrepo, met at the University of Manaos, Brazil, to develop the course syllabus and structure and present this international course on American Rivers to the graduate programs of the four universities. During the PEER project supplemental activity which included the international meeting held in EAFIT in March 2018, the participants came up with an idea of developing river science short courses by using the expertise of LA scientists in different rivers in America. This idea is in agreement with the NSF program called International Research Experiences for Students (IRES), which includes a program for creating “Advanced Studies Institutes”, internationally, including short courses ranging in length from 7-21 days), that “engage advanced graduate students in active learning and research at the frontiers of knowledge.” During the last phase of the project, the team focused on developing an understanding of floodplain connectivity in the Magdalena River. Since the team have already covered project goals, during the remaining time of 2019 the team has been focusing on writing and submitting paper publications.
While all major outcomes have been already achieved, the challenge remains to increase the exposure of science towards river planning and decision-making, as one of the main goals of this PEER project is to bring satellite data to river planning authorities, decision makers, stakeholders, and scientists.
Plans for 2020:
(1) Continue the reviewing and publication process with Journal of Hydrology;
(2) PEER project results will be presented to the main environmental and hydrological authority of Colombia, IDEAM, Bogotá. This presentation will be focused on giving to IDEAM the whole platform of satellite stations developed along the Magdalena River to estimate water discharge and floods on near-real time.
(3) PEER team will give a presentation at AGU Ocean Sciences meeting 2020 in San Diego California during February 16-21, 2020. The presentation will show the main results of the projects including how the team have used the DFO platform to obtain time series of water discharge from the Magdalena River into the Cartagena Bay.
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