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Cycle 8 (2019 Deadline)

Impacts of alluvial mining in the Madre de Dios Basin: physical effects and mitigation planning

PI: Mónica Moreno Brush (, Universidad de Ingeniería y Tecnología (original PI through February 4, 2021: Jorge D. Abad Cueva)
U.S. Partner: Eddy Langendoen, United States Department of Agriculture/ Agricultural Research Service
Project Dates: January 2020 - June 2021

Project Website:

Project Overview:
Despite many efforts in the Madre de Dios Basin to estimate the impacts of alluvial gold mining with regard to mercury concentration, deforestation, and socioeconomic implications (e.g., human trafficking, tax evasion), very few investigations have been conducted to understand the effects of extensive alluvial mining operations on the rates of sediment supply and morphodynamics of the rivers in southeastern Peru and on the spatiotemporal distribution of mercury concentrations. This is a time-sensitive project because mining activities advancing rapidly, producing drastic physical alterations to river systems, and the Peruvian National Government lacks adequate impact assessment methodologies of alluvial mining concessions, many of them already operating. Currently, basic analyses with satellite imagery feature these assessments, rather than analyses with multi-temporal and historical data to elaborate predictive models to determine principal sources and sinks of mercury across the watershed and gold deposits that indicate potential areas to be targeted for mining. The location and topography of the Madre de Dios headwaters, where alluvial gold mining occurs, create a high potential for escalating this environmental and public health problem, putting large portions of the basin at risk. There is a critical need to provide both a baseline of river morphodynamics and linkages between aquatic ecosystems and landscapes to develop not only decision-relevant indicators for environmental quality but also methods for identifying trends to determine environmental quality in the future.

This PEER-supported project will involve an integrated assessment of a coupled natural-human system in southeastern Peru where there is an urgent need to develop science-based sustainable practices and conservation of natural resources. By combining state-of-the-art techniques in field measurement, remote sensing, and mathematical modeling of riverine processes, this project will explore the interactions between flow, sediment transport, and channel change in rivers in association with the distribution of mercury along the food chain. The outcomes will provide useful insights for land managers and decision makers on river morphodynamics and function, a crucial gap in the understanding of rivers, currently a critical national priority for Peru. Local authorities and partners working in the region will be encouraged to share their knowledge about sediments in rivers in the area, as well as gaps that can be fulfilled with this research. They will also be encouraged to incorporate best practices and environmental standards in their management efforts and to include river morphodynamics as a component of natural resource management. Developing a more sustainable approach for the use and monitoring of the environment will promote and support responsible economic activity in the Amazon region through viable economic alternatives to illegal exploitation of natural resources and the development of alternative processes for extracting gold with the least possible negative impact on the surrounding ecosystems.

Summary of Recent Activities:

After very careful preparation to ensure the health and safety of team members and close coordination with their local partner CINCIA and relevant local and national authorities, the PI Dr. Abad and his colleagues successfully carried out a field campaign to their study area in the Madre de Dios region November 14 through December 6, 2020. Based on the sampling locations, expertise of the team members, and logistic arrangements, the researchers divided into three teams for the data collection and fieldwork:
  • Team 1: Madre de Dios River (stretch from Puerto Maldonado to Boca Colorado). Members: Bryan Santillan, Grecia Valdivia, and Segundo Satalaya from UTEC; Miguel Macedo from CINCIA; students from the National Amazonian University of Madre de Dios (UNAMAD), and a field assistant. Tasks: River geomorphology measurements and sediment and fish sampling.
  • Team 2: Mining area. Members: Yulissa Estrada from UTEC and Jorge Caballero and Jorge Martin Pillaca from CINCIA. Tasks: Sediment sampling and drone flights.
  • Team 3: Paleohydrology. Members: Isabel Quintana and Paula Sisniegas from UTEC and a field assistant. Tasks: Sediment coring in paleochannels.
After an initial coordination meeting in Puerto Maldonado November 16, fieldwork began in the surrounding area November 17-20 to conduct river geomorphological measurements (i.e, sedimentological, hydrodynamic, and hydrogeomorphological) in eight hydrodynamic cross-sections along the Madre de Dios River, where La Pastora harbor is located. These measurements, although not originally included in the project, were conducted for a better understanding of the sediment transport in the area and the erosion process related to the river dikes. The teams then divided up for their assigned field tasks. Team 1 sampled along the Madre de Dios River from Puerto Maldonado to Boca Ishiriwe using three boats. Two boats were used by UTEC for conducting measurements on river geomorphology (i.e. hydrodynamic, sedimentological, and geomorphological data), whereas the third boat was used by CINCIA for hydrobiological data collection (i.e. fish, macroinvertebrates, and plankton). Team 1 stayed overnight in tents. Team 2, in collaboration with the National Water Authority (ANA), sampled in Huepetuhe and Delta 1, the largest illegal gold mining areas in Peru. Field activities included surface sediment sampling in rivers for mercury analysis and drone flights for photogrammetry. The data will be used for mapping, monitoring, and modeling changes in the rivers. Team 2 reached the sampling sites by car and stayed overnight in the mining camps. Team 3 collected a total of 11 sediment cores from the oxbow lakes Palometayo and Mecenahua, important fishing locations at the Boca Colorado area. The sampling was conducted with the assistance of a local fisherman. Coring was also done at an aguajal (marshy flooded forest) impacted by illegal mining. After returning from the field, Grecia Valdivia, Yulissa Estrada, and Paula Sisniegas from UTEC spent November 30 through December 6 in Puerto Maldonado processing environmental samples.

8-235 Puerto Maldonado8-235 Site Visit 2020
Dr. Abad (at right) speaks to participants in the February 2-4 meeting with CINCIA and UTEC staff in Puerto Maldonado. (photo courtesy of Dr. Abad)PEER PI Dr. Jorge Abad (center) and colleagues welcome USAID Research Advisor Dr. Lily Sweikert and NAS Program Officer Ms. Lina Stankute-Alexander during their January 2020 visit to UTEC. (photo courtesy of Lina Stankute-Alexander)

For the field campaign, forestry students from the National Amazonian University of Madre de Dios (UNAMAD) were recruited as field assistants with the aim of providing scientific fieldwork training to local students. Also for the field campaign, the PI established a collaboration with the National Water Authority to assure safe entry to the mining operations Huepetuhe and Delta 1 for sampling. Finally, Dr. Abad also initiated a collaboration with the Environmental Geochemistry Department of the Technische Universität Braunschweig in Germany for the analysis of different mercury species in the sediment samples. The samples will first be analyzed for total mercury by CINCIA in Puerto Maldonado and then will be sent to Germany for speciation analysis. Sediment cores collected at paleochannels are expected to be processed and analyzed in a specialized laboratory in France.

On the outreach side of the project, team members made two virtual presentations at the American Geophysical Union Fall Meeting 2020 in December. Bachelor’s degree student Paula Sisniegas made an eLightning presentation entitled “Linkage between river dynamic patterns and deforestation at gold mining activities in the Madre de Dios (MdD) River, Peru.” This presentation explained the methods for paleochannel digitalization in the area between the Boca Colorado River and Puerto Maldonado in the Madre de Dios River Basin. The aim was to determine the deforestation distribution along the scroll bar, both in mining-affected and non-affected paleochannels. Master’s student Karla Paiva presented a virtual poster entitled “Modelling Runoff and Sediment Yield Delivered from Floodplain Mining Activities to the Madre de Dios River,” which showed the first results of the SWAT model simulation, specifically the increase in deforestation area and increases in turn of the amount of sediment reaching the river.

For the first half of 2021, Dr. Abad and his colleagues plan to analyze their samples and process the data collected during the field campaign of November-December 2020. The hydrodynamic and hydrogeomorphological data will be processed by UTEC, while the environmental data will be analyzed by both UTEC and CINCIA. UTEC will conduct the physical analysis of the samples in their laboratories in Lima, whereas CINCIA will be in charge of the chemical analysis at the Analytical Chemistry Lab of the Research Institute of the Peruvian Amazon (IIAP). Based on the results obtained by CINCIA, some sediment samples will be sent to the University of Toronto and the Technische Universität Braunschweig for further analysis. Once the results are available, the PEER team will organize events to disseminate their research findings among regional government agencies, local stakeholders, and the general public. Finally, they plan to have regular meetings with all project partners to discuss the research papers and other project deliverables they plan to produce. As of late January 2021, the Peruvian government is instituting new measures to control what could be the second wave of COVID-19 in Peru. Hence, the team may be forced to reschedule some of their project activities such as chemical analysis and data processing.

Previous Presentations:

On August 5, 2020, UTEC and CINCIA organized the webinar “Impactos ambientales de la minería ilegal e informal en la Cuenca del río Madre de Dios,” which was focused on the environmental impacts generated by artisanal and small-scale gold mining in the Madre de Dios region. The event was open to the public, with English-Spanish interpretation provided, and approximately 300 people were in attendance. Claudia Vega opened and moderated the event, and local keynote speakers were Luis Fernandez and Jorge Abad. Additional invited keynote speakers were Liset Rodriguez (Amazonian National University of Madre de Dios, UNAMAD), Monica Moreno-Brush (University of Freiburg), Heileen Hsu-Kim (Duke University), and Bridget Bergquist (University of Toronto). For more information, please visit the recording link:

At the V National Water Congress held at UTEC March 12-14, 2020, CINCIA and UTEC personnel presented the project in both oral lectures and scientific posters. UTEC presented the general outline of the project, preliminary measurements in the region, and future steps, which CINCIA covered data on mercury concentrations found in sediment and fishes along the Madre de Dios river, current changes in land cover (from forests into contaminated wetlands), and the loss of biodiversity. Abstracts can be downloaded from

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