Contact Us  |  Search  
The National Academies of Sciences, Engineering and Medicine
Partnerships for Enhanced Engagement in Research
Development, Security, and Cooperation
Policy and Global Affairs
Home About Us For Applicants For Grant Recipients Funded Projects Email Updates
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
U.S. Partner: Eddy Langendoen, United States Department of Agriculture/ Agricultural Research Service
Project Dates: January 2020 - June 2022

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.

8-235 Mining Area8-235 River Sampling
The mining site in the study area.A member of the research team collects sediment samples on the river (photo courtesy of Martin Pillaca).

Summary of Recent Activities:

Following are updates on the various work packages (WP) being carried out by the team under the direction of Dr. Monica Moreno Brush during the fourth quarter of 2021:

Mercury Pollution: Selected sediment samples were sent to the University of Toronto for mercury isotope analysis. Two research briefs showing the preliminary results of mercury levels in fish and the riverine transport of mercury are under preparation.

Sediment Transport Modelling: The hydrodynamic model is being developed in TELEMAC 2D including the built-in sediment transport capabilities for bed load and suspended load. The model is being used to characterize sediment transport in the study area of the confluence of the Colorado and Madre de Dios Rivers and is being run for time scales of up to a year. The model is currently being revised and adjusted according to the obtained results in order to improve the accuracy of the results.

Remote Sensing
: The maps of erosion-deposition, migration, sinuosity, and average channel width of the Madre de Dios River were generated for the period 1984-2020 and will be uploaded in the project GoogleSite. The research results of the quantitative analysis of morphometric parameters of the Madre de Dios River to characterize its spatio-temporal variability following alluvial gold mining activities were presented at the VIII CLS-Latin American Congress of Sedimentology. The morphometric parameters of the confluence of the Madre de Dios and Colorado rivers were also analyzed for the years 1984, 2001, 2007, 2011, 2013, 2017 and 2021.

Hydrogeomorphology: The bedforms and bedload transport of the Madre de Dios River were analyzed to assess the impact of alluvial gold mining activities in the river bedform. The research results were presented as oral presentations at the XII Regional Congress of Civil Engineering Students and the VIII CLS Latin American Congress of Sedimentology. A first draft of a scientific manuscript is under preparation.

Hydrobiology: The team is reviewing the final version of the research brief with the results of the work package.

Communications: Team members restructured and updated the project's Google Site, planned the agenda and data presentations for the project’s closing event, and prepared and published the executive summary of the online event on Sediment Management in Amazonian Rivers, which was held July 15-16, 2021. The document was published by mailing and on social networks to target audiences in December 2021. The executive summary was also published on the website of the National Service of Meteorology and Hydrology of Peru (SENAMHI), demonstrating the credibility of the research team and their work.

Due to staffing cuts at CITA-UTEC and the complexity of the logistics arrangements required in order to sample during the rainy season, the Hydrogeomorphology team had to reschedule their field campaign for early 2022 and modify their measurement plan. The new field campaign program includes a detailed mapping and characterization of the gravel layer along the Madre de Dios river. Given logistical difficulties for transporting large volumes of sample material, the team will use a photogrammetry technique. The Mercury Pollution team expects to receive the mercury isotope data from the University of Toronto early this year so they can begin drafting a journal article and prepare other research briefs. The Transport Modelling group will meet with senior researchers to discuss the model in early 2022 and prepare a research brief on the topic of hydrologic modeling with SWAT (Soil and Water Assessment Tool). The Remote Sensing team has changed its plan to write a Manual on Planimetric Characterization of Amazonian Rivers, given that CITA-UTEC issued a similar manual in November 2021 with funding from the Moore Foundation. Instead of a manual, the PEER researchers will prepare a technical report to present the applied methodology and obtained research results. Both the guide produced by CITA-UTEC and the report will be socialized with the stakeholders. The results generated, as well as the videos recorded with the drones during the field trip carried out in November 2020, will be uploaded to the open data map developed by CITA-UTEC (

In other plans for the first half of 2022, the Hydrobiology team will prepare a research brief for publication by CINCIA. The research brief, together with the research results of the work package will be presented in the closing event of the project. Meanwhile, the Communications team will be very busy updating the project’s Google Site, finishing and disseminating the final project fact-sheet and other written products, and organizing in-person and hybrid events to make the conclusion of the project. They will stakeholders from the Tambopata National Reserve Management Office (SERNANP) and the National Water Authority in Madre de Dios (AAA-MDD) to participate in a workshop or meeting to teach them the techniques and work protocols necessary to monitor the river's geomorphological parameters. Together with CINCIA, the PEER researchers will also organize a face-to-face event to meet with girls and adolescents from Puerto Maldonado participating in CINCIA´s program Women in Science. Female team members will share their professional experiences to encourage the girls to pursue STEM careers. At the project’s closing event in April, staff from each work package will present their research findings and recommendations. Representatives of other research projects from academia, civil society, and national government institutions addressing the problem of artisanal and small-scale gold mining in Madre de Dios will also be invited to present their research. 

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

Back to PEER Cycle 8 Grant Recipients