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Cycle 8 (2019 Deadline)

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

PI: Jorge D. Abad Cueva (, Universidad de Ingeniería y Tecnología
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:

During the second quarter of 2020, the PI Dr. Abad, his team members, and their U.S. partner Dr. Eddy Langendoen of the USDA Agricultural Research Service have been holding biweekly virtual meetings to continue their collaborative efforts despite the ongoing pandemic conditions. The Peruvian researchers had already collected sediment samples in the Madre de Dios basin before the pandemic struck in mid-March, but at the time of their most recent report in late July they were still awaiting shipment of the samples to Lima to be tested in their institution. Meanwhile, Dr. Abad and his group have been applying the SWAT model to determine the impacts of land cover changes (deforestation) and precipitation on streamflow and sediment transport in the Madre de Dios basin. They are also working with their partner organization CINCIA to use remote sensing and satellite data to characterize changes in river bed positions over time. They have found some correlations that could help indicate where illegal mining and deforestation might be more likely to occur. The team has also worked on a database covering illegal mining in Madre de Dios and its environmental impacts.

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)

On August 5, the PEER team held an online webinar entitled “Impactos ambientales de la minería ilegal e informal en la cuenca del río Madre de Dios” [Environmental impacts of illegal and informal mining in the Madre de Dios basin]. The target audience included technicians, faculty, and students, and the event was co-organized with CINCIA, USDA, and UNAMAD (the National Amazon University of Madre de Dios). Besides several Peruvian researchers, the program also included speakers from Duke University and the University of Toronto. Plans for August called for a meeting with stakeholders in Madre de Dios, as well as fieldwork to collect more water and sediment samples in the region. However, the Peruvian government has extended the state of emergency covering the region until October, which prevents the PEER team from traveling there. A no-cost extension has been issued on the project through June 30, 2021, to allow the PI and his colleagues to complete the following key activities:
  • Field campaign: Measurements of river hydrodynamics and bathymetry; photogrammetry; sampling of sediments and macroinvertebrates
  • Laboratory analysis: Mercury content in sediments and macroinvertebrates; sediment grain and size characterization
  • Model calibration: Calibration of inputs (e.g., Digital Elevation Model, bathymetry, land cover) and outputs (e.g., sediment transport fluxes and fate)
Their local project web page is at and the Events tab on the page ( features the August 5 webinar flyer and a YouTube link where the event video is posted.


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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