Degradation At the same time that the area covered by native forest is broken up into isolated non-devastated patches, the Doce River and its tributaries are heavily affected by pollution generated by waste arising from the activities of local industries, urban sewage, rampant
deforestation, mining, and excessive manipulation of its waters. Industrial and urban contamination, associated with the absence of environmental control, made the Doce River the tenth most polluted river in Brazil according to the
Social Development Index (IDS) calculated by the
Brazilian Institute of Geography and Statistics (IBGE) in 2011, therefore even before the dam collapse in Mariana in 2015. In 2014, the basin was identified as the most degraded in Minas Gerais.
In the urban context According to information from 2019, the Doce River receives the sewage discharged by at least 80% of the cities located on its banks without any type of treatment. The same percentage of municipalities in the basin also lack wastewater treatment, and pollution in the tributaries directly affects the main course. In several stretches along the entire watercourse and its tributaries, the presence of pollutants originating from sewage is sufficient to make the waters unsuitable for irrigation and for animal or human consumption, a situation that affects the population's living and health conditions and the transmission of diseases. although treatment plants had been under construction since 2014. At the same time, the riverbed was the main source of supply for the public network, but a new water intake source was being built from the
Corrente Grande River. Contamination extends as far as the Atlantic Ocean, with records of fecal coliforms in the river mouth region transported through the watercourse. Pollution of the watercourse was aggravated by the
long period of irregular rainfall that the region experienced throughout the 2010s, leading to a considerable decrease in its average level and the disappearance of springs in the basin. During this drought event, the river reached its lowest level since measurements began to be made, but, as noted earlier, average precipitation in the basin area began to decrease in the 1990s. On the other hand, occasional events of intense rainfall rapidly raise the river level and threaten populated zones that were established in risk areas.
In the socioeconomic context in the reservoir of the
Baguari Hydroelectric Power Plant, between
Periquito and Governador Valadares. in
Conselheiro Pena, in the middle Doce River. Mining activity, concentrated mainly in the basins of the Carmo and Piracicaba rivers, causes a strong silting process in both watercourses that affects the Doce River downstream. Large-scale eucalyptus plantations caused a profound change in the natural landscape, given that these are vast areas occupied by a single planted species. This reduced the region's forest
ecosystem and increased silting in view of large-scale soil manipulation. In addition, the use of
fertilizers and
pesticides is necessary to guarantee productivity, while the large quantity of water used by pulp industries depends on the basin's water sources. With regard to socioeconomic aspects, the lands occupied by eucalyptus cultivated by large industries cannot be used by local communities, disregarding regional habits and customs and human presence itself. The construction of hydroelectric plants also produced severe changes in the landscape, since the riverbed is dammed. The seat of the city of
Itueta had to be completely rebuilt elsewhere, from 1999 to 2004, for the implementation of the Aimorés Hydroelectric Power Plant on the course of the Doce River. Downstream, in turn, the level of the watercourse was abruptly reduced due to water retention. The mud burst from the mining tailings dam first reached the
Gualaxo do Norte River, then after 48 km it reached the Carmo River and 22 km downstream it flowed into the point where this river meets the Piranga River to form the Doce River. A total of 19 people died and 50 suffered injuries in the tragedy, and the nearby localities of
Bento Rodrigues and Paracatu de Baixo, downstream from the dam, in Mariana, were totally destroyed by the mudflow. At the time of the accident there was no mass alert of any kind for the communities. In addition, the tailings mud that invaded the Doce River over the following days and weeks made municipalities supplied by the watercourse unable to use its water, including Governador Valadares, which declared a state of public
disaster. The waters were contaminated by high levels of elements such as
arsenic,
manganese, lead, aluminium, and iron. while the river was already facing a water crisis due to prolonged drought. The tailings of toxic brown mudflows reached the Atlantic Ocean 17 days later, on November 22. The dam collapse caused an enormous ecological damage, and threatened life along the Doce River and the Atlantic Ocean near its mouth. In all, 1469 h of land were also affected in Minas Gerais and Espírito Santo. In January 2022, Governador Valadares recorded its
third-largest flood up to that point, surpassed only by the floods of 1979 and 1997. The impacts on the ichthyic fauna are still not fully known, but it is known that practically all fish in the upper Doce River that were affected died. One month after the tragedy at least eleven tons of fish had been collected throughout the entire watercourse. In the ocean the sediments traveled about 250 km north of the mouth of the Doce River and were recorded in the archipelago of
Abrolhos in June 2016, reaching an area with an
important set of marine ecosystems and
coral reefs. It is thus considered the
industrial disaster that caused the greatest
environmental impact in Brazilian history and the largest in the world involving tailings dams, with a discharged volume of more than 55 million cubic meters. Samarco resumed operations in Mariana in December 2020, at a time when no one had been tried for what had happened, no house had been delivered as compensation, and environmental recovery was still unfinished. Over the years the contamination caused by the accident decreased, but six years later, in 2021, metals such as iron and aluminium were present in the watercourse at levels higher than before. The estuary of the Doce River still had a manganese concentration nine times higher than normal. The impacts on the soil caused by metal intrusion also remained, limiting the reestablishment of vegetation and the
ecosystem.
Treatment and conservation on the boundaries of the
Rio Doce State Park, near Ponte Queimada. According to data relating to 2010, only 10% of the cities in the Doce River basin had some type of treatment for their urban
sewage. Among them,
Catas Altas,
Ipatinga,
Itabira,
Rio Doce, and
São José do Goiabal in Minas Gerais and
Rio Bananal and
São Gabriel da Palha in Espírito Santo were the only ones to treat 100% of the effluent. By 2022, 44 municipalities in the basin, approximately 20% of the total of 229, treated at least 30% of wastewater. Annually an average of 295 million cubic meters (m3) of sewage is collected, but only 8.3% of this amount is treated before being discharged into watercourses. At the same time, sewage collection and treatment services simultaneously covered 23.5% of the population of the drainage area. The Doce River has several water quality monitoring stations, managed by the National Water and Basic Sanitation Agency and by the Minas Gerais Water Management Institute (IGAM), with regular analyses of physicochemical and biological parameters. Monitoring was intensified after the Mariana dam accident in 2015. As a compensatory measure for the Mariana dam collapse in 2015, there was a
Termo de Ajuste de Conduta (TAC) agreed between Samarco, Vale, BHP Billiton, and the federal, Minas Gerais, and Espírito Santo governments that created the
Fundação Renova. It is a nonprofit organization whose objective is to repair the damage caused by the accident. In addition to dealing with compensation and the construction of houses for residents who lost their homes, Fundação Renova became responsible for the environmental recovery of the affected area. In this sense, the entity allocated resources to municipalities for the construction of sewage treatment plants and maintenance of sanitation systems in the Doce River basin. However, as already noted, compensation and environmental recovery have been marked by delays and low effectiveness was the subject of questions by the
Minas Gerais Public Prosecutor's Office (MPMG), which also accused the foundation of misleading advertising.
Water management located near the mouth of the
Ribeirão Ipanema in the Doce River in Ipatinga The Doce River is considered a river of national relevance because it flows through more than one state, as defined in the
Federal Constitution. The Doce River
Hydrographic Basin Committee (CBH-Doce), established under a resolution of the
National Water Resources Council (CNRH) in 2002, is the normative and deliberative body responsible for the
water resource management of the basin through mediation among actors in society. It is subordinate to the federal government and is composed of members of public authorities, companies, and civil society. Its functions include monitoring conflicts, promoting basic sanitation, preserving and restoring the basin's water resources, and charging for water use. Subordinate to the Doce River basin committee are six planning units in Minas Gerais, corresponding to the committees of the sub-basins of the Piranga, Piracicaba, Santo Antônio, Suaçuí (Pequeno and Grande), Caratinga, and Manhuaçu rivers. In Espírito Santo, there are the committees of the sub-basins of the Guandu, Santa Joana, and Santa Maria do Doce rivers, of the "Pontões e Lagoas do Rio Doce", and of "Barra Seca e Foz do Rio Doce". Among the actions of CBH-Doce are the funding and/or execution of water and sewage system works, programs for rational water use and water security, programs for living with floods, environmental education activities, and interventions to control sediment production; the improvement of rural properties with water capture and storage technologies; support for and follow-up of reforestation and environmental restoration works; and the preparation of integrated plans and studies for natural resource management.
Environmental preservation in Aimorés, an area of the basin considered a
private natural heritage reserve (RPPN). The coverage of
riparian forest along the course of the Doce River is restricted to 14.9% of its banks in Minas Gerais and 21.3% in Espírito Santo, but only 1% is preserved with native forest, The spring considered the first source of the Doce River, in Ressaquinha, is located on private property, but it was fenced by IEF-MG in 2019. However, the waters are compromised downstream by rampant mining and sewage. The estuary of the watercourse in Linhares, in turn, is monitored because it is a nesting site for
sea turtles. In the middle Doce River is located the
Instituto Terra, begun by
Lélia and
Sebastião Salgado with 700 h of degraded land reforested with native forest in Aimorés. This is the so-called Fazenda Bulcão, where the source of the Bulcão stream, a tributary of the Doce River, is located, and which was transformed into a private natural heritage reserve (RPPN). The initiative aims to extend this protection to other springs in the basin, encouraging landowners who have springs to protect them through the donation of materials to fence them off. In 2014, the NGO
The Nature Conservancy (TNC) began monitoring and providing technical advisory support for the restoration of 1500 hectares of forests in the Doce River basin, in association with the Espírito Santo Institute of Environment and Water Resources (IEMA). In 2020, the Doce River Hydrographic Basin Committee joined TNC's Water Governance Monitoring Protocol, which is a tool that evaluates and identifies management problems of the committee itself. It is also worth noting that research activities regarding the conditions of the watercourse and conservation of its waters are produced by educational institutions and universities. == Popular culture ==