At the same time, the availability of forests for timber extraction and water supply from the river encouraged the installation of metallurgy companies in João Monlevade and the current Steel Valley, driving demographic and economic growth.

On the other hand, the riverbed suffers severely from siltation, deforestation, the proliferation of eucalyptus monoculture, low coverage by riparian forests and the receipt of untreated urban effluents, making it one of the most degraded tributaries of the Doce River.

[8] Mining was Brazil's main economic activity in the 18th century, but its rise led to the first environmental impacts on the rivers in the affected areas, including the Piracicaba.

[9][10] The Rio Doce Valley used to be on a route for the precious stones mined in the central region of Minas Gerais, linking the Royal Road in Diamantina to the coast of Espírito Santo for export.

As a result, the royal crown banned settlement and new roads in the region in order to prevent the gold from being smuggled down the Doce River and its tributaries, such as the Piracicaba.

Despite the decline in gold availability,[11][12] the mineral diversity fuelled the maintenance of mining activity in the Ouro Preto region, including in the Piracicaba riverbed, over the following centuries.

The natives, in turn, faced military punishments, such as the expedition of Luís Diogo Lobo da Silva in the 1760s, then governor of the Captaincy of Minas Gerais [pt].

The railway started in Vitória, Espírito Santo, and its initial objective was to reach Diamantina, but in order to transport iron ore the focus was shifted to Itabira when work was already underway.

[4]: 46–53  This process was aggravated from the 1930s onwards, when large areas of native Atlantic Forest in the basin were deforested for the extraction of timber and the production of charcoal to supply the Belgo-Mineira industrial complex in João Monlevade.

[17] Throughout the second half of the 20th century, the urban centres of João Monlevade and the Steel Valley kept growing due to industrialisation, as well as the expansion of eucalyptus monoculture to meet the needs of the power plants.

[4]: 46–53 [13]: 45 [18] Consequently, the dumping of urban and industrial effluents into the waters was intensified, a situation aggravated by the construction of new hydroelectric power stations along the river, extensive land use and mining.

The headwaters region, with the Cwb climate classification, has the highest average precipitation due to the incidence of orographic rainfall,[13]: 40–43  reaching 1,500 millimetres (mm) a year.

[22]: 39–41  The history of flood-related problems led to the installation of a series of rain gauge and fluviometer stations on the rivers in the basin, which are managed by the National Water Agency (ANA) and which aim to warn the population of possible overflows.

[27] It is worth noting that during the rainy season it is also common for water turbidity to rise, due to the faster current and the intensified movement of sediment, humus and plankton.

[26]: 70  Downstream, the river intersects the dissected plateaus of south-central and eastern Minas Gerais, which occupy most of the area and have an undulating relief, the so-called ‘mares de morros’.

Although it is a type of soil prone to grazing and agriculture, it is volatile to erosion when exposed to intense rainfall in undulating or mountainous terrain, which is why its use in the basin is more suited to silviculture.

With wells ranging from five to 20 metres, this type is found in the Steel Valley Metropolitan Region,[22]: 17–18  where it serves as the main source of public water supply.

[22]: 30–34   Among these, the riverbed bathes the urban perimeter of the municipalities of Rio Piracicaba, Bela Vista de Minas, Nova Era, Antônio Dias, Timóteo, Coronel Fabriciano and Ipatinga.

[32] In addition to fishing, the waters of the spring are used for recreation by people living along the banks, but the excess of pollutants is a health risk[33] and drownings occasionally occur.

[22]: 39–41  The Guilman Amorim HPP, which supplies electricity to the ArcelorMittal Aços Longos plants in João Monlevade and Samarco in Mariana,[36] is the largest in terms of power generated.

[37] At the same time as the area covered by native forest is dissolving in isolated spots that have not been devastated, the river and its tributaries have been severely punished by pollution generated from waste caused by local industries,[25][30] unbridled deforestation, mining and the proliferation of eucalyptus monoculture.

The greatest impacts on the riverbed would occur if the Upper South Dam at the Gongo Soco mine in Barão de Cocais, belonging to Vale, were to break, which was identified as being at risk of collapse due to the instability of the northern slope of its pit.

The mud would destroy 383 hectares of native Atlantic Forest, cause soil infertility in the affected areas and jeopardise the operation of hydroelectric power plants.

[19]: 23 An analysis carried out at the request of Estado de Minas, published in April 2014, showed that the river's waters had 161% more faecal coliforms than what is acceptable under the National Environment Council (CONAMA), after leaving the Iron Quadrangle region and before entering any urban centres.

[23] In addition, the pollution of the source was aggravated by the long period of irregular rainfall that the region faced throughout the 2010s, leading to a considerable decrease in its average level and the extinction of several springs in the basin.

[46][47] The water used by Aperam South America and Usiminas, located in Timóteo and Ipatinga respectively, is extracted and treated from the river by the companies themselves, while the effluent is reused or released into the same stream after undergoing treatment plants.

[51] In the same year, the operation of a sewage treatment plant in the Limoeiro neighbourhood in Timóteo was authorised, with the initial intention of serving 165,000 inhabitants of the city and neighbouring Coronel Fabriciano.

In 2019, for example, the so-called ‘Piracicaba Expedition - For the Life of the River’, promoted by researchers, CBH and supporters, travelled the entire riverbed to analyse water quality, land use and occupation, sediments and polluting sources, as well as carrying out socio-environmental and cultural awareness campaigns in the cities they visited.

[1][58][13]: 57–58 The Piracicaba River is dammed, invaded, exploited, drained, polluted, silted up, mined, excavated, diverted, altered, fenced off, attacked, dumped, poisoned, stepped on, fished, drunk, researched, used and nobody says thank you!!

The artefact was acquired by the local administration, which added it to the José Avelino Barbosa Museum collection as a reference to the canoeists who had settled in the city since before its urban core was established[66] In 2019, restoration work began on the ruins of Pedra Mole Station in Ipatinga.