The majority of large rivers worldwide are highly impacted by dams (Nilsson et al., 2005). When a dam is settled, several environmental (Agostinho et al., 2008a) and sociological (Rothman, 2008) impacts are expected. For instance, dams modify the landscape and have consequences on terrestrial and aquatic biota (Barletta et al., 2010). Furthermore, dams may displace peoples (McCully, 1996), suppress local cultures (Leite and Bahia, 2012), disable sustainable economic activities (Vainer, 2008) and destroy historic (Miranda, 2012) and archeological sites (Chmys, 2004).

Within this context, the goal of this manuscript is to make public a strategy on contesting hydroelectric projects considered to be detrimental to rivers and to local interests. Thus, we present a guide based on recent successful efforts to protect two river basins considered of high-priority for conservation. We do not provide exhaustive legal and managerial details, but we assert that the outcomes presented are legally supported and possible to be applied in any river in Brazil with high-priority for conservation and/or with relevant potential to promote social disruption due to damming. We also provide details on the outcome of such strategies applied in the Ivaí and Piquiri Basins, the only two remaining dam-free tributaries of Paraná River in Paraná State.

First, we highlight that we do not deliberately advocate against new dams. Instead we believe that remaining rivers proven to be important for several reasons should stay free-of-dams. Thus, we present a framework (Fig. 1) based on successful actions developed to avoid dams in Paraná State. Due to the fact that Paraná State already had most of its major watersheds impounded (with significant surplus of hydropower production) and that social, environmental and economic losses have been a common consequence of the several dams built throughout the decades, there is overspread awareness about detrimental dams in the state.

Fig. 1.

The framework with pathways of actions to prevent dams in rivers with high-priority for conservation and/or with relevant threat of social disruption by damming is shown. The framework starts with joint initiatives (a) of three stakeholders (populations, law experts, and universities), who are able to put into practice actions (b), that may result in legally supported products (c), which are expected to turn impracticable the implementation of new dams (d). White arrow indicates that public hearings can be requested by any of the stakeholders regardless the meetings.

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The strategies are mostly based on the union of three independent stakeholders (local communities, law experts, and universities). The experience in Paraná State has been that, as soon as development plans (projects of new dams) became public, even before permitting procedures are initiated, affected communities, law experts, and researchers from different academic fields (Natural and Social Sciences) started coordinated actions to set strategies to contain such projects. Crucial to those efforts from this net of stakeholders is the sharing of information about the potential losses caused by planned dams. This shared awareness was brought about through several meetings congregating the general public from municipalities targeted by planned impoundments and experts (Fig. 1, a).

In those meetings (143 in both basins), the exchanges of knowledge and perspectives have strengthened the shared interest for conservation, providing for the development of different strategies. Those include enactment of local statutes declaring basins, rivers or segments of rivers as of local importance for preservation; the registering of riverine features as part of the State Patrimony or natural heritages; and the establishment of new protected areas by affected municipalities.

The strategy presented in order to preclude the construction of new dams in the tributaries of the Paraná River within Paraná State was conceived due to their importance to biodiversity conservation. The Paraná River Basin in Brazil is the most impounded in the Neotropics and has about 72% of its hydraulic potential already exploited (Agostinho et al., 2007). In spite of several negative impacts associated with the construction of dams, Brazil still projects expansion of its energy system through impoundment of rivers (EPE 2007 – Plano Nacional de Energia 2030). Thus, the possible exploitation of dam-free rivers for hydroelectric development has generated conflicts among local communities and government entities that bear the burden associated with river impoundment.

The remaining dam-free stretch of the Paraná River inside the Brazilian territory is about 230km long and includes the Upper Paraná River Floodplain (PRF), a very complex and biodiverse waterscape (Agostinho et al., 2000). PRF is the last riverine refuge available for fish and includes significant proportion of much of the original fauna of this basin.

The ecological integrity of the PRF is closely dependent on four large tributaries still not dammed in their main courses (see Agostinho et al., 2004a,b; Baumgartner et al., 2004). Two of those, Ivaí and Piquiri rivers (798km and 485km long, respectively), represent the major tributaries on the East margin of the PRF, in Paraná State, Brazil (Gubiani et al., 2006; Parolin et al., 2010, see map in supplementary material). Those rivers are highly important for the maintenance of fish diversity and stocks once they are used as spawning grounds for migratory fishes that inhabit the Paraná River (Baumgartner et al., 2004; Antonio et al., 2007; Gubiani et al., 2010). Second, they harbor several rare and endemic species of different taxonomic groups (Gubiani et al., 2006; Volkman-Ribeiro and Parolin, 2010) and present several species still not described by science (i.e.Dei Tós et al., 2014) revealing taxonomic incompleteness and spatial biases on geographic distribution of species (Linnaean and Wallacean shortfalls, Brown and Lomolino, 1998). In addition, they house endangered species (Agostinho et al., 2008b; ICMBio, 2014).

Although these rivers are free-of-dams, Piquiri's integrity is threatened by projects of 16 impoundments on its main channel (EPE, 2013, Plano Decenal de Expansão de Energia 2022). Other several dams are projected for the upper sections and the main channel of the Ivaí basin. The fragmentation of these rivers by successive impoundments would not only prevent access of fish to key habitats, negatively affecting their distribution, reproduction and fisheries, it would affect the landscape of the basin with serious ecosystem effects. The biota of the Upper Paraná River basin currently confined to its last dam-free stretch would likely be in peril.

Furthermore, economics linked to artisanal fisheries on the free flowing section of Paraná River and in Itaipu reservoir depend on fish species that use these tributaries as spawning and nursery areas. Thus, the deprivation of access to these rivers may result in damage to fisheries and in impacts on the livelihood of fishers (Agostinho et al., 2004a,b). Beyond that, indigenous areas (Mota, 2013), as well as archeological sites (Chmyz et al., 2008; Parellada, 2013) are common along the Ivaí and Piquiri rivers. Additionally, both rivers have several waterfalls, rapids and other waterscapes that withstand local tourism. Consequently, the construction of dams in those areas would promote multiple losses. These were all clearly described to the local society during public hearings.

In addition, new dams in Paraná state would be economically harmful. First because to build a dam, large tracts of fertile soils are flooded, dramatically affecting local economic chains, suppressing local tax revenue and invalidating local sustainable economic activities based on agriculture. As an example, the projects of Ercilândia and Apertados would affect 800 farms along the Piquiri basin.

It seems obvious that new dams have economic rewards and would benefit those in need of new sources of electric power, a product easily commercialized. Actually, hydropower plants provide about 92% of the total energy produced in Paraná State (IPARDES, 2013) and the total production of the state is about 230% higher than what is consumed internally. The surplus is distributed to other states with no compensation whatsoever, because Section 155, Paragraph 1, X, b) of the Brazilian Federal Constitution, forbids taxation of electricity exchanged among states.

If it was not for the mentioned above, the commercialization of the energy could generate local and state tax revenues by trading this surplus, which would partially compensate economic losses. In conclusion, apart from hindering traditional economic activities, dams have no potential for withstanding local economy with taxes benefits. In addition, small power plants (Pequenas Centrais Elétricas), which are usually the ones planned to minor tributaries, do not need to pay royalties to local municipalities, what worsen the situation.

We additionally highlight disagreements among government entities (federal and/or state levels) with regard to conservation plans, which are frequently ignored by “development” plans. This paradoxical countersense is made explicit when at federal level, Portaria do Ministério do Meio Ambiente (09/2007) indicates the lower Piquiri River as one of the areas of high priority for conservation and sustainable use. At state level, Resolução Conjunta (SEMA-IAP 05, September 2009), proposed by the Secretaria do Meio Ambiente e Recursos Hídricos and by the Instituto Ambiental do Paraná (IAP), establishes the mapping of strategic areas for the conservation and restoration of Paraná State biodiversity, including the lower Piquiri River. A major paradox resides here: how can areas declared as of high-priority for conservation at federal, state and local levels be even considered for hydropower plants? This was clearly presented during public hearings.

We proposed a strategy to avoid new dams in rivers of high-priority for conservation that was strongly based on successful examples of collinear actions of society, law experts (mainly public prosecutors) and scientists in Paraná State. The strategies presented here are encouraged to be adopted all-around Brazil where similar situations occur and where societies desire to conserve the rivers and prevent impacts caused by dams.

As evidenced in practice, a series of factors have contributed to successful results obtained so far: the rivers under scrutiny are remnants recognized as of environmental importance by governmental entities; they are in a State with significant surplus of energy production (for which is not rewarded); the areas threatened by impoundments are economically productive; and the institutional environment comprises several universities, prosecutors’ offices and non governmental organizations that were able to support local populations and governments on their struggle to prevent “developments” which would be detrimental to local interests (see WCD, 2000).

Finally, we emphasize that our goal falls short from entering the dispute between development and conservations strategies. Nonetheless, we highlight the lack of adequate strategies to mitigate ecological, sociological and economical impacts regarding construction of new dams.

The authors declare no conflicts of interest.