Case study:ReNaturalize
Project overview
Status | Complete |
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Project web site | |
Themes | Environmental flows and water resources, Fisheries, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality |
Country | Brazil |
Main contact forename | Carolina |
Main contact surname | Pinto |
Main contact user ID | User:Carolfp10 |
Contact organisation | Aplysia |
Contact organisation web site | http://www.aplysia.com.br/site/en/ |
Partner organisations | FAPES, FINEP, CESAN, MCTI |
Parent multi-site project | |
This is a parent project encompassing the following projects |
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Project summary
The project ReNaturalize consisted on the installation of large wood (LW) in the River Mangaraí, ES-Brazil. It is an innovative initiative from Aplysia Environmental Solutions. In this project British techniques of river restoration were used where tree trunks are installed on the riverbed as a form of river restoration.
The aim was to restore natural river processes that can support healthier and more biodiverse aquatic environments.
In other words, the project aims to restore the natural function of the river, that happens when riparian vegetation grows wirth trees and branches falling naturally in the river, creating healthier environments in a sustainable manner.
We also seek the integration with local communities. To integrate the community's goals with the project objectives aligning interests.
The installations included techniques listed below: - 'D' structures; - Flexible anchoring large wood; - Rigid anchoring; - 'Staking'; - Dragon's Tooth;
Monitoring surveys and results
The water quality results showed that, in general, the Mangaraí River is affected by deteriorated water quality when it comes to nutrients (total phosphorus), especially during the dry season (April-September). The low quality is also indicated by the low levels of dissolved oxygen (DO) found in both the ReNaturalize and Reference sections. The second major finding was that despite the low DO content in one of the campaigns, the ReNaturalize stretch demonstrated higher DO.
The research also showed that for the water turbidity analyzed ever 15 days there were no significant differences between the three reaches sampled.
For the quality of the sediments collected during the seven campaigns, results suggested that the ReNaturalize stretch presented higher retention of nutrients and organic matter. However, there was no significant difference in the results of organic matter, nitrogen and total phosphorus.
The grain size analysis showed a trend towards the composition of thinner material in the ReNaturalize reach and greater diversification of the local sediemnt profile. This could be confirmed by the hydromorfological assessments through riverbed mapping that showed the significant increase of the heterogeneity of the riverbed after the installation of LW.
The quarterly data of the abundance of ichthyofauna monitored in the restored section point to the success of the technique with regard to the improvement of the fish populations (increased abundance aprox. 80%) in the restored reach.
Lessons learnt
The aim of the project Renaturalize was to evaluate if techniques of river restoration widely used in the United Kingdom were effective in the River Mangaraí located in the Brazilian Atlantic Forest. The ReNaturalize project was developed to apply and evaluate effectiveness of the use of logs and wood branches within the river channel in a tropical environment. The evaluation of the efficacy of the British method in a tropical environment was based on assessments of water quality, sediment and aquatic biota, as well as achievements of work with the local community.
- In general, installed wood structures had good durability. The anchoring techniques that best fit the hydrodynamics of the River Mangaraí were the "rigid" type with anchorage at the margin. "D" structures have shown rapid benefits for insect colonization and habitat creation for fish, but they had a short life. To play the role of sediment retention and habitat creation, so-called 'dragon tooth' structures have proven to be more effective. The flexible structures served as a shelter for fish and are more durable. The trunks anchored to the margins presented an excellent function of sediment retention and increased riverbed heterogeneity and differential flow creation.
- Fixed Point photographs are a very useful tool to present the results of the Renaturalize project. We suggest that in future projects these photographs be made in panoramic mode to perfect the technique.
- Although this project focused on environmental quality parameters, the results of the ReNaturalize project have shown that the integration, environmental education and income generation provided to the local community generated socio-environmental benefits. This provides gains for both biodiversity and the surrounding community. From the implementation of the project, it was understood that local communities had a misconception about the presence of wood logs within rivers. Although environmental education activities were not foreseen within this project, their development was extremely important for the local community to change this conception. In addition, the training of the work team sought to develop notions of management of LW in rivers.
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