Case study:ReNaturalize

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Location: -20° 10' 45", -40° 30' 7"
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Project overview

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Status Complete
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
No
Project ReNaturalize River Mangaraí ES Brazil

Project summary

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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

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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

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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.


Image gallery


Installation of flexible structure
Faggot bundles
D structure
Steel cable anchor
RENATURALIZE 2015-08-14 11-24-58 edit reduzida.jpg
ShowHideAdditionalImage.png


Catchment and subcatchment

Catchment

River basin district East- Atlantic
River basin Santa Maria da Vitória

Subcatchment

River name Mangaraí
Area category 100 - 1000 km²
Area (km2) 174
174 km²
17,400 ha
Maximum altitude category 500 - 1000 m
Maximum altitude (m)
Dominant geology
Ecoregion
Dominant land cover Woodland, Rough unimproved grassland/pasture, Plantation forestry, Irrigated land
Waterbody ID



Site

Name
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology Single channel, Over-widened, shallow
Reference morphology
Desired post project morphology
Heavily modified water body No
National/international site designation
Local/regional site designations
Protected species present No
Invasive species present Yes
Species of interest
Dominant hydrology Groundwater
Dominant substrate Sand
River corridor land use Broadleaf/mixed woodland (semi natural), Rough unimproved grassland/pasture
Average bankfull channel width category 10 - 50 m
Average bankfull channel width (m)
Average bankfull channel depth category Less than 0.5 m
Average bankfull channel depth (m)
Mean discharge category 1 - 10 m³/s
Mean annual discharge (m3/s)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2) 2
2 W/m²


Project background

Reach length directly affected (m) 200
200 m
0.2 km
20,000 cm
Project started 2014/11/20
Works started
Works completed
Project completed
Total cost category 100 - 500 k€
Total cost (k€)
Benefit to cost ratio
Funding sources FINEP, FAPES, MCTI

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design 1 - 10 k€ Aplysia, CESAN, AGERH Carolina Pinto
Stakeholder engagement and communication 1 - 10 k€
Works and works supervision 10 - 50 k€ Aplysia Carolina Pinto
Post-project management and maintenance 1 - 10 k€ Carolina Pinto
Monitoring 10 - 50 k€ Aplysia Carolina Pinto



Reasons for river restoration

Mitigation of a pressure Riparian development, Drinking water storage and supply
Hydromorphology Silting, In-stream Habitat Heterogeneity
Biology Biodiversity loss
Physico-chemical Suspended Solids, Turbidity
Other reasons for the project High levels of suspended sediment


Measures

Structural measures
Bank/bed modifications Introducing large woody debris
Floodplain / River corridor Introducing large woody debris
Planform / Channel pattern Introducing large woody debris
Other
Non-structural measures
Management interventions
Social measures (incl. engagement) Community Education, Engagement with schools
Other Exit Plan


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Substrate conditions Yes Yes Yes Yes Yes Improvement
Flow velocities No Yes No Yes Yes Improvement

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Fish: Abundance Yes Yes No Yes Yes Improvement
Fish: Species composition Yes Yes No Yes Yes Inconclusive
Invertebrates: Abundance Yes Yes No Yes Yes Inconclusive
Invertebrates: Taxonomic composition Yes Yes No Yes Yes Improvement

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Oxygen balance Yes Yes Yes Yes Yes Improvement
Nutrient concentrations Yes Yes Yes Yes Yes Inconclusive
PH Yes Yes Yes Yes Yes Inconclusive
Temperature Yes Yes Yes Yes Yes Inconclusive
Transparency Yes Yes Yes Yes Yes Inconclusive

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Channel bed morphology. Yes Yes Yes Yes Yes Improvement
Habitat mapping Yes Yes Yes Yes Yes Improvement
Substrate particle size/composition. Yes Yes Yes Yes Yes Improvement


Monitoring documents



Additional documents and videos


Additional links and references

Link Description
http://www.youtube.com/watch?v=E61NqM1Ew-4 Video ReNaturalize Portuguese
http://www.youtube.com/watch?v=PoN0ra4VwPo Video ReNaturalize English

Supplementary Information

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