RESTORE - User contributions [en]

File:101 1345.JPG

2015-12-18T13:41:46Z

Samj: Reprofiling of river bansk and removal of invasive Arundo donax stands

Reprofiling of river bansk and removal of invasive Arundo donax stands

Case study:Restoration of R. Odelouca

2015-12-18T13:37:15Z

Samj:

{{Case study status
|Approval status=Draft
}}
{{Location
|Location=37.244909528644136, -8.497407641261816
}}
{{Project overview
|Status=Complete
|Themes=Environmental flows and water resources, Fisheries, Hydromorphology, Monitoring
|Country=Portugal
|Main contact forename=Rui
|Main contact surname=Cortes
|Main contact id=Rcortes
|Contact organisation=UTAD
|Contact organisation url=www.utad.pt
|Multi-site=No
|Project summary=The Odelouca River, situated in the Algarve Region of southern Portugal is considered to have high conservation value because of the former presence of intact and floristically diverse riparian galleries along the large stretches of the river corridor (now cleared and submersed following completion of the Odelouca Dam in 2010) and the presence of critically endangered species such as the endemic fish species, the Iberian nase Iberochondrostoma almacai and the Iberian Chub Squalius aradensis and the presence of the Iberian Lynx Lynx pardinus (Fernandes et al., 2007; Hughes et al., 2012; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). The River Odelouca is situated in the Monchique Natura 2000 Network (PTCON0037).
The construction and completion in 2010 of the Odelouca Dam, ostensibly for improving water supply in the Algarve Region, has been highly contested. Initially embargoed as a result of protests presented to the European Commission (EC) by the Liga para a Protecção da Natureza (LPN) concerning violation of the area’s intrinsic conservation value and Natura 2000 status, construction finally went ahead following a ministerial decision (2005) to reactivate the dam under the condition, stipulated by the EC, that an extensive programme of monitoring, mitigation and compensatory measures be implemented to offset dam construction impacts and habitat loss.
The intact riparian corridors of the Odelouca basin were diverse in plant species. The original riparian communites of this basin have overstoreys of Fraxinus angustifolia, Salix atrocinerea, S. australis, Alnus glutinosa with sedges of Nerium oleander and Tamarisk africana and Erica lusitanicum. Community continuity and integrity changed along the watercourse, as well as habitat quality and diversity. The highest quality and most diverse riparian corridors occurred in the midsection of the course, most of which is now submerged by the Odelouca reservoir. Upstream and downstream, less well preserved corridors occur in a predominantly agricultural landscape. The lower course is the most degraded stretch in terms of habitat quality, subject to resectioning and canalization in some areas. In many places the riparian woody vegetation has been replaced by invasive reed and giant reed beds.
|Monitoring surveys and results=Research actions included in the protocol were:
• characterization of the presently existing composition and structure of the aquatic and riparian vegetation in the Odelouca river and assessment of its integrity and longitudinal continuity;
• characterization of in stream habitats and banks; assessment of quality and degree of human disturbance;
• Characterization of key animal communities of the river banks (birds) and river channel (macroinvertebrates and fish) and their relation with riparian and habitat features and human disturbance;
• development of nursery practices for local woody species and best methodologies for field implanting during rehabilitation,
• The study of the functional role of riparian communities in shaping and structuring in-stream habitats and driving river processes.
o Application of this knowledge to the development of rehabilitation proposals for selected river stretches (next phase).
• Modelling abiotic and biotic changes resulting from river rehabilitation actions. Validation of the model results through biomonitoring.
The next phase of activities carried out following the work described above comprised:
• Development and implementation of a proposal for a programme of requalification and rehabilitation measures for Odelouca riparian galleries and fish habitats for selected river stretches;
• Monitoring of requalification and rehabilitation measures for Odelouca riparian galleries and fish habitats at sites situated along a selected reach of river.

A set of monitoring sites provides data that (i) enable validation of proposals based upon modelling results and in depth data analyses and (ii) to correct deviations from the original line of desirable change.

Characterisation of the Odelouca study site was carried out at a total of 30 sites in 2005 and 2006 covering almost the entire length of the river, except the final downstream tidal section (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). Sampling programmes comprised detailed phytosociological surveys, habitat quality surveys using the River Habitat Survey methodology (Raven et al., 2009) and sampling of biological quality elements comprising fauna and flora (BQE; benthic macroinvertebrates, fish, birds and macrophytes) and physicochemical parameters following WFD compliant protocols (INAG, 2008b; INAG, 2008c; INAG, 2008).
The character of BQE was assessed in relation to longitudinal changes in habitat quality, including riparian quality (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). Using the KT method which divides the study area into groups of physically similar units and then assesses the extent of given pressures within each unit, habitat and riparian integrity and types of impact were quantified in the study area (Figure 4) allowing impact specific rehabilitation and mitigation measures to be drawn up (Fernandes et al., 2007; Cortes et al., 2002). The KT method can also be applied to characterise and resolve issues in the NWRM context.
Macroinvertebrate communities were found to respond to key habitat elements particularly depth, flow and flow while fish species showed distinct distribution patterns in relation to large scale impacts related to changes in land use and river regulation. Bird communities associated with woods and associated features (canopy cover) predominated in the midsection but were substituted by aquatic and generalist species in the downstream reaches (Hughes et al., 2010; Hughes, Ferreira & Cortes, 2008a; Hughes et al., 2009b.
Cuttings and seeds from all dominant woody species were collected and tested for survival in greenhouse conditions at ISA. Regional nursery managers have been encouraged to be actively involved in this process to debate and demonstrate greenhouse techniques for growing on local tree species.
The well preserved middle course riparian communities, now cleared and submerged, were used as reference sites for the rehabilitation of the selected degraded river sections earmarked for rehabilitation. Emphasis was given to the river segment immediately upstream of the area to be inundated and to the river segment immediately downstream of the dam where minimal flow requirements for maintaining the aquatic biota are now applied. Habitat modelling (river 2D model) was be used to predict fish habitat preference changes according to suggested rehabilitation proposals (Boavida et al., 2011b).

Biophysical Impacts: description of the impact
Biophysical impacts along the Odelouca River were primarily linked to (i) the process of river regulation such as major earthworks, changes in flow regime and associated biophysical processes (natural patterns of erosion and deposition) and habitat destruction (e.g. clearance of riparian galleries) and (ii) changes in land use due to agricultural activities (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010).
The large scale pressures describe changes in land use related to agriculture (e.g. the presence of monocultures) and associated physical impacts at lower spatial scales (river reach and habitat) to bank side and channel (clearance of native riparian vegetation, reinforcement and embankment of the banks to protect against flooding and maximize space for cultivation).

A subsequent programme of requalification, based mostly on natural engineering techniques, was carried out as part of an INTERREG SUDOE financed project called RICOVER (River Recovery in the SUDOE Region). A reach of over 7km in length, situated downstream of the now completed Odelouca dam, was selected and a total of 6 sites selected for intervention measures and subsequent monitoring. Three sites where no intervention measures were carried out were “set aside” as control sites for comparison with the 6 intervention sites as part of the ongoing monitoring programme.
Summary of some of the natural/bio- engineering measures
The construction works commenced in 2011 (Fig. 6, 7 and 8). Most of the natural engineering methods were used to rehabilitate highly eroded and degraded river banks as a result of human intervention (see Table 1) and are briefly summarized below:
• Resectioning of river banks and placement of geotextile (in some cases pre-treated with herbicide) to prevent erosion, retain soil moisture, prevent (re)growth of weeds and invasive plants and create favourable conditions for planted native plants;
• Construction of a crib wall and placement of stone filled gabions to stabilise river banks;
• Planting of rehabilitated banks with native plant species, collected from cuttings and seeds in the area and grown on in local nurseries (e.g. Tamarix, Oleander, buckthorn and ash);
• Construction of artificial islands in the river channel to augment habitat heterogeneity;
• Clearance of invasive riparian plant species (Arundo donax and Acacia sp).~

The rehabilitated sites were monitored in 2011 and 2012 as part of the RICOVER project (benthic macroinvertebrate and fish fauna; physicochemical quality) and in 2013 – 2014 as part of a contract with Águas do Algarve, SA (River Habitat Survey – to assess habitat quality, sampling of benthic macroinvertebrate and fish fauna; physicochemical quality and phytosociological surveys of the river banks). Water Framework Directive compliant protocols are followed in the field, with the exception of the phytosociological surveys.
• Total cost of the initial sub programme of compensation measure (avifauna, fish fauna, riparian galleries and monitoring studies) 5,430,664 €
• Project RICOVER – Rehabilitation of the riparian galleries 267,636 €.
• Ecological Monitoring of the Odelouca River is carried out by UTAD under contract to Águas do Algarve, SA. and is ongoing.
Results show overall ecological status as “Excellent” and “Good”, despite the fact that the Monchique site continues to be heavily organically polluted. This anomalous result may be due to the innate “hardiness” of the Mediterranean BQE, which are adapted to the extreme environmental conditions of drought and flow and therefore may be more resistant (and therefore less responsive) to some types of impact.
|Lessons learn=Expect the unexpected: Planting carried out in the winter of 2011 was followed by an exceptionally dry spring and summer, which placed the planted native species under considerable hydric stress and presented a real threat to their survival during the 1st year. However, surveys carried out in 2013 show that although the plants had a “rough start”, most of them have survived. The Mediterranean climate is characterised by notable annual and interannual variation in precipitation levels as a result of different phases of the North Atlantic Oscillation or NAO (Hughes et al., 2012; Trigo et al., 2004). Negative phases result in higher precipitation levels while positive phases result in higher temperatures and lower precipitation levels. Although these large scale climate patterns are beyond the control of any rehabilitation or NWRM project, they must be taken into account as part of the programme of measures.
Poor local stakeholder engagement: The implementation of the characterisation programme and subsequent rehabilitation programme along the river banks was initially met with much suspicion and some resistance by local farmers and land owners. The local farmers’ general perception was that land that was subject to intervention was being taken away from them, that risk of flooding would be increased, that project personnel were “trespassing” although, according to Decreto–Lei 54/2005 (República, 2005), the river banks and channel are in the public domain (although access has never been refused, local residents and land owners remain suspicious) and that the native plants planted along the intervention zones were of no commercial value and should be replaced by fruit trees, for example. Future actions to alert and educate locals to the value of lotic ecosystems, the presence of threatened species and NWRM must be more effective and interactive.

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Case study:Restoration of R. Odelouca

2015-12-09T17:56:00Z

Samj:

{{Case study status
|Approval status=Draft
}}
{{Location
|Location=37.244909528644136, -8.497407641261816
}}
{{Project overview
|Status=Complete
|Themes=Environmental flows and water resources, Fisheries, Hydromorphology, Monitoring
|Country=Portugal
|Main contact forename=Rui
|Main contact surname=Cortes
|Main contact id=Rcortes
|Contact organisation=UTAD
|Contact organisation url=www.utad.pt
|Multi-site=No
|Project summary=The Odelouca River, situated in the Algarve Region of southern Portugal is considered to have high conservation value because of the former presence of intact and floristically diverse riparian galleries along the large stretches of the river corridor (now cleared and submersed following completion of the Odelouca Dam in 2010) and the presence of critically endangered species such as the endemic fish species, the Iberian nase Iberochondrostoma almacai and the Iberian Chub Squalius aradensis and the presence of the Iberian Lynx Lynx pardinus (Fernandes et al., 2007; Hughes et al., 2012; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). The River Odelouca is situated in the Monchique Natura 2000 Network (PTCON0037).
The construction and completion in 2010 of the Odelouca Dam, ostensibly for improving water supply in the Algarve Region, has been highly contested. Initially embargoed as a result of protests presented to the European Commission (EC) by the Liga para a Protecção da Natureza (LPN) concerning violation of the area’s intrinsic conservation value and Natura 2000 status, construction finally went ahead following a ministerial decision (2005) to reactivate the dam under the condition, stipulated by the EC, that an extensive programme of monitoring, mitigation and compensatory measures be implemented to offset dam construction impacts and habitat loss.
The intact riparian corridors of the Odelouca basin were diverse in plant species. The original riparian communites of this basin have overstoreys of Fraxinus angustifolia, Salix atrocinerea, S. australis, Alnus glutinosa with sedges of Nerium oleander and Tamarisk africana and Erica lusitanicum. Community continuity and integrity changed along the watercourse, as well as habitat quality and diversity. The highest quality and most diverse riparian corridors occurred in the midsection of the course, most of which is now submerged by the Odelouca reservoir. Upstream and downstream, less well preserved corridors occur in a predominantly agricultural landscape. The lower course is the most degraded stretch in terms of habitat quality, subject to resectioning and canalization in some areas. In many places the riparian woody vegetation has been replaced by invasive reed and giant reed beds.

|Monitoring surveys and results=Research actions included in the protocol were:
• characterization of the presently existing composition and structure of the aquatic and riparian vegetation in the Odelouca river and assessment of its integrity and longitudinal continuity;
• characterization of in stream habitats and banks; assessment of quality and degree of human disturbance;
• Characterization of key animal communities of the river banks (birds) and river channel (macroinvertebrates and fish) and their relation with riparian and habitat features and human disturbance;
• development of nursery practices for local woody species and best methodologies for field implanting during rehabilitation,
• The study of the functional role of riparian communities in shaping and structuring in-stream habitats and driving river processes.
o Application of this knowledge to the development of rehabilitation proposals for selected river stretches (next phase).
• Modelling abiotic and biotic changes resulting from river rehabilitation actions. Validation of the model results through biomonitoring.
The next phase of activities carried out following the work described above comprised:
• Development and implementation of a proposal for a programme of requalification and rehabilitation measures for Odelouca riparian galleries and fish habitats for selected river stretches;
• Monitoring of requalification and rehabilitation measures for Odelouca riparian galleries and fish habitats at sites situated along a selected reach of river.

A set of monitoring sites provides data that (i) enable validation of proposals based upon modelling results and in depth data analyses and (ii) to correct deviations from the original line of desirable change.

Characterisation of the Odelouca study site was carried out at a total of 30 sites in 2005 and 2006 covering almost the entire length of the river, except the final downstream tidal section (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). Sampling programmes comprised detailed phytosociological surveys, habitat quality surveys using the River Habitat Survey methodology (Raven et al., 2009) and sampling of biological quality elements comprising fauna and flora (BQE; benthic macroinvertebrates, fish, birds and macrophytes) and physicochemical parameters following WFD compliant protocols (INAG, 2008b; INAG, 2008c; INAG, 2008).
The character of BQE was assessed in relation to longitudinal changes in habitat quality, including riparian quality (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010). Using the KT method which divides the study area into groups of physically similar units and then assesses the extent of given pressures within each unit, habitat and riparian integrity and types of impact were quantified in the study area (Figure 4) allowing impact specific rehabilitation and mitigation measures to be drawn up (Fernandes et al., 2007; Cortes et al., 2002). The KT method can also be applied to characterise and resolve issues in the NWRM context.
Macroinvertebrate communities were found to respond to key habitat elements particularly depth, flow and flow while fish species showed distinct distribution patterns in relation to large scale impacts related to changes in land use and river regulation. Bird communities associated with woods and associated features (canopy cover) predominated in the midsection but were substituted by aquatic and generalist species in the downstream reaches (Hughes et al., 2010; Hughes, Ferreira & Cortes, 2008a; Hughes et al., 2009b.
Cuttings and seeds from all dominant woody species were collected and tested for survival in greenhouse conditions at ISA. Regional nursery managers have been encouraged to be actively involved in this process to debate and demonstrate greenhouse techniques for growing on local tree species.
The well preserved middle course riparian communities, now cleared and submerged, were used as reference sites for the rehabilitation of the selected degraded river sections earmarked for rehabilitation. Emphasis was given to the river segment immediately upstream of the area to be inundated and to the river segment immediately downstream of the dam where minimal flow requirements for maintaining the aquatic biota are now applied. Habitat modelling (river 2D model) was be used to predict fish habitat preference changes according to suggested rehabilitation proposals (Boavida et al., 2011b).

Biophysical Impacts: description of the impact
Biophysical impacts along the Odelouca River were primarily linked to (i) the process of river regulation such as major earthworks, changes in flow regime and associated biophysical processes (natural patterns of erosion and deposition) and habitat destruction (e.g. clearance of riparian galleries) and (ii) changes in land use due to agricultural activities (Fernandes et al., 2007; Hughes et al., 2009; Hughes, Ferreira & Cortes, 2008; Hughes et al., 2010).
The large scale pressures describe changes in land use related to agriculture (e.g. the presence of monocultures) and associated physical impacts at lower spatial scales (river reach and habitat) to bank side and channel (clearance of native riparian vegetation, reinforcement and embankment of the banks to protect against flooding and maximize space for cultivation).

A subsequent programme of requalification, based mostly on natural engineering techniques, was carried out as part of an INTERREG SUDOE financed project called RICOVER (River Recovery in the SUDOE Region). A reach of over 7km in length, situated downstream of the now completed Odelouca dam, was selected and a total of 6 sites selected for intervention measures and subsequent monitoring. Three sites where no intervention measures were carried out were “set aside” as control sites for comparison with the 6 intervention sites as part of the ongoing monitoring programme.
Summary of some of the natural/bio- engineering measures
The construction works commenced in 2011 (Fig. 6, 7 and 8). Most of the natural engineering methods were used to rehabilitate highly eroded and degraded river banks as a result of human intervention (see Table 1) and are briefly summarized below:
• Resectioning of river banks and placement of geotextile (in some cases pre-treated with herbicide) to prevent erosion, retain soil moisture, prevent (re)growth of weeds and invasive plants and create favourable conditions for planted native plants;
• Construction of a crib wall and placement of stone filled gabions to stabilise river banks;
• Planting of rehabilitated banks with native plant species, collected from cuttings and seeds in the area and grown on in local nurseries (e.g. Tamarix, Oleander, buckthorn and ash);
• Construction of artificial islands in the river channel to augment habitat heterogeneity;
• Clearance of invasive riparian plant species (Arundo donax and Acacia sp).~

The rehabilitated sites were monitored in 2011 and 2012 as part of the RICOVER project (benthic macroinvertebrate and fish fauna; physicochemical quality) and in 2013 – 2014 as part of a contract with Águas do Algarve, SA (River Habitat Survey – to assess habitat quality, sampling of benthic macroinvertebrate and fish fauna; physicochemical quality and phytosociological surveys of the river banks). Water Framework Directive compliant protocols are followed in the field, with the exception of the phytosociological surveys.
• Total cost of the initial sub programme of compensation measure (avifauna, fish fauna, riparian galleries and monitoring studies) 5,430,664 €
• Project RICOVER – Rehabilitation of the riparian galleries 267,636 €.
• Ecological Monitoring of the Odelouca River is carried out by UTAD under contract to Águas do Algarve, SA. and is ongoing.
Results show overall ecological status as “Excellent” and “Good”, despite the fact that the Monchique site continues to be heavily organically polluted. This anomalous result may be due to the innate “hardiness” of the Mediterranean BQE, which are adapted to the extreme environmental conditions of drought and flow and therefore may be more resistant (and therefore less responsive) to some types of impact.

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{{Hydromorphological quality elements header}}
{{End table}}
{{Biological quality elements header}}
{{End table}}
{{Physico-chemical quality elements header}}
{{End table}}
{{Other responses header}}
{{End table}}
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{{Monitoring documents end}}
{{Additional Documents}}
{{Additional Documents end}}
{{Additional links and references header}}
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{{Supplementary Information}}
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Case study:Restoration of R. Odelouca 2

2015-10-13T15:09:19Z

Samj:

{{Case study status
|Approval status=Draft
}}
{{Location
|Location=37.244909528644136, -8.497407641261816
}}
{{Project overview
|Status=Complete
|Themes=Environmental flows and water resources, Fisheries, Hydromorphology, Monitoring
|Country=Portugal
|Main contact forename=Rui
|Main contact surname=Cortes
|Main contact id=Rcortes
|Contact organisation=UTAD
|Contact organisation url=www.utad.pt
|Partner organisations=Águas do Algarve, SA
|Multi-site=No
|Project summary=This is an integrated restoration programme in a Mediterranean catchment with a significant conservation value. R. Odelouca drains about 520 km2 and flows along 83 km from an altitude of 509 m, discharging at about sea level into the Arade estuary. The basin drains mainly schists and greywackes from the Carbonic period. The climate is Mediterranean with oceanic influence, with warm to hot, dry summers and cool, wet winterThe construction of the River Odelouca dam for improving water supply in the Algarve region of south Portugal, located in Natura 2000 protected area, involved the definition of a variety of compensation measures including environmental requalification of selected river segments not affected by the reservoir. We cover the whole sequence of the project: a) characterization and selection of reaches to rehabilitate based on the definition of physiographic units and the relative quantification of impacts; b) implementation of soil engineering techniques for improving riparian habitat, bank stability and to control invasive species c) defining best river channel habitat improvement options for endangered endemic fish populations using two-dimensional hydraulic modeling (R2D); d) post-project appraisal and monitoring of floristic succession, fish, benthic fauna and habitat .

|Monitoring surveys and results=Upstream reaches show well-developed riparian vegetation galleries dominated by alders Alnus glutinosa, willows Salix spp. and ashes Fraxinus angustifolia, but below the dam, in the considered segment, banks are collapsing because of the fluvial erosion and agriculture (with dominance of orange orchards) and the invasive giant-reed Arundo donax finds here the appropriate conditions to spread even if Mediterranean sclerophyllous and evergreen scrub as well as cork oaks are still the characteristic landscape. Fish assemblages include a pool of native species, where we face the reduction of two endangered cyprinids _Iberochondrostoma almacai and chub Squalius aradensis. Other native species are present like the loach (Cobitis paludica), eel Anguilla anguilla and Barbus sclateri occurs sparsely (Pires et al., 2010). The degradation of habitat and water quality have given an increasing role to the highly abundant mosquito fish Gambusia holbrooki, and pumpkinseed Lepomis gibbosus, largemouth bass Micropterus salmoides, chameleon cichlid Australoheros facetus, carp Cyprinus carpio, and straight-mouth nase Pseudochondrostoma polylepis. The American crayfish has extended also its dispersion area after the artificial reservoir.
A laborious appraisal of the problem was assessed in all catchment by using different layers of information related to geology, climate and soil cover which allowed to define the physiographic units. Other layers containing descriptors of disturbance (habitat modification, roads, point and non-point pollution) allowed to define those units where rehabilitation should take place. The designed measures to stop the enlargement of the river channel, in the most critical reaches were based on soil engineering techniques after the convenient bank reprofiling, such as vegetated gabions and rip-rap and cribwall to stabilize the banks, whereas the invasive cane was controlled by a double-matt (organic and synthetic) of bio-degradable geotextile after clear cutting. In these places were also conducted an extensive plantation of riparian trees and shrubs to improve those measures and to control the advance of the invasive giant-reed. With that purpose plant material was collected in the area of the reservoir (before it was filled), and a plant nursery was created. Therefore there was a strict genetic control and plantation of trees (mainly ash trees and willows) and shrubs (such as Tamaryx and Oleander spp.) followed the observed longitudinal succession in previous surveys.
This study applied 2-D hydraulic simulations to evaluate the habitat improvement of two the two mentioned endangered cyprinid species, resulting from the implementation of distinct instream structures – i) placement of three islands in the middle of the river channel; ii) introduction of two lateral bays on opposite banks; and iii) introduction of four alternate current deflectors - in a modified river reach of a Mediterranean river. Though the use of such instream structures has been considered in many habitat improvement projects (e.g. Vehanen et al. 2003; Garcia de Jalón and Gortázar 2007), no previous analysis of their potential effectiveness on fish habitat has been carried out in non-salmonid rivers. This information can prove extremely useful elsewhere, namely in other Mediterranean-type rivers, where the implementation of instream structures and compensatory measures as a means of recovering other threatened fish populations has been questioned. The River2D model (Steffler 2000), was used with this purpose: This finite element model simulates hydraulic conditions from topographic data input and uses the habitat suitability index curves containing known fish biological preference data, to calculate the potential habitat for specific life-history stages by the Weighted Usable Area (WUA).
The habitat improvement measures were concluded in the end of spring 2012, and monitoring to assess its efficiency was conducted in specific periods in 2013 and 2014, which were compared to the previous situation. Such monitoring considered the succession of floristic communities in the river corridor, as well as in the aquatic habitat, where the surveys included benthic communities and fishes. In both years all sites were electrofished (DC, 300–700 V) during late spring−early summer base flow. In this period stream flows were lower (but still had full connectivity between habitats), thus ensuring a higher fishing efficiency (Oliveira et al., 2012). Electrofishing distances followed CEN standards for assessing fish species composition and abundance for wadeable sites (CEN, 2003). This distance was at least 20 times the mean wetted width of the channel to encompass complete sets of the characteristic stream form (e.g., riffles, pools, runs) with a minimum sampled length of 100 m. The entire widths of streams were fished by wading slowly upstream during daylight, using natural barriers, mostly shallow habitats, to delimit survey zones. To compare changes in fish communities and to evaluate the biological quality of sampled sites we used the fish-based index of biotic integrity for Portuguese wadeable streams (F-IBIP) (INAG and AFN, 2012).
Results and Discussion
In the two-year study it was collected 11 species of fish (seven native, three exotic and one translocated taxa), representing a total of 4521 individuals. In both years fish communities were clearly dominated by three species (A. anguilla, C. paludica, and G. holbrooki), which represented more than 70% in almost all samples. The populations of native cyprinids have always represented a small fraction of the communities, although they were present in all 2011 sites; however, these species were absent from segments E and K in 2012, the most degraded stream reaches of our study. The abundance of alien species varied considerably between segments and years, but generally represented a relevant proportion (> 25%) of the total species. Our results also seem to indicate a dispersion of the translocated species P. polylepis – an endemic species to central Portugal – with the number of occurrences increasing from 2011 (one site) to 2012 (three sites). Thus, independently of the year of study, all segments presented highly degraded fish communities, dominated by very tolerant species, with low proportion of native invertivores cyprinids and native lithophilics, and with a significant presence of alien forms. Results of the F-IBIP calculation reflected these observations, with all stream reaches presenting bad or poor biological quality in both years; in three of the segments (E, K, M) the F-IBIP score was even lower than in 2012, decreasing from poor to bad.

|Lessons learn=The success of the defined measures was hampered by three principal factors, firstly failure to engage local landowners early in the programme; the timing of key tasks, such as planting riparian trees; continued difficulty to control sources of environmental disturbance, in particular serious and continuous point pollution from animal husbandry. Consequently fish assemblages in all stream reaches were still dominated by aliens and highly tolerant species, and native cyprinids were low abundant or absent, revealing the fish index of biotic integrity a low environmental quality.
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|File name=Restored segment 1.JPG
|Caption=restored section: invasive species were erradicated and replaced by a willow after a cribwall structure
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|File name=Restored segment 2.JPG
|Caption=Exotic species (giant reed) were replaced by willows, after cutting of invasive species and stabilization of bank with cribwall
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|File name=Island for fishes.JPG
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|File name=Cribwall detail, with eucalypt logs.jpg
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|File name=Vegetated gabions.jpg
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|File name=Planting shrubs in organic matt after reprofiling.jpg
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|File name=Fiber matt with meditteranean shrub plantation.jpg
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{{Case study subcatchment}}
{{Site
|Name=River Odelouca
|Heavily modified water body=No
|Local site designation=iberian nase_Iberochondrostoma almacai and chub Squalius ar
|Protected species present=Yes
|Invasive species present=Yes
|Species=iberian nase_Iberochondrostoma almacai and chub Squalius aradensis.
|Dominant hydrology=mediterranean river with intermittent flow
|Dominant substrate=cobbles and stones
|River corridor land use=orchards (orange and lemmon trees)
|Average bankfull channel width category=10 - 50 m
|Average bankfull channel depth category=0.5 - 2 m
|Mean discharge category=1 - 10 m³/s
}}
{{Project background}}
{{Motivations}}
{{Measures}}
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|Link=www.nwrm.eu/sites/default/files/case_studies_ressources/cs-pt-01-final_version.pdf
|Description=Case study for NRWM: Natural bank stabilization and riparian buffer galleries along the Odelouca River, Portugal
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Case study:Restoration of R. Odelouca 2

2015-10-13T15:04:38Z

Samj:

{{Case study status
|Approval status=Draft
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{{Location
|Location=37.244909528644136, -8.497407641261816
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{{Project overview
|Status=Complete
|Themes=Environmental flows and water resources, Fisheries, Hydromorphology, Monitoring
|Country=Portugal
|Main contact forename=Rui
|Main contact surname=Cortes
|Main contact id=Rcortes
|Contact organisation=UTAD
|Contact organisation url=www.utad.pt
|Partner organisations=Águas do Algarve, SA
|Multi-site=No
|Project summary=This is an integrated restoration programme in a Mediterranean catchment with a significant conservation value. R. Odelouca drains about 520 km2 and flows along 83 km from an altitude of 509 m, discharging at about sea level into the Arade estuary. The basin drains mainly schists and greywackes from the Carbonic period. The climate is Mediterranean with oceanic influence, with warm to hot, dry summers and cool, wet winterThe construction of the River Odelouca dam for improving water supply in the Algarve region of south Portugal, located in Natura 2000 protected area, involved the definition of a variety of compensation measures including environmental requalification of selected river segments not affected by the reservoir. We cover the whole sequence of the project: a) characterization and selection of reaches to rehabilitate based on the definition of physiographic units and the relative quantification of impacts; b) implementation of soil engineering techniques for improving riparian habitat, bank stability and to control invasive species c) defining best river channel habitat improvement options for endangered endemic fish populations using two-dimensional hydraulic modeling (R2D); d) post-project appraisal and monitoring of floristic succession, fish, benthic fauna and habitat .

|Monitoring surveys and results=Upstream reaches show well-developed riparian vegetation galleries dominated by alders Alnus glutinosa, willows Salix spp. and ashes Fraxinus angustifolia, but below the dam, in the considered segment, banks are collapsing because of the fluvial erosion and agriculture (with dominance of orange orchards) and the invasive giant-reed Arundo donax finds here the appropriate conditions to spread even if Mediterranean sclerophyllous and evergreen scrub as well as cork oaks are still the characteristic landscape. Fish assemblages include a pool of native species, where we face the reduction of two endangered cyprinids _Iberochondrostoma almacai and chub Squalius aradensis. Other native species are present like the loach (Cobitis paludica), eel Anguilla anguilla and Barbus sclateri occurs sparsely (Pires et al., 2010). The degradation of habitat and water quality have given an increasing role to the highly abundant mosquito fish Gambusia holbrooki, and pumpkinseed Lepomis gibbosus, largemouth bass Micropterus salmoides, chameleon cichlid Australoheros facetus, carp Cyprinus carpio, and straight-mouth nase Pseudochondrostoma polylepis. The American crayfish has extended also its dispersion area after the artificial reservoir.
A laborious appraisal of the problem was assessed in all catchment by using different layers of information related to geology, climate and soil cover which allowed to define the physiographic units. Other layers containing descriptors of disturbance (habitat modification, roads, point and non-point pollution) allowed to define those units where rehabilitation should take place. The designed measures to stop the enlargement of the river channel, in the most critical reaches were based on soil engineering techniques after the convenient bank reprofiling, such as vegetated gabions and rip-rap and cribwall to stabilize the banks, whereas the invasive cane was controlled by a double-matt (organic and synthetic) of bio-degradable geotextile after clear cutting. In these places were also conducted an extensive plantation of riparian trees and shrubs to improve those measures and to control the advance of the invasive giant-reed. With that purpose plant material was collected in the area of the reservoir (before it was filled), and a plant nursery was created. Therefore there was a strict genetic control and plantation of trees (mainly ash trees and willows) and shrubs (such as Tamaryx and Oleander spp.) followed the observed longitudinal succession in previous surveys.
This study applied 2-D hydraulic simulations to evaluate the habitat improvement of two the two mentioned endangered cyprinid species, resulting from the implementation of distinct instream structures – i) placement of three islands in the middle of the river channel; ii) introduction of two lateral bays on opposite banks; and iii) introduction of four alternate current deflectors - in a modified river reach of a Mediterranean river. Though the use of such instream structures has been considered in many habitat improvement projects (e.g. Vehanen et al. 2003; Garcia de Jalón and Gortázar 2007), no previous analysis of their potential effectiveness on fish habitat has been carried out in non-salmonid rivers. This information can prove extremely useful elsewhere, namely in other Mediterranean-type rivers, where the implementation of instream structures and compensatory measures as a means of recovering other threatened fish populations has been questioned. The River2D model (Steffler 2000), was used with this purpose: This finite element model simulates hydraulic conditions from topographic data input and uses the habitat suitability index curves containing known fish biological preference data, to calculate the potential habitat for specific life-history stages by the Weighted Usable Area (WUA).
The habitat improvement measures were concluded in the end of spring 2012, and monitoring to assess its efficiency was conducted in specific periods in 2013 and 2014, which were compared to the previous situation. Such monitoring considered the succession of floristic communities in the river corridor, as well as in the aquatic habitat, where the surveys included benthic communities and fishes. In both years all sites were electrofished (DC, 300–700 V) during late spring−early summer base flow. In this period stream flows were lower (but still had full connectivity between habitats), thus ensuring a higher fishing efficiency (Oliveira et al., 2012). Electrofishing distances followed CEN standards for assessing fish species composition and abundance for wadeable sites (CEN, 2003). This distance was at least 20 times the mean wetted width of the channel to encompass complete sets of the characteristic stream form (e.g., riffles, pools, runs) with a minimum sampled length of 100 m. The entire widths of streams were fished by wading slowly upstream during daylight, using natural barriers, mostly shallow habitats, to delimit survey zones. To compare changes in fish communities and to evaluate the biological quality of sampled sites we used the fish-based index of biotic integrity for Portuguese wadeable streams (F-IBIP) (INAG and AFN, 2012).
Results and Discussion
In the two-year study it was collected 11 species of fish (seven native, three exotic and one translocated taxa), representing a total of 4521 individuals. In both years fish communities were clearly dominated by three species (A. anguilla, C. paludica, and G. holbrooki), which represented more than 70% in almost all samples. The populations of native cyprinids have always represented a small fraction of the communities, although they were present in all 2011 sites; however, these species were absent from segments E and K in 2012, the most degraded stream reaches of our study. The abundance of alien species varied considerably between segments and years, but generally represented a relevant proportion (> 25%) of the total species. Our results also seem to indicate a dispersion of the translocated species P. polylepis – an endemic species to central Portugal – with the number of occurrences increasing from 2011 (one site) to 2012 (three sites). Thus, independently of the year of study, all segments presented highly degraded fish communities, dominated by very tolerant species, with low proportion of native invertivores cyprinids and native lithophilics, and with a significant presence of alien forms. Results of the F-IBIP calculation reflected these observations, with all stream reaches presenting bad or poor biological quality in both years; in three of the segments (E, K, M) the F-IBIP score was even lower than in 2012, decreasing from poor to bad.

|Lessons learn=The success of the defined measures was hampered by three principal factors, firstly failure to engage local landowners early in the programme; the timing of key tasks, such as planting riparian trees; continued difficulty to control sources of environmental disturbance, in particular serious and continuous point pollution from animal husbandry. Consequently fish assemblages in all stream reaches were still dominated by aliens and highly tolerant species, and native cyprinids were low abundant or absent, revealing the fish index of biotic integrity a low environmental quality.
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|File name=Restored segment 1.JPG
|Caption=restored section: invasive species were erradicated and replaced by a willow after a cribwall structure
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|File name=Restored segment 2.JPG
|Caption=Exotic species (giant reed) were replaced by willows, after cutting of invasive species and stabilization of bank with cribwall
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|File name=Island for fishes.JPG
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|File name=Cribwall detail, with eucalypt logs.jpg
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|File name=Vegetated gabions.jpg
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|File name=Planting shrubs in organic matt after reprofiling.jpg
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|File name=Fiber matt with meditteranean shrub plantation.jpg
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{{Case study subcatchment}}
{{Site
|Name=River Odelouca
|Heavily modified water body=No
|Local site designation=iberian nase_Iberochondrostoma almacai and chub Squalius ar
|Protected species present=Yes
|Invasive species present=Yes
|Species=iberian nase_Iberochondrostoma almacai and chub Squalius aradensis.
|Dominant hydrology=mediterranean river with intermittent flow
|Dominant substrate=cobbles and stones
|River corridor land use=orchards (orange and lemmon trees)
|Average bankfull channel width category=10 - 50 m
|Average bankfull channel depth category=0.5 - 2 m
|Mean discharge category=1 - 10 m³/s
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{{Project background}}
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{{Hydromorphological quality elements header}}
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{{Monitoring documents}}
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{{Additional Documents}}
{{Additional Documents end}}
{{Additional links and references header}}
{{Additional links and references
|Link=http://www.nwrm.eu/sites/default/files/case_studies_ressources/cs-pt-01-final_version.pdf
|Description=Case study for NRWM: Natural bank stabilization and riparian buffer galleries along the Odelouca River, Portugal
}}
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{{Supplementary Information}}
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