Property:Monitoring surveys and results
Jump to navigation
Jump to search
This is a property of type Text.
E
Elimination of a pond along the Erve River and conservation of the historical heritage in Sainte-Suzanne-et-Chammes +
The natural evolution of the river is monitored by the River board which may decide to intervene in certain areas, if necessary.
The pre-works monitoring was carried out in 2010 outside the zone of influence of the former reservoir and dealt with the benthic macrofauna (WFD- IBG biological index). No hydromorphological monitoring was done during the project.
Since the elimination of the flap gates in 2011, annual monitoring of the fish community (IPR index), the benthic macrofauna (WFD- IBG biological index) and diatoms (IBD index) has been carried out. This monitoring work was undertaken inside the zone of influence of the former reservoir.
Visually speaking, the project is a success and the river rapidly carved out its bed in the area previously occupied by the reservoir. Vegetation colonised the banks, thus creating alternating zones of light and shade along the river. The flow patterns became more diversified and the previously uniform substrate now varies between sand, stones and large rocks. A general improvement in the fish and invertebrate compartments is due to the diversification of habitats in the former impounded reach (1.3 km).
The results of the macro-invertebrate and diatom indices are positive, including a significant improvement in the WFD- IBG biological index from 2012 to 2014. The level of quality for the index was quite high in 2014, with greater taxonomic richness and the presence of taxa more sensitive to pollutants.
For the IBD diatom index, the situation has remained stable since 2011, with a varied and balanced diatom community and high physical-chemical quality of the water, notably in terms of nutrients (nitrogen, phosphorous, suspended matter, etc.).
Monitoring of the fish community revealed a reduction in the number of species adapted to lentic environments (roach, bream) or those less sensitive to the quality of the environment (stone loach), and an increase in species adapted to lotic environments (bullheads, minnows). No juvenile trout were noted in the sector, an indication that the necessary reproductive conditions may not be available for the species. In 2014, no eels or brook lampreys had yet been observed on the site. Their absence may be due to the presence, downstream, of transversal structures that block the movement of the species.
This project opened up 2.6 km of river in the upper section of the Erve basin. River continuity nonetheless remains a serious problem because there are still 22 weirs downstream that block the movement of fish and the nearest is only 400 metres away.
R
The new Lower Rossåga power plant was commissioned on July 26, 2016, and the first fish studies in the river (juvenile fish recording by electrofishing from a boat) were carried out after about two months of operating the new water supply in the "Sjøforsløpet". A spawning fish count was carried out in mid-October. The juvenile fish records showed that juvenile salmon had already taken up the new river stretch, and the relative density was almost as high as in the best production areas further down the river. The spawning fish count showed that well over 50 salmon, or approx. 30% of all salmon observed in Rossåga stayed in the "Sjøforsløpet" during the spawning season. +
The new gravel islands enhance the landscape and the Danube as a natural habitat. The LIFE Nature project has linked dry old tributaries to the Danube once again and created refuges for fish fauna. The higher reaches of the slopes which lead down to the Danube are predominantly forested and are of special significance as protection and recreational forests. Dry grasslands & grassy slopes
64ha of forests have been transformed into natural forests and sustainable management has been established for 80 ha of dry meadows. The project has undertaken intensive media work and networking activities with experts from Austria, Germany, Switzerland, Japan, and Poland. The project was awarded first prize in the ‘Milestones - Dr. Erwin Pröll future prize’ in the ‘In Uniso with Nature’ category.
Further information on the monitoring can be found in the project websites and additional links (see references) +
K
The number of species causing an increase in upstream water level has declined. +
S
The original stream valley vegetation has re-established eitself in the area. As a consequence, the rare brook lamprey (Dutch: beekprik) can now be found in the stream again. Water retention has increased as well, so that downstream peak discharges and erosion can be mitigated. +
The original stream valley vegetation types have started to recover after the measure was implemented. The water retention capacity of the stream has improved as well. +
N
The outcomes of the project are planned to be the following:improving water quality and river and floodplain habitats. +
The outcomes of the project are planned to be the following:improving water quality and river and floodplain habitats. +
The outcomes of the project are planned to be the following:improving water quality and river and floodplain habitats. +
The outcomes of the project are planned to be the following:improving water quality and river and floodplain habitats. +
The outcomes of the project are planned to be:
improving water quality and river and floodplain habitats. +
The outcomes of the project are planned to be:improving water quality and river and floodplain habitats. +
The outcomes of the project are planned as the following:improving water quality and river and floodplain habitats. +
The outcomes of the project are the following:improving water quality and river and floodplain habitats. +
H
The outlet of the stream has become richer in great manna grass and sludge. The stream remains within its planned meandering zone. The lower temperature proves suitable for species that prefer higher flow velocities, like fish and dragonflies. +
C
The overall scheme has an integrated maintenance and management plan, while wetland has separate maintenance and management plan written by Wildfowl & Wetlands Trust and with prime focus of this being simplicity of management. With both plans integrated as part of site’s long term maintenance, this will ensure as the site develops and establishes, appropriate management will be conducted by agreed respective parties, to ensure in the long term the flood basin remains a functioning flood risk asset, but also an important new local wildlife and amenity resource for future.
Fixed point photography overlooking the new wetland has been installed on neighbouring flats which will monitor the establishment of newly constructed scheme.
The new wetland is also attracting interest from local monitoring groups, including Greater Manchester birders through Winter Wetland Bird Blitz organized by Greater Manchester Ecology Unit and results will be updated to the Greater Manchester Records Centre.
The University of Salford are also keen to monitor the wetland as part of their future courses for environmental studies. +
R
The pre works monitoring done in 2012 dealt with
the biological (benthic macroinvertebrates) and
morphological (topographic surveys of the long and
cross profiles, sedimentation levels) compartments.
The first survey after the works in 2015 (n+1) dealt
with the morphological compartment (topographic
surveys of the long and cross profiles, water depths,
substrates and current velocities) at four points along
the riverbed and the flood plain, in a zone stretching
400 metres upstream and downstream of the former
weir. The monitoring programme is scheduled to
continue for two more years (n+2 and n+3).
This project opened and restored 800 metres of the
Iton (though there remain five structures downstream
and 200 upstream) and restored 600 metres
of favourable habitats for category-1 species thanks
to the elimination of the impounded reach. Sediment
transport was previously blocked by the weir,
but has now been restored. The restoration of the
meadow provides the river with a flood expansion
zone and would appear to be a potential habitat for
the yellow-bellied toad, whose presence has been
observed near the site.
One year after the works, the hydromorphological
studies on the Iton at the site of the former weir revealed
a modification in the long profile with a drop
of 25 centimetres in the water level upstream and
an increase of 25 to 30 cm downstream. In economic
and flood-security terms, the project is beneficial for
SCA Tissue France in that the firm succeeded in protecting
its installations from the river and avoided
maintenance costs. The risk of accidental pollution
was reduced by returning the Courtieux stream to
the talweg and by filling in the factory channel.
However, due to the small amount of available land,
the new bed of the Courtieux stream is straight and
the banks could not be planted as planned.
The drop in the water level indirectly damaged the
foundations of the industrial installations along the
river by exposing them to freezing temperatures.
That being said, SCA Tissue France and its partners
consider the project a success because it met both
the economic and ecological objectives, thanks to
the technical support from Saviton and the implication
of the industrial company.
The pre-works baseline fish survey completed in 2012 recorded a total of 45 fish of 7 species. The repeat survey in 2013, one year after restoration, recorded 143 fish of 11 species. The improved habitat has seen 3-spined stickleback, brown trout, dace and stone loach moving into the reach. Fish density increased from 1.4 fish per 100m² in 2012 to 3.2 fish per 100m² in 2013. Fish standing crop saw a moderate drop from 2057 grams 100m² to 1606 grams per 100m² over the same period. The change in standing crop is largely accounted for by the reduction in numbers of pole caught in the 2013 sample.
Kick sampling for invertebrates has shown a post-restoration increase in the diversity of taxa in all but one of the sample locations within the restored reach. It was particularly exciting to find two species of stonefiles, which require a pebbly substrate with plenty of small spaces and high dissolved oxygen levels. Caseless caddis flies were absent from the pre-works survey, but were recorded across the whole reach in the post-works survey. These species required larger stable substrates and will have benefited from the installation of the gravel glides. Mayfly species diversity has increased in the post-restoration survey samples. Despite these encouraging signs the number of invertebrates found was quite low. This might indicate high predation pressure from the invasive non-native signal crayfish which are abundant in this section of the Wensum.
Aquatic plant populations remain poor on the restoration reach. Again, this may relate to the large population of signal crayfish. +
H
The preparatory studies and scientific work of the project partners was of excellent quality. Automatic water and sediment monitoring stations were installed at a lagoon and at the main river stream to provide continuous data which is sent automatically to the Fisheries Research Institute of the National Agricultural Research Foundation. +
F
The project achieved two main results. The project contributed towards the work by the competent authorities to reinstate a more natural flooding regime in the Dijle valley, which would increase water retention upstream and so prevent flooding in Leuven. It secured and restored large coherent blocks of land to Annex I habitat status, by removing poplar plantations, weekend cottages, overgrowth etc, re-modelling former fishponds and installing appropriate recurring management - partly in close collaboration with local farmers via a direct marketing scheme for environmentally sound produce. Hydrology and vegetation had been mapped before the project began. +