Property:Monitoring surveys and results
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G
Following the implementations, the river seems more biologically active with greater fish populations. The flow of the channel is also greatly improved and the issues of slow velocities and silting-up of the channel are no longer present. +
R
For all phases, visual inspections and regular fixed-point photographs are being undertaken to monitor the integrity and performance of the enhancement works and record any changes they are making to river morphology. Specific to Phase 2, modifications to the channel profile as a result of the woody material introduction upstream of Dunkirk Cottage can be determined by comparison with a baseline cross-section in this location and the effects on turbidity and invertebrate populations will also be monitored here. For phase 3, in addition to an annual redd (trout spawning “nest”) survey of the new riffles, the established annual fish monitoring downstream of Easton Walled Garden and invertebrate sampling at Easton Lane Bridge will be used to detect any changes as a result of the works. +
S
For all sites where construction work has taken place an extended phase 1 habitat survey and subsequent protected species surveys including badger, otter, bat and water vole have taken place. A large amount of badger work had to be done including closing a number of setts under license. On-going monitoring took place during and after the construction works. A mitigation sett was created and is well used with new foraging routes and evidence of bedding being changed.
All of the new planting works are subject to a 5 year monitoring and maintenance program to ensure establishment. The areas are vegetating up well and will be regularly checked by a landscape architect to ensure they continue in this way.
The EA has a regular WFD monitoring looking at the biological and physio-chemical elements of the watercourses in the area.
Beetles and incidental invertebrates are being recorded by a volunteer VC55 Recorder at Ellis meadows to record pioneer species. Botanical surveys for the phase 1 works are being undertaken by the city ecologist and the Leicestershire & Rutland Ornithological society undertake monthly bird recording
Waterside Care groups report on group activity and habitat work. To date the river Soar groups have undertaken 348 volunteer hours and removed 98 bags of rubbish from the Soar and undertaken & water quality testing activities. This water quality data is submitted to the EA and in time we will be able to monitor any change. In addition six community groups around the city monitor water quality and submit results to FreshWater Watch
The University of Southampton have undertaken a sediment fingerprinting study on the Willow brook catchment and this will feed into future work on NFM and sediment management. +
W
For each scheme we monitor the impacts of restoration on fish, invertebrates, aquatic macrophytes, and protected species (e.g. water vole). Fixed point photography is also undertaken. +
D
For evaluation including results of resident acceptance survey and data of rain garden hydrological performance see http://www.susdrain.org/case-studies/case_studies/nottingham_green_streets_retrofit_rain_garden_project.html +
R
For wider project benefits as part of the larger "River Wandle Restoration Scheme" please see the parent project.
Monitoring was completed for Mycofilters, Siltex, Smart Sponges and Downstream Defenders.
Downstream Defenders: A Downstream Defender (DD) was monitored using upstream and downstream flow meters and water samples were taken using autosamplers during heavy rainfall events. Samples were sent to a UKAS accredited lab to be analysed, and contaminant load was calculated. The surface water pipe along which the DD was positioned had unexpectedly high flows (up to 50 l/s). When flows were within the operating range of the DD it was effective at removing around 47% of Total Suspended Solids (TSS), however, over the a whole data period it removed 9%. These numbers are within the range found by Dr Thomas Curwell, who investigated multiple rainfall events in DDs and found that they were effective in removing 9-49% TSS. Despite the low removal inefficiencies, the units remain the most effective measure if only a few square meters are available to SERT's knowledge, and are likely to have a cumulatively positive effect. The Trust are currently working on a sediment trap-wetland treatment train in an area where there is more space as an alternative method, following promising results from the scientific literature.
Mycofilters: Upstream and downstream water samples were taken for Mycofilter sites and control sites (using straw bags with no oyster mushroom).
Smart Sponges: The concentration of hydrocarbons collected in the gully pots with and without the sponges is being monitored.
Siltex: Silt and water are being monitored. +
G
From the analysis of over 2 years of river flow and in-stream sediment concentration data prior to, and following the diversion of Glaisdale Beck, it is clear that the sediment transfer regime has become more restrictive. This is evidenced by
- Reductions in median suspended sediment concentrations from 35.19 to 18.98 mg/L,
– 5 % reduction in flow-weighted mean sediment concentrations.
– Negative trend in sediment concentrations.
- Dampened response of sediment concentration during periods of high flow.
Although direct monitoring of the hydrology and sediment dynamics at Glaisdale beck was concluded in 2009, 2 years after the channel diversion, the longer term development of the site was observed through site visits up until 2014. During this period, continued erosion in the form of a headward migrating knick point (visible as a step in the river bed) has resulted in a progressive wave of channel instability that has migrated upstream. This is the response to over-steepening of the channel gradient in the vicinity of the original channel diversion.
Due to a lack of appropriately engineered grade control (drop) structures in the engineered reach this has resulted in channel bed lowering, bank undercutting and lateral bank failures upstream. During this time extensive bank erosion and channel widening occurred. At this particular site, erosion was evident only 2 weeks after the initial diversion with the knickpoint migrating through the reach, lowering the bed elevation. In response, the banks started to slump. However, due to increased channel width the final phase of bank collapse resulted in a soil wedge at the base of the bank which appears to have protected the toe of the bank preventing further lateral expansion. +
D
Frome: Plant and soil surveys twice a year to show enhanced diversification of floodplain sward through ditch clearance. Pre and post electrofishing surveys to monitor improvements to fish habitats in the opened up channels.
Corfe River: Pre and post photographs over a number of years and water quality testing to show development of marginal vegetation and improvements to historically badly managed areas.
Bourne Stream: Bathing water quality testing to monitor changes in water quality entering the Sea from the Bourne.
Tarrant: Plant and soil surveys twice each summer for 5 years and monthly Dipwell data to be written up annually and evaluated at the end of 5yrs.
Stour: Netting of fry bays to see use by coarse fish during regular periods throughout the year. +
W
Further monitoring will be needed to deduce the level of improvements resulting from our works. However, as a start, BART note the following:
Electrofishing surveys at 5 sites along the Wellow Brook (pre-barrier removal and woody habitat installation)
Visibly improved flow diversity – levels dropped by 0.5 metres and new gravel bars and riffles exposed
Visibly reduced sedimentation of the riverbed in the weir removal project areas which will result in improved spawning potential in the coming years.
Local angling club feedback: “Mayflies absolutely off the chart at the moment, free rising trout and a squadron of ducklings in the background at the end of the clip. Heaven. The Wellow is having a super year @Bristol Avon Rivers Trust thanks for all the in-river improvements, they really seem to be having an impact!”
We have had a huge amount of positive feedback from our engagement sessions, including: “Thank you … it was a brilliant day. All the staff are now talking about taking their classes down to the river back and feeling more confident about the activity. The children learnt a lot about the creatures living in their local river and the parents thought it was a really well organised event.” +
R
Habitat diversity, bird species, fish densities are included. Improved fish density and catchment. +
H
Half field trials have been undertaken to assess the effect subsoiling and grassland aeration have on soil infiltration rates.
Leaky woody dams are being monitored to assess their effect on the flood hydrograph and in-channel geomorphology and habitats. FWAG SW are working with Bristol University and providing sites to monitor; so far monitoring equipment has been installed in a floodplain storage scheme and other sites are being identified for investigation.
Results to be made available in due course. +
Healthy Rivers works in close partnership with NRW to monitor the rivers to access the impact of fish passes and modifications. Healthy Rivers works with NRW to electro fish rivers to monitor the fish stocks and carry out walkover to record salmon and trout redds. In the winter of 2013 walkover surveys discovered the presence of salmon redds in the upper reaches of the River Sirhowy for the first time in 100 years as a direct result of removing and modifying weirs further downstream.
Fish passes are regularly monitored to ensure that they are working effectively and not becoming clogged up with floating debris. Each project is evaluated upon completion to assess what went well and what could be done better next time. This evaluation process is essential in improving process and projects in the future
We record monthly programme data in Programme Performance Measures which records: number of projects, area of land improved, number of volunteers, schools engaged and litter and waste removed from green spaces.
Groundwork Wales is Investors In People certified and working towards Investors In Volunteers which requires regular monitoring and evaluation of volunteer experiences and reviews of training achieved by volunteers and staff. +
A
Hydrological and ecological parameters are regularly monitored. This includes water levels, discharges, bed profiles, terrestrial biodiversity, water quality and macroinvertebrate numbers. +
Z
Hydrological and ecological parameters are regularly monitored. This includes water levels, discharges, bed profiles, terrestrial biodiversity, water quality and macroinvertebrate numbers. The new mowing regime increases the inundation risk of upstream areas, which are mitigated by local mowing. +
G
Immediately after mowing, variation in flow velocity was observed and the fish population increased. However, the effect on water quality was very small. The water has remained eutrophic and the existing domination of floating vegetation was not broken. Instead, the species that were already abundantly present covered a larger area two years after mowing. The composition of the macroinvertebrate population differed between mowing regimes in the first year of the experiment, but showed a return to normal conditions in the second year. +
P
Implement improved riparian habitat in the River Borgie - commercial forestry within riparian zones will be replaced with native riparian woodland and old forestry drainage ditches will be blocked - 55280 tress planted in the target area. +
Implement improved riparian habitat in the River Oykel - commercial forestry within riparian zones will be replaced with native riparian woodland and old forestry drainage ditches will be blocked - 49,000 tress planted along the target area. +
Implement improved riparian habitat in the River Evelix - commercial forestry within riparian zones will be replaced with native riparian woodland and old forestry drainage ditches will be blocked - 3720 trees planted in the target area.
Reduce nutrient and sediment input from diffuse pollution sources in the River Evelix - the Evelix catchment will be surveyed, using established best practice methods, to establish potential diffuse pollution sources and their likely impacts on freshwater pearl mussel populations. The survey work will identify the key strategic points within the catchment where concrete conservation action to reduce nutrient and sediment inputs will be most appropriate. This will be delivered through SRDP schemes - pearl mussel surveys were undertaken at 16 locations over a wide area of the Evelix catchment. this facilitated a great understanding of the spatial distribution and abundance of pearl mussels in the catchment. +
R
In 2010, before the demolition, the Seine-Normandie Water agency established a monitoring point (physical-chemical quality, macro-invertebrates, diatoms) 200 metres upstream of the weir. This monitoring point is checked every two months for the physical-chemical data and every two years on average for the hydrobiological data.
Post-works monitoring was carried out one month, six months and one year after the demolition, directly by Onema and the Water agency. This monitoring dealt with the spawning redds of sea lampreys and with the hydromorphological compartment (topography, flow patterns, substrate measurements, etc.).
The Departmental federation for fishing and the protection of aquatic environments for the Manche department monitors each year salmon populations, including an index on the abundance of juvenile salmon.
In 2012, the geomorphology (erosion dynamics, stream power, etc.) was monitored by an intern from the University of Caen. The Intermunicipal board for the development and maintenance of the Sienne (SIAES) undertook photographic monitoring of the changes in the riverbed and the banks for the first three years following the project.
The removal of the Ver mill weir made possible a return to a natural riverbed in the formerly impounded reach, over a distance of 1.7 kilometres.
The elimination of the reservoir resulted in an array of diverse flow patterns of running water. For example, seven riffles reappeared, alternating with rapids and more lentic flow patterns. The return of the riffles has made available a surface area of 2 400 square metres suitable as spawning habitats for fish species.
The removal of the weir also significantly improved the upstream migration conditions (wounds, delays, etc.) for salmonids, eels and sea lampreys between the English Channel and the Airou tributary. In 2012, 13 spawning redds for sea lampreys were observed on the site of the former impoundment, thus confirming the suitability of the habitats made available following the elimination of the structure.
The discovery of riffles in the sector entailed the creation of a monitoring point for the abundance index of salmon juveniles (IAS index). In 2011, the index stood at 49 at the monitoring point (high status). That represents significant progress for the monitoring point because the index was zero (no riffles) prior to the removal of the weir. These results indicate effective restoration of continuity for fish. The areas upstream of the Ver mill are now available and the suitability of the reproduction habitats in the former impoundment is also manifest.
An increase in fishing activities has also been observed in the sector, due notably to the increase in the salmon population.
However, the improvement in the passage of migratory fish at the Ver mill is limited by the existence of other structures blocking movement in the river. There remain two or three structures that make passage difficult or impossible for fish and block their access to spawning redds upstream and in the tributaries.
The physical-chemical monitoring revealed an improvement in the oxygenation of the river waters and the river effectively achieved good physical-chemical status in 2011. Samples of benthic macro-invertebrates taken in the years following the removal of the weir indicate very high habitat quality.
Geomorphologically speaking, the Sienne would appear to have returned to a more natural hydraulic gradient. Post works, major quantities of coarse sediment reappeared on the site of the former impoundment. This sediment has been and continues to be transported by two-year winter floods. The river has also recommenced natural adjustment via lateral erosion in the concavity sections of meanders.
In 2010, the Seine-Normandie Water agency launched a study to obtain a comprehensive and shared assessment of the hydraulic structures in the Sienne basin. The study contained proposals for work on structures to restore river continuity, taking into account local environmental, economic and social issues, while also assessing the value of maintaining the structures. The overall objective of the study was to look at a strategy to restore river continuity in the Sienne basin, taking into account the heritage value of the structures.
C
In 2016, a total 7818 fish were recorded migrating upstream, mainly in April-May and October. Bream Abramis brama dominated with almost 5000 individuals, followed by anadromous species – sea trout Salmo trutta L., and vimba Vimba vimba at 8111 and 1123 respectively. Asp Aspius aspius, barbel Barbus barbus, catfish Silurus glanis, carp Cyprinus carpio, ide Leuciscus idus, perch Perca fluviatilis, atlantic salmon Salmo salar, chub Leuciscus cephalus, grass carp Carassius gibelio and roach Rutilus rutilus were also noted. The total number of fish were almost two times higher than in 2015 (Dębowski 2017). During present year tens of thousands of records were collected and still under analyzing. Much more numerous in this year is vimba and white bream Abramis bjoerkna. Also, white-eye bream Ballerus sapa was recorded.
In 2016, system with six PIT antennas was lunched in fishpass. First antennae on the entrance, second on the first corner, two next below and above Vaki scanner, fifth on last corner and last on the exit. Nine adult sea trout were caught in trap installed in last fishpass chamber and tagged with 12 mm PITs in November during spawning migration. Tagged fish were released after anesthesia below dam. Four of them again entered a fishway and move upstream. One female which successfully passed was recaptured half year later in Gulf of Gdańsk by commercial fisherman. In 2017 new experiment with three antennae system has been conducted. In 18 October, 112 specimens from nine species included; bream, asp, vimba, sea trout, dace, barbel, ide, white-eyed bream and bleak were tagged and released below the weir. The system is already running. +