Dresnagh 001 Riparian and Instream Works
The Dresnagh 001
The Dresnagh Habitat Improvement Works is located between 226266 E, 394153 N and 225588 E, 393501 N (Irish Grid Reference). The land in this area is primarily improved agricultural land all along the stretch, although there are some urban housing developments present also.
There are many different pressures in this area such as:
The Finn catchment is an area of high biodiversity and conservation value. The area is protected by a number of National and International designations that can be explored on this map.
The Dresnagh_001 waterbody has been identified as an ‘Area for Action’ within the second cycle River Basin Management Plan for Ireland 2018-2021. These actions will be prioritised to achieve WFD objectives and will be directed towards pressures such as agriculture, urban waste water, domestic wastewater and forestry.
Issues on Site
The Dresnagh River at this section suffers from erosion on both sides along its length. The site has no or very little buffer zone with fencing at approximately 0.5m from the water’s edge on both sides (when going through agricultural land). Site walkovers undertaken by CatchmentCARE in the prioritisation elements of the projected highlighted evidence of livestock entering the river at numerous points and significant poaching. Some fencing was even observed in the river to facilitate livestock access to drinking water. This is likely due to the high quality of the land, which is used primarily for dairy cattle. The river itself has been straightened and deepened at several locations and these areas lack habitat diversity for fish. The proximity of agricultural land, poaching and natural debris dams were issues that impacted the RHAT Score.
Data before Works
Prior to the works this site was identified as requiring environmental improvement measures based on surveys undertaken in the prioritization elements of the CatchmentCARE project. The metrics surveyed included RHATS (River Hydromorphology Assessment Techniques), macroinvertebrates surveys, fish EQRs (Ecological Quality Ratios) and chemical exports. Every potential site was also walked over by the CatchmentCARE team in order to design bespoke remediation works for the site .
RHAT Survey - Moderate
The River Hydromorphological Assessment Technique (RHAT) is a survey developed by NIEA specifically for the Water Framework Directive (Murphy and Toland, 2012). Hydromorphology describes the physical habitat of a river constituted by the physical form (abiotic and biotic) and flow of the river.
RHAT is designed to be a holistic visual assessment and can be used to assess individual sites. This generates data for 8 relevant variables of habitat quality within 10 sub-sections of a 500m length of channel. Key elements include the flow, sediment type, channel and floodplain dimensions, topography and substratum, continuity and connectivity of a river. Anthropogenic features such as bank protection works, artificial barriers (weirs, dams) and modifications to processes are also included. It is assumed that natural systems support ecology better than modified systems. Hence the RHAT method classifies river hydromorphology based on a departure from naturalness. It assigns a morphological classification directly related to that of the WFD: High, Good, Moderate, Poor and Bad, based on semi-qualitative and quantitative criteria.
More detailed information can be found in the RHAT guidance handbook
Fish EQR – Moderate
Electric fishing is undertaken as the standard sampling strategy. A timed, 10-minute fishing protocol is used. In shallow water locations electofishing backpacks are used as a power source and a team of two or three persons undertake the fishing, wading in an upstream direction, one undertaking the fishing and one carrying a bucket to retain captured fish. All fish encountered during the 10-minute fishing period, including crayfish and larval lamprey, are collected and retained in a holding bucket of clean water. All fish are subsequently measured and held in a recovery bin of water from the sampling site until all data collection is completed. Fish are then returned into the sampling site on completion of the site survey. Key elements of the data collection are (a) recording of all fish species encountered i.e. the fish community composition and (b) the length range of all fish within any species (Note: Loughs Agency record length range for salmonids only).
Macroinvertebrates- Stream at Risk
An agreement between the Loughs Agency and IFI was made to use the ‘Small Stream Risk Score’ method as a component of the overall EQR value for waterbodies on the Finn. These will be carried out by LA and DCC staff at the same sites that 10 minute electrofishing surveys take place, which are an additional component of the overall EQR scoring system. These data will be used to establish a baseline and will be monitored throughout the life of the project.
Data collected on macroinvertebrate populations will be in a format which can be used to calculate Q-Value scores (which are the standard EPA scoring system) and ASPT & BMWP Scores (which are the standard scoring systems used in Northern Ireland). This will allow these data to be compared temporally to data collected by the LA and EPA at corresponding sites in the past, facilitating observation of a longer trend in data for the use of CatchmentCARE project objectives.
Chemical Export
Remediation Works
Each work package carried out by the Loughs Agency within the Finn Catchment SAC has undergone a thorough Appropriate Assessment and has received approval from the National Parks and Wildlife Service (NPWS). The appropriate assessment for this package can be found bellow:
The Loughs Agency, as a partner of the CatchmentCARE Project, proposed to carry out stream bank improvement works and instream improvement works along both banks of the Dresnagh River near Castlefinn, which is a tributary of the River Finn in the Finn River Catchment, Co. Donegal. The Riparian work involves the installation of fencing and replacement of old fencing to create a riparian buffer zone, installation of 1800mm unigates, stiles and installation of water troughs for livestock using solar powered water pumps to provide a source of drinking water in lieu of access to the river by livestock. Bush trimming will also be carried out over approximately two thirds of the stretch in a targeted manner to increase the amount of light penetrating to the rivers surface. A small area of the river mouth, at the confluence to the Finn River, has been impacted with silt and this was removed. Some small areas of land needed to be cleared and levelled by plant machinery to allow for the placement of fencing. Cleared material can be deposited on site at locations designated by the landowners. A barrier to fish migration was also removed at one location and replaced with a clear span structure to allow landowners to access their land across the river. These works will be conducted between the co-ordinates 54.798605N -7.593277W (Irish Grid: 226204E 394584N) & 54.781070N -7.613610W (Irish Grid: 224908E 392625N).
Below is a list of the installations, including quantities, which comprise the Riparian works: • 5,144m of fencing, including posts, splitters and strainers where appropriate. • Plant machinery with bush trimming attachment and/ or cherry picker to thin trees that are blocking light to river; • 35 x Unigates; • 2 x double 8ft wooden gates; • 1 x 8ft wooden gate; • 19 x stiles; • 24 x Low spec Solar powered pumps and associated screens, filters and pipes; • 4 x high spec Solar powered pumps and associated screens, filters and pipes to pump water to a higher elevation and a further distance than low spec pumps; • 73 x 80 Gallon twin reservoir Drinking Troughs; • 4 x 14ft Galvanised steel sheep gates; • Plant machinery with long digger arm to remove silt from area near confluence with River Finn – Silt to be disposed of offsite in appropriate manner.
Within the habitat improvement works in this area there has been an installation of 5,144m of fencing, which also includes the installation of posts, splitters and strainers where appropriate. This fencing was a mix of new fencing and replacement of old fencing to prevent livestock entering the Dresnagh River. The majority of the fencing was sheep wire, however, there was an 806m length of fencing which simply needed the addition of two lines of horizontal barbed wire to the existing fence, with replacement of a few of the older posts. Of the sheep wire above, posts for a length of 530m needed to be creosote treated to meet the aesthetic of the area in which they were installed (a recreational walk). Approx. 626m of fencing was comprised of two strands of high tensile electrified fence fitted with appropriate batteries fitted with solar powered recharging units.
Due to fencing preventing livestock from entering the river landowners were provided with 28 solar powered pasture pumps and 73 80 gallon twin reservoir troughs for their livestock. They have been installed in various areas throughout the stretch.
For access within the fenced off margins there has been the installation of 19 stiles, 1 single wooden gate, 2 double wooden gates, 35 unigates and 4 14ft gates.
Bush trimming was completed in approximately two thirds of the work area over an estimated 2152m stretch to reduce the dense overgrowing canopy and allowing light into these areas. Trimming was targeted so as to provide an increase in light penetration through the tree canopy to the rivers surface.
Other remediation projects included the restoration of an old bridge that landowners used for field access. The bridge was deteriorating and could have hampered fish migration in the river if it had collapsed. Furthermore, the bridge had an uneven, rough surface, which could pose a safety risk to users. The construction of a new, more stable clear span bridge was a good option to solve the problems that came with the existing bridge. The new concrete bridge is more secure and long-lasting than the old one. The new bridge also includes hand rails on both sides for user safety. A gate was installed at one side of the bridge to prevent cattle from roaming freely between fields.
Sheep Dips
The CatchmentCARE Team in partnership with Teagasc have created a best practice demonstration video for the correct procedures for dipping sheep and the disposal of spent sheep dip as well as an infographic leaflet on the correct disposal of spent sheep dip.
CatchmentCARE & Teagasc Sheep Dip Demonstration
Info-graphic advising on the safe disposal of sheep dip can be found here:
Info-graphic on Good Agricultural Practice for the Protection of Waters can be found here:
Outcome based Results
RHAT - Moderate
2022 Survey (Survey completed prior to bridge completion)
RHAT Moderate
The River Hydromorphological Assessment Technique (RHAT) is a survey developed by NIEA specifically for the Water Framework Directive (Murphy and Toland, 2012). Hydromorphology describes the physical habitat of a river constituted by the physical form (abiotic and biotic) and flow of the river.
RHAT is designed to be a holistic visual assessment and can be used to assess individual sites. This generates data for 8 relevant variables of habitat quality within 10 sub-sections of a 500m length of channel. Key elements include the flow, sediment type, channel and floodplain dimensions, topography and substratum, continuity and connectivity of a river. Anthropogenic features such as bank protection works, artificial barriers (weirs, dams) and modifications to processes are also included. It is assumed that natural systems support ecology better than modified systems. Hence the RHAT method classifies river hydromorphology based on a departure from naturalness. It assigns a morphological classification directly related to that of the WFD: High, Good, Moderate, Poor and Bad, based on semi-qualitative and quantitative criteria.
Macroinvertebrates - Bad
2022 Autumn Survey (Survey completed before barrier removal and replacement completion)
Macros- Bad
An agreement between the Loughs Agency and IFI was made to use the ‘Small Stream Risk Score’ method as a component of the overall EQR value for waterbodies on the Finn. These will be carried out by LA and DCC staff at the same sites that 10 minute electrofishing surveys take place, which are an additional component of the overall EQR scoring system. These data will be used to establish a baseline and will be monitored throughout the life of the project.
Data collected on macroinvertebrate populations will be in a format which can be used to calculate Q-Value scores (which are the standard EPA scoring system) and ASPT & BMWP Scores (which are the standard scoring systems used in Northern Ireland). This will allow these data to be compared temporally to data collected by the LA and EPA at corresponding sites in the past, facilitating observation of a longer trend in data for the use of CatchmentCARE project objectives.
Fish EQR - Moderate
2022 Survey (Survey completed during Riparian works and Bridge Completion)
Fish EQR - Moderate
Electric fishing is undertaken as the standard sampling strategy. A timed, 10-minute fishing protocol is used. In shallow water locations electofishing backpacks are used as a power source and a team of two or three persons undertake the fishing, wading in an upstream direction, one undertaking the fishing and one carrying a bucket to retain captured fish. All fish encountered during the 10-minute fishing period, including crayfish and larval lamprey, are collected and retained in a holding bucket of clean water. All fish are subsequently measured and held in a recovery bin of water from the sampling site until all data collection is completed. Fish are then returned into the sampling site on completion of the site survey. Key elements of the data collection are (a) recording of all fish species encountered i.e. the fish community composition and (b) the length range of all fish within any species (Note: Loughs Agency record length range for salmonids only).
Project Legacy
All restoration projects completed under the CatchmentCARE Project in the Finn Catchment have a built in legacy element. The sites will continue to be monitored by Loughs Agency using macroinvertebrate surveys and electrofishing so that any changes in the river fauna can be detected over time. There is a need to be mindful of seasonal changes and natural fluctuations in the rivers which can only be accurately ascertained with continuous monitoring. Many of the mitigations put in place by the CatchmentCARE Project could take years to really meet their full potential in terms of improving water quality. Legacy sampling regimes will help give a clearer understanding of how works undertaken by CatchmentCARE impact the rivers in the long term.