Hydromorphology is a relatively new discipline which is described in the Water Framework Directive. It refers to the physical character of the river and includes the flow of water in the river, the course the river takes or the form and shape of the river channel.
It stems from the term ‘fluvial geomorphology’, a subject that focuses on the processes of water and sediment movement and the features that these processes create in a river such as pools, riffles and glides. These processes and features create and maintain habitats for invertebrates, fish and plants.
Hydromorphology pressures are anything that impacts negatively on the form or flow of the a river, for example: weirs and dams which may impede fish passage; drainage works which straighten and deepen the channel and thereby damage important habitat features for aquatic species and soil or bank erosion which can cause siltation of the river bed.
Changes to the hydromorphological characteristics of surface waters is estimated to be a significant pressure in almost 29% of high status objective waterbodies that are At Risk of not meeting their environmental objectives. It is the most prevalent significant pressure within high surface objective water bodies.
Two of the catchments selected within the €20 million Waters of LIFE project deal with hydromorphology
River name: The Shournagh
Water Framework Directive Reference: Lee SC 060
Location: Co Cork (near Tower and Blarney)
Significant Pressures: Agriculture, Hydromorphology, domestic wastewater, urban runoff, OPW Area for Action
River name: The Awbeg
Water Framework Directive Reference: Blackwater SC 060
Location: Co. Cork (Near Kanturk)
Significant Pressures: Agriculture, Hydromorphology
Why are heavily modified waterbodies on peatland not included?
The EPA review considers the following specified uses:
- Water storage and regulation (i.e. major impounding structures such as dams and reservoirs);
- Flood protection;
- The urban environment;
- Arterial drainage;
It does not appear to directly consider heavily modified water bodies in the context of peatland drainage schemes and/or peatland rehabilitation schemes
Please note two IFI submissions on BnM hydromorphological conditions which do address the issues:
Correspondence between BnM and DAFM suggest that the main heavily modified water bodies will not be remediated as part of the current PCAS programme – the programme is very much aimed at improving water chemistry, not restoring the modified watercourses. This is only addressing half the problem, heavily modified waterbodies on peatland cannot support life.
Peatland pressures are listed in EPA data, but there does not appear to be a process in place similar to LAWPRO to ASSAP Ag Referrals to address those peatland pressures. In fact, the overall enforcement regime for peatland drainage is unclear, and unlicensed drainage/unlicensed peat extraction occurs at the same time on the same sites. There are ongoing issues with digging drainage for peat extraction on SACs, and drainage for peat extraction on sites that are hydrologically connected to SACs.
304 turloughs listed in the Geological Survey Ireland Karst Database (2006)
Extend along the Western region of Ireland, from Co. Donegal to Co. Cork, with clusters of turloughs occurring in Co. Clare, Co. Galway, Co. Mayo and Co. Roscommon.
Includes site reports and maps for 22 turloughs studied in detail
NPWS project investigated a relatively small number of turloughs (22 for most aspects of the project, and 8 sites for the invertebrate work)
For locations of turlough sites which might potentially end up being impacted e.g. by OPW drainage, a better source of information is the Geological Survey of Ireland karst database, which has national mapping of karst features including turloughs.
This is available to view online on their Groundwater Data Viewer at https://dcenr.maps.arcgis.com/apps/MapSeries/index.html?appid=bc0dba38f3f5477c8fd400f66b5eedcd
The turloughs are shown within the Groundwater Karst Data layer with a capital T inside a box. This dataset is also available for download from a link at https://www.gsi.ie/en-ie/data-and-maps/Pages/Groundwater.aspx#KarstFeatures
There are more than 300 turloughs in the database (unknown how many of them have been ground-truthed and verified)
Summary of threats to Turlough SACs
Adjacent quarry impact on hydrology
Fertiliser and grazing by sheep and cattle
Housing development and septic tanks
Overwintering of horses
Farm run off and slurry
Drainage, land reclamation and reseeding
Enrichment from abattoir
Enrichment from intensive dairy farms
Drainage and peat cutting
Soil excavation / turlough basin scraped out / permanent pond deepened
Options report on the current situation at Emyvale weir with a view to altering a proportion of river flow to favour the Mountain Water main channel downstream of Emyvale weir.
Under the current situation, the weir is in use to divert water to Emy Lough. The diverted water does not return to the Mountain Water from Emy Lough but rather flows directly into the Ulster Blackwater river.
This diversion creates a significant impact on hydromorphological conditions downstream as there are insufficient water volumes to sustain natural environmental regimes
The hydrology bulletin outlines the flows in rivers, rainfall, lake levels, groundwater levels and spring outflows of over 300 stations across Ireland.
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