Integrated Water Quality-South Eastern River Basin District 2013

The South Easterns River Basin (SERBD) is one of Ireland's largest river basin districts covering 13,000 km2 of land area and a further 1,000 km2 of marine waters.  The SERBD covers all of counties Carlow, Wexford and Kilkenny, most of Waterford, Tipperary and Laois, parts of Kildare, Offaly and Wicklow and a small part of Limerick and Cork.  The main catchments are the Barrlow, Nore and Suir catchments but there are also many smaller cathcments.  There are 151 groundwater bodies and five lakes in the SERBD and it is bounded by both the Celtic Sea and the Irish Sea.  The SERBD shares borders with the Eastern RBD, the South Western RBD and the Shannon International RBD.

While there are improvements in the physico-chemical quality in rivers in the south east with levels of ortho-phosphate and nitrate decreasing over the period since the WFD started, the average levels of both nutrients in rivers still exceed the EQS values.

Compliance with the ortho-phosphate EQS for good quality in the SERBD rivers is 50% which is slightly lower than the national figure of 59%. 
None of the five lakes in the SERBD are compliant with the EQS for good status for phosphorus which is the main nutrient of concern for the SERBD lakes.  Rivers in the south east also contribute 25% of the national nitrogen and phosphorus loading to the transitional and coastal water bodies (TrACs).

While the compliance with the phosphorus EQS in the SERBD is comparable with the national picture the compliance rate for nitrate in the SERBD rivers is almost half the national compliance rate.  Thirty-three percent of all rivers in the SERBD meet the Good quality EQS for nitrate as compared with 61% nationally.  Nitrate is also the main pressure on groundwater in the SERBD.

Rivers and lakes in the SERBD with Poor biological status typically display poor compliance with the phosphorus and/or nitrate EQS's.  In the most recent biological survey period (2011-2013) only 11% of the river monitoring stations achieved High status (Q5, 4-5).  There are no Q5 sites in the SERBD and 44% of the river monitoring stations fail to meet Good status.  Diffuse agricultural pressures and urban wastewater discharges are the main reasons why these sites are not achieving Good status.  Table 1 shows the suspected causes of pollution for river stations in the SERBD and the respective percentages for each pressure.

Suspected
Pressure

County
Carlow

County
Kilkenny
County
Laois
County
Tipperary
County
Waterford
County
Wexford
Total%
Agriculture 24 19 17 27 3 19 109 42.7%
Aquaculture       1     1 0.4%
DWWTS 2   1     1 4 1.6%
Hydro-morphology       3     3 1.2%
Industrial 4 2 2 9     17 6.7%
Landfill 1       1   2 0.8%
Mixed Rural Influences 10 8 8 10 1 8 45 17.6%
Siltation 4 1       1 6 2.4%
Urbanisation 5 4 3 5 1 2 20 7.8%
Urban Wastewater 10 7 7 11 3 10 48 18.8%

Table 1 - Suspected causes of pollution for SERBD river stations which are in an unsatisfactory condition (i.e. biological classification of less than Good status, <Q4.)

Nutrient enrichment (from both phosphorus and nitrate) is the main threat to water quality in the SERBD.  The main sources of these nutrients are runoff from agricultural land and discharges from urban wastewater treatment plants.  The main challenges towards improving water quality in the SERBD relate to eliminating these and other sources of pollution.  Where the source of the pollution is not readily identified investigations will be needed to determine the cuase and mitigation measures will then have to be put in place.  These mitigation measures, along with infrastructure investment in WWTP's, good agricultural practices and implementation of the south east river basin management plan (RBMP), which is currently under revision, should help to improve and maintain water quality into the future.

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Integrated Water Quality Report for the South Eastern River Basin District 2013