Surface Water and Groundwater Status
Donal Daly
Hydrometric & Groundwater Section
Environmental Protection Agency
Acknowledgement: Colleagues in EPA and on WFD Groundwater Working Group
WFD Water Status WFD Water Status ““A measure of the A measure of the
present”present”
Based on an evaluation of: pressures, physical settings
and monitoring results
Status is the key element determining the measures to be
employed in the RBD Management Plans to achieve the objectives of
the WFD
Ecological Status for Surface Waters
Pass WFD
Fail WFD
Surface Water Body Classification process
Interim Status Assessment of Rivers
River Quality – WFD Interim Status
Ecological Class Number of Water Bodies
HHiigghh 117733 ((99%%))
Good 738 (40%)
Moderate 509 (28%)
Poor 389 (21%)
Bad 41 (2%)
Interim Status Assessment of Lakes
Lake Quality – WFD Interim Status Biological Class Number of Lakes Surface Area (km2)
HHiigghh 7766 ((2288..00%% )) 336699..66 ((3377..11%% ))
Good 75 (27.7% ) 204.4 (20.5% )
Moderate 94 (34.7% ) 397.9 (40% )
Poor 17 (6.3% ) 7.1 (0.7% )
Bad 9 (3.3% ) 16.5 (1.7% )
Transitional and Coastal Water Status
Main Causes of “less than good” Status Surface Water Bodies Discharges from Wastewater
Treatment Plants (nutrients)
Diffuse Agriculture (resulting in inputs of P, PO4 and N)
Forestry (sediment and P)
Urban areas
GWBs are classified as either POOR or GWBs are classified as either POOR or GOOD STATUS for GOOD STATUS for bothboth quantitative and quantitative and
chemical elementschemical elements
Groundwater Bodies (GWBs): the
management unit of the WFD (not aquifers)
GROUNDWATER BODIES ARE NORMALLY LARGE
(10s to 100s km2)
WILL HAVE SEVERAL SW
BODIES ASSOCIATED
WITH EACH ONE
3-Dimensional
Geological/hydrogeological
boundaries
Aquifer bounda
ry
GWB bounda
ry
Groundwater Status
WFD + ‘Daughter’ Groundwater Directive
The overall aim of the WFD is to achieve “Good StatusGood Status” for all GWBs by 2015
Scale: Status assesses Average Average GWB ConditionsGWB Conditions
Local issues are managed under site specific “Prevent or Limit”“Prevent or Limit” legislation, but they may still impact on status
GWB Results:Quantitative Status
4 GWBs at Poor Status2 due to
unsustainable long-term abstraction
2 due to abstractions impacting on the supporting water level/flow conditions of wetlands
GWB Results:Chemical Status 111 GWBs at POOR
STATUS
Relates to 14% of RoIs area Main Drivers:
MRP contributing to SW Eutrophication (101 GWBs)
Metals from Historic Mining Activities (5 GWBs)
Contaminated land / Urban (2 GWBs)
Diffuse NO3 (2 GWBs)
Issues Arising (Selected)1) Nitrogen & TRAC waters2) Groundwater as an input and a pathway
to surface water3) Groundwater Dependent Terrestrial
Ecosystems (GWDTEs)4) Phosphate in karst groundwater
impacting on surface water ecosystems5) Groundwater Threshold Values (TVs)6) High status sites7) OSWTSs8) Nitrate Trends
Who undertakes water body classification? EPA undertakes and is responsible
for this work
Small Stream Risk Score (SSRS) method not used for status; but part of investigative monitoring
Drifting Ulva blooms (Green tides) (‘sea lettuce’!!) on the Brittany coast
N
n
Nitrogen, TRAC Waters and Sea Lettuce 16% of TRAC waters are eutrophic or potentially
eutrophic. Why? Due to the presence of nutrients, mainly N & P.
Coastal waters EQS (median) for N = 2.6 mg/l (or 12 mg/l as NO3) at fresh water interface
Main N Sources WWTPs and diffuse agriculture
Short–term Implications: A potential health hazard (H2S) An expensive and difficult collection & disposal issue
Medium to long–term Implications: Investment in upgrading WWTPs needed Reduction in nitrate loss to groundwater Lag time for reduction???
No longer sufficient to ‘see’ groundwater largely in terms of wells
Springs Wells
Groundwater as a contributor to Groundwater as a contributor to surface watersurface water
Weathered/broken rock zone as pathway for water and contaminants
Hook Head, Co. Wexford
Pollardstown Fen - a GWDTE
Groundwater as a contributor Groundwater as a contributor to groundwater dependent to groundwater dependent
ecosystems (GWDTEs)ecosystems (GWDTEs)
GWDTEs - Progress
Very little
Environmental Supporting Conditions not known: N & P environmental quality standards
needed groundwater level and flow conditions
Progress, incl. monitoring, needed for next RBMP
Rivers in blue are
‘less than good’ status mainly due to diffuse pressures
PO4 in groundwater the main cause in red areas.
Specific measures to reduce PO4 “leakage” to GW may be needed
Will existing measures be sufficient?
Phosphate in GW: Discussion
Phosphate in GW: Discussion
Why an issue? Main cause of eutrophication of rivers
River MRP EQS low = 35µg/l P
P readily adsorbed in soil & subsoil, but where thin, can enter groundwater
Where an issue? Vulnerable aquifers (i.e. thin
soil/subsoil & sinking streams)
Karst aquifers, where high proportion of surface water comes from groundwater
Note: high pressures (e.g. LUs) not needed
Main cause: agriculture Subsidiary: OSWTSs
GWB Group Average MRP Concentration
Galway Karst 36 g/l
Mayo Karst 34 g/l
Cork Karst 25 g/l
Clare Karst 28 g/l
Roscommon Karst
25 g/l
Kerry – Limerick Karst
45 g/l
Measures Measures introduced to introduced to improve SW improve SW
Bodies will also Bodies will also have to consider have to consider GW inputs arising GW inputs arising
from diffuse from diffuse agriculture and, agriculture and,
in places, in places, OSWTSsOSWTSs
Groundwater Threshold Values (TVs)
TVs are in the Groundwater Regulations and have been reported to the EU
TVs are mean concentrationsmean concentrations TVs are notnot Emission Limit Values (ELVs) TVs are trigger valuestrigger values that prompt further investigation: notnot
the boundary between GOOD and POOR status TVs must be appropriate to the receptor, e.g.
n Human use (drinking water) n Surface watern Wetlands
Parameter Threshold Value Test Reason for TV
Nitrate 37.5 mg/l NO3 Drinking Water/General GWQ Protect Human Use
TCE/PCE 7.5 ug/l General GWQ Protect Human Use-Point Source
Chloride 24 mg/l Cl Saline Intrusion Upper Limit of NBL
Conductivity 800 uS/cm Saline Intrusion Upper Limit of NBL
MRP 35 ug/l P Surface Water Quality SW EQS
Ammonium 65 ug/l N Surface Water Quality SW EQS
High Status Surface Water Bodies 9% of rivers and 28% of lakes. Number of high quality river sites halved in last
20 years. High status WBs are critical to species
biodiversity Deterioration to ‘good’ not allowed, therefore
measures to prevent this of critical importance and a high priority
Sensitive to pressures (forestry, farming, peat extraction, rural housing) so ‘low level’ activities may cause the deterioration
Additional measures to protect these areas likely to be needed
OSWTSs (septic tanks etc) Groundwater Status
Not a major issue Individual wells affected If new EPA CoP followed, pollution of
groundwater should be minimal
But a legacy of existing polluted wells, particularly from ‘soak pits’
OSWTSs (septic tanks etc) Surface Water Status
Contributes ~7% P overall But significant locally Areas with minimal soakage the issue –
gley soils, clayey subsoils, low permeability bedrock
A legacy of bad decision-making by LAs The future
EPA CoP; Building Regs; DEHLG Circular Letter
Some sites are “unsuitable” in practice
Some Context!!Some Context!!
SinéadSinéad The Stray CatThe Stray Cat
holiday house in west of Ireland
Sewage pipe!!
32
Ponded effluent
33
34
Start of percolation
test
Next dayConclusion: Conclusion: site is not site is not suitablesuitable
20-30% of impact due to OSWTSs
Map source: CDM & Eastern RBD RBPM
Gley soils & limited soakage
Map source: CDM & Eastern RBD RBPM
Drinking Water Protected Areas Results of Status Results of Status
Test:Test:
2 GWBs at POOR STATUS
Durrow WS, LaoisDurrow WS, Laois
Ballyheigue WS, KerryBallyheigue WS, Kerry
Nitrate main driver:
howeverhowever many MPs > 25
mg/l NO3
But DWPA test only undertaken in MPs in EPA network!
Nitrate Trends in Rivers NO3 concentrations are stable
43% of all (surveillance + operational) stations had concs. <10mg/l, with 21% >25 mg/l
Over 70% of surveillance stations had concs.<10mg/l NO3, with 3% >25mg/l
But more time and data needed to test for statistical significance.
Nitrate Trends in Groundwater Trend analysis undertaken by EPA for
119 wells/springs Statistically significant downward trend
at 11 sites Statistically significant upward trend at
12 sites Environmentally and statistically
significant upward trend at 2 sites
There is no rivers EQS for nitrate. There is no rivers EQS for nitrate. If one is chosen that is lower than the 37.5 mg/l If one is chosen that is lower than the 37.5 mg/l
NONO33 TV, then it will have implications for TV, then it will have implications for groundwater body status. groundwater body status.
Arabic Proverb
Literally
“Into the well from which you drink do not throw stones”
[Care for the water upon which you depend]
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