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]