Water Framework Directive. Groundwater Monitoring Programme. Site Information. Tir na League

Transcription

1 Water Framework Directive Groundwater Monitoring Programme Site Information Tir na League ImagePath1: Tir na League\IE_NW_G_078_05_005_ A_PumpHouse.jpg Tir na League is an infiltration gallery situated in gravels and is used as a public water supply. In times of low flow it is augmented by two boreholes. The abstraction rate is 1400m³/day. The GSI has completed a source report. August 2011

2 Site Name: RBD: Site Use: Tir na League NWIRBD Easting: Northing: Drinking Water (PWS) Hydrometric Area: 40 Townland: Ownership: Water Quality Monitoring Network: CHURCHLAND QUARTERS County Council SITE INFORMATION County: EU Reporting Code: GWB Name: GWB Code: Drinking Water Code: Water Level Monitoring Network: Level IE_NW_G_078_05_005 Carndonagh Gravels IE_NW_G_ PUB1007 Surveillance Operational (Point) Operational (Diffuse) Y N N N Flow N Site Comments: Location and Access Information: SITE DIRECTIONS Located in the Churchland Quarters townland, close to the Tirnaleague Demesne, some 1.5 north to northwest of Carndonagh Town. Additional Comments: Monitoring Point Type: Borehole Log Available: BH WELL INFORMATION Abstraction Rate (m³/d): 1400 Ground Elevation (m OD): 16 Total Drilled Depth (m bgl): 7.3 Depth to Bedrock (m bgl): 15 Top of Casing (m agl): Upper Casing Diameter (mm): Lower Casing Diameter (mm): Final Borehole Depth (m): - Upper Casing Bottom Depth (m bgl) : Lower Casing Bottom Depth (m bgl): Screen Interval (m bgl): Grout Type (cement,bentonite): Screen Type (PVC,Steel,other): Screen Slot Size (mm): Grouted above (m bgl): Grout Volume Injected (m³): Gravel Pack Interval (m bgl): Potential Yield (m³/day): Gravel Pack Volume (m³): Open Hole Interval (m bgl): Specific Capacity (m³/d/m): 460 Comments on Monitoring Site: Static Water Level (m bgl): 14.5 Scheme Name: Source Report Info: Carndonagh (Tir Na League) Number of Abstraction Points in the Scheme: Source report prepared by GSI in Source Report Available Y Scheme Summary: The scheme comprises two infiltration galleries and two boreholes. During the summer the main gallery is augmented by water from the other gallery and the boreholes, as the main gallery can be pumped dry. Page 2 of 5

3 HYDROGEOLOGY GEOLOGY Soil: Subsoil: Bedrock: Shallow poorly drained mineral (AminSP) Glaciofluvial sands and gravels (GMp) Precambrian Quartzites, Gneisses & Schists Subsoil Permeability: n/a HYDROGEOLOGY ZONE OF CONTRIBUTION Aquifer Category: Estimated ZOC Size (²): ZOC Delineation Comments: Lg Vulnerability at Monitoring Extreme Flow Regime: Intergranular site: 1.09 ZOC Delineated By: Recharge Est Recharge (mm/yr): Estimate (mm/yr): The GSI delineated a ZOC based on abstraction rate, recharge, topography and the extent of the gravels. See the source report for details. GSI 577 Groundwater Vulnerability within ZOC (% area): Extreme (X) 1.27 Extreme (E) High Moderate 0.74 Low 0 High to Low 0 Unclassified 0 Hydrochemical Signature: Alkalinity (mg/l HCO3): Hardness (mg/l CaCO3): Conductivity (us/cm): Monitoring Record Period: Pressure (e.g., Nitrates, Phosphates, Abstractions): Average: 286 Average: 314 Average: 615 From: 1995 Ca-HCO3 Diffuse Range: Range: Range: To: 2010 HYDROCHEMISTRY Additional Water Chemistry Information: RISK ASSESSMENT Typical Contaminants: During the monitoring period: The average nitrate concentration was 16 mg/l NO3 and the maximum nitrate concentration was 30 mg/l NO3. The average ammonium concentration was mg/l N and the maximum ammonium concentration was mg/l N. The average molybdate reductive phosphorus (MRP) concentration was 0.01 mg/l P and the maximum MRP concentration was 0.03 mg/l P. The average chloride concentration was 28.9 mg/l Cl and the maximum chloride concentration was 35 mg/l Cl. Nitrate Risk Category: Not at risk, low confidence GWB Status: Good Impact Potential within ZOC (% area): Extreme: 0.00 High: 0.00 Moderate: 4.61 Low: Negligible: 9.33 OTHER INFORMATION Page 3 of 5

4 Pump House Well Location Manhole Page 4 of 5

5 Data Summary Sheet - July 2011 Disclaimer: The data in this document are based on the best available information and understanding at time of writing. Neither the Environmental Protection Agency, nor the individual bodies supplying data for this document and accompanying maps will be responsible for any loss or damage from the use or interpretation of these data. Rock Unit Geology Map: GSI, 2009 Aquifer Type Map: GSI, 2009 Groundwater Vulnerability Map: GSI, 2009 Soils & Subsoils Type: Teagasc, 2007 Recharge Map: GSI, 2009 Impact Potential Map: EPA, 2009 Risk Assessment Map: EPA WFD Risk Assessment, 2006 Groundwater Body Status: EPA WFD Status Assessment, 2008 Water Quality Data: EPA WFD Monitoring, 2008 Groundwater Threshold Values Groundwater threshold values for selected parameters: Nitrate - General Chemical Test/ Drinking Water Test (37.5 mg/i N03) Ammonium - Drinking Water Test (0.175 mg/i N) / Surface Water Test (0.065 mg/l N) Molybdate Reactive Phosphorus (MRP) - Surface Water Test (0.035 mg/i P) Chloride -Saline/Intrusive Test (24 mg/i) / Drinking Water Test (175 mg/i Cl) Electrical Conductivity -Saline/Intrusive Test (800 µs/cm) / Drinking Water Test (1,875 µs/cm) Further information on groundwater threshold values is contained in the Groundwater Regulations (S.I. No.9 of 2010). General Downgradient Distances General Downgradient Distances (XL) applied to boreholes sourced in bedrock aquifers are constrained to estimate approximate limits based on data at the GSl. ln some cases they may be higher or lower depending on local conditions. Rk, Rkd, Lk Lm Ll, PI 225 m 150 m 60 m It is assumed that groundwater downgradient of a spring cannot flow back up to the spring, however a precautionary 30m buffer is generally applied which allows for instances where pumping under dry weather periods may induce a drawdown or where the ground may be sloping toward the spring from the downgradient side. Version 0: Version 1: Version 2: Version 3: Version 4: Prepared by GSI Date: Prepared by OCM (DC) Date: Feb 2011 Prepared by Date: Prepared by Date: Prepared by Date: Page 5 of 5

6 Location Map for Tir na League Abstractions

7 Lg Aquifer Category Map for Tir na League Abstractions Fault Lg

8 ²!. Lg ") Bedrock Map for Tir na League!. Abstractions Precambrian Quartzites, Gneisses & Schists Lg Fault

9 Groundwater Vulnerability Map for Tir na League Abstractions E (Rock near surface or Karst) M (Moderate) Water E (Extreme) L (Low) No Data H (High) HL (unmapped - High to Low)

10 Subsoils Map for Tir na League Abstractions Alluvium Blanket peat Bedrock outcrop or subcrop Made ground Gravels derived from metamorphic rocks Till derived from metamorphic rocks

11 Soils Map for Tir na League Abstractions Acid Deep Well Drained Mineral Acid Shallow Poorly Drained Mineral Mineral Alluvium Acid Deep Poorly Drained Mineral Acid Shallow/Rocky/Peaty Mineral Made Acid Shallow Well Drained Mineral Blanket Peat