Water Framework Directive. Groundwater Monitoring Programme. Site Information. Gormanstown Usk

Transcription

1 Water Framework Directive Groundwater Monitoring Programme Site Information Gormanstown Usk ImagePath1: Gormanstown USC\27_006_Gormanstown_P2_ Site.jpg This monitoring point is a shallow borehole that is part of the Gormanstown USC group water scheme. The average abstraction rate is 295m³/day. A source protection report for Gormanstown USC was completed by the GSI in August 2011

2 Site Name: RBD: Site Use: Gormanstown Usk ERBD Easting: Northing: Drinking Water (GWS) Hydrometric Area: 9 Townland: Ownership: Water Quality Monitoring Network: Tober Co Co SITE INFORMATION County: EU Reporting Code: GWB Name: GWB Code: Drinking Water Code: Water Level Monitoring Network: Level IE_EA_G_046_27_006 Old Killcullen S&G IE_EA_G_ PRI3033 Surveillance Operational (Point) Operational (Diffuse) Y N N N Flow N Site Comments: The source is located near Tobber Demesne to the NE of Dunlavin. Most of the land is pasture for sheep and cattle. There are sand and gravel pits in the area, including the source. Location and Access Information: SITE DIRECTIONS From N81 take the road towards Dunlavin (R412). In the village turn right on R756 towards Hollywood and drive for about 3 until you pass the entrance to the cemetery on the left. The well is behind the fencing about 300 meters further down the road on the left-hand side. Additional Comments: --- Monitoring Point Type: Borehole Log Available: Borehole Y WELL INFORMATION Abstraction Rate (m³/d): 295 Ground Elevation (m OD): Total Drilled Depth (m bgl): 7.6 Depth to Bedrock (m bgl): >10 Top of Casing (m agl): --- Upper Casing Diameter (mm): 250 Lower Casing Diameter (mm): --- Final Borehole Depth (m): 7.6 Upper Casing Bottom Depth (m bgl) : 2 Lower Casing Bottom Depth (m bgl): --- Screen Interval (m bgl): Grout Type (cement,bentonite): Gravel Pack Interval (m bgl): Potential Yield (m³/day): >400 Screen Type (PVC,Steel,other): PVC slotted pipe Screen Slot Size (mm): Grouted above (m bgl): --- Grout Volume Injected (m³): Gravel Pack Volume (m³): --- Open Hole Interval (m bgl): The borehole was commissioned in There is no indication that the well was constructed with grout Specific Capacity (m³/d/m): 107 Comments on Monitoring Site: Static Water Level (m bgl): 1.2 Scheme Name: Source Report Info: Gormanstown Number of Abstraction Points in the Scheme: 1 Source Report Available The GSI published a Source Protection Zone report in 2004, that forms part of County Groundwater Protection Scheme. Y Scheme Summary: The source comprises a borehole located at Tober Demesne, approximately 650 m south of Tober cross roads, next to the burial ground. The borehole pumps water to a reservoir situated at Grangebeg Park in Co.. Page 2 of 5

3 HYDROGEOLOGY GEOLOGY Soil: Subsoil: Bedrock: Shallow well drained mineral (BminSW) Glaciofluvial sands and gravels (GLs) Silurian Metasediments and Volcanics Subsoil Permeability: High HYDROGEOLOGY ZONE OF CONTRIBUTION Aquifer Category: Estimated ZOC Size (²): ZOC Delineation Comments: Lg Vulnerability at Monitoring High Flow Regime: S&G site: 1.05 ZOC Delineated By: Recharge Est Recharge (mm/yr): Estimate (mm/yr): ZOC delineated by GSI on the basis of an abstraction rate of 525 m3/d (50% greater than actual rate, see source report by GSI). Well is located in a sand and gravel deposit. The borehole intercepts groundwater that would otherwise discharge naturally at the Tober spring. Topography around the spring forms a horseshoe, which drives groundwater westwards to discharge at the spring which is located at the point where the sand/gravel deposits pinch out. GSI ZOC is larger than water balance requires. GSI 376 Groundwater Vulnerability within ZOC (% area): Extreme (X) 0 Extreme (E) 0 High Moderate 9.64 Low 0 High to Low 0 Unclassified 0 Hydrochemical Signature: Ca-HCO3 HYDROCHEMISTRY The average concentration of MRP (0.05 mg/ L P) between the period exceeds the WFD threshold value of mg/l P. Alkalinity (mg/l HCO3): Hardness (mg/l CaCO3): Conductivity (us/cm): Monitoring Record Period: Pressure (e.g., Nitrates, Phosphates, Abstractions): Average: 341 Average: 373 Average: 689 From: 2007 Diffuse Range: Range: Range: To: 2008 Additional Water Chemistry Information: RISK ASSESSMENT Typical Contaminants: --- Risk Category: At risk, low confidence GWB Status: Good Impact Potential within ZOC (% area): Extreme: 0.00 High: 0.00 Moderate: Low: 9.64 Negligible: 0.00 OTHER INFORMATION The nearby spring is no longer in use. The estimated spring flow, as measured by the GSI in May 2002, was in the region of 2,900 m³/d. Page 3 of 5

4 Site Location Well Location Sampling Location 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: 01/12/2004 Prepared by CDM (HM) Date: Feb 2011 Prepared by Date: Prepared by Date: Prepared by Date: Page 5 of 5

6 ² 1400PRI3033 / IE_EA_G_046_27_006 Location Map for Gormanstown USC

7 ² Pu Pu Pl Tober Gravels Aquifer Category Map for Gormanstown USC Lemonstown Gravels Pu Pu Pl Fault Lg Pl Pu

8 Lg 1400PRI3033 / IE_EA_G_046_27_006 ² Lg Bedrock Map for Gormanstown USC Lg Silurian Metasediments and Volcanics Lg Fault

9 ² 1400PRI3033 / IE_EA_G_046_27_006 Groundwater Vulnerability Map for Gormanstown USC E (Rock near surface or Karst) M (Moderate) Water E (Extreme) L (Low) No Data H (High) HL (unmapped - High to Low)

10 ² 1400PRI3033 / IE_EA_G_046_27_006 Subsoils Map for Gormanstown USC Alluvium Cutover raised peat Gravels derived from limestones Lacustrine sediments Made ground Till derived from Lower Palaeozoic sanstones and shales Bedrock outcrop or subcrop Till derived from limestones

11 ² 1400PRI3033 / IE_EA_G_046_27_006 Soils Map for Gormanstown USC Acid Deep Well Drained Mineral Basic Deep Well Drained Mineral Mineral Alluvium Acid Deep Poorly Drained Mineral Basic Shallow Well Drained Mineral Lacustrine Acid Poorly Drained Peaty Mineral Basic Shallow Poorly Drained Mineral Made Acid Shallow Well Drained Mineral Cutover/Cutaway Peat