Water Framework Directive. Groundwater Monitoring Programme. Site Information. Galbally

Transcription

1 Water Framework Directive Groundwater Monitoring Programme Site Information Galbally ImagePath1: Galbally\Galbally1.jpg Galbally source is comprised of 2 boreholes situated in Devonian Old Red Sandstones and is used as a public water supply. The abstraction rate is 200m³/day. August 2011

2 Site Name: RBD: Site Use: Galbally Shannon IRBD Easting: Northing: Drinking Water Hydrometric Area: 16 Townland: Ownership: Water Quality Monitoring Network: Castlecreagh County Council SITE INFORMATION County: EU Reporting Code: GWB Name: GWB Code: Drinking Water Code: Water Level Monitoring Network: Level Bansha IE_SE_G_016 Surveillance Operational (Point) Operational (Diffuse) N N N N Flow N Site Comments: Location and Access Information: SITE DIRECTIONS Galbally Borehole is located on a farm/forestry laneway to the northwest of Galbally. The source is located on an elevated area approximately 100 m east of the R466. Water is pumped to the reservoir for distribution. Additional Comments: Monitoring Point Type: Borehole Log Available: BH WELL INFORMATION Abstraction Rate (m³/d): 200 Ground Elevation (m OD): 150 Total Drilled Depth (m bgl): 107 Depth to Bedrock (m bgl): Top of Casing (m agl): Upper Casing Diameter (mm): 250 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): Gravel Pack Interval (m bgl): Potential Yield (m³/day): Screen Type (PVC,Steel,other): Steel Screen Slot Size (mm): Grouted above (m bgl): Grout Volume Injected (m³): Gravel Pack Volume (m³): Open Hole Interval (m bgl): Static water level close to river level. Pumping water level below river level. Specific Capacity (m³/d/m): Comments on Monitoring Site: Static Water Level (m bgl): 30 Scheme Name: Source Report Info: Galbally Number of Abstraction Points in the Scheme: 2 Source Report Available N Scheme Summary: Galbally PWS comprises 2 boreholes approximately 5 m apart. The borehole supplies less than 200 m³/day to Galbally Village Page 2 of 5

3 HYDROGEOLOGY GEOLOGY Soil: Subsoil: Bedrock: Shallow well drained mineral (AminSW) Bedrock at or close to surface (Rck) Devonian Kiltorcan-type Sandstones Subsoil Permeability: N/A HYDROGEOLOGY ZONE OF CONTRIBUTION Aquifer Category: Estimated ZOC Size (): ZOC Delineation Comments: Vulnerability Rf at Monitoring Extreme Flow Regime: Productive site: fissured bedrock 0.12 ZOC Delineated By: TOBIN (CK) Recharge Est Recharge (mm/yr): Estimate (mm/yr): The static water level is deep below ground and suggests high permeability bedrock. Pumping water level and high conductivity suggests connection to the river. ZOC area is insufficient for 150% abstraction rate. It may be taking in river water or the topographic surface area needs to be ignored. Current ZOC is based on topography and geology. Groundwater Vulnerability within ZOC (% area): Extreme (X) Extreme (E) High 0 Moderate 0 Low 0 High to Low 2.26 Unclassified 0 Hydrochemical Signature: HYDROCHEMISTRY Limited dataset. Previous Iron Biofilm problems. Conductivity relatively low. Chlorides about 18mg/l. Nitrates about 14mg/l. Occasionally elevated iron. Alkalinity (mg/l HCO3): Hardness (mg/l CaCO3): Conductivity (us/cm): Monitoring Record Period: Pressure (e.g., Nitrates, Phosphates, Abstractions): Average: Average: Average: 161 From: Phosphates Range: Range: Range: To: Additional Water Chemistry Information: RISK ASSESSMENT Typical Contaminants: Risk Category: At risk, high confidence GWB Status: Good Impact Potential within ZOC (% area): Extreme: 0.00 High: Moderate: 0.00 Low: 0.00 Negligible: OTHER INFORMATION Page 3 of 5

4 Borehole! Borehole 2 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, 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 Date: 28/02/2011 Prepared by TOBIN (CK) Date: Feb 2011 Prepared by Date: Prepared by Date: Prepared by Date: Page 5 of 5

6 Location Map for Galbally PUB DWS

7 Rf Aquifer Category Map for Galbally PUB DWS Lk Lk Rf Fault

8 Bedrock Map for Galbally PUB DWS Fault Devonian Kiltorcan-type Sandstones Devonian Old Red Sandstones Dinantian Lower Impure Limestones Dinantian Pure Unbedded Limestones Dinantian Upper Impure Limestones Namurian Shales Namurian Undifferentiated Silurian Metasediments and Volcanics

9 Groundwater Vulnerability Map for Galbally PUB DWS E (Rock near surface or Karst) E (Extreme) H (High) M (Moderate) L (Low) HL (unmapped - High to Low) Water No Data

10 Subsoils Map for Galbally PUB DWS Alluvium Gravels derived from Devonian sandstones Bedrock outcrop or subcrop Lacustrine sediments Made ground Till derived from Devonian sandstones Till derived from Lower Palaeozoic sanstones and shales

11 Soils Map for Galbally PUB DWS Acid Deep Well Drained Mineral Acid Shallow Poorly Drained Mineral Acid Deep Poorly Drained Mineral Acid Shallow/Rocky/Peaty Mineral Acid Poorly Drained Peaty Mineral Basic Shallow Well Drained Mineral Acid Shallow Well Drained Mineral Basic Shallow Poorly Drained Mineral Mineral Alluvium Lacustrine Made