Glanworth PWS (Dunmahon BH)

Transcription

1 Water Framework Directive Groundwater Monitoring Programme Site Information Glanworth PWS (Dunmahon BH) ImagePath1: Glanworth PWS (Dunmahon BH)\IE_SW_G_025_04_016_A_( 800_x_600).jpg Glanworth PWS (Dunmahon Bridge) is a borehole used as part of a public water supply. The abstraction rate is 636 m³/day. August 2011

2 Site Name: RBD: Site Use: Glanworth PWS (Dunmahon BH) SWRBD Easting: Northing: Drinking Water (PWS) Hydrometric Area: 18 Townland: Ownership: Water Quality Monitoring Network: DUNMAHON County Council SITE INFORMATION County: EU Reporting Code: GWB Name: GWB Code: Drinking Water Code: Water Level Monitoring Network: Level IE_SW_G_025_04_016 Cappoquin Kiltorcan IE_SW_G_ PUB1509 Surveillance Operational (Point) Operational (Diffuse) N N Y N Flow N Site Comments: Glanworth PWS (Dunmahon Bridge) is a 52m deep borehole situated in Devonian Kiltorcan-type Sandstones and is used as a public water supply. The borehole is included in the operational chemical network. Location and Access Information: SITE DIRECTIONS Located 2.5 northeast of Glanworth in the townland of Dunmahon. Take the first left from the road heading east from Glanworth. The site is 1.5 from the junction along this road. Additional Comments: Monitoring Point Type: Borehole Log Available: Top of Casing (m agl): BH WELL INFORMATION Abstraction Rate (m³/d): 636 Ground Elevation (m OD): 88 Total Drilled Depth (m bgl): 52 Depth to Bedrock (m bgl): Upper Casing Diameter (mm): 200 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): Comments on Monitoring Site: Static Water Level (m bgl): Scheme Name: Source Report Info: Glanworth Number of Abstraction Points in the Scheme: 2 Source Report Available N Scheme Summary: The scheme consists of the borehole at Dunmahon Bridge and the spring at Tobermore. The borehole was installed to augment the spring which has been in use since The GSI have completed a source report for the spring 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 X-Extreme Flow Regime: Productive site: fissured bedrock 0.96 ZOC Delineated By: OCM (DC) Recharge Est Recharge (mm/yr): Estimate (mm/yr): The ZOC was delineated based on abstraction, rate, recharge and mainly topography. The entire hydrogeological catchment was used. There is expected to be increased flow along the fault to the east of the borehole. 241 Groundwater Vulnerability within ZOC (% area): Extreme (X) 7.18 Extreme (E) High 0 Moderate 0 Low 0 High to Low 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: 99 Average: 107 Average: 221 From: 2007 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 23 mg/l NO3 and the maximum nitrate concentration was 47 mg/l NO3. The average ammonium concentration was 0.02 mg/l N and the maximum ammonium concentration was 0.06 mg/l N. The average molybdate reductive phosphorus (MRP) concentration was mg/l P and the maximum MRP concentration was mg/l P. The average chloride concentration was 16.1 mg/l Cl and the maximum chloride concentration was 25.8 mg/l Cl. Nitrate Risk Category: At risk, high confidence GWB Status: Good Impact Potential within ZOC (% area): Extreme: 0.00 High: Moderate: 7.69 Low: 0.00 Negligible: OTHER INFORMATION Page 3 of 5

4 Pump House Borehole Sampling Point 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: Prepared by OCM (DC) Date: Feb 2011 Prepared by Date: Prepared by Date: Prepared by Date: Page 5 of 5

6 &% Location Map for Glanworth PWS (Dunmahon BH)

7 Rkd Pl Rf Pl Rf Pl Rf Aquifer Category Map for Glanworth PWS (Dunmahon BH) Rf Fault Pl Rkd

8 Bedrock Map for Glanworth PWS (Dunmahon BH) Devonian Kiltorcan-type Sandstones Dinantian Lower Impure Limestones Devonian Old Red Sandstones Dinantian Pure Unbedded Limestones Dinantian (early) Sandstones, Shales and Limestones Fault

9 &% Groundwater Vulnerability Map for Glanworth PWS (Dunmahon BH) 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 Glanworth PWS (Dunmahon BH) Alluvium Bedrock outcrop or subcrop Till derived from Devonian sandstones

11 &% Soils Map for Glanworth PWS (Dunmahon BH) Acid Deep Well Drained Mineral Acid Shallow Well Drained Mineral Mineral Alluvium Acid Deep Poorly Drained Mineral Basic Shallow Well Drained Mineral