Cullohill GWS (Toberboe Spring)

Transcription

1 Water Framework Directive Groundwater Monitoring Programme Site Information Cullohill GWS (Toberboe Spring) ImagePath1: Cullohill GWS (Toberboe Spring)\IE_SE_G_059_11_004_A _(800_x_600).jpg Cullohill GWS (Toberboe Spring) is a spring that has an average abstraction rate of 140m³/day. The total flow from Toberboe is approximately 5l/s. There are 7 other springs in the vicinity. A source report has been prepared for the source in August 2011

2 Site Name: RBD: Site Use: Cullohill GWS (Toberboe Spring) SERBD Easting: Northing: Drinking Water (GWS) Hydrometric Area: 15 Townland: Ownership: Water Quality Monitoring Network: NEWTOWN County Council SITE INFORMATION County: EU Reporting Code: GWB Name: GWB Code: Drinking Water Code: Water Level Monitoring Network: Level IE_SE_G_059_11_004 Durrow IE_SE_G_ PRI3001 Surveillance Operational (Point) Operational (Diffuse) N N Y N Flow Y Site Comments: At the spring, groundwater emerges from sands and gravels along four individual subsurface conduits to collect in a circular, 0.3m thick solid concrete chamber dug into the subsoil (approximately 4m in diameter by 2.0m deep), with a solid concrete roof just above ground level. The sump and drainage channel are fenced off relatively poorly, and the overflow channel is overgrown with weeds and scrub, as recorded on a number of site visits and by the caretaker. The water is then pumped to the pumphouse which is 950m to the north-northwest. Location and Access Information: SITE DIRECTIONS The pumphouse and springs are located between 2 and 3 east-northeast Cullahill Village, which is on the N9 between Durrow, County and Johnstown, County. Additional Comments: Monitoring Point Type: Borehole Log Available: Top of Casing (m agl): Spring WELL INFORMATION Abstraction Rate (m³/d): 140 Ground Elevation (m OD): 94 Total Drilled Depth (m bgl): n/a Depth to Bedrock (m bgl): 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): Gravel Pack Interval (m bgl): Potential Yield (m³/day): Screen Type (PVC,Steel,other): Screen Slot Size (mm): Grouted above (m bgl): Grout Volume Injected (m³): Gravel Pack Volume (m³): Open Hole Interval (m bgl): There are seven springs in the immediate vicinity of Toberboe not used for supply. Specific Capacity (m³/d/m): Comments on Monitoring Site: Static Water Level (m bgl): Scheme Name: Source Report Info: Cullahill GWS Number of Abstraction Points in the Scheme: Report prepared by Robbie Meehan/TOBIN/CDM/OCM Feb Source Report Available Y Scheme Summary: Toberboe Spring, was developed in 1938 and is used to supply the Cullahill Group Water Supply Scheme. Page 2 of 5

3 HYDROGEOLOGY GEOLOGY Soil: Subsoil: Bedrock: Alluviums (AlluvMIN) Alluvium (A) Dinantian Pure Bedded Limestones Subsoil Permeability: Moderate HYDROGEOLOGY Aquifer Category: Rkd Vulnerability at Monitoring High Flow Regime: Karstified site: ZONE OF CONTRIBUTION Estimated ZOC Size (): ZOC Delineation Comments: 2.11 ZOC Delineated By: Recharge Est Recharge (mm/yr): Estimate (mm/yr): There are 7 springs in the immediate vicinity and the ZOC is based on a total estimated discharge of 2000m³/day and measured groundwater levels. RM 362 Groundwater Vulnerability within ZOC (% area): Extreme (X) Extreme (E) High Moderate 7.12 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: 326 Average: 392 Average: 730 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 48 mg/l NO3 and the maximum nitrate concentration was 177 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 mg/l P and the maximum MRP concentration was 0.01 mg/l P. The average chloride concentration was 14.6 mg/l Cl and the maximum chloride concentration was 20 mg/l Cl. Nitrates & Phosphates Risk Category: At risk, high confidence GWB Status: Poor Impact Potential within ZOC (% area): Extreme: 0.00 High: 0.00 Moderate: 0.00 Low: Negligible: OTHER INFORMATION The water is pumped to the pumphouse which is 950m to the north-northwest, where it is chlorinated and fluoridated before flowing into a 40 m³ capacity tank in the fenced-off area outside, before being pumped to a reservoir at Graigueavoice with a storage capacity of approximately 300 m³ (80,000 gallons), which equates to just over 2 days storage. The chlorination tank and chemicals are stored in the pumphouse and a tap is present for untreated water samples. The entire pumphouse site area of c acres is fenced off with good quality fencing, and is partially surrounded further by a narrow belt of young forestry. Page 3 of 5

4 Site Location Site Overview Cover 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 Date: Prepared by Tobin (RM) Date: Feb 2011 Prepared by Date: Prepared by Date: Prepared by Date: Page 5 of 5

6 Location Map for Cullohill GWS (Toberboe Spring)

7 Ll Rkd Rkd Rkd Pu Aquifer Category Map for Cullohill GWS (Toberboe Spring) Fault Ll Pu Rkd

8 Aquifer Category Map for Cullohill GWS (Toberboe Spring) Fault Dinantian Pure Bedded Limestones Dinantian Upper Impure Limestones Namurian Sandstones Namurian Shales Westphalian Shales

9 Groundwater Vulnerability Map for Cullohill GWS (Toberboe Spring) X (extreme - outcrop or rock close) M (moderate) Water E (extreme) L (low) No Data H (high) HL (unmapped)

10 Subsoils Map for Cullohill GWS (Toberboe Spring) Esker comprised of gravels of basic reaction Karstified bedrock outcrop or subcrop Lacustrine sediments Gravels derived from limestones Till derived from limestones Fen peat Bedrock outcrop or subcrop Till derived from Namurian sandstones and shales Alluvium

11 Soils Map for Cullohill GWS (Toberboe Spring) Acid Deep Well Drained Mineral Basic Deep Well Drained Mineral Basic Shallow Poorly Drained Mineral Acid Deep Poorly Drained Mineral Basic Deep Poorly Drained Mineral Fen Peat Acid Shallow Well Drained Mineral Basic Poorly Drained Peaty Mineral Mineral Alluvium Acid Shallow Poorly Drained Mineral Basic Shallow Well Drained Mineral Lacustrine