MOE 2001 Terms of Reference

Transcription

1 February 17, 2015 Project No Mary McCuaig, CAO/Clerk Corporation of the Nation Municipality 958 Road 500 West, R.R. 3 Casselman, Ontario K0A 1M0 GUDI ASSESSMENT OF LIMOGES WELLS #3 AND #4, NATION MUNICIPALITY, ONTARIO Dear Mary: As per your request, Golder Associates Ltd. has prepared an assessment of the potential for water drawn from Limoges water supply wells #3 and #4 to be classified as groundwater under the direct influence of surface water (GUDI). The relevant guidance documents for GUDI assessments are Terms of Reference: Hydrogeological Study to Examine Groundwater Sources Potentially Under Direct Influence of Surface Water (Ontario Ministry of the Environment (MOE), October 2001) and Section 2 of Ontario Regulation (O.Reg.) 170/03, Safe Drinking Water Act. The locations of the wells are shown on Figure 1. MOE 2001 Terms of Reference Under the 2001 Terms of Reference, communal wells are flagged as potentially under the direct influence of surface water if a number of conditions are met. Flagged potentially GUDI wells are considered to be under the direct influence of surface water unless a hydrogeological study proves otherwise to the satisfaction of the MOE. The following table summarizes the status of Limoges wells #3 and #4 in relation to the conditions specified in the Terms of Reference. Condition Summary of Condition Limoges Wells #3 and #4 Status i ii Regularly contain Total Coliforms and/or periodically contain E. coli; or Are located within approximately 50 days horizontal saturated travel time from surface water or are within 100 m (overburden wells) or 500 m (bedrock wells) of surface water (whichever is greater) and meet one or more of the following criteria: During a 24-hour pumping test at Well #3, neither total coliforms nor E. coli were detected during sampling. During a 24-hour pumping test at Well #4, neither total coliforms nor E. coli were detected during sampling. As shown on Figure 1, a nearby municipal drainage ditch flows approximately 315 and 120 metres west of Limoges wells #3 and #4, respectively. As determined through wellhead protection area mapping, the 50-day travel time from wells #3 and #4 is shown on Figure 1; the 50-day travel time does not reach the municipal drainage ditch. The only surface water bodies within 100 m of the wells are shallow ditches constructed within the thick clay overburden. Golder Associates Ltd Robertson Road, Ottawa, Ontario, Canada, K2H 5B7 Tel: +1 (613) Fax: +1 (613) Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation.

2 Mary McCuaig, CAO/Clerk Corporation of the Nation Municipality February 17, 2015 Condition Summary of Condition Limoges Wells #3 and #4 Status ii a) ii b) ii c) ii d) ii e) Wells may be drawing water from an unconfined aquifer; Wells may be drawing water from formations within approximately 15m of surface; Wells are part of an enhanced recharge/infiltration project; When the well is pumped, water levels in surface water rapidly change or hydraulic gradients beside the surface water significantly increase in a downward direction; and/or, Chemical water quality parameters (such as temperature, conductivity, turbidity, total dissolved solids, ph, colour, oxygen) are more consistent with nearby surface water than local groundwater and/or if they fluctuate significantly and rapidly in response to climatological or surface water conditions. The buried sand and gravel esker from which the wells draw their water supply is confined by approximately metres of silty clay. The well casings of wells #3 and #4 extend to depths of 21 meters. Water from these wells is therefore drawn from formations deeper than 15 m of surface. No recharge/infiltration project exists at the site. No surface water bodies are located within close proximity of the communal wells. The temperature, conductivity, total dissolved solids and turbidity of samples taken during 24-hour pumping tests at wells #3 and #4 are entirely consistent with groundwater from the sand and gravel aquifer and are dissimilar to surface water chemistry. The Ontario Drinking Water Quality Standards aesthetic objectives for colour, ph and methane were exceeded in these samples. The levels of iron and manganese naturally present in the groundwater are interpreted to be the cause of the elevated colour readings. Methane is known to be naturally-occurring in the groundwater in the area, and may influence the ph. In summary, none of the above conditions apply for Limoges wells #3 and #4, therefore wells #3 and #4 are not flagged as potentially under the direct influence of surface water under the 2001 Terms of Reference. 2/4

3 Mary McCuaig, CAO/Clerk Corporation of the Nation Municipality February 17, 2015 Ontario Regulation 170/03 Under O.Reg. 170/03, a drinking water system is deemed to obtain water from a raw water supply that is ground water under the direct influence of surface water if any of the following conditions are met: Condition Description Limoges Wells #3 and #4 Status 1 A drinking water system that obtains water from a well that is not a drilled well or from a well that does not have a watertight casing that extends to a depth of six metres below ground level. 2 A drinking water system that obtains water from an infiltration gallery. 3 A drinking water system that is not capable of supplying water at a rate greater than 0.58 litres per second and that obtains water from a well, any part of which is within 15 metres of surface water. 4 A drinking water system that is capable of supplying water at a rate greater than 0.58 litres per second and that obtains water from an overburden well, any part of which is within 100 metres of surface water. 5 A drinking water system that is capable of supplying water at a rate greater than 0.58 litres per second and that obtains water from a bedrock well, any part of which is within 500 metres of surface water. 6 A drinking water system that exhibits evidence of contamination by surface water. 7 A drinking water system in respect of which a written report has been prepared by a professional engineer or professional hydrogeologist that concludes that the system's raw water supply is ground water under the direct influence of surface water and that includes a statement of his or her reasons for reaching that conclusion. Limoges wells #3 and #4 are drilled wells with casings extending greater than 6 metres below ground level. No infiltration gallery is present at the site. Does not apply. The wells are capable of supplying greater than 0.58 litres per second. Each well is capable of supplying 11.2 L/s. No surface water is present within 100 metres of the communal wells apart from shallow ditches constructed within the thick clay deposits. Does not apply. The wells obtain water from the overburden. Limoges wells #3 and #4 do not exhibit evidence of contamination by surface water. No such report has been produced. In summary, none of the above conditions apply for Limoges wells #3 and #4, therefore the wells are not deemed to obtain water from a raw water supply that is ground water under the direct influence of surface water as under O.Reg. 170/03. 3/4

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5 LIMOGES WELL #3 Northing (m) LIMOGES WELL #4 Easting (m) LEGEND NOTES: Waterbodies Roads 50-day simulated travel time Limoges Wells 1. THIS FIGURE IS TO BE READ IN CONJUNCTION WITH THE ACCOMPANYING GOLDER ASSOCIATES LTD. REPORT 2. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83, COORDINATE SYSTEM UTM ZONE 18 CLIENT PROJECT PARSONS INC LIMOGES COMMUNAL WELLS GUDI ASSESSMENT CONSULTANT YYYY-MM-DD PREPARED NB DESIGN NB TITLE SIMULATED 50 DAY HORIZONTAL GROUNDWATER TRAVEL TIME FOR LIMOGES WELLS 3 AND 4 REVIEW CAMC PROJECT No. PHASE/TASK Rev. APPROVED BJV /201 A. FIGURE 1