ALLISTON SAND AND GRAVEL PIT

Transcription

1 ALLISTON SAND AND GRAVEL PIT Township of Adjala - Tosorontio, Simcoe County Monitoring Protocol, Investigative Triggers and Mitigation Measures Summary prepared by: C.C. Tatham & Associates Ltd. 115 Sandford Fleming Drive, Suite 200 Collingwood, ON L9Y 5A6 Tel: (705) Fax: (705) info@cctatham.com prepared for Nelson Aggregate Co. CCTA File

2 TABLE OF CONTENTS 1 Introduction Site Description Extraction Operation 1 2 Surface Water Monitoring Baseline Surface Water Monitoring Surface Water Monitoring Protocol 5 3 Groundwater Monitoring Baseline Groundwater Monitoring Groundwater Monitoring Protocol 11 4 Investigative/Mitigative Triggers and Mitigation Investigative/Mitigative Triggers Mitigation Measures Spills Contingency Plan 16 5 Recommendations 17 LIST OF TABLES Table 1: Surface Water Quality Sampling Summary 5 Table 2: Surface Water Monitoring Program 8 Table 3: Groundwater Monitoring Wells 10 Table 4: Surface Water Quality Sampling Summary 11

3 LIST OF FIGURES Figure 1: Site Location Plan 2 Figure 2: Alliston Pit Monitoring Locations 4 Figure 3: Alliston Pit Future Monitoring Locations 6

4 1 Introduction C.C. Tatham & Associates Ltd. (CCTA) and Whitewater Hydrogeology Ltd. (Whitewater) have been retained by Nelson Aggregate Co. (Nelson) to prepare a standalone document summarizing the surface and groundwater monitoring requirements, investigative triggers, and mitigation measures for the. Specifically, this document is an assembly of the recommendations of the Revised Combined Level 1 and 2 Hydrogeological Assessment (Whitewater, June 2015), the Revised Surface Water Management Report (CCTA, June 2015) and ARA Site Plans prepared for the. 1.1 Site Description The subject property is located northwest of the intersection of Simcoe County Road 13 and Tosorontio Sideroad 5, approximately 2.5 km south of Everett as illustrated on Figure 1 Site Location Plan provided overleaf. The legal description of the site is Part of Lots 6 & 7, Concession 4, Township of Adjala Tosorontio (formerly Tosorontio Township), Simcoe County or 5556 and 5670 County Road 13. The subject properties current land use is agriculture and includes a single family residence and several out buildings consisting of barns and sheds. The site is bordered by agricultural lands to the east, forest and residential lands to the north, and former pits rehabilitated into pit lakes to the west and south. The Boyne River and Tosorontio Creek drain through the property from west to east. The site topography is flat with very little surface drainage expected to leave the site as overland flow. There is a very subtle topographical low through the middle of the property that drains to a culvert crossing Simcoe County Road 13 at the mid-point of the site and eventually feeds an off-site intermittent tributary of the Boyne River. 1.2 Extraction Operation The proposed pit will extract fine and coarse grained aggregate for miscellaneous construction uses, primarily granular road base. The extraction operation will occur below the water table in wet conditions so no dewatering or off-site discharge is required. The extraction operation will occur in three phases with the first phase commencing south of Tosorontio Creek then progressing north in subsequent phases. Material processing operations will occur on-site with the equipment initially installed in the southeast corner of the site as part of Phase 1 and the operations will move with the excavation. In the post extraction condition a pit lake will form covering the extraction area in a manner similar to the adjacent rehabilitated pit sites. The proposed extraction operation is fully described on the Site Plans (Existing Features Plan, Operations Plan, Progressive/Final Rehabilitation Plan, Cross-sections and Details and Notes) prepared in support of the ARA license application and should be referenced if additional details are required. Page 1

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6 2 Surface Water Monitoring Baseline surface water monitoring has been completed to characterize the existing surface water conditions in the two watercourses crossing the site. The baseline data has also been collected to establish a set of standard criteria to which the impacts from the proposed extraction operation can be identified and evaluated. With this in mind, a surface water monitoring protocol has been developed to measure trends in the surface water flow and temperature for comparison against the baseline data (investigative triggers) to monitor potential impacts from the operation on the watercourses and allow for the proactive mitigation of identified impacts. The baseline monitoring completed to date and the surface water monitoring protocol moving forward are summarized next. 2.1 Baseline Surface Water Monitoring The collection of detailed background surface water data commenced in April In April, monitoring stations collecting continuous stream flows and water temperatures were established in the Boyne River and Tosorontio Creek at the downstream limit of the site immediately upstream of County Road 13. June 2014, surface water monitoring locations were also established in the Boyne River and Tosorontio Creek where they enter the subject property and a surface water monitoring location was added in the pit lake west of the site after permission was received from the adjacent landowner to do so. April 30, 2015, two additional monitoring stations were established downstream of the two proposed pit lake overflow locations. These additional monitoring stations also collect continuous stream flows and water temperatures. The surface water monitoring locations are illustrated on Figure 2 Alliston Pit Existing Monitoring Locations provided overleaf and on the Site Plans prepared in support of the ARA license application. The monitoring completed to date has included the collection of continuous water level data (at 15 minute intervals) with in-stream pressure transducers installed to record water levels. For the stream / river installations, rating curves were established for the monitoring locations by collecting instantaneous in-situ stream flow and staff gauge measurements on a regular basis then establishing a rating curve to represent the flows for various measured depths. Frequent monitoring visits allowed for the collection of ten points of calibration for the stream flow rating curves established in In 2015, in-situ stream flow measurements and staff gauge readings were collected to develop rating curves for the additional monitoring stations established in 2015 and to further refine the rating curves for the monitoring stations established in In 2016, in-situ stream flow measurements and staff gauge readings continue to be collected for the refinement of the rating curves. Water quality samples were collected from the Boyne River and Tosorontio Creek monitoring station on three occasions, June 5, 2014, August 28, 2014 and May 19, The purpose was to collect baseline water quality results prior to extraction operations to understand existing water quality characteristics in the areas watercourses. The sampling locations and parameters are summarized in the following table. Page 3

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8 Table 1: Surface Water Quality Sampling Summary Watercourse Monitoring Location Sample Parameters Boyne River SW1 TSS, TDS, Turbidity, Conductivity, Anions, COD, BOD, ph, Alkalinity, Metals, Hardness, Dissolved Tosorontio Creek SW2 Inorganic Carbon, Carbonate, Bi-Carbonate, Colour, Ammonia and Ammonium The monitoring data collected to date is provided in the Revised Surface Water Management Report (June 2015). 2.2 Surface Water Monitoring Protocol It is recommended that the seven established monitoring stations remain active to collect additional baseline monitoring data prior to the commencement of extraction operations. Once operations commence, these monitoring stations are to remain active to allow any change within the watercourses / pit lake to be documented and assessed against the baseline data. It is recommended that the pit lake west of the subject property that is not currently being monitored be monitored along with the pit lake south of the subject property opposite Sideroad 5. Monitoring at these locations is not mandatory, however, would be beneficial to supplement the available data. The monitoring stations should be established prior to on-site operations to collect baseline data allowing any future change within each pit lake to be documented and assessed. Monitoring these two pit lakes is subject to approval from the landowners. Once extraction commences, monitoring stations are to be established in the on-site pit lakes as they are being formed. The pit lake water levels and temperatures are to be monitored continuously and quarterly water samples are to be collected. The existing and proposed monitoring locations are illustrated on Figure 3 Alliston Pit Future Monitoring Locations provided overleaf and on the Site Plans prepared in support of the ARA license application. Monitoring is to be conducted during the extraction period each year which is expected between the months of March and November. During this period, monthly field visits to collect in-situ stream flow and water temperature measurements from each monitoring station are to be completed and quarterly water quality samples are to be collected from select monitoring stations (SW1, SW2, SW6, SW7, SW10, SW12 and SW13). The in-situ streamflow measurements will be processed and the continuously recorded monitoring data from each monitoring device will be retrieved, processed and verified against climate data on a monthly basis. Page 5

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10 Following each year of operation, an annual surface water monitoring report is to be prepared and submitted to the MNRF and NVCA summarizing the results of the monitoring program for the operational season by March 1 st of the following year. The recommended monitoring program is summarized as follows and in the following table: 1. Manual stream flow, manual water level and water temperature measurements shall be completed monthly at all on-site and off-site surface water monitoring locations March through November of each operating year. 2. Continuous stream flow and temperatures shall be collected from surface water monitoring locations SW1 through SW4 and SW6 and SW7 March through November of each operating year. 3. Continuous water level and temperatures shall be collected from the off-site pit lakes (monitoring locations SW5, SW8 and SW9) subject to approval from the landowners March through November of each operating year. 4. Continuous water level and temperatures shall be collected from the on-site pit lakes (monitoring locations SW10, SW11, SW12 and SW13) following the commencement of operations March through November of each operating year. 5. The in-situ streamflow measurements will be processed and the continuous streamflow monitoring data will be retrieved, processed and verified against climate data on a monthly basis March through November of each operating year. 6. Quarterly water quality samples shall be collected from monitoring locations SW1, SW2, SW3, SW4, SW6, SW7, SW10, SW12, and SW13 and be analyzed for general chemistry, major anions, oil and grease, and bacteria each operating year. 7. An annual report summarizing the surface water monitoring program for the operational season shall be prepared and submitted to the MNRF and NVCA by March 1 st of the following year. Page 7

11 Table 2: Surface Water Monitoring Program Monitoring Station Water Level Continuous Temperature Monthly In-Situ Stream Flow Measurement Quarterly Water Quality Samples SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 a SW9 a SW10 b SW11 b SW12 b SW13 b Note(s): a Monitoring station subject to permission from landowner b Pit lake monitoring stations Page 8

12 3 Groundwater Monitoring Baseline groundwater monitoring has been completed to characterize the existing groundwater conditions in the vicinity of the site. Based on the geological and hydrogeological conditions of the site, the baseline groundwater monitoring has focused on the shallow unconfined aquifer below the site. A key component of the program was to collect data that would allow for an evaluation of the horizontal and vertical groundwater flow gradients in the vicinity of the Boyne River and Tosorontio Creek. In addition, the groundwater monitoring considers the potential thermal influence the existing up-gradient ponds may have on the groundwater regimes. The baseline data has also been collected to establish a set of standard criteria to which the impacts from the proposed extraction operation can be identified and evaluated. The proposed groundwater monitoring protocol has been designed to ensure that any unforeseen influences from the proposed operation are detected before potential adverse impacts occur. The baseline monitoring completed to date and the groundwater monitoring protocol moving forward are summarized next. 3.1 Baseline Groundwater Monitoring 11 new shallow groundwater monitoring wells were installed on-site in addition to the five wells which were already located within the property boundary (a total of 15 groundwater monitoring well locations). Due to the shallow nature of the groundwater table (~1 m below ground surface), the new wells were constructed to maximum depths of 3 m to comply with the Ontario Water Resources Act (Ontario Regulation 903: shallow works). The location of the groundwater monitoring wells are illustrated on Figure 2 Alliston Pit Existing Monitoring Locations and on the Site Plans prepared in support of the ARA license application. Summaries of the well construction details and lithology are provided in the following table: Page 9

13 Table 3: Groundwater Monitoring Wells Well No. Top of Casing Elevation (masl) Screen Interval (mbgs) Lithology Easting Location Northing AA Sand and Gravel 585,053 4,891,447 AA Sand and Gravel 584,736 4,891,663 AA Sand and Gravel 584,375 4,891,550 AA Sand and Gravel 584,416 4,891,329 AA Sand and Gravel 584,655 4,891,372 AA Sand and Gravel 584,074 4,891,224 AA Sand and Gravel 584,966 4,890,985 AA Sand and Gravel 584,770 4,890,914 AA Sand and Gravel 584,509 4,890,846 AA Sand and Gravel 584,537 4,890,757 AA Medium Sand 584,587 4,890,463 AA Sand and Gravel 584,713 4,890,695 AA Sand and Gravel 584,205 4,890,652 AA Sand and Gravel 584,715 4,891,113 AA Medium Sand 584,581 4,890,676 Notes: All wells encountered m of clayey silt topsoil. Monthly manual water level measurements have been collected since January In addition to the manual measurements, 11 of the 15 wells are equipped with automatic pressure transducers, which measure water levels and groundwater temperatures on a 6 hour frequency. Pressure data is corrected to barometric conditions and calibrated to the monthly water levels. Water quality samples were collected from the groundwater monitoring wells on four occasions, May 28, 2014, June 5, 2014, August 28, 2014 and May 14, 2015 to determine if seasonal trends in water chemistry exist. The sampling locations and parameters are summarized in the following table: Page 10

14 Table 4: Surface Water Quality Sampling Summary Groundwater Well AA-1 through AA-14 Sample Parameter Chloride, Fluoride, Nitrate, Nitrite, Phosphate, Sulphate, Alkalinity, ph, BOD 5, COD, Conductivity, Turbidity, TDS, Bicarbonate, Carbonate, Ammonia, True Colour, DIC, Total Hardness, Metals, Bacteria, Oil, and Grease To gain an improved understanding of the interaction between groundwater and Tosorontio Creek, three mini-piezometers (MP1, MP2, and MP3) were installed in the creek. The locations of the minipiezometers are illustrated on Figure 2 Alliston Pit Existing Monitoring Locations and on the Site Plans prepared in support of the ARA license application. Up until June 5, 2015, the mini-piezometers at the site were comprised of a 1.8 m t-bar attached to a 2.54 cm diameter steel pipe. The bottom 0.3 m of the steel pipe is perforated creating a screened section. The base of the steel pipe was crimped closed to limit sediment intake as the minipiezometers were hammered 0.9 m into the streambed. MP1 was installed into fine silt/clay materials, which represent modern alluvium deposits. MP2 and MP3 were installed into the coarse sand and gravel aquifer unit. These mini-piezometers were replaced with steel drive points to ensure they maintain their integrity in the long-term and specifically, throughout the winter when mini-piezometers are prone to damage. The monitoring data collected to date is provided in the Revised Combined Level 1 and 2 Hydrogeological Assessment (June 2015). 3.2 Groundwater Monitoring Protocol The proposed groundwater monitoring program has been designed to ensure that any unforeseen influences from the proposed operation are detected prior to potential adverse impacts occurring. The proposed groundwater monitoring program is summarized as follows: 1. Manual water levels and temperature measurements shall be completed monthly at all on-site groundwater monitoring wells between March and November of each operating year. 2. Continuous water levels and temperatures shall be collected from groundwater monitoring wells AA-1, AA-2, AA-3, AA-7, AA-8, AA-10, AA-13, AA-14 and AA-15 between March and November of each operating year. Groundwater monitoring well AA-16 will be installed between the pit and Boyne River adjacent to surface water monitoring station SW1 prior to the commencement of extraction in Phase 2. Continuous water levels and temperatures shall be collected from groundwater monitoring well AA- 16 between March and November of each monitoring year. Page 11

15 3. If permission is granted and locations are accessible, domestic water wells located within 500 m of the extraction area should be included in the groundwater monitoring program. Prior to operations water samples shall be collected from the participating domestic water wells and analyzed for general chemistry, major anions, oil and grease, and bacteria. Subsequent samples should be collected and analyzed on an annual basis at the end of the operational season (late fall). Continuous water level will be collected from each participating domestic well and the data retrieved on a semi-annual basis. 4. The continuous groundwater monitoring data will be retrieved, processed and verified against climate data on a monthly basis March through November each operating year. 5. An annual report summarizing the groundwater monitoring program for the operational season shall be prepared and submitted to the MNRF and NVCA by March 1 st of the following year. Page 12

16 4 Investigative/Mitigative Triggers and Mitigation Although no adverse impacts to the areas surface water features are expected as a result of the onsite operations, the monitoring data collected to date has allowed for the establishment of triggers that identify changes in the surface water features from historic baseline conditions. In the case that changes do occur, mitigation strategies have been considered to resolve any adverse impacts on the surface water features, specifically the Boyne River, Tosorontio Creek and the existing pit lakes. 4.1 Investigative/Mitigative Triggers Precautionary triggers have been established for the operation based on the surface water monitoring data collected to date to ensure no unforeseen impacts occur to the areas surface water features as a result of extraction and to provide sufficient time to implement mitigation measures should changes be discovered in the Boyne River, Tosorontio Creek, and/or the existing pit lakes once operations commence. The mitigative triggers have been set to measure the change in flow/temperature across the site based on the analysis of historical monitoring data. The intent is to review the data and confirm if trends are being observed that are of concern. If the data trend is approaching the mitigative trigger values (within 3% of flow and 1 0 C of temperature triggers) the MNRF will be notified within 10 business days of month end and site conditions investigated. As such, the investigative triggers are data trends within 3% of the flow and 1 0 C of the temperature mitigative triggers. The mitigative triggers are as follows: Boyne River The maximum / minimum monthly average difference in baseflow between monitoring station SW3 and SW1 (upstream to downstream) on the Boyne River of +15% and -10%, respectively. Increase in the maximum average daily water temperature across the site (SW1 downstream compared to SW3 upstream) for any seven (7) day period of C. Water quality results from the Boyne River that fall outside the historic surface water trend. The water quality objectives will be established as additional baseline water quality samples are collected. Tosorontio Creek The maximum / minimum monthly average difference in baseflow between monitoring station SW4 and SW2 (upstream to downstream) on Tosorontio Creek of +8% and -16%, respectively. Increase in the maximum average daily water temperature across the site (SW2 downstream compared to SW4 upstream) for any seven (7) day period of 5.7 o C. Page 13

17 Water quality results from Tosorontio Creek that fall outside the historic surface water trend. The water quality objectives will be established as additional baseline water quality samples are collected. Off-Site Pit Lakes Reduction of the existing off-site pit lake water level west of the subject property (monitoring station SW5) of greater than 0.4 m from the monitored seasonal average water level. Reduction of the existing off-site pit lake water level south of the subject property (opposite Sideroad 5) of greater than 0.3 m from the seasonal average water level. On-Site Pit Lake Overflows Maximum pit lake overflow water temperature of 22 o C for any overflow from the on-site pit lakes to the site outlets (monitoring stations SW6 and SW7). Water quality results from the pit lake discharge that fall outside the historic surface water trend. The water quality objectives for the operation will be established as additional baseline water quality samples are collected. Surface water monitoring is currently being conducted on-site and is proposed throughout the life span of the pit. Following each monthly round of surface water monitoring, the monitoring data will be processed and the results will be analysed. The analysis will include evaluating the data trends to determine if the mitigative triggers are being approached. As discussed, if the trends are within 3% of the flow triggers and 1 0 C of the temperature triggers, the MNRF will be notified within 10 business days of month end and site conditions investigated to consider mitigation measures. It is noted, additional baseline monitoring is being completed in As such, refinement of the surface water triggers following the 2016 monitoring period may be warranted. Only surface water triggers have been established as it is premature to establish groundwater triggers at this time. The groundwater level and temperature data collected on-site will be evaluated monthly at the time of sampling and on an annual basis as part of the annual monitoring report to determine if appropriate groundwater triggers can be established to protect the Boyne River. If the monitoring data reveals that groundwater triggers are appropriate for the Boyne River, thresholds will be developed in co-operation with the MNRF and NVCA. Extraction is to commence in the Phase 1 extraction area south of Tosorontio Creek and not expected to occur in Phase 2 for several years after the aggregate licence is issued. As such, several years of additional baseline groundwater monitoring data will be collected and evaluated to determine if groundwater temperature and level triggers are appropriate for the Boyne River before extraction moves north of Tosorontio Creek. Page 14

18 4.2 Mitigation Measures If a mitigative trigger is exceeded, mitigation will be required. The first step is to confirm the accuracy and potential causes for the results: Boyne River / Tosorontio Creek The continuous baseflow and/or temperature data is to be reviewed to determine if the exceedance is a persistent condition. Recent site operations are to be reviewed and in-situ stream flow and/ or temperature measurements are to be collected to verify the results and determine if pit operations are a source contributing to the exceedance. Off-Site Pit Lakes The continuous water level data is to be reviewed to determine if the exceedance persists. Recent site operations are to be reviewed and in-situ water level measurements are to be collected to verify the results and determine if pit operations are a source contributing to the exceedance. On-Site Pit Lake Overflows The water temperature is to be re-measured and/or the water samples are to be recollected to verify the results and determine if pit operations are a source contributing to the exceedance. If the results are confirmed and an mitigative trigger has been exceeded due to suspected pit operations, mitigation is required. MNR will be notified and a determination of whether extraction activities should cease will be made. Further investigation as to the cause of the exceedance and development and implementation of mitigation options should occur. The following mitigation measures have been considered in the development of the Site Plans recognizing the surface water features of interest and the soils available on-site. Adverse changes in flow or increases in water temperature across the site in either the Boyne River or Tosorontio Creek resulting from the influence of the operation or proposed pit lakes may be mitigated by buffering the connection between the operation/pit lake and the watercourse by placing less permeable material such as clay along the pit lake interface between the pit lake and watercourse. The placement of less permeable material on the pit lake interface will reduce its influence by reducing the flow, and consequently the temperature flux leaving the pit lake. Declines in the off-site pit lake water levels may be mitigated by buffering the connection between the existing and proposed pit lakes by placing less permeable material such as clay along the proposed pit lake interface between the existing and proposed pit lakes. The placement of less permeable material on the pit lake interface will reduce its influence by reducing the flow leaving the existing pit lake. Water temperatures leaving the proposed pit lakes through the proposed bottom draw outlets that exceed the specified trigger may be mitigated through modification of the bottom draw outlet. Page 15

19 Site operations are to be reviewed to determine the cause of the baseflow, temperature and water quality result fluctuation outside the historic range and develop mitigation measures to address the parameter in question. 4.3 Spills Contingency Plan Spills of petroleum products and other hazardous materials can be minimized by establishing a predetermined action plan. A spills response plan has been developed for the proposed extraction operation as documented on the Site Plans. The spills response plan for the pit is as follows: 1. All employees and contractors on-site must obey to the following instructions when handling potential contaminates. 2. All employees and contractors handling fuel and/or other potential contaminates will be instructed as to the proper, safe handling of such material. 3. Storage of potential contaminates will be stored and handled as required by provincial legislation. 4. All spills or release of contaminates are to be cleaned up immediately and transported to an approved waste disposal site by a licensed hauler. Any spill must be immediately contained to prevent further spread until proper disposal can be arranged. 5. In case of a spill, the following actions will be taken: a) Check for hazards (flammable material, noxious fumes, etc.). If flammable liquid, turn off engines and nearby electrical equipment. If serious hazards are present leave the area and call 911. If in doubt, consult the applicable Material Safety Data Sheets for hazards. b) Stop the source of the spill (plug hole, upright the container, shut off valve, etc.). c) Call co-workers and supervisor for assistance and to make them aware of the spill and potential dangers. d) Stop the spill from spreading (excavate and contain contaminated soil, use absorbents, etc.). e) Clean-up the spill, contaminated soil, and/or absorbent and dispose of the material in a container for off-site disposal as hazardous waste. f) Call the Ministry of the Environment Spills Action Centre (SAC) at g) Complete a spills reporting sheet and provide a copy to the Ministry of the Environment. 6. All spills or released contaminants must be immediately report to the Ministry of the Environment. 7. The spills response plan shall be posted on-site at all times. All employees and contractors are to be informed of and required to comply with the spills response plan. Spill containment and clean-up equipment will be kept on-site. Page 16

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