May 5, 2009 AEC 04-103 595 9th Avenue East Owen Sound, ON · PDF file595 9th Avenue East Owen Sound, ON N4K 3E3 Attention: Mr. Scherzer MCIP RPP ... After listening to Frank Brunton's

May 5, 2009 AEC 04-103 Mr. Randy Scherzer County of Grey 595 9th Avenue East Owen Sound, ON N4K 3E3 Attention: Mr. Scherzer MCIP RPP

Senior Planner/GIS Coordinator RE: Final Model Response – M.A.Q. Aggregates Inc. Dear Sir: Azimuth Environmental Consulting, Inc. and Earthfx, Inc. are pleased to provide the County of Grey with the final response to Mr. Neville’s review of the numerical ground water flow model. The ground water flow model was developed to assist in the understanding of the potential cumulative impacts associated with the development of the Highland and Duntroon Quarries. This response was prepared to address the comments presented in the letter dated February 9, 2009. It is hoped that this final response provides the information required for Mr. Neville to conclude his technical review. If you have any questions or concerns, please feel free to contact the undersigned. Yours truly, AZIMUTH ENVIRONMENTAL CONSULTING, INC. Tecia White, M.Sc., P.Geo. Senior Hydrogeologist cc. Mr. Quinn Moyer (M.A.Q. Aggregates, Inc. ) Mr. Chris Neville (S. S. PAPADOPULOS & ASSOCIATES, INC.)

Response to peer review of MAQ Highland Quarry hydrogeologic modelling: FINAL

Z:\2_Highland\Working File (2008 - 2009)\Model review correspondences\Agency Review\Model Review\Earthfx Response Reports\FINAL_Peer Review Response (April 2009).doc Page 1 of 12 5/5/2009

Peer Review Comments Response to Comments Overview 1. Address the Peer Review comments dated February 9, 2009. To bring closure to our modelling peer review, we recommend that the comments in our final peer review of February 9, 2009 be addressed. We will be meeting with Azimuth Consulting and Earthfx on April 2, 2009 to discuss these comments.

Following the distribution of the February 9, 2009 report completed by Mr. Neville, Azimuth/MAQ met with the agencies on March 23, 2009 to discuss the findings and the outstanding items. Following this meeting Mr. Neville prepared a letter dated March 26, which summarized the items to be addressed by MAQ/Azimuth/Earthfx. A technical meeting between Mr. Neville, Earthfx, and Azimuth occurred on April 1, 2009. The outcome of these correspondences is believed to have resolved the outstanding issues. The responses provided below are a follow-up to the technical discussions held on April 1, 2009.

2. Assess the goodness-of-fit of the analysis of current conditions with respect to annual average and seasonal streamflow data. The results of the updated (2007) analyses conducted for the proposed extension of the Duntroon Quarry suggest that relatively significant modifications to the model were required to match transient water level and flow data. Only steady-state analyses have been conducted for the proposed Highland Quarry. We recommend that the model be extended for the simulation of seasonal trends. Monthly estimates of water surplus are presented on Table 3-2 of the main Azimuth Consulting report (March 2006). These estimates may serve as a basis for specifying recharge rates that vary through time. The objective of the analyses would be to assess the ability of the model calibrated for current average conditions to approximate seasonal trends in water levels and stream flows.

We agree that conducting a transient calibration often leads to improvements in the conceptual and numerical models. It should be noted, however, that the Duntroon model was run in transient model specifically to address questions related to Escarpment springs which are likely to be strongly influenced by seasonal patterns of recharge and more likely to be affected by dewatering close to the escarpment However, it is questioned as to the added value of applying the transient model to the Highland Quarry at this time. The existing model provides a conservative analysis on the potential impact to the surface water systems, identifying key areas which are incorporated into the AMP (i.e., trigger locations). Both the Highland steady-state model, and the Duntroon transient model predict a limited influence on the Beaver River. It is proposed that a transient model be developed as a component of the AMP. The AMP currently recommends the steady-state model be re-calibrated in a five-year period once a sinking cut has been established. At this time there will be considerable “real time” drawdown data in proximity to the quarry face (continuous water level data), providing additional data critical to the calibration of a transient model. Furthermore, in September 2008, CC Tatham and Azimuth installed a continuous surface water monitoring station at a key location along the Beaver River (SW6A). The objective of this flow station was to establish baseline (pre-quarry) conditions for the stream and to gain further insight to the changes in the flow regime over the different seasons. The transient calibration would benefit greatly from having one to two years of continuous record at this station.

3. Assess the significance of local conditions in the vicinity of observation well OW5. The modelling of the proposed extension of the Duntroon Quarry suggested that there might be a zone of elevated hydraulic conductivity within the footprint of the proposed Highland Quarry. Although relatively little is known about this area, results obtained with the calibrated JHL model suggest that predictions are relatively sensitive to the properties of this feature. A detail from their calibrated model is reproduced below (JHL, October 2007: Figure A-1). The zone with K = 10-3 m/s is included in JHL model layers 1, 2, 3 and 4, corresponding to the full thickness of the Amabel Formation. Observation well cluster OW5 is located at the eastern end of this zone.

We believe that the water level data can provide information on the presence of zones of varying hydraulic conductivity in the area although the zones do not necessarily correspond to those inferred by JHL (October 2007) The figure below shows the mid-range ((min+max)/2) of the water level data used as targets for the calibration. When you look at spatial distribution, you can see two general classes: water levels below 510 masl (yellow dots) and water levels above 512 masl (orange to red dots). The lower water levels fall within the K zone in Layer 4 representing the "508 fracture". The higher water levels fall within the K zone in Layer 4 corresponding to the mega-ripples which was assigned a lower K. We had a reasonable confidence that the two K zones were real but did not have a good explanation for them. After listening to Frank Brunton's description of the Gasport-Goat Island contact in the Guelph and Hamilton areas, it may be that the situation here is similar and the mega-ripples represent the Lower Amabel (Gasport?) rising above 508 masl and the contact zone with the Goat-Island(?) in the troughs at 508 masl. Additional investigation and re-examination of the core data may shed some light on whether this theory has potential.



The well coverage shown in the detail suggests that there are little data to support the inference of the extent or properties of this zone of elevated hydraulic conductivity. The incorporation of the high-K feature near OW5 in the JHL model has been motivated by the water level data from the wells at the OW5 cluster. As shown below, there is a relatively large difference between the water levels at OW5-IV and the other three wells in the cluster. An alternative interpretation is suggested in the main Azimuth Consulting report (p. 58); the interpretation is that OW5-IV is located in an isolated zone that is not connected to the overlying fracture network. We request additional information for this area obtained of the model developed for the proposed Highland Quarry.

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It should be noted that all the inferred zones of high K in the Duntroon model fall within our high-K zone. The difference is that we believe that our analysis of the water level data and our conceptual understanding of the hydrogeology gives us the ability to infer the extent of this zone well beyond the site. In looking at the water level data from OW5-4, the behavior of this well is very different from all other well clusters (OW1, 2, 3,4, and 6) and we also do not see such a big difference in well response and heads between wells in any other cluster (max 0.5 m in OW-6). It has been concluded that this layer is not hydraulically connected to the overlying fracture based on both water level and water quality. The hydraulic head increases approximately 1.5 m during this period from a low of 506 masl and peaking at approximately 507.5 masl. This response is typical of an isolated or “confined” flow system, which is not hydraulically connected to the overlying fracture network. This interpretation is further supported by the upward gradient. At OW5-IV the measured response is considered to be that of an actual ground water flow zone, which is isolated from a direct hydraulic connection to a vertical joint. This is inferred because the geochemical signature of the deeper water at OW5-IV is different than that above (i.e., OW5-III) even though there exists an upward gradient. The measured response from OW5-IV has lead to the interpretation that this well intersects an isolated flow zone. A full hydrogeochemical and isotopic analysis was completed to further support this interpretation The two ground water samples were taken from OW5-I (upper Amabel) and OW5-IV (base of Amabel) and analysed for enriched tritium (3H). As discussed in the previous section, the ground water sampled at OW5-IV had a distinctively different hydrogeochemical signature then the shallower ground waters. This hydrogeochemical signature suggested that waters from this flow zone are older in terms of distance along the flow path and residence time, or age of the water. Therefore, the purpose of this analysis was to assist in the assessment of the recharge mechanisms and recharge rates on the infiltrating surface waters. Tritium concentrations measured in ground waters collected from OW5-I and OW5-IV are 17.9 and less than 0.8 TU, respectively. The 3H data are seen to support the proposed ground water classification and chemical evolutionary sequence in that the deeper flow system contains a significant component of more mature “pre-bomb” ground water that was infiltrated prior to 1953. Based on this analysis, it is felt that OW5-IV is located in an isolated zone that is not connected to the overlying fracture network.



What are the inferred hydraulic conductivities in this area? How close is the match to the targets for the individual wells in the OW5 cluster? We recommend that additional sensitivity analyses be conducted to assess the significance of properties in the vicinity of OW5. If model predictions are sensitive to the properties, we recommend that additional site characterization be conducted to assess conditions in this area.

The discussion of the anomalous behavior of OW-5 was not a key point. The information that can be gleaned from the hydrographs was that, in general, (1) the well clusters do not show significant vertical gradients, (2) wells in cluster OW-5, with the exception of OW5-4) have lower values than the other clusters. We used a K of 1x10-4 for the High K zone in Layer 4. Our model, however, did not have as high a level of contrast in properties between zones as the Duntroon model. The calibration could be improved by assigning a K identical to the Lower Amabel (layer 5) in the mega-ripple zone and a higher K in the 508 zone. The simulated head near OW-5. was about 512 masl while the mid-range value was 512.7 which is comparable to the heads in nearby wells OW-2 (513.4) and JHL BH03 (514.6). The simulated value was comparable to the mid-range values in nearby wells OW-2 (513.4) and JHL BH03 (514.6)" (see scatter plot)





4. Assess the significance of the 508 metre zone We request further information on the representation of the 508 m zone, and an examination of its significance through sensitivity analysis. We are not completely clear on how the 508 m zone is represented in the analysis. We understand that the 508 m zone is represented as a relatively thin, discrete model layer (model layer 4). We further understand from Figure J-2 that the zone is not present everywhere; over the western portion of the model the surface of the top of the Amabel Formation is below 508 m. The horizontal hydraulic conductivity of the 508 m zone is shown in Figure J-9. It is not clear what hydraulic conductivity values are specified for the zone, and no discussion is presented for its relatively complex distribution of hydraulic conductivity. Furthermore, it is not clear how the 508 m zone is handled in the area where it is absent. It appears that this area corresponds to the light green area shown in Figure J-9. However, the hydraulic conductivity of this area does not appear to be the same as the hydraulic conductivity assigned for model layer 5 (Figure J-10).

We approximated the presence of the 508 fracture in the (dark green zone) as a thin layer with higher K (1x10-4). The light green zone was assigned a lower K (5x10-5) and the orange zone (where the elevation of the zone is corrected to follow the top of the Amabel) was assigned the K of the upper Amabel (1x10-5). The explanation for the K distribution is as noted above. We agree, in hindsight, that the fracture/contact zone is likely not present in the light green area (as opposed to being infilled or not as open) but is higher up and we could have used a K of the Lower Amabel to improve the calibration.

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The properties of the 508 m zone are summarized clearly on Page 33 of the main Azimuth Consulting report. The evidence to suggest that this is a continuous flow zone is mixed, and Azimuth write, “...the significance of the 508 masl fracture from a ground water flow perspective, in this locale, is questionable.” This raises two questions: Is this zone significant with respect to the predictions of changes in groundwater discharge to streams that may occur due to the development of the Highland Quarry and/or extension of the existing Duntroon Quarry? We recommend that the significance of this zone be examined through sensitivity analysis. Is the incorporation of this zone in the analyses of the Highland Quarry significant with respect to calculation of water levels and flows for existing conditions, or for the estimation of changes in flows for the predictive scenarios?

We believe that the 508 fracture zone does exist. In addition to the water level data, many of the springs in the study area emerge at an elevation close to 508 m as can be seen in the figure. The others tend to emerge at about 502-503, maybe indicating the presence of another bedding plane fracture zone (as opposed to a stream-following K zone proposed by JHL).



5. Expand the description of conditions assumed for the predictive scenarios. It is not clear what specific conditions are assumed for each of the predictive scenarios analyzed. To assist in our understanding we have prepared the table below indicating our current understanding. We request that the table be completed for each simulation.

Simuation Feature Condition 1 No Quarry No quarry dewatering 2 Existing Duntroon Quarry Duntroon Quarry fully extracted as per Site Plans and

dewatered to 509 masl 3 Proposed Highland Quarry

Extension, Phase 1 Existing Duntroon Quarry dewatered to 509 masl

Duntroon Phase 1 Expansion dewatered to 500 masl Duntroon Phase 2 Expansion dewatered to 500 masl Highland Phase 1 Expansion dewatered to 490 masl

4 Proposed Highland Quarry Extension, Phase 2

Existing Duntroon Quarry dewatered to 509 masl Duntroon Phase 1 Expansion dewatered to 490 masl Duntroon Phase 2 Expansion dewatered to 500 masl Highland Phase 1 Expansion dewatered to 490 masl Highland Phase 2 Expansion dewatered to 490 masl l

5

Proposed Duntroon Expansion Only

(Used to isolate effects of Duntroon only)

Existing Duntroon Quarry dewatered to 509 masl Duntroon Phase 1 Expansion dewatered to 490 masl Duntroon Phase 2 Expansion dewatered to 500 masl

6 Proposed Highland Quarry Phase 2 only

(Used to isolate effects of Highland only)

Existing Duntroon Quarry dewatered to 509 masl Highland Phase 1 Expansion dewatered to 490 masl Highland Phase 2 Expansion dewatered to 490 masl l

7 Rehabilitation All quarry pits simulated as lakes (High K with drain set to overflow elevation)



6. Present quantitative bases for the assumed lake levels in the predictive scenarios. It is our understanding that mined-out quarries are represented as constant-head conditions in the predictive scenarios. For example, for Simulation 2, a level of 510 m is assumed for the lake in the existing Duntroon Quarry. This raises two questions: • Is a level of 510 m achievable? and • What levels may be achieved in the other quarry lakes beyond the mining period? In their analyses of the proposed extension of the Duntroon Quarry, Jagger Hims used the MODFLOW Lake Package (LAK3) for the analyses of the proposed Duntroon Quarry extension. This approach has the advantage of not requiring a-priori assumptions of final lake levels. The analysis also explicitly incorporates a water balance for the lakes. We recommend that water balance calculations be developed for each quarry lake, for each predictive scenario. We recommend that either the approach incorporated in the Lake Package be adopted, or the high-K approach (Anderson and others, 2002).

We did not use constant head cells to represent the quarries. Instead, we represented seepage into the floor of the quarry with drains set at the elevation of the quarry floor (Zq). The length and width (L,W) of the drain segment was set equal to the length and width of the cell. So the darcy flux into the cell is Q = L * W * K' (Ha - Zq) /B' where Ha is the head in the aquifer (represented by the head in the cell) and K',B' are hydraulic conductivity and thickness of the material overlying the aquifer or permeable fracture zone. Seepage out the side of the quarry wall was also represented using a drain. Here the elevation was set to be a small height (e.g. 0.1 or .0.5 m )above the bottom of the permeable zone. The width was the length of the drain along the wall. The width was assumed to be a the same height above the base of the permeable zone. B' was assumed to be the distance back from the edge of the wall (half the cell width) and K' was the K of the permeable zone. Ha is the head in the cell. For quarry lakes, we set the drain at the proposed maximum elevation (e.g. 507 masl) and assigned a high K zone to the footprint of the quarry (similar to Anderson and others, 2002). The high K zone allows the model to determine the lake elevation. The drain prevents the lake from exceeding the maximum elevation. In this way, the lakes are either controlled by groundwater levels in the area surrounding the lake or, if inflow from the surrounding area is high, then the final lake levels are controlled by topography (overflow controlled).

This figure was to show the extent of areas of extremely high K (magenta zones) assigned to the quarry pits for the rehabilitation scenario



7. Predicted changes to groundwater discharges to streams should be reported on a subwatershed basis. The most significant effects of the proposed Highland Quarry and extension of the Duntroon Quarry are likely to be to groundwater discharges to surface water features. In light of the sensitivity of the ecosystem in the study area, it is important that the predictions be reported on the basis of individual watersheds. These watersheds are: • Pretty River subwatershed, as recorded at surface water monitoring location SW18; • Batteaux Creek North subwatershed, as recorded at surface water monitoring locations SW14 and SW15; • Batteaux Creek South subwatershed, as recorded at surface water monitoring locations SW22 and SW22A; and • Rob Roy Wetland Complex (Beaver River subcatchment), as recorded at surface water monitoring locations SW6, SW6, and SW6A6. Rates of groundwater inflow should also be reported for the individual quarries.

SW18 is well beyond the model boundary. It is also well beyond the boundary of the JHL model so I am unclear how they calculated discharge for comparison at this point SW14 and SW15 are also well beyond the model boundary SW22 and SW22A are beyond the model boundary We will compare flow changes at SW6. For example, baseline groundwater discharge was 34.5 L/s, observed total flow (average from May to Nov in 2003 to 2006) was reported as 53.8 L/s in JHL (2007). Their simulated groundwater discharge was 20.9 L/s



8. An expanded treatment is required for the term of the water budget identified as “Net Lateral Flow Out”. The water balance summaries shown in Figures 10-1, 10-2, 10-3 and 10-4 indicate a significant component of the balance that is identified as “Net Lateral Flow Out”. This component needs to be described in more detail. Does this component represent the average groundwater discharge to the Mad River system? If it does not, then this quantity should be broken down into the flows to the different subwatersheds.

Quarry Scenario Beaver

River Mad River

Pretty River

Bateaux River

1 Existing Conditions 36.7 24.1 85.5 15.9 2 Pre-Quarry 38.5 24.4 85.7 17.6 3 Highland Phase 1;

Duntroon Phases 1 and 2 26.9 24.0 85.2 15.6

4 Full Development Highland Phase 1 and 2; Duntroon Phases 1, 2 and 3

25.5 24.0 84.5 15.7

5 Highland Full Development (no Duntroon Expansion)

26.1 24.2 84.7 15.7

6 Duntroon Expansion Full Development (no Highland Quarry

35.0 24.2 84.7 15.7

All units in L/s

Subwatersheds outlines used in mass balance



9. A table listing the observation wells, target groundwater levels and model results. An indication of which target levels are developed from high reliability wells (logged by a professional geoscientist, and for which a time series of water levels in available)

It should be noted that, with the exception of OW-1 to OW-6, JHL-BH03-7-2, and 2 overburden wells, all wells used as targets (by JHL and us) are open hole. Therefore, there separating out the water level targets by bedrock layer was not considered since the majority of the observations likely reflect an average of bedrock water levels. Therefore, the comparison was completed for the observed heads against those in Layer 5 (previous table) for simplicity.



10. A map of the model residuals for each model layer (a residual is the difference between the observed and calculated water level)

11. A scatterplot of observed and calculated groundwater levels The scatterplot was presented as a comparison of our model results to the same calibration targets as used in the JHL report. The wells they used were

a mix of shallow and deeper ones. Based on the hydrographs for well clusters OW1-OW6, there is little (max 0.5 m at OW6) difference in recorded water levels except for OW5-4 which was discussed earlier so comparison of a mix of wells should not be an issue.

12. A summary of observed and calculated flows at target locations Simulated groundwater discharge to streams under existing and future conditions was covered in an earlier response. Comparisons against the same flow data as used in the JHL study (Table 2-4 to 2-6) is provided in the table below.

Catchment Gauge Observed Flow

2003-2006 (L/sec)

Simulated Flow (L/sec)

JHL Simulated (L/sec)

Pretty River SW18 4.8 (Low Flow) 6.1 8.3 Batteaux Creek North SW14/15 2.4 (Low Flow) 1.26 2.4 Batteaux Creek South SW 22/22A 0.9 (Low Flow) 4.17 3.8 Beaver Creek SW6 53.8 (Average) 38.7 20.9

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May 5, 2009 AEC 04-103 595 9th Avenue East Owen Sound, ON · PDF file595 9th Avenue East Owen Sound, ON N4K 3E3 Attention: Mr. Scherzer MCIP RPP ... After listening to Frank Brunton's