1 Introduction ROBERTSON GEOCONSULTANTS INC. October 19, 2015 RGC Project No:

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1 ROBERTSON GEOCONSULTANTS INC. A Robertson Group Company Consulting Engineers and Scientists for the Mining Industry Suite 900, 580 Hornby St., Vancouver BC, Canada V6C 3B6 Phone (778) Fax (604) October 19, 2015 RGC Project No: Chris Hamilton BC Environmental Assessment Office 1st Floor 836 Yates St PO Box 9426 Stn Prov Govt Victoria BC V8W 9V1 RE: 2015 Hydrogeological Review, Garibaldi at Squamish 1 Introduction 1.1 Terms of Reference Garibaldi at Squamish Inc., a BC based company with its head office in Vancouver, BC. is proposing to develop a large all seasons resort on the slopes of Brohm Ridge, approximately 15 km north of Squamish. The Garibaldi at Squamish ( GAS ) resort project includes plans to build and operate a mountain ski resort and summer recreation. The resort will require an estimated year-round water supply of up to 70 L/s for potable water, snowmaking, fire protection and irrigation. In the most recent submission (Addendum #4), the developer proposed to use groundwater from in the Cheakamus Valley Aquifer ( CVA ) in Paradise Valley, north of Squamish, B.C., to provide sufficient water for its planned operations. In June 2012, the BC Environmental Assessment Office ( EAO ) retained Dr. Christoph Wels ( the author ) from Robertson GeoConsultants Inc. ( RGC ) to review the hydrogeological information provided by the proponent. This initial review 1 concluded that significant data gaps remained for an environmental assessment of the proposed groundwater extraction and provided several recommendations for further work, including (i) monitoring of seasonal groundwater levels, (ii) completion of a 10-day pumping test 1 RGC (2012) Hydrogeological Review of Garibaldi at Squamish (GAS), Letter report submitted to EAO, July 27,

2 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 (during dry summer/early fall conditions), (iii) updating of the conceptual groundwater model and (iv) updating/recalibration of the groundwater flow model for the CVA. In September 2013, the author was retained by the Paradise Valley Community Association ( PVCA ) to assist in the review of additional hydrogeological studies and public consultation process of the proposed groundwater extraction in Paradise Valley. The 2013 review 2 concluded that the CVA has adequate capacity (and recharge) to sustain the proposed groundwater abstraction during the wet winter/spring/early summer periods with very limited effect (interference) on the neighboring wells. However, the author suggested that additional analysis was required to evaluate the influence of groundwater abstraction during the dry late summer/early fall period, specifically during drought conditions. Several recommendations for additional work were provided for further impact assessment, including update and calibration of a transient groundwater flow model and use of this model to predict groundwater drawdown in CVA in response to proposed groundwater abstraction by the proposed GAS project. In June 2015, EAO retained the author to review additional hydrogeological information provided by the proponent and to assist EAO in finalization of potential EA Certificate conditions ( Conditions ) required to protect the CVA. This letter report summarizes the author s review comments. The draft Conditions reviewed as part of this assignment are provided in Appendix A 3. 2 Data Reviewed The following new hydrogeological reports and data were reviewed by the author for this independent review: Piteau (2014) Garibaldi At Squamish Inc. Hydrogeological Investigation for Groundwater Supply, Cheakamus River Valley, Squamish, B.C. Piteau Associates Engineering Ltd, October Piteau (2015) Additional Model Simulations to Evaluate River Recharge Sensitivity - Garibaldi at Squamish Project, Letter report submitted to Chris Gilham, Aquilini Development and Construction Ltd., July 14, RGC (2013) 2013 Hydrogeological Review of GAS Groundwater Supply, Cheakamus Valley Aquifer, Letter report submitted to PVCA, October 8, These are the draft Conditions provided by EAO as of September 2015, and may have small editorial changes made by EAO prior to submission to ministers for consideration. 2

3 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 In addition, the author met with representatives from EAO, FLNR, District of Squamish and Squamish First Nations on June 27, 2015 in Vancouver to review draft Conditions and attended a meeting hosted by the PVCA on July 29, 2015 to discuss these draft Conditions. 3 Key Findings of Review Based on a review of the new information, the author concludes the following: The proponent has completed significant additional assessment work since the last review in 2013, including (seasonal) monitoring, conceptual modeling as well as numerical modeling recommended in an earlier review (RGC, 2013). The new assessment work confirms that the Cheakamus Valley Aquifer has adequate capacity (and recharge) to sustain the proposed groundwater abstraction during the wet winter and spring periods with very limited effect (interference) on the neighboring wells. However, monitoring and modeling demonstrates that the Cheakamus Valley Aquifer is susceptible to seasonal drawdown during the dry late summer/early fall period (specifically during drought conditions) which will require restrictions on groundwater abstraction. The draft Conditions developed by EAO for the GAS project and reviewed as part of this assignment (see Appendix A) address remaining uncertainties and provide, in the author s opinion, adequate protection of the Cheakamus Valley Aquifer and users of this groundwater resource. 4 Review Comments on Additional Information 4.1 Groundwater Monitoring & Conceptual Model Groundwater Conditions during Dry Season (Aug-Sep 2013) Piteau (2014) presented time trends of groundwater levels in selected wells in the CVA for the period January 2013 to April 2014 (Figure 10 in their report). Also shown are daily precipitation and surface water levels in the Cheakamus River and Swift Creek. Piteau (2014) used the monitoring period January 2013 to April 2014 to develop a water balance and estimate ground water flows. During this period the lowest groundwater level at monitoring well OBS-1 was observed in late August 2013 (~56.5 m amsl) and the responding groundwater flow in the aquifer along this section was estimated to be about 520 L/s. 3

4 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 Section 5.5 in Piteau (2014) describes the final calibrated water balance model for the CVA. Of particular interest is the water balance for the dry summer/early fall months when precipitation is very low or absent. During the driest month (September 2013), the total inflow was estimated to be 737 L/s (Table E4) which is about 40% higher than the groundwater flow estimated from hydraulic gradients (i.e. 520 L/s). During this period the primary sources of inflow to the CVA were (i) recharge from the Cheakamus River (512 L/s) and (ii) deep groundwater recharge (142 L/s). In the author s opinion, there is significant remaining uncertainty about the magnitude of recharge from those two sources, and significantly lower recharge rates, in particular for periods of low flow and drought, cannot be ruled out at this time Summer/Fall 2014 Monitoring Data An updated version of the time trend plot of monitoring data (with monitoring data up to late Nov 2014) is reproduced in Figure of the Supplementary Application Report (ERM, 2015). Additional monitoring during the subsequent (drier) summer/fall of 2014 indicated that groundwater levels at OBS-1 had declined further (to about 55.1 m amsl in mid-october). Based on the observed trends at the Hatchery well, hydraulic gradients and hence groundwater flow in the aquifer would likely have been lower in October 2014 than estimated for August To the best of the author s knowledge this much drier summer/fall period was not considered in Piteau s conceptual (and numerical) modeling. For example, the lowest predicted groundwater level for OBS-1, assuming drought conditions, was about 55.7m amsl (Figure G1; Piteau (2014)). This predicted groundwater level for drought condition is still 0.6m higher (!) than groundwater levels observed in October Clearly, the simulated drought condition is not sufficiently conservative. One potential reason for the overprediction of groundwater levels during dry summer/fall conditions is the conceptualization of recharge from the Cheakamus River. For the prediction of drought conditions, a drought precipitation record was fabricated (see pp in Piteau, 2014). However, during drought conditions, stream flow in the Cheakamus River can also be expected to decrease and result in lower river stage (as observed in Sep/Oct 2014) and thus recharge to the aquifer. It is unclear whether, and if so how, the influence of lower river stage on aquifer recharge was considered in the prediction of drought conditions. In summary, more recent monitoring data collected during the summer/fall of 2014 raise some doubt about the validity of estimates of aquifer recharge to the CVA during the dry 4

5 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 summer/early fall period. An overestimation of recharge to the CVA could result in an underestimation of drawdown due to groundwater abstraction. 4.2 Review of Groundwater Modeling General Comments Piteau developed a numerical model of the CVA to predict the drawdown in the CVA to the proposed pumping at the production well TW-1. The aquifer was represented as a single layer and discretized into 50m x 50m grid cells. The model was calibrated in transient mode to (i) seasonal (monthly) water levels observed for calendar year 2013and (ii) water levels observed during the period February 16 to April (including a 4-day pumping test). In the author s opinion, the numerical model represents a reasonable, albeit simplified, representation of the CVA and modeling inputs and boundary conditions are consistent with available data and conceptual modeling. The calibrated transient model reproduces the observed groundwater level time trends reasonably well, in particular near the test well and OBS-1. The hydraulic aquifer properties (K and Sy) determined during model calibration were generally consistent with values obtained from pumping test analysis. As pointed out by Piteau (2014), the range of specific yield values obtained during calibration (0.045 to 0.1) are considered to represent a lower bound for such a coarse-grained aquifer material. Selected model input parameters (K, Sy, recharge) were varied in a sensitivity analysis to illustrate the effect on model calibration. The sensitivity analysis illustrates that hydraulic conductivity of the aquifer is relatively well constrained (say +/-10%). However, higher specific yield values, in combination with higher recharge and higher K, could provide a similar good match. The author agrees with Piteau that the adopted Sy values likely represent lower bound estimates which are more conservative for estimation of drawdown in response to pumping Simulation of River Seepage As discussed in section 4.1, seepage from the Cheakamus River to the CVA is a major recharge mechanism to the CVA and strongly controls groundwater flow during the critical dry summer/fall periods. Numerically, seepage from the Cheakamus River is adjusted in the model by varying the conductance of the river sediments. However, this model parameter is difficult to measure directly in the field and is usually determined during model calibration. At the same time, it is not practical to measure stream losses along the 5

6 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 model reach directly hence river seepage rates could not be calibrated directly, but only indirectly through calibration of heads. This approach introduces uncertainty in the estimates of river recharge. Model calibration yielded a river bed conductivity of 5.7*10-7 m/s (assuming a 2m thick river bed) and monthly recharge to the CVA via river seepage ranging from 462 to 567 L/s. To the best of the author s knowledge the width of the river channel (i.e. saturated crosssectional area of the river bed) was assumed constant throughout the year. In reality, the river width is known to vary by a factor of 2 to 3 depending on stream flow and river stage (Piteau, 2015). The sensitivity of river conductance on model calibration was not evaluated in the initial sensitivity analysis (Piteau, 2014). Piteau, at the request of EAO with advice from the author, completed selected additional sensitivity runs in which river conductance was reduced to 75% and 50% of the original calibrated value (2015). These sensitivity runs demonstrate that a reduction in stream conductance (and hence river seepage and recharge to the aquifer) results in a decline of groundwater levels during dry summer/fall periods. For example, a reduction in river conductance to 75% of the calibrated conductance value resulted in a decline in the simulated groundwater level at OBS-1 by 0.6m in September 2013 (Figure 1 in Piteau, 2015) and a reduction in simulated recharge from the river by about 25% (from 511 to 387 L/s, see Table I in Piteau, 2015). These sensitivity analyses support the hypothesis that the lower groundwater levels observed in OBS-1 during the dry summer/fall period of 2014 are likely caused by a significant reduction in river recharge to the CVA (due to a reduced river stage height and hence narrower channel width). This transient aspect of river recharge has not been accounted for in the current model. It follows, that the model may overpredict river recharge during extended periods of dry weather (such as observed in summer/fall of 2014 and 2015) and thus underpredict the resulting decline in aquifer flows and groundwater levels. Significant temporal variations in river recharge should be considered for simulation of drought conditions Model Predictions for Pumping Piteau (2014) modeled two different pumping regimes for the proposed production well TW-1: A constant pumping rate of 72 L/s year-round, and A seasonal pumping regime with 6

7 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, 2015 o 90 L/s from Nov - Jan o 75 L/s from Feb - Jul and o 54 L/s for Aug - Oct. For the constant pumping regime, the model predicted a drawdown of 0.68m at the test well (OBS-1) and a drawdown of 0.48m to 0.61m within a distance of about 800m (Table IX and Figure 18 in Piteau, 2014). The seasonal pumping regime is predicted to reduce the drawdown in the drier summer/fall period by up to 0.13m (at OBS-1). These model predictions are generally plausible and consistent with the observations during a 4-day pumping test which showed very limited drawdown for a 72 L/s pumping rate. Note, however, that the cone of depression due to continued pumping is predicted to extent several kilometers upgradient and downgradient of the production well. However, the 4-day pumping test (completed in February 2013) did not stress these more distant areas of the CVA (due to the short duration and high precipitation). As a result there is more uncertainty about the hydraulic properties and hence predicted drawdown in those areas. It should also be noted that the model assumes a constant head boundary at the southern model boundary. This boundary condition dampens the predicted drawdown to the south of the production well. The author notes that very limited information was available to constrain hydraulic properties in the southernmost portion of the model domain and the downstream boundary itself. Hence, predictions of drawdown and discharge of groundwater to side channels in this area are, in the author s opinion, less reliable than near the production well. Besides an average year, Piteau (2014) also predicted drawdown due to pumping for a drought year and a climate change year. In both cases, drier conditions are predicted to prevail throughout the summer/fall resulting in extended decline in groundwater levels into late October. For the case of seasonal pumping, the increase to 90 L/s in November produces significantly higher drawdown in November than in October (see Figure G2 in Piteau, 2014). This is particularly problematic for the drought year where groundwater levels are predicted to further decline into November. In the author s opinion, maximum pumping rates in a seasonal pumping regime should be restricted to a period when the aquifer had adequate time to recover from summer/fall drought conditions, i.e. no earlier than mid-november. 7

8 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, Model Limitations In the author s opinion, the numerical model developed by Piteau (2014) is a useful tool for predicting the effects of pumping on drawdown in the aquifer and the private wells in reasonable proximity of the pumping well (say 1 km radius). However, like any other model, it is a simplification of actual aquifer conditions which should be kept in mind when using the model. Based on a review of the information provided, the author has identified the following key remaining uncertainties in model calibration and prediction: Calibration of hydraulic properties in the upgradient and downgradient portion of the model (say >1 km radius from TW-1) and hence predicted drawdown due to pumping; Simulation of river seepage and deep groundwater recharge, in particular for drought conditions; Prediction of groundwater discharge to side channels in the southern portion of the model domain (for current conditions and future pumping scenarios). The author recommends that the current model only be used for an assessment of pumping at the currently proposed test well TW-1 (or a nearby alternative location). Additional aquifer characterization and monitoring (including pumping test(s), followed by recalibration of the model, would be required before other well locations (at a distance of say >500m from TW-1) could be evaluated. In the author s opinion, the remaining model uncertainties listed above have been adequately addressed in the draft Conditions reviewed as part of this assignment, both through conservative water use restrictions and additional studies (see Appendix A). 8

9 BC Environmental Assessment Office Garibaldi at Squamish 2015 Hydrogeological Review October 19, Closure We trust that the information provided in this letter report meets your requirements at this time. Should you have any questions or if we can be of further assistance, please do not hesitate to contact the undersigned. ROBERTSON GEOCONSULTANTS INC. Prepared by: Christoph Wels, Ph.D., M.Sc., P.Geo. (B.C.) Principal and Senior Hydrogeologist END 9

10 APPENDIX A DRAFT EA CERTIFICATE CONDITIONS 1

11 DRAFT Groundwater Conditions October 19, a. The Holder must not withdraw, from the Paradise Valley Aquifer, more than: i. 90 l/s, measured on a daily basis, from November 15 - February 28 ( Winter Season ); ii. 54 l/s, measured on a daily basis, from March 1-April 31 ( Spring Season ); and, iii. 35 l/s, measured on a daily basis, from May 1-November 14 ( Summer Season ). b. The Holder may apply to Environmental Assessment Office (EAO) for approval to increase withdrawal rates from the Paradise Valley Aquifer by up to 20 l/s during the Spring Season and/or Summer Season by preparing and delivering to EAO: i. a water conservation plan; and, ii. a report setting out the results of the groundwater monitoring completed under condition 3, that are to the satisfaction of EAO. The Holder must not increase the withdrawal rates in paragraph (a) unless approved in writing by the EAO. If increased withdrawal is approved by EAO, the Holder must implement the water conservation plan. c. The Holder must, prior to withdrawal of any water from the Paradise Valley Aquifer: i. develop a Groundwater Protection Action Plan that outlines the specific measures the Holder will undertake to achieve maximum reduction of water use in relation to the Project; and ii. obtain the approval of Ministry of Forests, Lands and Natural Resource Operations (FLNRO) for the such Groundwater Protection Action Plan. d. If, pursuant to condition 6, the Main Pumping Well is located at the Original Location and the groundwater level at OBS-1 falls below the Holder s predicted minimum geodetic water level at OBS-1 1 during the Summer Season, the Holder must, within three days of 1 monthly predicted geodetic groundwater level at OBS 1 for seasonal pumping scenario (see Figure G 2 in Piteau, October 2014).

12 learning of such water level, implement the Groundwater Protection Action Plan referred to in paragraph (c). e. If, pursuant to condition 6, the Main Pumping Well is located at a location other than the Original Location, the Holder must: i. by [date/deadline], retain a Qualified Professional (QP) to direct the location and installation of a monitoring well to be used as an alternative to OBS-1; ii. install such alternative monitoring well by [deadline/date]; iii. cause such QP to develop a model that predicts the minimum geodetic water level at such alternative monitoring well by [deadline/date]; and iv. if, during the Summer Season, the groundwater level at such alternative monitoring well drops below the predicted minimum geodetic water level for such well, within three days of learning of such water level, implement the Groundwater Protection Action Plan referred to in paragraph (c). f. Prior to the commencement of pumping operations, the Holder must develop a public, online information website which shows: i. Daily pumping rate of the main production well; and ii. Live monitoring results of the observation well referred to in paragraph (d) or (e), as applicable. g. The Holder must monitor pumping rate and live monitoring results under paragraph (f) on a [daily] basis to ensure that the Holder is aware of groundwater levels for the purpose of paragraph (d) and (e), as applicable. 2 a. Prior to the Holder commencing pumping operations which would remove groundwater from the Paradise Valley Aquifer, the Holder must identify all wells existing which meet the following criteria: i. a 2km radius of the Main Pumping Well for the Project; and ii. the Paradise Valley Aquifer or the Cheakamus Valley, (each an Existing Well) as of the date of this EAC, and measure the available drawdown in each Existing Well. b. If an Existing Well does not have an available drawdown that exceeds: i. the documented drawdown referenced in 2b, ii. plus:

13 1. if, pursuant to condition 6, the Main Pumping Well is located at the Original Location, four meters below the lowest predicted water level at the location of the subject well, based on the drought scenario predicted for mid-november in Piteau, 2014; or 2. if, pursuant to condition 6, the Main Pumping Well is located at a location other than the Original Location, a distance below the lowest predicted water level at the subject well, as determined by a QP retained by the Holder in a manner consistent with the methodology used in Piteau, 2014, then the Holder must make reasonable efforts to offer to the owner or operator of such Existing Well to drill a new well and install associated infrastructure such as pumps and wiring (each a Replacement Well), which in the case of domestic wells, will not exceed 6 inch pipe diameter. For greater certainty, if the Main Pumping Well is located at a location other than the Original Location, the Holder must cause a QP to complete the modeling contemplated in paragraph (b)(ii)(2) by [date/deadline]. c. The Holder must make reasonable efforts to deliver offers of Replacement Wells to applicable well owners and operators at least 6 months prior to the Holders planned date to commence pumping operations that would remove groundwater from the Paradise Valley Aquifer (Pumping Commencement). The Holder must cause all Replacement Wells for which it received accepted offers at least 3 months prior to Pumping Commencement to be installed and operational by the date of Pumping Commencement. d. Prior to Pumping Commencement, the Holder must provide EAO with a report which: i. provides a map of the Existing Wells which meet the criteria in paragraph 2b ii. the name and address of each owner or operator of an Existing Well who was offered a Replacement Well; and, iii. the current operating status of each Replacement Well. 3 The Holder must develop a groundwater research and monitoring program which, at a minimum, contains the following elements: a. groundwater quantity and quality monitoring at a minimum of six monitoring wells to be installed by the Holder within 2 years of the issuance of an EAC as follows:

14 i. one well within 20 m of the main production well for the Project; ii. one well approximately halfway between the main production well for the Project and the Tenderfoot hatchery; iii. one well 500m upgradient of the main production well for the Project; iv. one well 1000m upgradient of the main production well for the Project; and v. the two wells required under condition 4. b. a monitoring program for Swift Creek which will monitor water volumes and flow on a quarterly basis; and, c. a requirement for the Holder to submit an annual report to EAO, FLNRO, the District of Squamish and the Squamish Nation by December 15 of each year, that describes the results of monitoring under paragraphs (a) and (b). The Holder must obtain approval of EAO and FLNRO of the groundwater research and monitoring program prior to (i) the third anniversary of this EAC, and (ii) the commencement of construction of the Project, whichever comes first. The Holder must implement the program consistent with the timelines set out in the program. 4 The Holder must, prior to (i) the third anniversary of this EAC, and (ii) the commencement of construction of the Project, whichever comes first, complete and deliver to EAO a written study that determines potential adverse effects from the construction and operation of the GAS groundwater pumping project on the fish and fish habitat in the side channels located between the Tenderfoot Hatchery and the North Vancouver Outdoor School as illustrated in diagram XX in the CPD. The study must, at a minimum, include the following components: a. an investigation into the seasonal use of the side channels by anadromous and non-anadromous fish and benthic invertebrates; b. an investigation into the sources of water which supply the side channels (surface water or groundwater) and the various contributions of those sources, including, but not limited to, the water sources during late summer drought conditions; c. the installation of a minimum of two groundwater monitoring wells that will be monitored by the Holder in order to provide primary information to support the study (see condition 3(a)(v));

15 5 6 d. an assessment of the role of the Cheakamus River in supplying water to the side channels. Prior to commencing this study, the Holder must (i) consult with FLNRO, District of Squamish and the Squamish Nation on the scope of work of the study, including the location of the groundwater wells, and (ii) obtain the approval of EAO for the scope of work included in the study. If the study results demonstrate that mitigation actions are required to ensure that adverse effects on fish and fish habitat do not occur, the Holder must develop and implement a Side Channels Fish and Fish Habitat Management Plan on timelines and in a manner that are to the satisfaction of EAO. The Holder must not use any groundwater withdrawn from the Paradise Valley Aquifer to fill the Project s snowmaking reservoir during the Summer Season. Prior to (i) the second anniversary of this EAC, and (ii) the commencement of construction of the Project, whichever comes first, the Holder must: a) in addition to the original proposed location (as described on page xx of the CPD; the Original Location ) of the Main Pumping Well (as described on page xx of the CPD; the Main Pumping Well ), identify at least two alternative locations for the Main Pumping Well with a view to locating the Main Pumping Well in a manner that will minimize the noise, safety and aesthetic effects residents in the Paradise Valley as of the date of this EAC; b) make reasonable efforts to consult with the District of Squamish (DOSFLNRO and the Paradise Valley Community Association (PVCA) regarding their respective views on the potential effects of alternative locations identified by the Holder pursuant to paragraph (a); and c) submit to EAO and DOS a report, in a form satisfactory to EAO, that includes, among other things: (i) a revised effects assessment that compares the predicted effects of the alternative locations identified by the Holder pursuant to paragraph (a) to the predicted effects of the

16 Original Location described in Chapter Five of the Supplemental Application (April 2015); (ii) a summary of the consultations carried out pursuant to paragraph (b), including a consultation log and summary of the views expressed by DOS, FLNRO, and PVCA during such consultations; and (iii) the Holder s views as to whether the Original Location or any of the alternative locations described by the Holder pursuant to paragraph (a) are ideal in terms of (A) technical viability, (B) overall predicted effects, and (C) acceptability to the Holder, and (D) the views of DOS, FLNRO and PVCA. If the EAO provides written notice to the Holder of the required location of the Main Pumping Well within 60 days of receipt of such report, the Holder must locate the Main Pumping Well in accordance with any such indication by the EAO. If the EAO does not provide any such indication, the Holder must locate the Main Pumping Well at the Original Location.