Surface Water Impact Assessment – Green Lake & Madawaska River, Madawaska Valley Township, Renfrew County Revision: 1 (Final) Prepared for: Combermere Lodge Ltd. 118 Annie Mayhew Road Combermere, ON K0J1L0 Prepared by: Project Number: 17-223-1 Document ID: 17-223-1_SWIA_R1.docx July 30, 2018 Surface Water Impact Assessment Final Report Green Lake & Madawaska River, Renfrew County Doc. ID: 17-223-1_SWIA_R1.docx Surface Water Impact Assessment – Green Lake & Madawaska River, Title: Madawaska Valley Township, Renfrew County Client: Combermere Lodge Limited Project Number: 17-223-1 Document ID: 17-223-1_SWIA_R1.docx Revision Number: 1 Date: July 30, 2018 Prepared by: Drew Paulusse, B.Sc., Robert Walsh, Ph.D., P. Eng. Reviewed by: Kenneth Raven, P.Eng., P.Geo. Approved by: Robert Walsh, Ph.D., P.Eng. July 30, 2018 i Surface Water Impact Assessment Final Report Green Lake & Madawaska River, Renfrew County Doc. ID: 17-223-1_SWIA_R1.docx TABLE OF CONTENTS 1 INTRODUCTION .................................................................................................................................. 1 1.1 Purpose ........................................................................................................................................ 1 1.2 Objectives and Scope of Work .................................................................................................. 1 2 STUDY AREA SETTING ..................................................................................................................... 5 2.1 Landforms, Soils and Geology ................................................................................................. 5 2.2 Surface Water Features ............................................................................................................. 5 3 FIELD INVESTIGATION METHODOLOGY ........................................................................................ 7 3.1 Surface Water Sampling ............................................................................................................ 7 3.2 Borehole Investigations and Monitoring Installation ............................................................. 8 3.3 Groundwater Elevation Monitoring and Groundwater Sampling ......................................... 8 3.4 Recreational Crowding Assessment ........................................................................................ 9 4 LAKESHORE CAPACITY MODEL ................................................................................................... 10 4.1 Development and Application ................................................................................................. 10 4.2 Model Calibration ...................................................................................................................... 10 4.2.1 Input Data ................................................................................................................... 10 4.3 Summary .................................................................................................................................... 12 5 RESULTS ........................................................................................................................................... 13 5.1 Surface Water Investigations .................................................................................................. 13 5.1.1 Trophic Status ............................................................................................................. 13 5.1.2 Green Lake and Labrador Lake Thermal Stratification ................................................ 14 5.1.3 Surface Water Quality ................................................................................................. 16 5.1.3.1 Dissolved Organic Carbon .............................................................................. 16 5.1.3.2 Phosphorus ..................................................................................................... 17 5.1.3.3 Nitrogen .......................................................................................................... 18 5.1.3.4 Chlorophyll ɑ ................................................................................................... 18 5.1.4 Water Quality Summary .............................................................................................. 18 5.2 Madawaska River Discharge ................................................................................................... 19 5.3 Surficial Geology ...................................................................................................................... 20 5.4 Groundwater Elevation and Flow Direction .......................................................................... 20 5.4.1 Horizontal Groundwater Gradients .............................................................................. 26 5.4.2 Groundwater Velocity .................................................................................................. 26 5.5 Recreational Crowding ............................................................................................................ 27 6 DISCUSSION ..................................................................................................................................... 28 6.1 Phosphorus as a Contaminant of Concern ........................................................................... 28 6.2 Comparison to the Analog Site ............................................................................................... 29 6.3 Implications of Site Hydrogeology on Septic Impact ........................................................... 29 6.4 Implications of Site Geochemistry on Septic Impact ........................................................... 30 6.5 Phosphorous Loading to the Madawaska River ................................................................... 31 7 RECOMMENDATIONS ...................................................................................................................... 33 July 30, 2018 ii Surface Water Impact Assessment Final Report Green Lake & Madawaska River, Renfrew County Doc. ID: 17-223-1_SWIA_R1.docx 8 CONCLUSIONS ................................................................................................................................. 34 9 CLOSURE .......................................................................................................................................... 35 10 REFERENCES ................................................................................................................................... 36 LIST OF REPORT FIGURES Figure 1 Site Location ................................................................................................................. 3 Figure 2 Site Layout .................................................................................................................... 4 Figure 3 Spring and Fall Temperature and Dissolved Oxygen Profiles of Green Lake .............. 15 Figure 4 Groundwater Elevations and Flow Direction: October 2017 ........................................ 22 Figure 5 Groundwater Elevations and Flow Direction: May 2018 .............................................. 23 Figure 6 Groundwater Elevations and Flow Direction: July 2018 ............................................... 24 Figure 7 Cross Section A-A’: Northwest Portion of Site ............................................................. 25 Figure 8 Cross Section B-B’: Central Portion of Site .................................................................. 25 Figure 9 Cross Section C-C’: Southeast Portion of Site ............................................................. 26 LIST OF REPORT TABLES Table 3.1 Summary of Surface Water Investigations ..................................................................... 7 Table 4.1 Shoreline Development Phosphorus Loading Coefficients .......................................... 11 Table 4.2 Summary of Lake Capacity Model Results .................................................................. 12 Table 5.1 Relationship Between TSI Vales and Trophic State .................................................... 13 Table 5.2 TSI Values for Green Lake and Labrador Lake ........................................................... 14 Table 5.3 Surface Water Analytical Results for Green Lake and Madawaska River .................... 16 Table 5.4 Madawaska River Discharge at Palmer Rapids ........................................................... 19 Table 6.1 Comparison of Test Site to Analog Site ....................................................................... 29 LIST OF APPENDICES Appendix A Lake Capacity Model Input Sheets Appendix B Lake Capacity Model Output Sheets Appendix C Data Summary Tables Appendix D Laboratory Analytical Reports July 30, 2018 iii Surface Water Impact Assessment Final Report Green Lake & Madawaska River, Renfrew County Doc. ID: 17-223-1_SWIA_R1.docx 1 INTRODUCTION Geofirma Engineering Ltd. was retained by Combermere Lodge Limited to complete a Surface Water Impact Assessment in support of zoning amendment and plan of subdivision application for part of Lots 2, 3 & 4, Concession 9 and part of Lots 2, 3, 4 & 5, Concession 8 in Madawaska Valley Township. The site location is provided on Figure 1. 1.1 Purpose The proponent is seeking a zoning amendment and plan of subdivision approval to develop an approximately 77.3 hectare (ha) property into a permanent residential subdivision. The proposed plan of subdivision borders