Sooke Watersheds, Inlet, Harbour and Basin Water Quality Assessment and Proposed Objectives
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ENVIRONMENTAL PROTECTION DIVISION MINISTRY OF ENVIRONMENT AND CLIMATE CHANGE STRATEGY Water Quality Assessment and Proposed Objectives for Sooke Watersheds, Inlet, Harbour and Basin TECHNICAL REPORT January 2019 WATER QUALITY ASSESSMENT AND PROPOSED OBJECTIVES: SOOKE WATERSHEDS/INLET/HARBOUR/BASIN Prepared by: Rosie Barlak Environmental Impact Assessment Biologist Environmental Protection Division MINISTRY OF ENVIRONMENT AND CLIMATE CHANGE STRATEGY ii WATER QUALITY ASSESSMENT AND PROPOSED OBJECTIVES: SOOKE WATERSHEDS/INLET/HARBOUR/BASIN EXECUTIVE SUMMARY This document presents a summary of the ambient water quality of Sooke Inlet, Harbour and Basin, and the streams in the surrounding watersheds that drain into these marine areas, near the District of Sooke, British Columbia (BC). The water quality assessment conducted here forms the basis for proposed water quality objectives (WQOs) to protect existing and future water uses. The WQOs have recently been approved and can be found in the following document “Water Quality Objectives for Sooke Inlet, Harbour, and Basin, and Tributary Streams” (BC ENV, 2019). There are 12 major watersheds that drain into the Sooke Inlet, Harbour and Basin. Nine are designated community watersheds, including four that are part of the Greater Victoria Water Supply Area (GVWSA). The T’Sou-ke Nation traditionally used to harvest shellfish in the Sooke marine areas; however the area has been closed to harvesting for many years. The designated water values/uses to be protected are shellfish harvesting, recreation and wildlife in the marine waters of the inlet/harbour/basin; and drinking water, aquatic life, recreation, irrigation and wildlife in the freshwater rivers and streams. There are many activities that can potentially affect water quality both in the marine and freshwater environments, such as rural and urban development, industry, agriculture, forestry, recreation and wildlife. Water quality monitoring in the marine areas and the freshwater streams (downstream of the protected GVWSA) was conducted in 2008 and 2009, respectively. The results of this monitoring indicated that the overall state of the water quality is good. All chemical, physical and biological parameters met provincial water quality guidelines with the exception of temperature, turbidity, total organic carbon, fecal coliforms, enterococci and Escherichia coli, which exceeded the drinking water guidelines on occasion; dissolved aluminum, total copper, and total zinc also exceeded the aquatic life guideline on occasion. In order to maintain and protect the water quality in the Sooke watersheds and marine areas, ambient water quality objectives were proposed for fecal coliforms and enterococci in the marine areas, and for temperature, dissolved oxygen, turbidity, total phosphorus, and E. coli in the freshwater rivers and streams. Future monitoring is recommended to ensure protection of the environment. MINISTRY OF ENVIRONMENT AND CLIMATE CHANGE STRATEGY iii WATER QUALITY ASSESSMENT AND PROPOSED OBJECTIVES: SOOKE WATERSHEDS/INLET/HARBOUR/BASIN Proposed Water Quality Objectives for Sooke Inlet/Harbour/Basin Time Period Variable Objective Value Use Short-term (5-10 Enterococci 35 CFU/100 mL (geometric mean based on a primary years) minimum 5 weekly samples collected over a 30- contact day period) recreation and 70 CFU/100 mL (single sample maximum value) cultural uses Long-term Fecal Coliform < 14 CFU/100 mL (median based on a minimum aquatic life – (>10years) 5 weekly samples collected over a 30-day period) shellfish 43 CFU/100 mL (90th percentile based on a harvesting minimum 5 weekly samples collected over a 30- day period) Enterococci < 4 CFU/100 mL (median based on a minimum 5 aquatic life – weekly samples collected over a 30-day period) shellfish harvesting Designated water uses: aquatic life – shellfish harvesting, recreation and wildlife Proposed Water Quality Objectives for Sooke Watersheds Variable Objective Value Use Temperature Sooke River: 17oC (max) aquatic life, Any water intake: < 15 oC (max) drinking water supply Dissolved oxygen ≥5 mg/L (min) aquatic life ≥8 mg/L (average) Turbidity At any intake: drinking water <5 NTU maximum Oct – Dec <2 NTU maximum Jan – Sept 95% of samples ≤1 NTU at intake Total phosphorus 0.010 mg/L max aquatic life, 0.005 mg/L avg aesthetics (based on a minimum of monthly samples collected from May – Sept) Escherichia coli Any water intake: raw drinking water – Jan-Sept: 10 CFU/100 mL (90th percentile) disinfection only, Oct-Dec: 40 CFU/100 mL (90th percentile) recreation and culture To protect recreational and cultural uses: 200 CFU/100 mL (geomean of five weekly samples in 30 days) 400 CFU/100 mL (single sample maximum value) Designated water uses: drinking water, aquatic life – shellfish harvesting, recreation, irrigation and wildlife Note: all calculations are based on a minimum of 5 samples in 30 days, unless stated otherwise. Parameters apply at all freshwater sites downstream of the GVWSA in the lower Sooke watersheds, unless stated otherwise. MINISTRY OF ENVIRONMENT AND CLIMATE CHANGE STRATEGY iv WATER QUALITY ASSESSMENT AND PROPOSED OBJECTIVES: SOOKE WATERSHEDS/INLET/HARBOUR/BASIN TABLE OF CONTENTS EXECUTIVE SUMMARY ........................................................................................................ III TABLE OF CONTENTS .......................................................................................................... V LIST OF FIGURES ................................................................................................................ VII LIST OF TABLES ................................................................................................................ VIII 1.0 INTRODUCTION................................................................................................................1 1.1 PROGRAM BACKGROUND ......................................................................................... 1 1.2 SITE SPECIFIC BACKGROUND ................................................................................... 3 1.3 WATER QUALITY OBJECTIVES ................................................................................. 6 2.0 WATERSHED PROFILE AND HYDROLOGY ........................................................................7 2.1 BASIN PROFILE ......................................................................................................... 7 2.2 HYDROLOGY AND PRECIPITATION .......................................................................... 12 2.3 OCEANOGRAPHY .................................................................................................... 14 3.0 WATER USES .................................................................................................................16 3.1 WATER LICENSES ................................................................................................... 16 3.2 RECREATION ........................................................................................................... 17 3.3 FISHERIES ............................................................................................................... 18 3.3.1 Shellfish Harvesting ......................................................................................... 18 3.4 FLORA AND FAUNA ................................................................................................ 19 3.5 DESIGNATED WATER USES .................................................................................... 20 4.0 INFLUENCES ON WATER QUALITY ................................................................................21 4.1 LAND OWNERSHIP .................................................................................................. 21 4.2 PERMITTED DISCHARGES ....................................................................................... 25 4.3 LICENSED WATER WITHDRAWALS ......................................................................... 27 4.4 FOREST HARVESTING AND FOREST ROADS ............................................................ 28 4.5 RECREATION .......................................................................................................... 29 4.6 WILDLIFE ............................................................................................................... 30 4.7 MINING .................................................................................................................. 30 5.0 STUDY DETAILS AND METHODOLOGY ...........................................................................32 5.1 SAMPLING SITES AND SCHEDULE ............................................................................ 32 5.2 QUALITY ASSURANCE / QUALITY CONTROL .......................................................... 40 5.2.1 Quality Assurance / Quality Control Results ................................................... 40 6.0 WATER QUALITY ASSESSMENT .....................................................................................42 6.1 PH ……………………………………………………………………………...42 6.2 DISSOLVED OXYGEN .............................................................................................. 42 6.3 TEMPERATURE ....................................................................................................... 45 6.1 CONDUCTIVITY ...................................................................................................... 48 6.2 TURBIDITY ............................................................................................................. 50 6.3 TOTAL SUSPENDED