Grafton Lake Watershed Study 2002-2003
Basics
Title
Grafton Lake Watershed Study 2002-2003
Description
AI-generated: This report presents the results of a comprehensive watershed study of the Grafton Lake watershed on Bowen Island, B.C., conducted by Whitehead Environmental Consultants Ltd. for the Cove Bay Water System and Bowen Island Municipality. The study had three primary objectives: (1) a land use vulnerability assessment to identify risks to drinking water quality; (2) design and implementation of a water quality monitoring program at four stream stations within the watershed; and (3) development of a watershed-level public education and communication program for source water protection. The Grafton Lake watershed occupies approximately 696 hectares (16% of Bowen Island) and supplies water to approximately 40% of the island's 3,400 residents. Of 156 water quality parameters measured in 2002, five exceeded Canadian and/or B.C. maximum acceptable concentrations for raw drinking water: colour, pH, iron, manganese, and fecal coliform. The report provides detailed recommendations for continued water quality monitoring, hydrological monitoring, land use bylaw development, and a phased public education and communication program for 2003-2007.
Date
January 1, 2003
Creator Organization
Whitehead Environmental Consultants Ltd.
Authors
Alan Whitehead | D.G. Blair-Whitehead
Document Type
report
Document URL
Full Text URL
Subject Area
Conservation & Protected Areas > Environmental education | Policy & Governance > Environmental planning | Ecosystems > Freshwater ecology | Water Resources > Groundwater | Water Resources > Hydrology | Policy & Governance > Municipal Planning | Policy & Governance Data | Water Resources > Water quality | Water Resources | Water-supply | Water Resources > Watershed management
Metadata
Keywords
Grafton Lake
|watershed
|Bowen Island
|source water protection
|water quality monitoring
|fecal coliform
|Cove Bay Water System
|CBWS
|Bowen Brook
|Harding Brook
|land use assessment
|drinking water
|septic systems
|turbidity
|iron
|manganese
|pH
|nutrients
|pesticides
|Bromacil
|PAH
|PCB
|public education
|outreach
|watershed management
|sub-watersheds
|vulnerability assessment
|water quality baseline
|coliform bacteria
|hydrology
Relationship - isPartOf
Document ID
2605181247
Relationship - hasPart
Document ID
2605181247
Document ID
2605181247
Document ID
2605181247
Document ID
2605181247
Document ID
2605181247
Copyright holder
Whitehead Environmental Consultants Ltd.
Document Filename
whitehead_grafton_watershed_2003_2605181247.pdf
Storage Location
analysis/alan-whitehead
Key Findings
Of 156 water quality parameters measured at four stream stations in 2002, five exceeded Canadian and/or B.C. maximum acceptable concentrations for raw drinking water: colour, pH, iron, manganese, and fecal coliform. Water quality was highest in the headwaters and decreased progressively downstream. Harding Brook (sub-watershed 4) consistently showed lower water quality than Bowen Brook, reflecting the greater degree of human land use alteration in that sub-watershed. Fecal coliform contamination was found at all stations at levels exceeding the B.C. maximum acceptable concentration of less than 1 cell per 100 mL; the highest reading of 430 cells/100 mL was recorded at Station 7 (Harding Brook at McDonald Farm) in November 2002, likely attributable to free-range domestic turkeys. The herbicide Bromacil was the only pesticide detected, at a concentration 150 times below the USEPA drinking water guideline. No hydrocarbons, solvents, PAHs, PCBs, or other pesticides were detected. Iron and manganese were the only metals exceeding guidelines, with criteria based on aesthetics rather than health. The vulnerability analysis identified six land uses posing high risk to drinking water quality: failing septic systems, waste incineration, construction waste dumping, commercial logging, horses, and poultry/small livestock. Waste incineration and dumping were rated as highest concern and recommended to be prohibited in the watershed. The 2002 monitoring program established a preliminary baseline; a minimum of two additional years of monitoring is required to characterize natural variability reliably.
Methodology
Watershed vulnerability assessment was completed by delineating sub-watershed and catchment boundaries using the provincial SHIM program, the Bowen Island Geolibrary (Journeay and Dunster 2002), the BIFWMS GIS, and limited field inspections; a helicopter over-flight was conducted on April 2, 2002. Land uses were identified through local knowledge and personal interviews, review of the 1997 Long Range Plan, the helicopter over-flight, and ground inspections. Water quality monitoring consisted of collecting duplicate water samples at four stations (Stations 4, 7, 14, and 20) on two sampling dates (June 26 and November 7, 2002), representing end-of-wet-season dry weather conditions and end-of-dry-season first flush conditions respectively. Samples were analyzed by ALS Laboratories Inc. in Vancouver for 156 parameters including physical properties, anions, nutrients, total metals, hydrocarbons, and bacteriological parameters. An additional sample at Station 7 was analyzed for PAHs, PCBs, organochlorine pesticides, organophosphate pesticides, herbicides, acid-extractable herbicides, and pyrethroids, funded by the BIFWMS. Bacteriological sampling for total and fecal coliform was carried out separately by the Bowen Island Municipality. Water temperature and pH were measured in the field. The education and communication component involved literature review, gap analysis of existing community programs, development of a conceptual framework, and program design following best practices in environmental education.
Map Descriptions
Page 11 (Figure 1): Map of Bowen Island showing location of the Grafton Lake Watershed. Features include topography at 20 m contour intervals, road networks (main rural, minor rural, residential/rural/local), wetlands, stream networks, lakes, and watershed boundary. Key labeled features: Snug Cove, Collins Mountain, Mount Gardner, Apodaca Mountain, Tunstall Bay, Grafton Lake, Killarney Lake, Bowen Bay, Deep Bay. Scale bar 1-2 km. Prepared November 16, 2002.
|Page 23 (Figure 3): Detailed map of Grafton Lake Watershed and Sub-watersheds, Bowen Island. Shows watershed boundary (bold red outline), four main sub-watersheds numbered 1-4 with sub-catchments 1-1 through 1-16 and 4-1 through 4-3, creek networks, Grafton Lake (105 m elevation), Josephine Lake, wetlands, roads, topographic contours (20 m), Crown Land areas, Ecological Reserve 48, Apodaca Mountain, and Mt. Gardner. Scale 500 m to 1000 m. Rev. 4, 28-Mar-03.
|Page 30 (Figure 4): Map of Recommended Water Quality Sampling Stations, Grafton Lake Watershed. Shows all 21 recommended sampling stations numbered 1-21, with the four stations sampled in 2002 (Stations 4, 7, 14, 20) shown with distinct symbols. Includes watershed boundary, sub-watershed boundaries, roads, streams, wetlands, lakes, topographic contours (20 m), Crown Land, Ecological Reserve 48. Scale 500 m to 1000 m.
|Page 31 (Figure 5): Map of coliform sampling stations on Harding Brook and its unnamed tributary, Bowen Island, November 17, 2002. Shows stations 7, 7a, and 7b. Features include Grafton Lake, Bowen Brook, Harding Brook, unnamed tributary, Clink Brook, Grafton Road, Harding Road. Scale 100 m to 200 m.
Graph Descriptions
Page 32 (Figure 6): Bar graph showing Colour in streams of the Grafton Lake Watershed, June 26 and November 7, 2002. Y-axis shows True Colour Units (0-70). June values: Station 4 = 20, Station 7 = 34, Station 14 = 20, Station 20 = 17. November values: Station 4 = 52, Station 7 = 58, Station 14 = 50, Station 20 = 23. Guideline of 15 CU shown as horizontal dashed line.
|Page 33 (Figure 7): Bar graph showing Conductivity (uS/cm) at four stations, June and November 2002. June values: 120, 150, 155, 145. November values: 113, 145, 192, 157.
|Page 34 (Figure 8): Bar graph showing Total Dissolved Solids (mg/L) at four stations. June values: 80, 102.5, 114.5, 100.5. November values: 84, 110.5, 137, 120.
|Page 35 (Figure 9): Bar graph showing Water Hardness (mg/L as CaCO3) at four stations. June values: 41.9, 44.1, 47.9, 42.4. November values: 36.7, 45.6, 56.3, 43.7.
|Page 37 (Figure 10): Combined graph showing Water pH at four stations, both field and laboratory measurements. Field readings in June: 6.2, 7.0, 7.2, 7.0. Field readings in November: 5.7, 5.4, 5.7, 5.6. Laboratory readings in June: 7.76, 7.82, 7.74, 7.55. Laboratory readings in November: 7.65, 7.59, 7.67, 7.54.
|Page 39 (Figure 11): Bar graph showing Total Alkalinity (mg/L as CaCO3) at four stations. June values: 36, 41, 49, 37.5. November values: 28, 35.5, 38, 35.
|Page 40 (Figure 12): Bar graph showing Total Suspended Solids (mg/L) at four stations. June values: 3, 5, 3, 3. All November values below detection limit of 3 mg/L.
|Page 41 (Figure 13): Bar graph showing Turbidity (NTU) at four stations. June values: 1.0, 4.4, 0.9, 0.5. November values: 1.9, 3.4, 1.0, 0.7. Federal criterion of 5 NTU implied.
|Page 42 (Figure 14): Bar graph showing Chloride (mg/L) at four stations. June values: 16.6, 14.0, 16.7, 14.1. November values: 18.75, 20.2, 15.6, 13.65.
|Page 43 (Figure 15): Bar graph showing Sulphate-sulphur (mg/L) at four stations. June values: 7, 6, 6, 2. November values: 8, 18, 8, 4. Guideline of 500 mg/L shown.
|Page 45 (Figure 16): Multi-series bar graph showing Nitrogen content (mg/L) at four stations for ammonia-N, organic-N, and nitrate-N in June and November 2002. Nitrate-N June values: 0.55, 0.35, 0.40, 0.01. Nitrate-N November values: 0.85, 1.15, 0.80, 0.20. Federal guidelines for nitrate (10 mg/L) and ammonia (2.2 mg/L) shown.
|Page 46 (Figure 17): Bar graph showing Dissolved orthophosphate-P (mg/L) at four stations. June values: 0.002, 0.006, 0.002, 0.001. November values: 0.006, 0.006, 0.005, 0.002. Guideline of 0.010 mg/L shown.
|Page 52 (Figure 18): Bar graph showing Fecal Coliform content (cells/100 mL) at all sampled stations for August and November 2002. Stations: Grafton Lake, Station 4, Station 7, Stations 7a, 7b, Station 14, Station 20. November values range from 7 (Station 7a) to 430 (Station 7). Maximum Acceptable Concentration of less than 1 cell/100 mL shown.
|Page 55 (Figure 19): Bar graph showing average variation (%) between duplicate samples at four stations in June and November 2002. June values: 11.3%, 2.9%, 5.8%, 2.7%. November values: 1.9%, 1.2%, 0.3%, 0.4%.
Image Descriptions
Page 1 (cover image): Bowen Island Source Water Protection logo showing stylized forest, winding blue stream, and underground cross-section with groundwater represented by dots and a blue water droplet, surrounded by the text OUR DRINKING WATER and PROTECT THE SOURCE.
|Page 14 (Figure 2): Watershed classification hierarchy diagram applied to the Grafton Lake Watershed, showing five nested layers (Basin, Sub-Basin, Watershed, Sub-watershed, Catchment) corresponding to Terminal-Killarney, Terminal Creek, Grafton Lake, Bowen Brook, and Proudlock Brook. Adapted from Center for Watershed Protection (2002).
|Page 65 (Figure 20): Bowen Island Source Water Protection Logo. Circular logo with text OUR DRINKING WATER at top and PROTECT THE SOURCE at bottom. Upper half shows stylized conifers with a blue stream. Lower half shows a ground cross-section with soil particles and a blue water droplet. Adapted from US EPA public domain materials with assistance from Dr. Bob Turner and Natural Resources Canada.
|Page 66 (Figure 21): Flow diagram showing overview of tasks in development and implementation of a public education and communication program. Central processes include Conceptual Support, Program Design(s), Goals and Objectives, Evaluation, Audience Analysis, Program activities, Program location, Key Concepts, and Financial Resources, feeding into Implementation across the Outreach, Information, Education, and Technical Assistance continuum.
|Page 73 (Figure 22): Timeline chart showing Recommended Education and Communication Programming 2003-2006 with four levels of engagement (Awareness, Facts/Information, Analysis and Decision, Implementation with technical assistance) progressing across years with axes for Increasing understanding and Increasing watershed health.
|Appendix B (pages 83-87): Ten aerial and ground-level photographs: Photo 1 - aerial view of watershed looking east toward Grafton Lake; Photo 2 - aerial view of residential lots in Harding Road neighbourhood showing Grafton Lake; Photo 3 - aerial view of equestrian facilities near catchments 1-14 and 1-1; Photo 4 - aerial view of cropland, hobby farms, nursery, and kennels near catchments 1-3, 1-4, and 1-1; Photo 5 - aerial view of rock quarry and scrap metal dump in headwaters of catchment 1-13 (Billington Creek); Photo 6 - aerial view of solid waste dump in headwaters of catchment 1-2; Photo 7 - aerial view of lumberyard, hardware store, residential, hobby farm and agriculture in subwatershed 4; Photo 8 - site of commercial logging in subwatershed 4 on lower slopes of Apodaca Mountain; Photo 9 - aerial view of former soil quarry and sediment ponds in catchment 1-2 (Mac-Wha Creek); Photo 10 - ground-level photo of flock of free-range turkeys beside Harding Brook in subwatershed 4-1.
Page Count
96
Publisher Location
Bowen Island, B.C.
File Size
4.8 MB
File Format
application/pdf
Geographic Locations
Bowen Island | Grafton Lake | Bowen Brook | Harding Brook | Grafton Valley | Josephine Lake | Terminal Creek | Cove Bay | Apodaca Mountain | Mount Gardner | Adams Road | Grafton Road | Harding Road | Buchanan Road | Sunset Drive | Westside Road | British Columbia | Canada
GIS Layer Geometry
Polygon
Street Address
P.O. Box 279, Bowen Island, B.C. V0N 1G0 (Bowen Island Municipality / CBWS) | R.R. 1 CH-11, Bowen Island, B.C. V0N 1G0 (Whitehead Environmental Consultants Ltd.)