Climate Data
Climate data were collected from Environment Canada’s climate data base (http://climate.weather.gc.ca) and included daily and monthly mean, maximum and minimum temperatures (˚C), total snow (cm), and total precipitation (mm). Monthly climate data were collected from the Gibsons climate station (ID 1043150) from 1962 to 1970 and from the Gibsons Gower Point (GGP) Climate Station (ID 1043152) from 1971 – 2013. Daily climate data were collected from the Sechelt AUT (Automatic Climate Station) (ID 1047172) from 2009 to 2013.
Table 1: The climate stations used for collecting historic climate data on the Sunshine Coast, BC (Environment Canada, 2014)
| Station Name | Station ID | Latitude | Longitude | Elevation (m) | Years |
| Gibsons | 1043150 | 49 23’48”N | 123 30’48” W | 62 | 1962-1970 |
| Gibsons Gower Point | 1043152 | 49 23’08”N | 123 32’29” W | 34 | 1971-2013 |
| Sechelt AUT | 1047172 | 49 27’28”N | 123 42’54”W | 86 | 2009-2013 |
Discharge Data
Chapman Creek discharge data were collected from the Water Survey of Canada’s (WSC) archived hydrometric data (http://www.wsc.ec.gc.ca). The discharge data included average monthly mean, maximum and minimum flows for Chapman Creek. Hydrometric data for Chapman Creek was available from 1962 to 1988 and 1993 to 2003. For Chapman Creek, station 08GA046 was used between 1962-1970 and had a drainage area of 71.5km2, station 08GA060 was used for 1971-1988 and station 08GA078 for 1993 – 2003, where both of the latter stations were in the same location and had a drainage area of 64.5km2. To estimate the average monthly flows for the entire period on Chapman Creek, the flows at 08GA046 were adjusted for a drainage area of 64.5 km2 by using a conversion factor of 0.902 (Chapman and Reksten, 1991).
Because Chapman Creek is regulated by daily withdrawal, discharge data for the Capilano River were collected from the WSC fro the same time period as Chapman Creek to show that discharge trends in other watersheds within the region match the trends in Chapman Creek. Comparing historic discharge from Chapman Creek to the Capilano River allowed the Chapman Creek data to be analyzed in confidence when discussing impacts to available water supply. Geographically, the Capilano watershed, which is situated in North Vancouver, is approximately 40 km south east of the Chapman watershed.
Table 2: The Hydrometric stations sourced for collecting discharge data on Chapman Creek, on the Sunshine Coast, BC and the Capilano River, North Vancouver, BC (Water Survey of Canada, 2014)
| Station Name | Station Number | Latitude | Longitude | Drainage Area (km2) | Years | Tot. Avg. Q(m3/s) |
| Chapman Creek near Wilson Creek | 08GA046 | 49 26’31″N | 123 43’14″W | 71.5 | 1962-1970 | 4.7 |
| Chapman Creek above Sechelt Diversion | 08GA060 | 49 28’56″N | 123 42’39″W | 64.5 | 1971-1988 | 4.7 |
| Chapman Creek Below Sechelt Diversion | 08GA078 | 49 28’56″N | 123 42’39″W | 64.5 | 1993-2003 | 4.7 |
| Capilano River above intake | 08GA010 | 49 23’46″N | 123 8’45″W | 173 | 1962-2012 | 20.4 |
Pacific Decadal Oscillation and El Nino Southern Oscillation Data
The Pacific Decadal Oscillations (PDO) and EL Nino Southern Oscillations (ENSO) event data were referenced from Kiffney et. al. (2002), which was compiled based on PDO/ENSO event classifications from five different sources: the Southern Oscillation Index, the NINO3 index, the NINO3.4 index, events listed in Hoerling et al. (1997) and a list compiled by the National Oceanographic and Atmospheric Agency. The data time spanned from 1962 to 1998 (Table 3), encompassing 14 years of cool PDO phase and 21 years of warm PDO phase. As described by Fleming et. al. (2007), it is unclear if a shift occurred post-1998, which is why this study only examined data to 1998. The ENSO events were classified as either El Nino (W) or La Nina (C) as per Kiffney et al. (2002).
Table 3: Pacific Decadal Oscillation (PDO) and El Nino Southern Oscillation (ENSO) events from 1962 to 1998, in water years, as sourced by Kiffney et al., 2002 – PDO events are defined as Cool or Warm and ENSO events are defined as El Nino (W) or La Nina (C)
| Water Year | PDO | ENSO Event |
| 1962 to 1964 | Cool | El Nino (W) |
| 1964 to 1965 | Cool | La Nina (C) |
| 1965 to 1970 | Cool | El Nino (W) |
| 1970 to 1971 | Cool | La Nina (C) |
| 1972 to 1973 | Cool | El Nino (W) |
| 1973 to 1976 | Cool | La Nina (C) |
| 1976 to 1988 | Warm | El Nino (W) |
| 1988 to 1990 | Warm | La Nina (C) |
| 1991 to 1995 | Warm | El Nino (W) |
| 1995 to 1996 | Warm | La Nina (C) |
| 1997 to 1998 | Warm | El Nino (W) |
Population Data
Population data for the service population on the Chapman water system and future population projections were referenced from the SCRD’s Comprehensive Regional Water Plan (2013). Service population for the Chapman water system for 2012 and 2013 was estimated based on the average annual growth from 2003 to 2011, which was 0.9% per year.
Tourism Population
Tourism population data on the Sunshine Coast was estimated using monthly ferry ridership data from BC Ferries from 2009 to 2013 (www.bcferries.com). The ridership data consisted of the number of people travelling from Horseshoe Bay and from Langdale along the route between Horseshoe Bay and the Sunshine Coast. The total monthly ridership’s from Horseshoe Bay and Langdale were averaged then divided by the number of days in that particular month and multiplied by 75% (percentage of Sunshine Coast population serviced by Chapman water system). The month with the lowest annual ridership was assumed to represent the number of commuters (residents of the Sunshine Coast who commute back and forth daily to Vancouver for work). All of the other months were assumed to experience some degree of tourism and the increase in population was estimated by calculating the difference in the average daily ridership in the lowest month of the year from all other months. It is recognized that delivery drivers for imported goods to the Sunshine Coast are included in the ridership, however, it is difficult to determine the number of delivery drivers and it is assumed that this number is negligible for the purposes of this estimation.
Water Consumption Data
Water consumption data were obtained from the SCRD’s annual water consumption records. Annual consumption data were available from 1991 to 2013, monthly consumption data were available from 2003 to 2013, and daily consumption data were available from 2009 to 2013. Periods with watering restrictions were obtained by reviewing comments in the SCRD’s daily water use, lake level, and streamflow monitoring records and by reviewing SCRD press releases on watering restrictions over the last 5 years.