SSI FreshWater Catalogue - Fern Creek (FNCK)

SSI FreshWater Catalogue

SSI, SOUTH Watersheds

Fern Creek (FNCK, 2104) Watershed Notes - W̱ENÁ¸NEĆ (Fulford Bay)

- Hope Hill, Mt. Tuam flanks, Fulford Harbour, central, south side -

LAST UPDATE 2021/06/03

SSI South Area - overview watersheds (colour coded, CRD, 2018) & watershed note area

South Island, Fern Creek (2104) Watershed

From our ongoing South Island, Freshwater Cataloguing - notes on the Fern Creek (FNCK) watershed area. Cf. the SSI FWC webmap for field locations and charted information (where available).

The content of these "Notes" entries is dependant on the information that is currently available, from FWC volunteer work, FWC reporting or from other sources. A big thank you to our FWC volunteers for contributions in this area.

Note - if you have additional insights into this area (the watershed, it's creeks or wetlands), can help with site(s) access, or are interested in being involved in data collection for this project area, please contact the SSIFWC Project Lead.

For now these notes draw heavily on extracts from our monthly FWC "Which Creek Is It" Competition, or from our Salt Spring Island FreshWater Catalogue Watershed Stewardship Group Facebook page, with "field note" addendums where additional FWC/other information has become available. Additional volunteer resources and research, for the development of watershed notes content, will enable us to do more!

The data collected from our FWC field work in the Fern Creek watershed gathers year-round flow and chemistry baseline data, investigating watershed surface water and groundwater baseflow(?) discharge to the sea - a key component to any planned watershed, or water budget, and input to validating groundwater recharge potential models, and with potential impacts on estuary ecosystems...

General Watershed & FWC Creek(s) Information:

Fern Creek is located in the South Island, FernCreek (2104) watershed. The creek is located in the central, south valley side, in Fulford Harbour. Fern Creek was our April 2021 Which Creek Is It competition entry.

SOUL watershed overview (LiDAR & satellite backdrops). Images show examples of Fern Creek - creek inland and at the coastal outfall

Fern Creek (2104, "FNCK") Watershed

Fern Creek at the sea outfall is single creek supporting the FNCK watershed surface freshwater flow, with the watershed a mix of forest ecosystems and agricultural land. The WCIT images site is close to the single Ferncreek watershed creek outflow and discharge to the sea - via culverts (CMPs) at Hamilton Beach. The watershed area drains from the north flanks of Tuam Hill (625m) and Mount Tuam (606m).
The FNCK watershed is small in size, some 87 hectares (216 acres) in size, somewhat smaller than the Geralds Creek watershed immediately to the north. Importantly, from a potential flow volume perspective, the Fern Creek catchment does not extend to the higher elevations of the nearby upland source areas. These upland areas act as a catchment for the juxtaposed Geralds Creek and Larlow Creek respectively
The FNCK watershed receives something like 828,400,000 litres (218,865,000 gallons) of rainfall (precipitation, or surface water) per annum (water volumes are approximate with no consideration of surface/terrain conditions, nor rainfall variability within the catchment area - cf. Precipitation Glossary entry)
By comparison with some of the island’s biggies(!) this is a small but (always) important potential rainfall catchment (and aquifer recharge) watershed area. Part of the watershed water flow (with surface and subsurface in-stream creek groundwater baseflow, may influence near coastal ecosystems in the Fulford Harbour
The watershed has a relatively low number of subsurface (ca 20) wells. Though, anecdotally there is shallow water and surface creek abstraction within the watershed
As per other areas around the island “shallow”, and even stream abstractions do not always factor into area water resource (budget) numbers (nor maps)… though these are a key part of the water resource story!

Note - abstractions from shallow wells and surface creeks are candidates for "casual" water intake (and ecosystems!) contamination by anthropogenic activities, and it has happened. Please look after our creeks!

Historical & Other Watershed Insights:

N/A

Note - any other local insights, or interested in contributing to the historical/other notes on our islands' watersheds, please contact the SSIFWC Project Lead.

FWC "Citizen Science" Watershed Reporting:

Fern Creek is the single FNCK watershed outfall. As at 2021/06 we have close to three years of FWC data from Fern Creek. The creek shows the classic signs of in-stream groundwater (base flow) contributions through the year, including: year-round flow, and an inverse relationship between water temperature and air temperature, though groundwater related conductivity vs flow relationships are not apparent.

FWC field data graphing - examples illustrating developing watershed working models. For further site specific "dynamic" charting cf. the SSIFWC webmap. (Acknowedgement to North Shore Streamkeepers for the time vs flow graphic).

FWC findings to-date indicate that Ferncreek was/is a permanent (groundwater fed) creek, with relatively healthy groundwater flow (though from a small watershed catchment area), even during the summer.

Compared to adjacent FWC creek and watershed systems measured - Fern Creek system flow levels are clearly impacted by a smaller watershed area.

Fern Creek data illustrates an inverse relationship between water temperature and air temperature (air warm water cool and vica versa), the result of groundwater temperature remaining relatively constant during the course of the year, while air temperature changes seasonally.

Measured Fern Creek conductivities indicate seasonal variability in contributions from rainwater (winter, groundwater dilution) vs groundwater (summer, groundwater dominated). However, a Fern Creek conductivity vs flow correlation is non-existent (cf. other watershed note examples, eg Ruby Alton) this suggests no mechanism to calculate the seasonal variability in a groundwater baseflow and total inflow flow into the stream at the sea-outfall (future background reading on conductivity vs flow will be available on our Background Reading webpages - under development).

Groundwater baseflow (and watershed discharge to sea) are important components of an area freshwater budget/balance determination, and support improved groundwater recharge/discharge modelling.

Offsets (delays) in Fern Creek flow rates, vs the timing of significant rainfall events, give clear insights into potentially complex shallow vs deep "interflow" vs shallow/deep "groundwater" inflows (cf Dumont, Shelly Creek reporting) flow paths influencing this creek.

Potential groundwater inflows (“base flow”) within the FNCK watershed (2104) within Fern Creek likely originate from shallow/deep sedimentary rocks - McLaughlin Ridge Formation (greywacke) and/or Haslam Formation (shales). Exposures from recent landslips along the creek path suggest that unconsolidated overburden may also contribute to creek (inter?)flow volumes.

The FNCK watershed is another good candidate for gathering field data for a “ground-truthed” groundwater recharge potential (watershed recharge efficiency) model for one of our island’s watersheds. Local data collection gives improved insights into how this watershed (and related freshwater ecosystems) work, are impacted by seasonal (or climatic…) changes, and will help with an improved understanding of how surface water catchments in the island’s watersheds contribute to aquifer recharge and local water resource availability...

FWC Images and Videos:

Fern Creek watershed images. Note - all FreshWater Catalogue images & videos copywrite belongs with the WPS and the FWC. We are grateful for due acknowledgement of our copywrite in any use, or publication, of these educational resources.

Other Local Area Resources:

Barnett et al., 1993., Salt Spring Island Water Allocation Plan.
Manley, D., & Stewardson, M., 2014., Salt Spring Island Riparian Areas Regulation Mapping Project. Mainstream Biological Consulting, sponsored by IT.
Howe K., & Allen D., 2020., - Linkages between Stream Chemistry and Groundwater Chemistry, Salt Spring Island, British Columbia, SFU.

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