The Kwakshua Watersheds Observatory, central coast of British Columbia, Canada

Abstract

The Kwakshua Watersheds Observatory (KWO) is an integrative watersheds observatory on the coastal margin of a rain‐dominated bog‐forest landscape in British Columbia (BC), Canada. Established in 2013, the goal of the KWO is to understand and model the flux of terrestrial materials from land to sea – the origins, pathways, processes and ecosystem consequences – in the context of long‐term environmental change. The KWO consists of seven gauged watersheds and a network of observation sites spanning from land to sea and along drainage gradients within catchments. Time‐series datasets include year‐round measurements of weather, soil hydrology, streamflow, aquatic biogeochemistry, microbial ecology and nearshore oceanographic conditions. Sensor measurements are recorded every 5 min and water samples are collected approximately monthly. Additional observations are made during high‐flow conditions. We used remote sensing to map watershed terrain, drainage networks, soils and terrestrial ecosystems. The watersheds range in size from 3.2 to 12.8 km2, with varying catchment characteristics that influence hydrological and biogeochemical responses. Despite local variation, the overall study area is a global hotspot for yields of dissolved organic carbon, dissolved organic nitrogen and dissolved iron at the coastal margin. This observatory helps fill an important gap in the global network of observatories, in terms of spatial location (central coast of BC), climate (temperate oceanic), hydrology (very high runoff, pluvial regime), geology (igneous intrusive, glacially scoured), vegetation (bog rainforest) and soils (large stores of organic carbon).

Seasonally and Spatially Variable Organic Matter Contributions From Watershed, Marine Macrophyte, and Pelagic Sources to the Northeast Pacific Coastal Ocean Margin

“…The lowest salinity was observed in Rivers Inlet during the summer, concomitant with the highest discharge from the Wannock River. Seasonal variability in salinity was also observed within the Koeye Estuary, with lower salinity in the autumn and winter, reflecting exports from the rain-dominated Koeye River (Giesbrecht et al, 2021). Salinity within Kwakshua Channel and Fitz Hugh Sound were similar and exhibited little seasonal variation.…”

“…Varying proportions of rain, snowmelt, and glacial meltwater contributions to terrestrial runoff occur across the region, often following a topographic gradient from small, low relief rainfalldominated watersheds on outer-coast islands to larger mainland watersheds that transport a mix of rain, snowmelt, and glacial melt to fjords (Giesbrecht et al, 2022). A longitudinal transect across the study area reflects just such a gradient (Giesbrecht et al, 2021). Rain-dominated watersheds occur at low-tomoderate elevations and are exemplified in this study by the Koeye River (171 km 2 ; maximum elevation = 1304 meters above sea level (m.a.s.l.)…”

“…Coastal watersheds within the NPCTR receive upwards of 3000 mm of precipitation per year most of which falls between October and March. These watersheds range from small, low relief, rainfalldominated watersheds that export substantial quantities of organic matter to coastal waters (Oliver et al, 2017) to larger mainland watersheds that export a mix of rain, snow and glacial melt waters (Giesbrecht et al, 2021). Coastal waters within this region also receive upwelled nutrients and materials from offshore and inshore features (e.g., sills) that fuel high primary production during the spring and summer (Foreman et al, 2011;Jackson et al, 2015).…”

High-resolution streamflow and weather data (2013–2019) for seven small coastal watersheds in the northeast Pacific coastal temperate rainforest, Canada

“…The Kwakshua Watersheds Observatory (KWO), established in 2013, helps fill this observational data gap by providing continuous and high-resolution hydrometeorological data from seven small (< 13 km 2 ) watersheds. The KWO also monitors aquatic biogeochemistry, microbial ecology, and nearshore oceanographic conditions (Giesbrecht et al, 2021), and to date, the observatory has supported studies showing that this area of the NPCTR is a hot spot of soil organic carbon storage (McNicol et al, 2019) and that high riverine fluxes of dissolved organic matter (Oliver et al, 2017) have a significant effect on the estuarine waters of the NPCTR (St. Pierre andOliver et al, 2020, 2021). In the regional context, the KWO is broadly representative of a rain-dominated watershed type that spans > 16 000 km 2 in the NPCTR with similar climate, topography, and streamflow regimes (Giesbrecht et al, 2022).…”

Streamflow and weather conditions of seven small coastal watersheds, British Columbia, Canada, 2013–2019

“…Seven hydrometric and fourteen meteorological stations were installed in a tight network spanning most of the elevation gradient (Giesbrecht et al, 2021;Fig. 1), as the study area's complex topography leads to rapid changes in Air temperature, relative humidity and rain were measured at two meters above ground for all stations, except 'East Buxton' where seasonal snowpacks necessitate the precipitation gauge orifice and air temperature/relative humidity sensor to be installed at 4.5 and 4 meters above ground respectively.…”