Stream Event Sampling - Calvert Island

The Stream Event Sampling survey is a part of the Kwakshua Watersheds Program. It was designed to investigate the change in river water chemistry (with a focus on Dissolved Organic Carbon) with changing river flow associated with a rain event. On the one hand the goal was to collect high flow water samples for a wide range of rain events and across seasons for the seven focal stream outlets of the Kwakshua Watersheds Program. For each rain event, a single high flow sample has been selected and used in the estimate of dissolved organic carbon flux from these watersheds (Oliver et al. manuscript in preparation). On the other hand the goal was to collect a detailed sequence of stream water samples along the rising and falling limbs of the storm hydrographs of the seven focal streams.

High flow water samples along the rising limb were taken with the aid of an automatic rack sampler. This is a mechanical device that samples water at pre-defined water stages. Several bottles are mounted at vertical increments above low water level. As the water level rises, bottles fill in sequence. Each bottle has an intake device that allows it to fill curing the rise while preventing further exchange of sample water with the stream. The exact water stages are determined with the aid of an Odyssey water stage logger installed nearby. In fall 2015, an automatic electronic pump sampler was installed at watershed 708, which allowed us to remotely (or programattically) trigger the collection of stream samples. Samples taken prior to a rain event and along the falling limb of an hydrograph were taken manually. These three distinct sample methods are named Rack Sample (RS), Auto Sample (AS) and Grab Sample (GS).

Sample water was analyzed for SUVA from HI Calvert; DOC and Fe from NRAL; TDN and TDP and O18 from U of A.

All sample ID's consist of the watershed ID number followed by the 'Sampling bout'. The sampling bout can be a letter or a number and defines the chronological sequence of different samples taken at the same location and during the same rain event. The 'Original sampling bout' is a letter when the sample is taken either prior to a rain event or during the falling limb of the hydrograph of a rain event. The 'Original sampling bout' is a number when the sample is taken along the rising limb of the hydrograph of a rain event. In case of a combination of Grab Samples and Rack Samples, a letter always signifies a Grab Sample and a number always signifies a Rack Sample. Letters and numbers increase alphabetically and numerically respectively during the course of a rain event (See thumbnail for example). Because the Hakai Data Portal does not accept letters as a valid sampling bout, an extra sampling bout number was assigned to each sample ('Sampling bout in data portal'). The first sample taken during a rain event at a particular location was assigned '1' and each following sample during that specific event and at that specific location got the next increasing number after that.

The rack samples and auto samples were assigned a quality control label or a combination of labels according to the following scheme:
C: the filled sample bottle was collected more than one day after sample time. Deterioration of the sample by warm air temperatures, non-acidified and aerobic conditions has possibly started (RS and AS)
S: uncertain sample time due to erroneous data in the Odyssey stage logger (RS)
M: the water sample was a mixture of two rain events. Two events were considered mixed if the sample was taken during the rising limb of an event, that occurred before the recession of the previous event was completed (RS, only for 2014 data)
F: water stage rose too quickly to fill a sample bottle entirely. As a consequence, the sample consists of a mixture of rising and falling stage water. A stage rise larger than 1 cm per minute was considered too fast. This threshold was estimated based on the filling speed and the distance between the inlet tubes (RS, only for 2014 data. This problem was resolved for later surveys)

Sample locations changed for watershed 819, 703 and 708 after the summer of 2014. These locations are currently not used and are therefore labeled 'Used in 2014 only'. A link to the sample locations is available on this page. Two stream event surveys were conducted in great detail for a late summer and an early fall event and for all seven watersheds in 2014. In addition several discrete high flow samples were taken during that summer. In summer 2015, one rain event was captured entirely by stream event samples for all seven watersheds. After installation of the pump sampler at watershed 708, several rain events were sampled at that location in the fall of 2015. In 2016, only discrete high flow samples were collected for two rain events in April. The data collected in 2014 have been analyzed and reported in the MSc thesis of M.C. Korver (2015). The data of 2015 and beyond are here available but have yet to be analyzed.

Codes/acronyms: GG Hatch = , HI = Hakai Institute (formerly HBI = Hakai Beach Institute), NRAL = North Road Analytical Lab, UBC = University of British Columbia, U of A = University of Alberta, DOC=Dissolved Organic Carbon, SUVA = Specific UltraViolet Absorbance, Fe = Iron, TDN = Total Dissolved Nitrogen, TDP = Total Dissolved Phosphorus, O18 = Oxygen 18. Time/date format: YYYY-MM-DD Time zone: Field observations recorded in Pacific standard time (PST).

References: Korver MC. 2015. Dissolved organic carbon fluxes of seven watersheds in a bog forest ecosystem at Calvert Island, British Columbia, Canada

Credits: Maartje Korver, Ian Giesbrecht, Ilja van Meerveld, Bill Floyd, Maarten Waterloo, Allison Oliver, and Suzanne Tank.

Acknowledgements: We wish to thank all the field assistants that have been involved in collecting these data, often under challenging conditions: Chris Coxson and David Norwell who have taken temporary leading roles, Christian Standring, Libby Harmsworth, Lori Johnson, Ben Millard-Martin, Stewart Butler, Ondine Pontier, Kaia Bryce, Carolyn Knapper and Midoli Bresch. Many thanks to Matthew Foster for his general IT support and help with data management, and also to James McPhail and Shawn Hateley for the installation of the Autosampler. Finally, we are grateful for the excellent care of the facility staff at Calvert Island.

With questions please contact: Ian Giesbrecht ( and Maartje Korver (

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Licence: Appropriate credit must be given to Hakai Institute and the authors of the dataset.

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Metadata Created October 26, 2018, 22:48 (UTC)
Metadata Updated October 26, 2018, 22:48 (UTC)
Reference Date(s) 2016-05-03 (Creation)
2016-05-12 (Publication)
Frequency of Update asNeeded
Metadata Date October 17, 2018, 22:43 (UTC)

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