The Nature Trust of British Columbia and Coastal First Nations deploy RBR loggers to enhance sustainability of wild BC fish stocks

In fall of 2019, The Nature Trust of British Columbia (The Nature Trust of BC), Canada, launched a five-year monitoring program using RBRsolo³ Tu turbidity loggers and RBRmaestro³ multi-channel water quality loggers to determine the resilience of 15 estuaries to sea-level rise and climate change. The Enhancing Estuary Resilience Project is a partnership between The Nature Trust of BC, the West Coast Conservation Land Management Program, and Coastal First Nations, and will use a multi-parameter index to score estuaries on their ability to weather climate change and rising seas. Resilience scores will inform estuary restoration projects meant to enhance the sustainability of BC’s wild fish stocks. 

Steven Henstra, Restoration Biologist at The Nature Trust of BC, says “the study boils down to looking at the percentage of the vegetated area that falls below the mean highwater mark, looking at the level of sediment accretion, and seeing if the marsh platform can keep pace with sea-level rise, or if it will be inundated and drowned.” The 15 estuaries that are part of the project are located on Vancouver Island, the central coast, and the islands of Haida Gwaii.

Sedimentation is important for maintaining and building up the marsh platform, and Henstra says, “turbidity is one of the metrics by which we’re looking to measure the amount of sediment flux.” 

RBRsolo³ Tu loggers with wipers have been moored at two locations per site; the river outflow to each estuary, and just at the outer extent of the estuary, to measure turbidity. Turbidity is one of 10 parameters being collected in order to determine the five criteria of ecosystem resilience: marsh elevation distribution, change in elevation, sediment supply, tidal range, and rate of sea-level rise.

The project is also collecting water quality data using 10 RBRmaestro³ multi-channel water quality loggers. The RBRmaestro³s are equipped with sensors to measure conductivity, temperature, depth, optical dissolved oxygen, pH, and turbidity. The instruments are mounted in cages to protect and weight the loggers during vertical profiling. Profiling will be undertaken by The Nature Trust of BC and by local Coastal First Nations communities.  

The data will be fed into the Marsh Resilience to Sea-Level Rise (MARS) tool, developed by the U.S. National Estuarine Research Reserve System. Henstra explains that the MARS tool is “a multi-metric index to assess the sites’ relative resilience to sea-level rise; basically their vulnerability.”    

Estuaries are highly productive ecosystems: they are the sites of mixing, upwelling, and nutrient deposition from the continents, leading to high levels of primary productivity, and making estuaries important habitats for many species. On the west coast of Canada, they are critical habitats for Pacific Salmon. In particular for rearing of juvenile salmon, estuaries are home to smolting salmon (which are adjusting to saltwater) during their out-migration toward the ocean.

Estuaries can be made more resilient to climate change by taking measures to restore estuarine hydrology and improve tidal connectivity. Options can be the removal of historical agricultural dykes or berms, the construction or reconnection of tidal channels, and making land available so that estuaries can migrate upstream with rising water levels. The estuary data will be used to identify and inform feasibility studies of candidate restoration projects.

Data collection began at some sites as far back as 2016. Looking at the initial results, Henstra says “some sites are seeing a lot of sediment flux, so there’s good potential for the marsh platform to stay ahead of sea-level rise, but others not so much.”

During the proposal phase of the project, The Nature Trust of BC established partnerships with several Coastal First Nations communities. These communities supported the identification of sites for instrument installation and are participating in data collection. Tom Reid, West Coast Conservation Land Manager at The Nature Trust of BC, explains that one of the long term goals of the project is to “create long-lasting partnerships with Coastal First Nations, to build capacity and understanding, and create an ongoing coastal dialogue amongst all partners and communities who are interested in the sustainability and resilience of these coastal ecosystems.”

Years 1 to 3 (2019 to 2021) of the project are focusing on data collection and resilience scoring of the estuaries. Years 4 to 5, on the restoration of estuarine hydrology and connectivity.

Reid says they chose RBR instruments for their reputation, in terms of what “academic and government agencies around the world are using.”

The RBRsolo³ Tu turbidity logger is our most compact, lightweight, and versatile turbidity logger; the RBRmaestro³, our most flexible, option-packed, multi-channel logger. RBR loggers are your intuitive and reliable solution for citizen science and for peer-reviewed publication. Check out our full suite of standard loggers or contact us for help or more information.

Funding for the Enhancing Estuary Resilience project comes from the BC Salmon Restoration and Innovation Fund, a contribution program funded jointly between Fisheries and Oceans Canada, and the Province of BC.