*THIS EC IS BEST DONE AT LOW TIDE SO YOU CAN VIEW THE SEDIMENT ACCUMULATION :)*
Welcome to Iona Beach Regional Park!
Iona Beach Regional Park has more than 20km of windswept shoreline. The park began in 1990 with a 30-hectare section. Eighty more acres were added to the park in 1995, through the Lower Mainland Nature Legacy Program and the efforts of Canadian Forest Products, the Province of BC, Environment Canada, and metro Vancouver. A restoration program, done with the assistance of Nature Vancouver, included the restoration of two marshes and shoreline habitat.
Iona Jetty is located in Iona Beach Regional Park and is a 4km piece of land that juts out into the Salish Sea. The jetty was formally an island but is now connected to Sea Island and Metro Vancouver's sewage system. A pipeline runs underneath the jetty but the top is a popular path for recreational use, shared between walkers, joggers, and cyclists and offering great views of the region.
What is a Jetty?
A jetty is a structure built outward from a shoreline into a river, estuary or ocean. Jetties are commonly constructed to direct water flow, stabilize a navigation channel, protect shorelines and influence the movement of sediment. At Iona, the jetty works together with other engineered structures in the Fraser River estuary to influence the direction and concentration of river flow. Because moving water is responsible for transporting sediment, changing the speed and direction of the water can change where sediment is eroded, transported, and deposited.
As you walk along the jetty towards GZ, look at the material used to construct it. Large rocks and other engineered materials form a protective barrier between the water and the jetty. These rocks are subjected to waves, currents, changing water levels and weather. They must withstand continuous physical forces. You may notice areas where sediment has accumulated in more areas than others.These differences are clues that sediment is being moved rather than remaining in one place.
The Fraser River
The Fraser River begins high in the Rocky Mountains and travels approximately 1375km before reaching the Pacific Ocean. During its journey, the river erodes and transports sediment including clay, silt, sand, and gravel. Fast-moving water can transport larger particles, while slower-moving water is more likely to allow heavier particles to settle.When engineers constructed the jetties, they changed the shape of the river channel and the way water could move through the estuary.
Erosion and Deposition
Two of the most important processes to understand here are erosion and deposition. Erosion occurs when material is removed by moving water or other processes. Deposition occurs when transported material settles and accumulates.These processes are connected. If water has enough energy to erode and transport sediment from one location, that sediment must eventually be deposited somewhere when the transporting energy decreases. The jetty influences this process by changing how water moves through the area.
Logging Requirements
As there is no physical container, please answer the following questions and send them to the CO. No need to wait for a response to log your find, I will contact you if there are any issues :)
1. What type of material is primarily used to protect the jetty from the water? Describe the approximate size and shape of the material you observe.
2. In your own words, explain why concentrating the river’s flow can be useful for maintaining a navigation channel.
3. Describe one feature that provides evidence that sediment is being transported or deposited.
4. Why can a structure that reduces erosion in one location potentially increase erosion or deposition somewhere else?
5. At GZ, Find the Legal British Columbia Survey Marker. What is the year below the crown? (This is to prove you made it to the posted coords).
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