littoral zone

Monitoring the Littoral Zone

River hydrology

"As the river is in flood and all the gates of the Chelsea dam are wide open, it has created what the engineers call pre-development flows. What it means is the reach upstream of the Chelsea dam that is typically back-flooded is much lower, there are rapids and there are areas of the riverbed that are visible right now that we rarely see." Meredith Brown, Ottawa Riverkeeper. (May 7, 2017)

The following are some views and comments by Marc Theoret, John Almstedt, Tony Anderson, Bob Kelland and Jason Jones on happenings in the littoral zone during the most extreme lowering of the water level from May 3-10, 2017

In 1927 the construction of the Chelsea dam was completed creating the river we see today. The present lowering of the water level to reduce the threat of flooding has provided a wonderful opportunity to look into the past.

In this 1926 photo "A" is the up-river shoreline of Marina Bay and where the influence of the dam ended until logging stopped in the late 1980s - early '90s when the water was further raised to drown their presence. "B" is the general area of the rapids in the below picture, rapids that probably have never been seen since the river was flooded in 1927. The yellow line is the general proximity of the current shoreline and explains why so many tree stumps have recently re-appeared.

As the river is in flood and all the gates of the Chelsea dam are wide open, it has created what the engineers call pre-development flows, so from approximately May 3 to May 10 when the river was lowered approximately 2m the site of ancient rapids re-appeared for the first time in many years.

This picture and the above one were taken by Bob Kelland from his shoreline on May 9, 2017.

The red line represents normal summer water level which illustrates an approx. 2m drop.

What now?

1. How many and what type of dams are there along the Gatineau (Mercier, Paugan, Chelsea, Rapides-Farmers??) and how did they operate during this flood period?
2. What’s the strategy for managing these dams related to the environment, for instance there probably was a huge mussel kill over the past week
3. How could the once very visible rapids near point "A" in the 1926 heritage photo not show up over the past week when rapids that I don’t think anyone has ever seen before appeared in the vicinity of point "B"?

Mussels

The following mussel comments come from the Museum of Nature's Andre Martel.

eastern lampmussels (Lampsilis radiata)

eastern elliptios (Elliptio complanata)

Without water the presence of mussels were numerous and easy to identify with the help of Andre Martel from the Canadian Museum of Nature. The eastern lamp and eastern elliptios appear to be the dominant mussels in our section of the littoral zone. Their seemingly great numbers are an indicator of the river's good health. According to Andre one mussel can filter up 38 litres of water per day (Ottawa Riverkeeper also has some additional mussel information).

An eastern lampmussel trail. The mussel uses a long muscular body part that can protrude from the shell to propel it by pulling at the sand/silt.

The 4 elliptios at the top right are more elongated with a darker periostracum (the thin organic coating or "skin" which is the outermost layer of the shell) than the eastern lampmussel.

There were several piles of shells - likely from predators such as ducks, raccoons and muskrats. Eastern lamp mussels are aesthetically attractive with beautiful greenish rays on a yellowish shell.

Both mussel species are thought to use a variety of fish hosts for reproduction, including rockbass, pumpkinseed, bluegill, smallmouth bass, longear sunfish, largemouth bass, white perch, sand shiner, yellow perch, bluntnose minnow, and black crappie. The wide variety of fish hosts are used as prey for larval development. The larval stage, known as glochidia, are external parasites that feed on fish as a host.

What now?

Without water for close to two weeks there has now likely been a significant mussel kill.

The eastern lamp and eastern elliptio mussels are commonly found in most tributaries of the Ottawa River. Andre asks that if we're to find evidence that the Hickorynut mussel has lived, even better, still lives in the Gatineau River, this would be of scientific significance – and of interest to local media and general public because of its fish connection to sturgeons. There are 21 different species of freshwater mussels living in the Ottawa River watershed which represents 35% of Canada’s native mussels fauna, a stunning statistic" according to Andre.

The absence of mussels in the vicinity of the proposed new ski trail illustrates the impact sedimentation has already had from shoreline erosion flowing from the nearby Marina trail (refer to "erosion and sediments" section below).

Erosion and Sediments

The up-river shoreline (A) of Marina Bay remained in its natural width while the down-river shoreline displayed the results of excessive sedimentation as a result of the erosion from a road constructed to the shoreline in the 1970s.

Looking down-river from the above picture the width and length of shoreline sedimentation is considerable considering that 90 years ago this was all shoreline forest as is evidenced by the stumps. The polygons circled in red highlights the presence of leda clay deposited by the ancient Champlain Sea..

The red line marks the current stream channel and (A) shows the up-river shoreline without sedimentation.

Until the late 1920s when the dam was constructed the current mouth of the Marina creek (also referred to as Cascades Creek) was part of the shoreline forest as is evidenced by the protruding tree stumps.

Two granite erratic boulders with interesting abrasion marks from the ice age of 12,000 years ago.

The littoral zone in areas with a stabilized shoreline has minimal sedimentation.

Even undercut shoreline downstream from the area of the proposed new ski trail remains stable in its natural setting where there has been no human interference.

Clay sediment at the outlet of a small seasonal stream.

The thin layer of clay sediment appears to be covering organic debris that likely comes from a nearby road (100 m) constructed in the 1990s.

A clay sediment spit protruding from a small bay where there has been some shoreline development

Cultural influence

Former logging raft

logging related chain

Cut pulp log illustrate the preservation affect water has on submerged logs

Pulp logs illustrate the results of water preserving logs by inhibiting attacks by insects and sapwoodstain fungi. (reference Pg 223)

Plants and Wildlife

The littoral zone showed no evidence of plant life. But, there were lots of tracks in the mud from raccoons, big shore birds and others.

A very large, old and still active (a few new sticks) beaver lodge.

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