Very little silt is flowing into Marina Bay from Golf Course Creek, according to a report received by Sylvan Lake councillors last Tuesday.
That contradicted Marina Bay homeowners who have a long-standing concern that their marina and outlet channel have been adversely affected by silt from the upstream creek.
An initial investigation was undertaken by the town in 2008 to attempt to determine the status of the creek in terms of possible sources and potential problems with water quality and movement of soils.
The outcome of that was that more extensive collection and sampling was needed as well as a survey to determine the present configuration of the marina.
No further work was undertaken by the town until a meeting in Dec. 2012 with Homeowners’ Association representatives to receive a report they funded for restoration of Marina Bay. Then council approved further investigation by Tagish Engineering and allocated $35,000 for the budget.
An executive summary of the Tagish study reported on testing which took place during 2013 and provide recommendations for construction of wetlands to further filter and cool water prior to it entering the marina.
The study stated substrate samples taken from the creek and lake are significantly different in content than those in the marina.
“The Marina Bay samples would have to be much closer in composition to the Golf Course Creek and Sylvan Lake Basin samples (which are both similar in composition to each other) for those samples to indicate any measurable amounts of siltation in the bay coming from Golf Course Creek or the Sylvan Lake basin.”
Another concern of homeowners was increasing water temperatures in the summer. Water sampling and testing was competed to establish if there was significant sediment or biological loading being transferred into Marina Bay.
The report stated that total suspended solids and turbidity in samples collected just downstream of the golf course were lower than flow coming out of Fox Run and Landway Landing subdivisions. This “would indicate that a certain amount of sediment has precipitated out as the flow crosses the golf course.”
The report concluded, “Overall, tests conducted by Tagish Engineering on water and substrate samples from the Golf Course Creek and Marina Bay area, as well as the site evaluation and data analysis, show only a very small amount of siltation could be credited to the flow in Golf Course Creek. From the field data collected, it appears Marina Bay may not have been completed excavated to the original design concept, and without records of completed construction, or as-builts, it is difficult to determine what depth the bay was excavated to at the time of construction in 1988.”
On construction of the bay, the summary stated, “From the survey and analysis, it appears that Marina Bay was excavated to a depth that would generate sufficient fill material required to create a grade suitable for building construction. The elevation maps … show that the deepest excavations in Marina Bay are directly adjacent to the area of development that would have required the largest volume of material to elevate the site.”
Several recommendations were included in the report. Among them were to continue with the existing aeration system in Marina Bay.
A storm water retention pond and wetlands was recommended for the area south of Lakeshore Drive and behind houses on Willow Springs Crescent to allow water to cool down and sediment to settle before flowing into Marina Bay.
A similar storm water retention pond and wetlands was recommended for an area directly west of Fox Run subdivision when the town expands to incorporate land west of 60th Street.
Councillors accepted the study for information and directed the findings be presented to Marina Bay Homeowners’ Association for further discussions.