TAMRMS#: B06
8.1
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Sediment and Erosion Control
Notice given by: Councillor Killick
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BUDGET POSTPONED MOTION:
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That the Storm-007 Sediment and Erosion Control remove $3,059,000 from 2023 10 Year Utility RMR Capital Plan.
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Administration’s Understanding of the Intent of the Motion:
This motion appears eliminate the funding for the 2023 portion only of the Sediment and Erosion Control (Storm-007) program from the 10 Year Utility RMR Capital Plan
Operational or Organizational Impacts if Motion is Approved:
Sediment and debris from these outfall locations would continue to accumulate in the Sturgeon River. The input of sediment and other debris constitutes an input of a “deleterious substance”, which is an illegal activity under the federal Fisheries Act and would put the City at risk of large penalties for endangering fish populations in the Sturgeon River.
Sediment input smothers fish eggs, harms invertebrates, makes predation difficult due to murky water, damages fish habitat and increases the input of nutrients to the river. More nutrient inputs lead to declines in water quality and increased aquatic plant and algae growth, leading to declining oxygen levels and mass fish kills. Sediments can also be associated with heavy metals that are toxic to the aquatic environment. In addition to being a federal offence, contamination of other contaminants such as hydrocarbons can lead to substantial penalties under the provincial Environmental Protection and Enhancement Act.
Through our internal water quality monitoring program, we can see that the installation of oil and grit interceptors makes a notable difference to water quality in the river. It is the City’s due diligence to maintain this program, and minimize our impacts to the Sturgeon River, which is already ecologically impaired. The Government of Alberta has defined guidelines for stormwater quality release, which we have an obligation to meet. The most efficient and effective way to do this is using oil and grit interceptors (OGIs).
Both of the outfall locations that are planned for renewal in the 2023 program were identified as having safety issues (see background below).
Outfall 6B includes sediment from St. Albert Trail, which results in complaints from residents due to the high profile location. Sediment at this outfall location includes trace amounts of hydrocarbon.
Currently operations is regularly filling the sinkhole upstream of outfall 17A with fill material. Completing this project would eliminate the active sinkhole and the need to regularly replace this fill material which is then entering the stormwater line and is being flushed into the Sturgeon River.
Financial Implications of Motions:
Motion would result in short-term cost savings for Utilities customers. However, the Stormwater Infrastructure Rehabilitation budget would need to be expanded to address the renewal of the outfalls without the installation of OGIs or upgrades to enhance sediment removal. The goal of continuing to reduce the amount of City sediment and debris from reaching the Sturgeon River would not advance in a cost-effective manner, resulting in either higher costs for Utilities customers or no reduction in debris and sediment in the Sturgeon River, which may result in substantial financial penalties to the City from federal and provincial government agencies.
Rented bins for the hydrovac debris processing station at the Badger Lands has a rental cost of $15,000 per year that would be eliminated with a system that is owned by the City.
Stakeholder Consultations:
Alberta Environment and Parks (AEP) should be consulted if the intent is to not install new OGIs or other upgrades to the stormwater collection system to further enhance the removal of sediment and debris.
Background:
The City of St. Albert has 49 outfalls discharging into the Sturgeon River and 12 into Big Lake (an Important Bird Area). In 2003, sedimentation and erosion were identified as concerns in the Sturgeon River as a result of these stormwater outfalls.
Once sediment and debris are within the Sturgeon River, it takes significant regulatory approval in order to remove them through dredging. Regular dredging of the Sturgeon River is not ecologically or logistically possible, as Alberta Environment and Parks sees this as a disturbance of fish habitat with potential negative impacts on fish, riparian areas, and wildlife. Dredging is an expensive process including specialized consultants, equipment, approvals, and contractors.
The installation of oil and grit interceptors (OGIs) on each outfall was identified as the best long-term solution. However, each OGI costs between $0.5M to $1.5M to install. Installing OGIs on all 61 outfalls at once would have been expensive at a cost of ~$61M and logistically very difficult. Instead a program was developed back in 2003 to install approximately one OGI per year with the installation of OGIs when the outfalls themselves were being renewed to reduce the cost and to identify outfalls where OGIs were not needed due to the low risk upstream. For logistics, the renewal costs of the outfalls and replaced pipe sections were moved to this program from the capital program for Stormwater Infrastructure Rehabilitation.
Since 2003, 9 of 49 outfalls into the Sturgeon River have had OGIs installed and 7 of 12 on outfalls into Big Lake (not all of these OGIs are related to this program - some are as a result of new development). The costs associated with renewal of the outfalls and the trunk mains between the outfalls and the OGIs is included in the program, along with repairs and CCTV inspections. In addition, the program includes repairs to the Sturgeon River itself where erosion has occurred and it is likely that stormwater flows have contributed to this erosion. The program also includes infrequent capital investment in the debris drying and processing stations currently located at the Badger Lands.
Specifically in 2023, the program includes reconstruction of outfalls 6B, 17A and 17B and the relocation of the hydrovac debris processing station. These two outfall locations were identified as a high priority for replacement in the recent 2021 outfall study. Outfall 6B (between Riverhouse Grill and St. Albert Trail bridge) was identified as a high priority because it has safety issues (no grate or fence at a location in close proximity to a pedestrian trail). An OGI is proposed at this location due to sediments and oils from St. Albert Trail. Outfall 17A was identified as a high priority due to safety as well (the formation of a sinkhole in the upstream piping in close proximity to a pedestrian trail). This sinkhole is apparently due to a gap/hole in the stormwater pipe and needs to be addressed. Outfalls 17A and 17B are to be combined into a single outfall. Due to the small size and low risk of the combined basin, a deep manhole will be installed at this location to collect settlement and debris rather than an OGI.
The current hydrovac debris processing station at the Badger Lands is a temporary facility with bins being rented. Whether or not the debris processing station needs to be relocated as a result of the solar farm, it is recommended that bins be purchased and the site redesigned with infrastructure owned by the City to reduce this operational cost.
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Report Date: June 7, 2022
Author: Regan Lefebvre, Senior Manager of Utilities
Department: Public Operations (Utilities)
Director: Jay Mason
Acting Chief Administrative Officer: Kerry Hilts