Xa'xtsa (Douglas First Nation) Wastewater and Sludge Management

Project Description:
The homes and community buildings throughout Tipella are serviced by on-site septic systems comprised of a buried septic tank with effluent disposal to ground via a drain field. Although many of the on-site septic systems are performing well, there are portions of the community where septic performance issues are persistent. These are generally in areas where the on-site septic systems have exceeded their useful life or where localized soil / groundwater condition issues exist. The remoteness of the community also presents challenges due to its distance from Mount Currie, where septic pump-outs are disposed.

Alternate wastewater servicing concepts for the Tipella community are assessed, specifically evaluation of the feasibility of on-site septic systems versus community wastewater servicing. A multiple accounts evaluation of each servicing concept is provided which considers social, environmental, operational, and economic factors.

Based on the comprehensive evaluation, a modified on-site wastewater servicing concept is selected as the preferred option. This servicing concept offers a reasonable level of service at a modest capital cost, taking a status-quo approach but introducing operational methods with sludge disposal to address financial and logistical challenges Tipella currently faces with relying on septic pump-out hauls to Mount Currie.

The proposed wastewater servicing concept generally consists of:
• Replacement of select on-site septic systems;
• Construction of local sludge disposal facility;
• Purchase of a septic tank truck / trailer for community operations staff to perform septic pump-outs and dispose locally, rather than through a hired contractor; and
• Other local community landscape upgrades to address surface water drainage impacts to septic systems.

Effluent Quality Parameters:
For design flows less than 22.7 m3/d, effluent disposal to ground is typically governed by the requirements set out in the BC Ministry of Health Sewerage System Standard Practice Manual (SSSPM). For on-site septic systems (less than 22.7 m3/d), the First Nations Health Authority (FNHA) issues a Permit to Construct a Sewage Disposal System.

The BC Municipal Wastewater Regulation (MWR) specifies effluent quality requirements for ground disposal of design flows greater than 22.7 m3/d.

However, it should be noted that neither the SSSPM or the MWR are necessarily applicable on reserve lands from a regulatory perceptive. The ISC Design Guidelines reference and incorporate several key concepts of the SSSPM and MWR as these are deemed generally accepted industry design standards.
For the purpose of this feasibility study, effluent quality parameters are based on the MWR requirements for Class D effluent disposal to ground.

Although ground discharges on reserve are not "registered" under the MWR, it is considered prudent to design such systems to MWR standards. The BC Ministry of Environment (BC MoE) is understood to be working with Indigenous communities to register on-reserve ground discharges moving forward.

Community Ground Disposal Options:
The location for testing and investigation to further assess suitability and performance of effluent to ground disposal systems was focused on two potential sites: within the BC Hydro right-of-way north of the Tipella community, and near the gravel pit to the southwest. Further field testing will be carried out during Pre-Design.

General findings, conclusions, and recommendations derived from the field investigation tests are summarized below:
• No groundwater was encountered at any of the five (5) excavated pits.
• The sediment profile of both subject site areas noted above is considered suitable for disposal of septic tank effluent to conventional absorption fields.
• The percolation rates (BC Hydro site) from testing were measured at 19:55, 22:30, and 21:12 (minutes:seconds per 25 mm). Additional testing will be required at the gravel pit area if this site is considered further.
• Groundwater (water table) depths are expected to be 5 m below ground surface for much of the year. However, levels during freshet may impose a design constraint. As such, it is recommended water table levels be monitored for further data.
• The BC Hydro site is considered favourable to the gravel site for wastewater disposal to-ground as it is down-gradient from the Tipella water supply wells and so disposal of effluent would not be expected to affect water quality. The gravel site is up-gradient of the wells and may pose a water quality risk within the well capture zone.

Septage Disposal Site:
A septage disposal site is proposed southwest of the Tipella community outside the Douglas IR #8 boundary, within a few kilometers to provide sufficient distance from settlement and from the community water supply wells, but reducing commute / hauling times. The site facility will take the form of basins or a series of trenches, with the following criteria for siting and construction:
• Have, at minimum, two basin cells for disposal so they can be alternated to rest and perform maintenance without removing the facility from operation;
• Constructed with granular soils, with water table minimum 4 m below top of trench / pit;
• Include a perimeter berm with freeboard;
• Fencing and signage installed for public awareness and safety; and
• Record logs kept for tracking volumes of sludge disposed.

A hydrogeological investigation and environmental impact study should be completed to determine the suitability of the sludge disposal site by confirming the location and assess its performance parameters.

Potential for Adverse Environmental Impacts
Adverse environmental impacts are not anticipated due to the relatively small footprint of the works and the localization of the proposed infrastructure to previously disturbed areas. 

Recommended Mitigation Measures:
The following mitigation measures and best practices are recommended for the proposed works:
• Dispose of construction waste at an appropriate facility;
• Refuel construction equipment at a dedicated location with appropriate spill containment and similar;
• Implement and maintain erosion and sediment control measures to minimize impacts to surrounding areas;
• If dewatering is required, ensure discharged water is directed to an appropriate location with erosion and sediment control in place; and
• Conduct vegetation / tree clearing between August 17th and March 12th which avoids the nesting season for migratory birds known to frequent the area. Alternatively, an active nest survey could be completed by a Qualified Environmental Professional.

Permits Required
The sludge disposal pit will require a permit from the BC Ministry of Environment (MoE). A Crown Land Right-of-Way, Tenure, or similar may also be required depending on the site location selected as well as the Addition to Reserve process status.

The sludge disposal pit is expected to require components of construction in areas not previously disturbed. Accordingly, archaeological considerations will need to be reviewed with Xa'xtsa to determine appropriate assessment / monitoring requirements.

Project Site Description
Water bodies / Navigable waters:
Lillooet River is approx. 250m northeast of community.

Vegetation:
Past assessment at Tipella conducted in November 2020 found that vegetation is dominated by Douglas-fir, western hemlock and western redcedar. Red-stemmed feathermoss dominates the understory with lesser amounts of huckleberry, sword fern and Prince's pine.

Birds:
Various migratory birds may use the project area during the spring and summer months. Bird species at risk that may be found in the project area include: band-tailed pigeon, common nighthawk, evening grosbeak, great blue heron, northern goshawk, olive-sided flycatcher, spotted owl, and western screech owl. Impacts to migratory birds can be avoided by clearing vegetation outside of the nesting season, between August 17th and March 12th.

Terrestrial wildlife:
Northern red-legged frog, western toad, dun skipper, little brown myotis, and rubber boa are all possible to occur within the project area.

Fish / Aquatic wildlife:
The nearest fish-bearing watercourse is the Lillooet River at a distance of 250 m; thus, impacts to fisheries resources are not anticipated.

Archaeological/Heritage Resources:
Avoid known archaeological/heritage resource sites as per the direction of Xa'xtsa. Have a chance find procedure in place prior to construction.

Air Quality:
Use water to suppress dust generated during construction as necessary.


The project is intended to have a net positive effect on human health by improving the existing sanitary waste disposal infrastructure.

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Latest update

June 26, 2023 - Indigenous Services Canada (ISC) issued its Notice of Determination and determined that the project:
- is not likely to cause significant adverse environmental effects.

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Contacts

Indigenous Services Canada
Fasih Siddiqui, Senior Engineer
1138 Melville Street
Vancouver, British Columbia V6E 4S3
Telephone: 604-376-0802
Fax: 604-775-7149
Email: Fasih.Siddiqui@sac-isc.gc.ca


  • Location

    • Douglas IR#8 (08013) (British Columbia)

  • Nature of Activity

    • Other, not otherwise specified

  • Assessment Status

    In progress

  • Start Date

    2023-05-26

  • Proponent

    Xa'xtsa (Douglas) First Nation

  • Authorities

    • Indigenous Services Canada

  • Assessment Type

    Project on federal lands

  • Reference Number

    84641
Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

 

Nearby assessments

...within 200 kilometres
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