Tributary To Stony Lake - 126158 - Appendix

Site Location

PSCIS crossing 126158 is located on Tributary To Stony Lake, on the eastern side of Stony Lake, approximately 100km southeast of Prince George, BC, in the Willow River watershed group (Figure ??). The crossing is located 0.8km upstream of Stony Lake, on Willow FSR, and is the responsibility of the Ministry of Forest.


 my_caption <- "Map of Stony"
 
 knitr::include_graphics("fig/gis/map_stony.jpeg")


Background

At PSCIS crossing 126158, Tributary To Stony Lake is a third order stream and drains a watershed of approximately 10.4km2. The watershed ranges in elevation from a maximum of 1870m to 956m near the crossing (Table 5.1).


PSCIS crossing 126158 was first assessed with a fish passage assessment in 2014 by Hooft (2015) and ranked as a barrier to fish passage with medium value habitat present. The crossing was reassessed in 2025 and a habitat confirmation assessment was conducted due to the presence of high value habitat and a significant amount of modelled habitat upstream. No fisheries information is documented for the stream; however, downstream in Stony Lake, bull trout and other species have been previously recorded (Norris [2018] 2024; MoE 2024).


A summary of habitat modelling outputs for the crossing are presented in Table 5.2.


fpr::fpr_table_wshd_sum(site_id = my_site) |>
  fpr::fpr_kable(caption_text = paste0('Summary of derived upstream watershed statistics for PSCIS crossing ', my_site, '.'),
           footnote_text = 'Elev P60 = Elevation at which 60% of the watershed area is above',
           scroll = F)
Table 5.1: Summary of derived upstream watershed statistics for PSCIS crossing 126158.
Site Area Km Elev Site Elev Min Elev Max Elev Median Elev P60 Aspect
126158 10.4 956 929 1870 1376 1297 SSW
* Elev P60 = Elevation at which 60% of the watershed area is above 


fpr::fpr_table_bcfp(scroll = F)
Table 5.2: Summary of fish habitat modelling for PSCIS crossing 126158.
Habitat Potential Remediation Gain Remediation Gain (%)
BT Rearing (km) 4.4 4.4 100
BT Spawning (km) 3.2 3.2 100
BT Network (km) 11.7 7.5 64
BT Stream (km) 10.2 6.0 59
BT Lake Reservoir (ha) 7.7 7.7 100
BT Wetland (ha) 11.4 11.4 100
BT Slopeclass03 (km) 1.4 1.4 100
BT Slopeclass05 (km) 2.9 2.9 100
BT Slopeclass08 (km) 1.6 0.7 44
BT Slopeclass15 (km) 3.7 0.8 22
* Model data is preliminary and subject to adjustments.


Stream Characteristics at Crossing 126158

At the time of the 2025 assessment, PSCIS crossing 126158 on Willow FSR was un-embedded, non-backwatered and ranked as barrier to upstream fish passage according to the provincial protocol (MoE 2011) (Table 5.3). The culvert had a 1.6m outlet drop and a 1.2m deep outlet pool.


The water temperature was 3\(^\circ\)C, pH was 7.4 and conductivity was 79 uS/cm.


fpr::fpr_table_cv_summary_memo()
Table 5.3: Summary of fish passage assessment for PSCIS crossing 126158.
Location and Stream Data
Crossing Characteristics –
Date 2025-10-05 Crossing Sub Type Round Culvert
PSCIS ID 126158 Diameter (m) 1.5
External ID – Length (m) 37
Crew AI Embedded No
UTM Zone 10 Depth Embedded (m) –
Easting 577622 Resemble Channel No
Northing 5918587 Backwatered No
Stream Tributary To Stony Lake Percent Backwatered –
Road Willow FSR Fill Depth (m) 8
Road Tenure MoF Outlet Drop (m) 1.6
Channel Width (m) 4.2 Outlet Pool Depth (m) 1.2
Stream Slope (%) 3 Inlet Drop No
Beaver Activity No Slope (%) 2.5
Habitat Value Medium Valley Fill Deep Fill
Final score 37 Barrier Result Barrier
Fix type Replace with New Open Bottom Structure Fix Span / Diameter 30
Comments: Huge outlet drop. Habitat confirmation assessments and EDNA samples conducted upstream and downstream. of the crossing. Originally prioritized by HOOFT in 2015.
Photos: From top left clockwise: Road/Site Card, Barrel, Outlet, Downstream, Upstream, Inlet. 


##this is useful to get some comments for the report
hab_site |>filter(site == my_site & location == 'ds') |>pull(comments)
hab_site |>filter(site == my_site & location == 'us') |>pull(comments)

Stream Characteristics Downstream of Crossing 126158

The stream was surveyed downstream from crossing 126158 for 240m (Figure 5.1). The habitat was rated as medium value for salmonid spawning and rearing. Abundant gravels were present throughout with no barriers observed between the road crossing and Stony Lake. The stream was relatively large with good flow, containing occasional shallow pools and sparse large and small woody debris. Total cover amount was rated as moderate with undercut banks dominant. Cover was also present as small woody debris, deep pools, and overhanging vegetation.The average channel width was 4.3m, the average wetted width was 2.2m, and the average gradient was 2.7%.The dominant substrate was gravels with cobbles sub-dominant.


Stream Characteristics Upstream of Crossing 126158

The stream was surveyed upstream from crossing 126158 for 330m (Figure 5.2). The habitat was rated as medium value. The dominant substrate was gravels with cobbles sub-dominant.The average channel width was 3.5m, the average wetted width was 2.7m, and the average gradient was 4.8%.Total cover amount was rated as moderate with undercut banks dominant. Cover was also present as small woody debris, large woody debris, boulders, and overhanging vegetation. Low-gradient stream with abundant gravels and diverse cover types including boulders, small and large woody debris, and undercut banks. Good flow with no natural barriers observed within the surveyed area.


Environmental DNA Sampling

eDNA samples were collected both upstream and downstream of crossing 126158 on Willow FSR, with sampling techniques summarized in Table 5.4.


my_caption <- paste0("Summary of eDNA samples collected at site ", my_site, ".")

tab_edna |> 
  dplyr::filter(site == my_site) |> 
  dplyr::select(-site) |> 
  dplyr::arrange(Site) |> 
  fpr_kable(caption_text = my_caption, scroll = FALSE)
Table 5.4: Summary of eDNA samples collected at site 126158.
Site Stream Habitat Type Sample Method Filter Type Filter Size (um) Volume filtered (L) Site Description
126158_ds_ed1 Tributary To Stony Lake riffle grab mce 1 1.9 Sampled collected 240m downstream of the culvert on the Willow FSR on the right bank. Walked down from the road on the left of the stream.
126158_us_ed1 Tributary To Stony Lake riffle grab mce 1 1.9 Sample collected 3m upstream of the culvert inlet on the left bank.


Structure Remediation and Cost Estimate

Should restoration/maintenance activities proceed, replacement of the Willow FSR crossing (126158) with a bridge (30m span) is recommended. At the time of reporting in 2025, the cost of the work is estimated at $900,000.


Conclusion

The habitat upstream of PSCIS crossing 126158 on Willow FSR was documented as medium value for salmonid spawning and rearing, and the crossing is rated as a high priority for replacement due to the large outlet drop.



tab_hab_summary |>
  dplyr::filter(Site %in% c(my_site)) |> 
  fpr::fpr_kable(caption_text = paste0("Summary of habitat details for PSCIS crossing ", my_site, "."),
                 scroll = F)
Table 5.5: Summary of habitat details for PSCIS crossing 126158.
Site Location Length Surveyed (m) Average Channel Width (m) Average Wetted Width (m) Average Pool Depth (m) Average Gradient (%) Total Cover Habitat Value
126158 Downstream 240 4.3 2.2 0.5 2.7 moderate medium
126158 Upstream 330 3.5 2.7 0.3 4.8 moderate medium 


my_photo1 = fpr::fpr_photo_pull_by_str(str_to_pull = 'ds_typical_2_')

my_caption1 = paste0('Typical habitat downstream of PSCIS crossing ', my_site, '.')
knitr::include_graphics(my_photo1)
Typical habitat downstream of PSCIS crossing 126158.

Figure 5.1: Typical habitat downstream of PSCIS crossing 126158. 


my_photo2 = fpr::fpr_photo_pull_by_str(str_to_pull = 'us_typical_1_')

my_caption2 = paste0('Typical habitat upstream of PSCIS crossing ', my_site, '.')
knitr::include_graphics(my_photo2)
Typical habitat upstream of PSCIS crossing 126158.

Figure 5.2: Typical habitat upstream of PSCIS crossing 126158. 

my_caption <- paste0('Left: ', my_caption1, ' Right: ', my_caption2)

knitr::include_graphics(my_photo1)
knitr::include_graphics("fig/pixel.png")
knitr::include_graphics(my_photo2)
knitr::opts_chunk$set(echo=FALSE, message=FALSE, warning=FALSE)
source('scripts/packages.R')
source('scripts/tables.R')
source('scripts/functions.R')
my_site <- 196085
my_site2 <- 203582