Hill Creek Culvert Fish Passage Remediation

1. Hill Creek Culvert Fish Passage Remediation Nathan Schmidt, Dan Ciobotaru and ZenoviaCraciunescuGolder Associates Ltd., Edmonton AB Larry PurckaNorthwest Territories Department of Transportation, Yellowknife, NT

2. Hill Creek Culvert Fish Passage RemediationIntroduction • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions Problem: • During highway widening, a 2.2 m diameter CSP culvert was extended from 24 m to 48 m long Above: the culvert outlet during low water conditions • Post-construction, this was observed by Fisheries and Oceans Canada (DFO) to block fish passage due to high flow velocities and length • Under the authority of the Fisheries Act, DFO required the owner, Northwest Territories DOT, to fix the problem • NTDOT wanted a solution that would be economical and not require a new structure

3. Hill Creek Culvert Fish Passage RemediationLocation • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions Hill Creek Watershed: 154 km2

4. Hill Creek Culvert Fish Passage RemediationAlternatives Alternatives initially considered by NTDOT included: • Replacing the existing culvert with a bridge or culvert with greater fish passage capacity • Estimated cost: $750,000. • Preliminary examination of a culvert backflood for tailwater control indicated that it could provide fish passage at a cost of less than $100,000, without requiring removal of the existing culvert or detour during construction. • Needed to demonstrate feasibility first! • Reduce flow velocity through existing culvert by installing roughness elements, and install a second culvert for flood conveyance. • Estimated cost: $100,000 to $200,000. • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

5. Hill Creek Culvert Fish Passage RemediationChallenges • Limited site-specific hydrometric data, data-sparse region • Bedrock outcrops at lake outlets have a major influence on flow regimes, making regional hydrological analyses potentially inappropriate • Short timelines: no proper hydrological baseline • Remediation would require raising the creek bed by upto 1.4 m, meaning multiple riffles would be required • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

6. Hill Creek Culvert Fish Passage RemediationHydrology • Limited flow and velocity measurements were available from prior monitoring • Data from that station, scaled by 11% greater drainage area, were used to derive a long-term record for Hill Creek • Selected approach was to compare manual discharge measurements to a nearby long-term hydrometric station of similar size (Baker Creek, centroid about 60 km east) • This was the largest source of uncertainty in the analysis • A sensitivity case was also examined with a 25% scaling value, to account for this uncertainty • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions Frequency Analysis Results for Hill Creek 3Q and 7Q Values

7. Hill Creek Culvert Fish Passage RemediationDesign Criteria (Flow Velocity) • What could we achieve with a backflood? • Velocity reductions by backflooding are limited by the culvert cross-sectional area: benefits of an elevated tailwater become smaller as flows increase • Tailwater depths and flow velocities were checked for a range of discharges • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions 3Q2 = 1.36 m3/s 3Q5 = 2.94 m3/s 3Q10 = 4.39 m3/s

8. Hill Creek Culvert Fish Passage RemediationDesign Criteria (Flow Velocity) • The previous table looked at mean flow velocities achievable for a specified discharge • Another way of looking at it is how often we can achieve a specified velocity, based on the flow record: • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

9. Hill Creek Culvert Fish Passage RemediationDesign Criteria (Fish Passage) • Key Question: What flow velocity did we need to achieve to pass Northern Pike? • Mean flow velocities through portions of the downstream channel were shown to naturally exceed 1.0 m/s • Haack (2003): 300 mm Northern Pike could pass through a 40 m culvert at ~0.7 m/s • Peake (2001): Northern Pike greater than 420 mm long could pass culverts up to 50 m long with mean flow velocities below 1.0 m/s. • Katopodis (1994) model for anguilliform fish swimming performance indicated 0.25 to 0.30 m/s is required to pass Northern Pike ≥ 300 mm long • A target of 0.8 m/s at 3Q5 was selected, in consultation with DFO • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

10. Hill Creek Culvert Fish Passage RemediationDesign Profile view of riffle design showing placement of earth and rock fill materials

11. Hill Creek Culvert Fish Passage RemediationDesign Quantities: • 15 m3 clay • 60 m3 6-inch minus bedding gravel Plan view of riffle design showing placement of earth and rock fill materials • 220 m3 well-graded gravel-cobble • 130 m3 600 to 900 mm rock riprap

12. Hill Creek Culvert Fish Passage RemediationConstruction • Completed in August-September 2009 “in the dry” • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

13. Hill Creek Culvert Fish Passage RemediationMonitoring • Flow monitoring in 2010 showed peak flows lower on Hill Creek than on Baker Creek (surrogate data set) • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

14. Hill Creek Culvert Fish Passage RemediationMonitoring • Riffle velocities at Q = 0.87 m/s • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

15. Hill Creek Culvert Fish Passage RemediationMonitoring • Northern Pike were observed at culvert outlet in 2010 • Monitoring in 2011 showed passage above the culvert • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

16. Hill Creek Culvert Fish Passage RemediationConclusions • The culvert fish passage remediation was successful at a construction cost of < $80,000 • This type of solution may not be suitable for all situations, e.g. those: • severely undersized • where flow capacity may be affected • prone to aufeis accumulation • Interesting question affecting design criteria for northern streams and spring spawners: • Is there a temporal separation between peak flows and optimal spawning temperatures? • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions

17. Hill Creek Culvert Fish Passage RemediationQuestions • Introduction • Location • Alternatives • Challenges • Hydrology • Design Criteria • Design • Construction • Monitoring • Conclusions • Questions Questions?