1. Level 2 BIM - RPW Scour Survey Level 2 BIM RPW Inspection Case Study
Hydrotechnical – Scour, RPW – related
ID deficiencies – condition and functionality
Require specialized equipment, analysis
Scour Survey :
1960 – Now, Systematic (1990’s), Now – Post Flood
Mostly pier related, some RPW
Not readily visible, use sonar
RPW Inspection :
Systematic ~ 2000, ID sites, base inspections (~ 200 sites, 120 inspected, some overlap with scour)
Functionality – bank tracking, Condition – site inspection
Case Study :
Examples - Pier Modification – BF315, BF78104; RPW Modification – BF79710, BF76474, BF09259, BF13078; Assessment Input – BF74381
Case Study – BF78104 – McLeod River near Peers on Hwy 32 – Flow alignment change – pier scour - underpinning

2. Scour Survey
General and Local Scour – difficult to see and quantify without survey

3. Scour Survey Scour Survey – 1960’s
Boom with sounder off superstructure
Boom carried on roof rack
Boom mounted on pier (BF73949, Peace River near Dunvegan)
Profile and contour survey results from 1960 at BF74381 – North Saskatchewan River on Hwy 22 near Drayton Valley

4. Scour Survey Handrail profile (1981) :
BF8800 – Red Deer River near Garrington
Hand plotted (artisitic, colourful)

5. Scour Survey Techniques :
Boom with sounder – truck, bridge – access difficulties
Boat with sounder + total station – more recent

6. Scour Survey Type – Contour, profile (handrail, cross section)
History – < 1960 – Now
Factors – floods, surveyor availability, ARC
Systematic – early 1990’s (next slide)
2005 – Post Flood

7. Scour Survey Systematic (early 1990’s) :
Initially, screen and prioritize based on theoretical scour depth vs. foundation depth
Later, refined based on observations
Survey (handrail, contour) all high priority sites ( )
Now, mostly post flood (next slide)
BPG #7, spread footings, DB of scour vulnerable sites decreasing in number

8. Scour Survey
Post 2005 Flood Survey – BF74381 – North Saskatchewan River, Hwy 22, near Drayton Valley
Note :
Comparison between past and current survey, superimposed on bridge foundation data
Longitudinal Profile – holes near spur and bridge

9. Scour Survey Field Scour Data Plot :
Presented at ASCE scour conference in 1993
Compares predictive equations to field data
ds = scour depth, b = pier width, y = flow depth
Alberta data-set one of most comprehensive at time

10. RPW Inspection
RPW :
Types – guidebanks, spurs (also dykes, grade control, embankment spurs, channel realignments)
Locations – bridges (e.g. Smoky River, Hwy 40), Hwy embankments (e.g. Red Deer River, Hwy 10)
Function – protect infrastructure by controlling flow alignment and minimizing bank movement
Configuration, susceptibility – depends on stability of stream, flood history

11. RPW Inspection Systematic Inspection :
formal program to complement scour survey program
ID sites based on assessment of channel stability, extent of existing RPW
~ 200 sites documented between 1998 and 2000
Functionality – airphoto assessment, bank tracking
Condition – site inspection

12. RPW Inspection Functionality – airphoto assessment : bank tracking
flow alignment
river processes
Local development – impacts on/of river

13. RPW Inspection
Condition - airphoto (BF81778 – Wapiti River adjacent to Hwy 40, south of Grande Prairie) :
Post flood airphoto – 1:2400 (exceptional)
damage apparent but still difficult to assess (even at zoom)
Note flow pattern marks between spurs – assessment of function

14. RPW Inspection
Condition – site inspection (BF81778 – Wapiti River adjacent to Hwy 40, south of Grande Prairie – during/post 1990 flood) :
Site inspection provides better assessment of condition of protection works
Can be difficult to assess/access under HW conditions
Loss of rock, fill, damage to concrete, adjacent bank erosion
Document – photo, video, rough measurements, location

15. Case Study
List of sites, observations, and recommended actions ~ 1997

16. McLeod River near Peers
Case Study
BF78104
McLeod River near Peers
Hwy 32
BF78104 – McLeod River at Peers, Hwy 32 - Photo of Bridge from RB U/S - illustrates :
Pier Scour – erodible rock, flow alignment impact
Lateral Instability – bank tracking over time
Action taken – pier underpinning

17. Case Study BF78104 – McLeod River at Peers, Hwy 32 1950 Airphoto :
note channel realignment associated with bridge construction
Extensive south (right bank) guidebank to protect from river returning to previous channel

18. Case Study BF78104 – McLeod River at Peers, Hwy 32 1999 Airphoto :
River has progressed to north (left bank) – resulting in large skew
Illustrates inability to totally predict river response – design for now, monitor for future

19. Case Study BF78104 – McLeod River at Peers, Hwy 32
1980 Flood – through opening

20. Case Study BF78104 – McLeod River at Peers, Hwy 32
1980 Flood – note HW can get in behind long U/S RGB, but well vegetated U/S

21. Case Study BF78104 – McLeod River at Peers, Hwy 32
1980 Flood – a lot of water in behind U/S LGB

22. Case Study BF78104 – McLeod River at Peers, Hwy 32
1980 Flood – scour survey at U/S end of LGB, note treed bank u/s

23. Case Study BF78104 – McLeod River at Peers, Hwy 32 1999 Airphoto :
bank tracking
erosion rates a function of flood history, stream power, current (pun intended) alignment, geology
also local factors – development (clearing), gravel mining…

24. Case Study BF78104 – McLeod River at Peers, Hwy 32
Impact of flow alignment on local scour at pier

25. Case Study BF78104 – McLeod River at Peers, Hwy 32
Contour survey and profile survey from 1998.

26. Case Study BF78104 – McLeod River at Peers, Hwy 32
Handrail profile from 1998.

27. Case Study BF78104 – McLeod River at Peers, Hwy 32
Scour survey superimposed on airphoto

28. Case Study BF78104 – McLeod River at Peers, Hwy 32
Underpinning Design – Built in 2000

29. Case Study BF78104 – McLeod River at Peers, Hwy 32
Photos during construction – berms and constriction of flow, caisson drilling operation