1. Proposed Novato Creek Bank Stabilization Guidelines Questa Engineering Corp.

2. Urban Bank Stabilization Problems Privately owned creekbed Typically incising bed creating retreat of bank tops Adjacent structures need to be protected Large mature canopy trees Long-term Geomorphic evolutionary tendencies

3. Guideline Development Steps Assess Existing Conditions Conduct Hydraulic Analysis Determine Long Term Trends Define basic Creek Management Approaches Describe suitable bank stabilization treatments Provide permitting guidance for design and permitting of bank stabilization structures

4. Existing Geomorphic Conditions Long Profile Analysis The channel has down cut about as far it can go. Natural bedrock controls prohibit extensive vertical degradation Bankfull Channel Dimensions Reach 1 - 33’ top width; Max depth 3 feet Reach 2 – 34’ top width: Max depth 3 feet Lack of Large Woody Debris Bedload D 50 – 17 mm surface; 4.8 mm subsurface Lateral erosion will be greatest erosion pressure in the reach

7. Existing Erosion & Canopy Reach 1Reach 2 Stable61%76% Eroded26%16% Protected14%9% # of Priority Sites56 Active erosion (ft)1,6851,194 Average Canopy Cover 50%71%

8. Existing Hydraulic Conditions Bankfull flows are at threshold of erosive velocities (Max. 5 to 7 fps) 10-year flows are above erosive velocity (Max. 9.7 to 12.1 fps) Bank erosion episodic and is likely to occur at flows greater than bankfull, at 5 to 10 year intervals Expect projects to be developed on a 5 to 10 year cycle

9. Existing Conditions Summary Channel is near stable vertically Lateral erosion may occur over the long- term The channel should managed to maintain at a minimum the average top-width and bottom width

10. Creek Management Approaches Fill Approach Cut Approach Vertical Approach

12. Design Approach Factors Adjacent structure setback - 20’ distance Presence of Trees larger than 12” DBH within 5’ of Top-of-bank Average Channel Top-width Average Channel Mid-width Presence of Trees larger than 48” DBH

13. Bank Stabilization Design Approach Flow Chart Existing Adjacent Structure or Utility Building Setback> 20’  Top Width is defined as the distance from top of bank to top of bank.  MidWidth is defined as the width at half the distance to top of bank from the channel thalweg  TOB = Top of Bank; DBH = diameter as base height (~4’ above ground)  Riparian tree is defined as any tree within 10 feet of existing top of bank  Adjacent structure/utility is a structure that is permitted through existing city ordinances or is more than 10 years old  Fences are not considered structures FIGURE 15 Riparian Trees < 12”DBH Multiple Trees > 12” DBH Single Trees < 12” DBH Top Width < 65’ Cut Solution Mid Width > 55’ Cut Solution Fill SolutionCut Solution Not Within 10’ of TOB <48” DBH Cut Solution Max. Feasible Mid Width <55’ Fill SolutionVertical Solution Mid Width <55’ Fill Solution Yes Multiple Trees Not Within 10’ of TOB >48” DBH<48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Mid Width <55’ Fill Solution Vertical Solution No >48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Top Width > 65’ Mid Width<55’ Mid Width > 55’ Trees Within 10’ of TOB Mid Width > 55’Mid Width <55’ Fill SolutionCut Solution DRAFT Fill Solution Mid Width > 55’ Within 10’ of TOB Cut Solution Cut Solution Mid Width > 55’ Fill SolutionCut Solution Top Width > 65’ Mid Width<55’ Mid Width > 55’Mid Width <55’ Building Setback< 20’ Vertical Solution or Cut Solution Max feasible Trees > 12” DBH Single Cut Solution Max. Feasible

14. Approach Check Station 83925 Priority R1-2 Structures –Shed within 20’ of TOB Trees – one stump within 5’ of TOB Top Width –55’ Mid Width – 46’ Solution  Vertical or Cut max feasible

15. Priority R1-3 (Station 84350) Structures –House within 20’ of TOB Trees – multiple trees less than 12” DBH within 5’ of TOB Top Width – 45’ Mid Width – 30’ Solution 

16. Bank Stabilization Design Approach Flow Chart Existing Adjacent Structure or Utility Building Setback> 20’  Top Width is defined as the distance from top of bank to top of bank.  MidWidth is defined as the width at half the distance to top of bank from the channel thalweg  TOB = Top of Bank; DBH = diameter as base height (~4’ above ground)  Riparian tree is defined as any tree within 10 feet of existing top of bank  Adjacent structure/utility is a structure that is permitted through existing city ordinances or is more than 10 years old  Fences are not considered structures FIGURE 15 Riparian Trees < 12”DBH Multiple Trees > 12” DBH Single Trees < 12” DBH Top Width < 65’ Cut Solution Mid Width > 55’ Cut Solution Fill SolutionCut Solution Not Within 10’ of TOB <48” DBH Cut Solution Max. Feasible Mid Width <55’ Fill SolutionVertical Solution Mid Width <55’ Fill Solution Yes Multiple Trees Not Within 10’ of TOB >48” DBH<48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Mid Width <55’ Fill Solution Vertical Solution No >48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Top Width > 65’ Mid Width<55’ Mid Width > 55’ Trees Within 10’ of TOB Mid Width > 55’Mid Width <55’ Fill SolutionCut Solution DRAFT Fill Solution Mid Width > 55’ Within 10’ of TOB Cut Solution Cut Solution Mid Width > 55’ Fill SolutionCut Solution Top Width > 65’ Mid Width<55’ Mid Width > 55’Mid Width <55’ Building Setback< 20’ Vertical Solution or Cut Solution Max feasible Trees > 12” DBH Single Cut Solution Max. Feasible

17. Priority R2-4 (Station 91900) Structures –within 20’ of TOB Trees – two trees greater than 12” DBH within 5’ of TOB; none greater than 48” DBH Top Width – 90’ Mid Width – 40’ Solution  Vertical solution

18. Bank Stabilization Design Approach Flow Chart Existing Adjacent Structure or Utility Building Setback> 20’  Top Width is defined as the distance from top of bank to top of bank.  MidWidth is defined as the width at half the distance to top of bank from the channel thalweg  TOB = Top of Bank; DBH = diameter as base height (~4’ above ground)  Riparian tree is defined as any tree within 10 feet of existing top of bank  Adjacent structure/utility is a structure that is permitted through existing city ordinances or is more than 10 years old  Fences are not considered structures FIGURE 15 Riparian Trees < 12”DBH Multiple Trees > 12” DBH Single Trees < 12” DBH Top Width < 65’ Cut Solution Mid Width > 55’ Cut Solution Fill SolutionCut Solution Not Within 10’ of TOB <48” DBH Cut Solution Max. Feasible Mid Width <55’ Fill SolutionVertical Solution Mid Width <55’ Fill Solution Yes Multiple Trees Not Within 10’ of TOB >48” DBH<48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Mid Width <55’ Fill Solution Vertical Solution No >48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Top Width > 65’ Mid Width<55’ Mid Width > 55’ Trees Within 10’ of TOB Mid Width > 55’Mid Width <55’ Fill SolutionCut Solution DRAFT Fill Solution Mid Width > 55’ Within 10’ of TOB Cut Solution Cut Solution Mid Width > 55’ Fill SolutionCut Solution Top Width > 65’ Mid Width<55’ Mid Width > 55’Mid Width <55’ Building Setback< 20’ Vertical Solution or Cut Solution Max feasible Trees > 12” DBH Single Cut Solution Max. Feasible

19. Priority R2-6 (Station 92200) Structures – none within 20’ of TOB Trees – roughly 6 trees greater than 12” DBH within 5’ of TOB; none greater than 48” DBH Top Width – 90’ Mid Width – 56’ Solution 

20. Bank Stabilization Design Approach Flow Chart Existing Adjacent Structure or Utility Building Setback> 20’  Top Width is defined as the distance from top of bank to top of bank.  MidWidth is defined as the width at half the distance to top of bank from the channel thalweg  TOB = Top of Bank; DBH = diameter as base height (~4’ above ground)  Riparian tree is defined as any tree within 10 feet of existing top of bank  Adjacent structure/utility is a structure that is permitted through existing city ordinances or is more than 10 years old  Fences are not considered structures FIGURE 15 Riparian Trees < 12”DBH Multiple Trees > 12” DBH Single Trees < 12” DBH Top Width < 65’ Cut Solution Mid Width > 55’ Cut Solution Fill SolutionCut Solution Not Within 10’ of TOB <48” DBH Cut Solution Max. Feasible Mid Width <55’ Fill SolutionVertical Solution Mid Width <55’ Fill Solution Yes Multiple Trees Not Within 10’ of TOB >48” DBH<48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Mid Width <55’ Fill Solution Vertical Solution No >48” DBH Cut Solution/ Preserve Tree Cut Solution/ Lose Tree Top Width > 65’ Mid Width<55’ Mid Width > 55’ Trees Within 10’ of TOB Mid Width > 55’Mid Width <55’ Fill SolutionCut Solution DRAFT Fill Solution Mid Width > 55’ Within 10’ of TOB Cut Solution Cut Solution Mid Width > 55’ Fill SolutionCut Solution Top Width > 65’ Mid Width<55’ Mid Width > 55’Mid Width <55’ Building Setback< 20’ Vertical Solution or Cut Solution Max feasible Trees > 12” DBH Single Cut Solution Max. Feasible

21. Stabilization Treatments Rock Toe-Retaining Wall CombinationX X Stitch PiersX Rock Slope with Live Plantings and Rootwad Deflector XX Vegetated Earth Filled GeogridsXXX Live crib-wallX Modular Pre-cast UnitsX Planted Rock Revetment XX Loose Rock Revetment XX Live Staking and Willow Wattles XX Erosion Control Fabric Planted w. Rooted Trees/Shrubs XX Brush Mattress XX Fiber rolls/ fiber rock rolls/ coir erosion blanketsXXX Flow deflectors/Rock SpursXXX Log, Rootwad, and boulder revetmentsXXX Boulder Clusters and Rock Vortex WeirsXXX Bank Stabilization TreatmentsVerticalCutFill Lunker Structures XX

22. Design Guidance Appendix Design Goals and Design Requirements Project Permitting & Approval Process Design Steps Existing County and City Ordinances