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North Paintbrush
Corridor Meeting
Thursday, February 20, 2014
6:30 – 8:30 PM
2
Welcome and Introductions
Supervisor Liz Archuleta
District 2
Coconino County
3
Opening Remarks
Lucinda Andreani
Coconino County
4
Tonight’s Goals
Review and Discuss Proposed 60% Plans
Review FLO2D Analysis Results
Review Next Steps
Opening Remarks
5
60% Designs
Reminder - Integrated Design Critical
Watershed Restoration on Forest and Off
Forest Conveyance Through the Neighborhood
to Lower Campbell Avenue Ditch
Forest Measures Contingent on Neighborhood
Measures and Vice-Versa
Project Delivers Important Flood Mitigation to
the Highly Impacted North Paintbrush
Corridor
6
Design Assumptions
5 Year, 6 Hour Design Storm Accounting for ~2 Years of Soil and Vegetative Recovery
Design Peak Flow Rate is 258 Cubic Feet Per Second
Create No Adverse Impacts
Stay Within Existing Right-Of-Way and New Easements on Private Property
Re-Vegetate Measures On and Off Forest
Provide Fencing Along Easements
60% Designs
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60% Designs
Design Through Neighborhood Reflects Feedback
from Initial Corridor Meeting & Individual Meetings
All Easements Secured From Private Property
Owners & Now Securing Mortgage Releases
Engineering Identified Need for Additional Sediment
Reduction
Less Alluvial Fan Area On Forest
South to North Conveyances Occur on Flat Grades
Reduce Future Maintenance Need & Cost
8
Basis of Design – Two Sections
On-Forest Measures
Natural Channel Design, Inc.
Forest Boundary to Lower Campbell
Ditch
Civiltec Engineering, Inc.
60% Designs
9
60% Design:
On-Forest Measures
Allen Haden
Natural Channel Design, Inc.
10
On-Forest Measures -
Key Considerations
Retain as Many Trees as Possible but Ensure Full
Value of Alluvial Fan Restoration
All Disturbed Areas will be Ripped, Seeded and
Mulched
Flows in Excess of Design Storm Will Flow in Historic
Flow Corridor
Private Properties Will See Flood Water from Storms
Greater than Design Storm; However, First 260+/-
CFS is in the Conveyance and NOT on Private
Property
Paintbrush On–Forest Measures
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Middle Fan in Thames, Spreading Water During Flows
Log rundown and fan in Lenox.
Log rundown and fan in Lenox15
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Log Sill Across Fan
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Log Run-Down Structure:
Brandis/Thames Watershed
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Terminal Trench:
Brandis/Thames Watershed
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Transition Channel Connects
to Neighborhood Conveyance
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60% Design:
Off-Forest Measures
Chris Dusza, P.E.
Civiltec Engineering, Inc.
21
Off Forest Flood Mitigation –
Key Considerations
Limited Right of Way Available for Improvements
Multiple Road and Driveway Crossings
Utility Considerations and Conflicts
Easements Needed from Multiple Property
Owners
Need for Additional Sediment Reduction and
Storage
Coordination of Corridor Improvements with ILM
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60% Design: Forest Boundary to
Lower Campbell Ditch
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TRM Channel
60% Design: TRM Channel
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TRM Channel
Wupatki Trails
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60% Design: Gabion-Concrete
Channel
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Gabion-Concrete Channel
Lower Campbell Avenue
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60% Design: Pipe
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60% Design: Sediment Reduction Site
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FLO2D Analysis
Chris Dusza
Civiltec Engineering, Inc.
FLO2D
Results
Any Frequency
5-Year, 100-Year, Etc.
Any Location
USFS
Private
Downstream
Every Grid Cell
Maximum Depth
30
No Adverse Impact Criteria
(NAI)
“An Approach by which the Action of Any Community
or Property Owner, Public or Private, will Not
Adversely Affect the Property Rights of Others”
Floodplain Management Initiative Developed by
the Association of State Flood Plain Managers
Does Not Mean No Development
Means that Any Adverse Impact that is or would be
Caused by a Project – or the Cumulative Impact of
Projects – Must be Mitigated31
No Adverse Impact Criteria
(NAI)
Board of Supervisors Adopted NAI Criteria for
County Projects in the Schultz Flood Area Only, on
April 2, 2013
Does Not Apply to Private Property Owners or
Work in Other Parts of the County, Only County
Mitigation Projects in the Schultz Area
Criteria Based on FLO-2D Modeling of
Differences Between Pre- and Post-Mitigation
Water Depths and Velocities
32
No Adverse Impact Criteria
(NAI)
Water Depth
No More than .1 Foot increase at 5 Year Storm
No More than .5 Foot Increase at 10 Year Storm
No More than 1 Foot Increase at 100 Year Storm
Water Velocity
No Increase Less than 1 Foot/Second or 10% of
the Pre-Project Condition
33
345 yr./6 hr. Storm - Existing Condition
355 yr./6 hr. Storm – Post Measures
3610 yr./6 hr. Storm - Existing Condition
3710 yr./6 hr. Storm – Post Measures
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FLO2D Results –
Five Year Storm Existing Condition100 yr./6 hr. Storm - Existing Condition
39100 yr./6 hr. Storm – Post Measures
Adverse Impact Conclusions
No Adverse Impacts at the 5, 10 or 100 Year
Storms
Important Reduction in Flood Impacts Resulting
from Five Year Design Storm Measures from
Forest Boundary and Downstream
Reduced Impact to the Paintbrush Corridor and
Therefore Provides Opportunity to Construct Flood
Mitigation for this Highly Impacted Corridor
Excess Flows Go Where They Go Now
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Moving Forward…
Lucinda Andreani
Coconino County
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Total Preliminary Costs: $2.9 Million to $3.2 Million
Benefits Entire Corridor
No Adverse Impacts
Secured Easements
Project Meets Feasibility Criteria
43
Secure Cost Share Approval from NRCS
Secure Final Approvals from Utilities
Complete Engineering Plans
Secure Any Necessary Temporary Construction
Easements
Approvals – FCD Board of Directors, NRCS & USFS
Target - April 1, 2014
Preliminary Construction Timeline – Weather
Permitting, Begin Construction On and Off Forest in
Early April and Complete Construction by June 30th
Next Steps . . .
44
Resources
Please Direct All Questions and
Comments To:
Schultz Flood Hotline: (928) 679-8390
Schultz Flood Email:
Schultz Flood Website:
www.coconino.az.gov/schultzfloodinform
ation
45
Thank You!
Breakout Sessions
to Review Preliminary Plan Sets
