SLIDE 1 Community Meeting #2| 4/21/16
DRYLAND LEVEE ALIGNMENTS
Planning Commission Presentation– June 28, 2016
SLIDE 2 Tonight’s Agenda
- Project Background
- Public Meetings
- Goals, Principles & Constraints
- Discussion of Alternatives
- Alternatives Comparison
- The Path Forward
SLIDE 3
Project Background
SLIDE 4 Background – Senate Bill 5
- Floods (1983, 1986, 1995, 1997)have caused over $3
billion in damage within Central Valley
- 2007 – CA Legislature passed 5 bills known as “2007 CA
Flood Legislation”
- Senate Bill 5 (SB 5) defined the criteria for “urban level of
flood protection”
- Level of protection needed to withstand a 1-in-200
chance of occurring in any given year
SLIDE 5 Background – Senate Bill 5
- Cities and Counties are required to take SB 5 into
account when making land use decisions in urbanized areas
- Manteca and Lathrop must show “adequate progress”
towards compliance by July 2016
- Adequate progress requires having the scope, schedule
and costs developed for needed projects
- Funding sources need to be identified
SLIDE 6
Reclamation District 17 (RD 17)
SLIDE 7
Background – SB 5
RD 17 Flood Plain Without Levee Project
SLIDE 8
Background – SB 5
RD 17 Flood Plain After Levee Project
SLIDE 9 Background – Expressway
(formerly McKinley Expressway)
- Expressway is needed based on
City’s current General Plan
- Manteca’s General Plan is based on 20 year horizon,
including transportation needs
- Expressway will be 2-4 lanes and 6 lanes at the
connections to SR 120 and SR 99
- Current General Plan has Expressway along Peach which
is inconsistent with expressway standards
SLIDE 10
Mailing List Notification Area
SLIDE 11 Background: Public Meeting # 1 (3/ 30/ 16)
Purpose of Meeting #1:
- Project Background
- Answer Questions/Concerns
- Group Exercise
- Gain better understanding of constraints & opportunities
- Introduction of Website
SLIDE 12 Background: April 5th City Council Meeting
- Council directed staff to focus workshops on dryland
levee alignments only
- Expressway alignment will be addressed with General
Plan update in 2016/2017 Expressway was separated from the Levee Discussion
SLIDE 13 Background: Public Meeting # 2 (4/ 21/ 16)
Purpose of Meeting #2:
- Reviewed feedback from previous workshop
- Presented levee alignment alternatives, costs and impacts
- Open House/Answered Questions/Provided Feedback on
Alternatives
SLIDE 14 Public Meeting # 3 (5/ 18/ 16)
Purpose of Meeting #3:
- Presented results from previous workshops
- Answered questions received
- Reviewed alternatives and comparison matrix
- Received feedback
SLIDE 15
Goals, Principles, & Constraints
SLIDE 16 Current Project Goal
- To build stakeholder consensus on a preferred alignment
for the dryland levee that meets the project principles, constraints and is compliant with SB 5 and State requirements.
SLIDE 17 Guiding Principles/ Constraints
- Minimize impact to farmland
- Minimize impacts to property owner access
- Stay on property lines as much as possible
- Utilize existing easements
- Respect the “right to farm”
- Accommodate entitled properties
- Consensus among stakeholders
- Meets DWR criteria for “wise use of floodplains”
- Cost
SLIDE 18 Constraints: Funding
- The City’s and County within RD-17 do not have sufficient
funds to deliver this project by themselves.
- To be eligible for potential State or Federal funding
- pportunities, the project must be consistent with DWR’s
Urban Flood Risk Reduction program guidelines and principles.
SLIDE 19 Constraints: Funding
- DWR’s principles and guidelines are based on the
following legislation and policies:
- Senate Bill 5 (2007)
- Central Valley Flood Protection Plan (2012)
- Governor’s California Water Action Plan (2016)
- Federal Executive Orders 11988 & 13690
Future State and Federal flood risk reduction investments must be consistent with these policies.
SLIDE 20 DWR Guidelines and Principles
- No increase in loss of life and expected damages; showing
a significant reduction in losses will result in a more competitive project;
- Promote wise use of floodplains with binding limitation
- n development in deep floodplains;
- Achieve multiple benefits in accordance with the
Governor’s California Water Action Plan;
- Preservation of agricultural land consistent with the 2012
CVFPP and the Delta Plan;
- Obtaining federal interest in the urban flood risk
reduction project for this basin.
SLIDE 21 Constraints: City’s Sphere of Influence
Existing Dryland Levee
SLIDE 22
Alternatives Discussion
SLIDE 23
Alternative 1
SLIDE 24 Alt 1: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $8.5M
Meets Criteria Partially Meets Does Not Meet
SLIDE 25
Alternative 1A
SLIDE 26 Alt 1A: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $12.1M
Meets Criteria Partially Meets Does Not Meet
SLIDE 27
Alternative 2
SLIDE 28 Alt 2: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $25.1M
Meets Criteria Partially Meets Does Not Meet
SLIDE 29
Alternative 2A
SLIDE 30 Alt 2A: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $12.1M
Meets Criteria Partially Meets Does Not Meet
SLIDE 31
Alternative 3
SLIDE 32 Alt 3: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $30.6M
Meets Criteria Partially Meets Does Not Meet
SLIDE 33
Alternative 4
SLIDE 34 Alt 4: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $52.4M
Meets Criteria Partially Meets Does Not Meet
SLIDE 35
Alternative 5
SLIDE 36 Alt 5: Conformance with Principles & Constraints
Minimize impact to farmland Minimize impacts to property owner access Stay on property lines as much as possible Utilize existing easements Accommodate entitled properties Consensus among stakeholders Meets DWR criteria for “wise use of floodplains” Cost – Approx. $11.6M
Meets Criteria Partially Meets Does Not Meet
SLIDE 37
Alternatives Evaluation Summary
SLIDE 38 Alternatives Comparison
Principles/Criteria Alt 1 Alt 1A Alt 2 Alt 2A Alt 3 Alt 4 Alt 5 Minimize Farmland Impact Minimize Impacts to Property Owner Access Follow Property Lines Utilize Existing Easements Accommodate Entitled Properties Consensus Among Stakeholders Meets DWR Criteria for “Wise Use of Floodplains” Cost Meets Criteria Partially Meets Criteria Does Not Meet Criteria
SLIDE 39 Alternatives Comparison
Principles/Criteria Alt 1 Alt 1A Alt 2 Alt 2A Alt 3 Alt 4 Alt 5 Minimize Farmland Impact Minimize Impacts to Property Owner Access Follow Property Lines Utilize Existing Easements Accommodate Entitled Properties Consensus Among Stakeholders Meets DWR Criteria for “Wise Use of Floodplains” Cost Meets Criteria Partially Meets Criteria Does Not Meet Criteria
SLIDE 40
Alternative 2A Recommended for Further Study in Environmental Phase
SLIDE 41 Alternative 2A Recommended for Further Study in Environmental Phase
- Follows Property Lines and Existing Easements to
Greatest Extent
- Minimizes Farmland Impact
- Minimizes Impacts to Property Access
- Consistent with DWR’s “Wise Use of Floodplains”
- Better Consensus from Stakeholders in Comparison to
Alternatives 1, 1A, 4 & 5
SLIDE 42
Moving Forward
SLIDE 43 What to Expect Next
- July 19th – Presentation of Recommendation to City
Council
- Environmental Process to start in late 2016
- Environmental and engineering studies to be conducted
- Actual alignment and footprint to be selected
- Additional public meetings will be conducted as part of environmental
study process
- Final Design & Right-of-Way Acquisition to begin in 2020
- Construction to begin in 2023
SLIDE 44
End
SLIDE 45
Common Questions & Answers
SLIDE 46 Paradise Cut
- The Phase 1 project to be constructed by River Islands
Development will: set back levees and remove the weir.
- Project will not entirely
resolve flooding because the I-5 and Railroad bridges constrain the hydraulic capacity of the channel.
impacts will the increased flows have on downstream communities?
Paradise Weir Channel Constraints
SLIDE 47
- In the event of a levee breach
upstream the water needs a way to get back to the river Turtle Beach Levee Break
SLIDE 48 Turtle Beach Levee Break
Levee at Turtle Beach can be removed as a “relief cut”
- This allows trapped water to
drain back to the San Joaquin river.
properties to the east during most storm events.
Turtle Beach Levee Cut
SLIDE 49 Turtle Beach Levee Cut Direction of surface drainage
Drainage of Existing Basin
SLIDE 50
Slurry Cut Off Wall vs. Seepage Berm
Q: Will cut-off walls be needed to control seepage? How will this affect the groundwater table?
SLIDE 51 Slurry Cut Off Wall vs. Seepage Berm
Seepage Berm Cutoff Wall/Slurry Wall
- Lower construction cost
- Preferred by stakeholders
- Won’t effect groundwater
- Higher construction costs
- Intended to be used when surface water
is always present on one side
- Deep structure interrupts groundwater
SLIDE 52 Slurry Cut Off Wall vs. Seepage Berm
A: Discussed constraints of using cut-off walls and RD17’s preference for using seepage berms instead of cut-off walls. The City is not supportive of cut-off walls and no determination has been made on this design detail yet. Preliminary analysis suggests that cutoff walls will not be
- required. However, if the Corp of Engineers requires it, the
City will conduct additional analysis to determine feasibility.
SLIDE 53
- Levee project is small compared to the overall
size of the basin.
- Propose levee alignments (1, 1A, 2 & 2A) will
have a nominal effect on the surface water elevation.
Proposed Alternatives Change in Water Surface
Elevation
SLIDE 54 RD-17: Wind Setup and Wave Runup Analysis
Wave Run up height is based on:
- 1. Depth of water at levee face
- 2. Velocity of wind
- 3. Design so waves break in a shallow zone in
front of the levee and not against the face
Evaluation Conclusions:
- 1. Wind Wave Runup at the proposed levee
will be less than 0.5 feet
- 2. Levee will be designed with 3 feet of
freeboard (6 foot minimum levee height)
SLIDE 55 Who are the “Stakeholders”
A: There are a number of stakeholders for this project including:
- Residents/Property Owners/Tenants/Developers
- Cities of Manteca & Lathrop
- San Joaquin County
- Reclamation District 17 & 2094
- Other State, Federal and Local Agencies
SLIDE 56 Where did the additional alternatives come from?
- Alternative 1A is what is being used by the cities and RD
17 as a placeholder to develop the Finance Plan.
- Alternative 2A was developed by the team after the
second public meeting as an alternative that potentially, can better meet the requirements of the State Department of Water Resources.
