Aquatic Gardens Public Mtg - 10-15-20 - AnnotatedAquatic Gardens
Drainage Improvement
Project
Project Goals
•Primary Goal –Provide Additional Protection to Homes
•Secondary Goal –Reduce Street & Property Flooding
•Duration
•Extent
•Provide Flexibility for Future Expansion
•Sea Level Rise
•Larger Rain Events
•Be Cost Effective
Hopkins Creek Drainage Basin
1943 Overlay
1980 Overlay
Present Day
Drainage Considerations
•Flat Terrain
•Tidal Influence
•Existing Development
•Reduced Conveyance and Storage
•Sea Level Rise
•Outfall through Neptune Beach
Impacts from Development
Source: CDM 2002
FEMA 100-Yr Flood Event
Estimates of Sea Level Rise
at Mayport
0
2
4
6
8
10
12
14
2044 2054 2064 2074 2084 2094 2104 2114Projected Sea Level (ft, NAVD88)NOAA 2017 - Int-High
NOAA 2017 - High
NOAA 2017 - Extreme
CARSWG 2016 - High
CARSWG 2016 - Highest
USACE 2013 - High
USACE 2013 - Int
IPCC AR5 RCP 8.5 - Median
100-Yr Flood in 2044
Case Study
August 2016 Storm Event
•2.3“ of Rain
•Storm Duration = 1 hour
•Resulted in ditch bank
overtopping and street flooding
August 2016 Storm Event
August 2016 Storm Event
Water Level Profile
Improvements Made to Date
RAISE BERM
HEIGHT
INSTALL
WEIR
EMERGENCY
PUMP STATIONADDITIONAL
STORAGE
Proposed Improvements
Proposed Improvements
10-Year Flood Event
10-Yr/24-Hr Storm = 7.3”
25-Year Flood Event
25-Yr/24-Hr Storm = 9.2”
Timeline
Design Complete Nov 2020
Award Bid Jan 2021
Complete Construction Dec 2021
Cost
Design $314,000
Construction $2,400,000
Total Cost $2,714,000
Funding Sources
HMGP Design Grant $236,000 -Awarded
HMGP Construction Grant $1,500,000 -Awarded
Legislative Appropriation $200,000 -Awarded
CDBG-MIT Grant $1,854,000 -Under Review
$3,790,000
With CDBG-MIT Grant award –Additional ditch widening and replacement of the box
culvert at Cutlass Dr. will be completed
Timeline & Cost
Future Improvements
•Enlarge Cutlass Dr. culvert
•Widen ditch to Plaza
•Work with Jax & Neptune Bch to
enlarge Florida Blvd & Forrest Ave
Culverts