Mayport Resiliency Assessment
Flood vulnerabilities and adaptation strategies for roadways
Project Overview
Northeast Florida’s transportation network is vulnerable to flooding. One of the more vulnerable areas is Mayport. The purpose of this study is to identify strategies to make roadways in the area more resilient.
The most critical segments were evaluated:
Segment A
includes A1A from Wonderwood Drive to the For George Ferry Terminal.
Segment B
includes Wonderwood Drive from A1A to Mayport Road.
Segment D
extends from Wonderwood Drive / Seminole Road at Mayport Road to the Naval Station Mayport Hanna Park Gate.
The segments were further divided into subsegments so that the vulnerability of shorter sections road could be assessed.
Flood Hazards
The study looks at three types of flooding.
One Hundred Year Storm
One type of flooding is the Federal Emergency Management Agency (FEMA) “100 year storm.” This is a flooding event that has a 1% chance of happening in any year. This image shows what Mayport might look like during a 100 year event. Most of the roadways around Mayport are vulnerable to this kind of flood.
Move the slider to view flooding from the 100 Year storm
Storm Surge
Storm surge occurs when strong hurricane winds push water onshore. Our study looked at flooding that could occur during Category 1, 2 or 3 hurricanes.
Move the slider to view the storm surge hazards.
All roadways would likely be affected by a Category 1 storm surge (green areas). Category 2 or 3 storm surge (yellow and red areas) make the situation worse.
Sea Level Rise
Sea levels are rising due to climate change. Seas have already risen about 8 inches in Florida since 1950. Recently, the rise has accelerated to about 1 inch every three years. Flooding from sea level rise (SLR) is different from the 100 year flood or storm surge because it is permanent.
How much sea level rise should we expect in the future? The answer depends on how society addresses its responsibility for climate change.
A proactive approach could reduce future sea level rise. A reactive approach could result in very high future sea levels.
We examined a variety of future scenarios and chose one in the middle, shown by the red dotted line in the figure below. This "USACE 2013 High Curve," predicts about 0.5 feet of rise by 2035, 2.0 feet by 2065 and 4.6 feet by 2100.
Sea Level Rise Scenarios
A1A could be affected by sea level rise as soon as 2035. By 2065, all segments could be affected. By 2100, it is virtually certain that all segments will be affected, and access to the Naval Station and Mayport Village will be compromised.
Up to a half a foot of sea level rise is expected by 2035.
A1A (Segment A)
Subsection A2 and A3 could be impacted in this scenario. The most significant concern is between the Sherman Creek Bridge and US Coast Guard Station. This section is surrounded by the river to the West and tributaries to Sherman’s Creek on the East and is highly susceptible to tidal influences.
Wonderwood Drive (Seg. B)
Although Wonderwood Drive is dry in this scenario, sea level rise may prevent stormwater from draining from the road causing intermittent flooding. The main area of concern is subsection B2.
Seminole Road (Seg. D)
This area is not a major concern for this scenario
By 2065 Mayport could experience 2 feet of sea level rise.
A1A (Segment A)
Conditions along subsection A2 and A3 worsen. A1A north of the bridge over Sherman Creek is impacted, including the commercial area and travel lanes at the Mayport Ferry Docks (subsection A4). Subsection A1 remains unaffected.
Wonderwood Drive (Seg. B)
Intermittent flooding around the Wonderwood Drive and Mayport Road intersection due to impaired drainage increases.
Seminole Road (Seg. D)
Key locations of the roadway along subsegment D2 are impacted due to impaired stormwater drainage.
By 2100 seas could rise by more than 4 feet.
A1A (Segment A)
Nearly all A1A subsegments are permanently wet, except near the Wonderwood Drive intersection.
Wonderwood Drive (Seg. B)
The intersection with Mayport Road is likely as not permanently wet (Subsection B2). Subsegment B1 remains dry.
Seminole Road (Seg. D)
The area around the Naval Station's Hanna Park Gate (subsegment D3) is still dry, but the other subsegments are partialy wet.
Vulnerability
Mayport’s roadways are very vulnerable to present and future flood risks, including flooding from a 100 year storm, storm surge and sea level rise.
Mayport Resiliency Study - Vulnerability and Adaptation Options
Some roadway segments are more vulnerable than others. To make this clear, we ranked the vulnerability of each roadway segment to all kinds of flooding from low, medium-low, moderate, moderate-high to high.
Adaptation Strategies
Potential strategies to address flooding were developed for the most vulnerable road subsections. There are various options that could be implemented depending on the needs of each segment. They have been classified as near-term (0-5 years), mid-term (5-15 years), or long term (15-25 years) solutions. They also have been classified by environmental impact and cost (low, medium or high).
Recommended adaptation strategies include raising the road and armoring nearby areas. Roadway profile elevations could be raised by overbuilding asphalt pavement, adding barriers, or by replacing the roadway with a bridge structure. Roadside slopes and areas adjacent the roadway could be protected with living shorelines, or by building a wall below the embankment in combination with riprap.
Segment A3: FL-A1A from Sherman Creek to the U.S. Coast Guard Station Mayport
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A-3 Option 1: Raise Roadway 1-Foot
This option would raise the existing road one foot by overbuilding the asphalt pavement. The roadside slopes would then be armored by constructing riprap or articulating block to protect slopes.
Timeframe: Near-Term
Potential Environmental Impact: Low
Potential Cost: Low
2
A-3 Option 2: Raise Roadway 2-Feet
This option would raise the existing road two feet and replace tie-down slopes. This would cause an increase in the existing road footprint. Additionally, this option would replace an existing concrete box culvert.
Timeframe: Mid-Term
Potential Environmental Impact: High
Potential Cost: Moderate
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A3 Option 3: Raise Roadway 2-Feet and Add Barrier
This strategy is like Option 2, however walls or guardrails would closely maintain the existing roadway footprint. This option would also replace an existing concrete box culvert.
Timeframe: Mid-Term
Potential Environmental Impact: Moderate
Potential Cost: Moderate
4
A3 Option 4: Replace Roadway with Bridge
This option would replace the existing roadway with a bridge.
Timeframe: Long-Term
Potential Environmental Impact: Moderate
Potential Cost: High
5
A3 Shoreline Option 1: Wave Energy Attenuation
This option would place offshore structures in the river along A1A near Sherman Point / the Little Jetties to reduce wave energy reaching the shore. These devices can facilitate the accretion of sediment and protect the roadway.
Timeframe: Short-Term
Potential Environmental Impact: Moderate
Potential Cost: High
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Shoreline Option 2: Armored Bulkhead
This option would install an armored bulkhead along the river parallel to A1A near Sherman Point / the Little Jetties. Unlike wave attenuation, bulkheads reflect wave energy to protect the shoreline and roadway.
Timeframe: Mid-Term
Potential Environmental Impact: High
Potential Cost: Moderate
Segment A2: SR A1A from Bayshore Drive to Sherman Creek
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A2 Option 1: Raise Roadway 1-Foot
This option raises the existing road one foot by overbuilding the asphalt pavement. The roadside slopes would then be armored by constructing riprap or articulating block to protect slopes.
Timeframe: Near-Term
Potential Environmental Impact: Low
Potential Cost: Low
2
A2 Option 2: Raise Roadway 2-Feet
This option raises the road two feet and replaces tie-down slopes. This would cause an increase in the existing roadway footprint. Additionally, this strategy would include replacing the existing bridge.
Timeframe: Mid-Term
Potential Environmental Impact: High
Potential Cost: Moderate
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A2 Option 3:Raise Roadway 2-Feet, Add Barriers, and Replace Bridge
This strategy is like Strategy 2, however walls or guardrails would closely maintain the existing roadway footprint. This option would also replace the existing bridge.
Timeframe: Mid-Term
Potential Environmental Impact: Moderate
Potential Cost: Moderate
4
A2 Option 4: Replace Roadway with Bridge
This option replaces the existing road with a bridge.
Timeframe: Long-Term
Potential Environmental Impact: Moderate
Potential Cost: High
Segment A4: SR A1A from Safe Harbor to the Ferry Terminals
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A4 Option 1: Raise Roadway 1-Foot
This option raises the road one foot by overbuilding the asphalt pavement. The roadside slopes would then be armored by constructing riprap or articulating block to protect slopes.
Timeframe: Near-Term
Potential Environmental Impact: Low
Potential Cost: Low
2
A4 Option 2: Raise Roadway 2-Feet
This option raises the road two feet and replaces tie-down slopes. This would cause an increase in the existing road footprint that could potentially affect adjacent properties.
Timeframe: Mid-Term
Potential Environmental Impact: Low
Potential Cost: Moderate
Segment B2: Wonderwood Drive from Sherman Creek to Mayport Road
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B2 Option 1: Raise Roadway 2-Feet
This option raises the road two feet by overbuilding the asphalt pavement and replaces the tie down slopes. This would cause an increase in the existing roadway footprint.
Timeframe: Mid-Term
Potential Environmental Impact: Moderate
Potential Cost: Low
2
Option 2: Raise Roadway 2-Feet and Add Barrier
This option would include raising the existing road two feet and adding walls (or guardrails) to more closely maintain the existing road footprint.
Timeframe: Mid-Term
Potential Environmental Cost: Moderate
Potential Cost: Low
Segment D2: Wonderwood Drive / Seminole Road within Hanna Park
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D2 Option 1: Raise Roadway 2-Feet
This option would include raising the existing road two feet foot by overbuilding the asphalt pavement and replacing the tie down slopes. This would cause an increase in the existing road footprint.
Timeframe: Mid-Term
Potential Environmental Impact: High
Potential Cost: Low
2
D2 Option 2: Raise Roadway 2-Feet and Add Barrier
This option would include raising the existing road two feet and adding walls (or guardrails) to more closely maintain the existing roadway footprint.
Timeframe: Mid-Term
Potential Environmental Impact: Moderate
Potential Cost: Low
Prioritization of Adaptation Options
Not all adaptation options have the same cost or benefit. These differences are important to consider. That’s because resources are always limited and priorities must be established.
We have preliminarily ranked the Adaptation options for each roadway segment using the following criteria:
- Concept level estimates of probable construction costs
- Environmental impact to adjacent surface waters or wetlands and other environmental impacts
- Societal impact, including maintenance of evacuation routes, emergency access, or increased travel time for alternate access, obstructed viewsheds, and requirements for eminent domain
- Construction feasibility
- The ability of the solution to address flood risks over time
- Public feedback on favorability of options
We have combined these considerations into a single favorability score for each option that could be used to prioritize action shown in the table below.
Favorability scores for adaptation actions.
Next Steps
Adapting is an ongoing, iterative process. The strategies presented above are a starting point. They require more study before being implemented. Funding must be secured, and stakeholders and the public consulted to achieve consensus on the way forward.
Future Studies
Additional study may be needed to model future flooding and evaluate shoreline erosion at a project scale. Project Development and Environment (PD&E) studies may need to be completed prior to construction. Because climate and sea level rise impacts are an ongoing concern, a Planning Update should be performed in 2035 to reevaluate vulnerabilities in view of changing conditions.
Funding
There are many types of funding options available for planning and implementation of adaptation strategies. Examples include grant funding, green bonds, and public-private partnerships. Recognition of the importance of adaptation at both the state and federal level means support is increasingly available for resilience projects.
Contact Us:
Your support is important too. To get engaged in planning on our region's transportation future, contact us.
North Florida Transportation Planning Organization
980 N Jefferson St, Jacksonville, FL 32209
(90 4) 306-7500
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