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San Juan Metro (Back Bay) Coastal Storm Risk Management Feasibility Study

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This study was first scoped to look at the San Juan coastline, and did not include a coastal flooding focus.  However, as a result of the community feedback during the National Environmental Policy Act of 1969 (NEPA) Scoping meeting which took place in San Juan on November 8, 2018 the scope of this project has been revised to address coastal flooding in the San Juan Metro area.  The San Juan coastline will now be addressed in the Puerto Rico Coastal Study, which is a separate study and on a similar timeline to this study.  The Puerto Rico Department of Natural Environmental Resources (DNER) is the non-Federal sponsor for both studies.

The purpose of this study is to determine Federal interest in a recommended plan to reduce damages to infrastructure as a result of coastal flooding as a result of storm surge, tide and waves from coastal storms and hurricanes along the back bay areas in the municipality of San Juan and adjacent municipalities. The report has considered an array of alternatives and their effects, under NEPA and recommends a plan for Federal participation. 

The Final Integrated Feasibility Report and Environmental Assessment is available for a 30-day State and Agency Review.  The final report documents are available on this website. Answers to frequently asked questions (FAQs) can be found on this website.

During coastal storms, physical conditions such as storm surge, tide, and waves cause extreme flooding from lagoons and back bay areas.  This results in damages to critical infrastructure, residential and commercial structures; negative environmental and social effects; losses to the regional and national economy; and lack of resilience for affected communities.

The study area has approximately 20,000 structures and vehicles, with a combined estimated value of approximately $3.4 billion. Coastal flooding from storm surge, tide and wave contributions cause major damages to these structures and vehicles, and will continue to do so with increased risk from sea level change.

Authority for the San Juan Metro coastal storm risk management (CSRM) study is granted under Section 204 of the Flood Control Act of 1970, Public Law 91-611.  Study funds were appropriated under the Bipartisan Budget Act of 2018 Public Law 115-123. Corps feasibility studies under this authorization are by law required to be completed in 3 years and with $3 million or less, unless waivers are requested and approved. The study schedule and milestones are shown below.  The study has examined alternative solutions, and has recommended one plan that meets Corps criteria to be the Tentatively Selected Plan.  If the alternative is supported by Corps decisions makers, it will receive an approved Chief’s Report recommending it for authorization.  The plan will then need to receive congressional authorization and appropriations for construction.

This study analyzed 32 measures, resulting in a focused array of 23 alternatives which were then evaluated and compared according to USACE planning principles.  The recommended plan reasonably maximizes net benefits to contribute to national economic development (NED) and is consistent with protecting the nation's environment, pursuant to national environmental statutes, applicable executive orders, and other Federal planning requirements. 

The recommended plan consists of a collection of key structural and natural and nature-based features in strategic locations designed to appropriate elevations which work together to reduce the risk of damages as a result of coastal flooding from storm surge, tide and waves during coastal storms and hurricanes along with the effect of sea level change in the San Juan Metro Area.

  • December 13, 2018 - Alternatives milestone
  • December 2018 to June 2020 - Plan formulation, engineering and economic modeling
  • June 16, 2020 - Tentatively selected plan milestone
  • July 28 ,2020 - Draft report and NEPA - public technical and policy review
  • October 2020 - Agency decision milestone
  • July 2021 - Final State and agency review
  • September 2021 - Chief of Engineers report
  • 2022/2029 - Project engineering and design, construction*

*Contingent on authorization and appropriations 

Compiled Q&A from draft report public comments

 

  1. What is the purpose of the proposed project?

The purpose of the study is to determine the federal interest in a plan to reduce damages from coastal flooding due to storm surges, tides, and waves, with sea level rise, in the most vulnerable interior back bay areas of the San Juan Metro Area.

  1. Who is conducting the study and why?

 

The U.S. Army Corps of Engineers has conducted the study with the non-federal sponsor the Department of Natural and Environmental Resources (DNER). In response to these problems, USACE is pursuing this study to determine a recommended plan to reduce coastal flooding damages, under Section 204 of the Flood Control Act of 1970, Public Law 91-611, with funds provided under the Bipartisan Budget Act (BBA) of 2018 Public Law 115-123.

 

  1. What is the proposed project?

The Recommended Plan consists of a collection of key structural and natural and nature-based features in strategic locations designed to appropriate elevations which work together to reduce the risk of damages as a result of coastal flooding from high water events that result from storm surge, waves, tides and sea level change, and combinations of these forces, in the San Juan Metro Area.

The Recommended Plan is at a feasibility level of design, or approximately 10% level of design, and includes levees (1.5 miles), a series of breakwaters over 0.7 miles along the Cataño shoreline, seawall/floodwalls (6.5 miles), elevated living shoreline (0.7 miles), discharge structure on the Malaria Canal, and associated inland hydrology features (to ensure that rainfall runoff is able to continue to outflow as it currently does, with the Recommended Plan features in place).

 

  1. Is environmental mitigation a part of the recommended plan?

Yes.  The Recommended Plan contributes to creation of habitat in some areas.  In other areas, although the Recommended Plan was formulated to avoid and minimize impacts to the extent practicable, some  impacts to submerged aquatic vegetation, mangroves, and wetlands are expected to occur and would be addressed through mitigation, which is evaluated in the preliminary mitigation plan in Appendix F, Environmental, Attachment 4, and in Chapter 4 in the Main Report. There is some uncertainty in terms of the quantity and siting of  compensatory mitigation which would be further evaluated during the Preconstruction Engineering and Design (PED) Phase of the project when site-specific survey data is available. Upon final design, any functional lift (habitat creation) provided by the construction of the Recommended Plan would be incorporated into the functional assessment and the final mitigation plan.

 

  1. Will my property experience flooding as a result of the project?

 

No. All alternatives were formulated to ensure that rainfall runoff would still be accounted for behind the proposed features, through appropriately sized culverts or pumps, which will allow the rainfall runoff to pass through the features to the locations they currently do, without the features in place.This will ensure that communities behind the features will not incur additional flooding from rainfall runoff as a result of the features. To reduce long term operation and maintenance, gravity flow culverts are included in the design whenever possible and small pump stations are only used when absolutely necessary.

 

 

  1. How tall will the proposed features be?

The study team did their best to balance storm damage reduction, life safety, public acceptability, cost, and economic justification during the feasibility planning process. While the current 10% level of designs in WSJB 1B, 2, and 3 assume a design elevation of 9 ft-PRVD02 and WSJB 4 at 8.5 ft PRVD02, the actual height of the seawall that is seen by the community from a street view would generally be less than that, depending on the ground elevation.  On average seawall heights would be 4-5 feet from street level.  For example, along the Ferry Terminal in Catano, the wall would be approximately 3 feet high, due to higher ground elevations in that area.   On average, the living shoreline along Condado Lagoon would be 4-5 feet from street view.  The design team understands the concerns regarding the potential impacts to economic development and will continue coordination with the non-federal sponsor and community leaders, pending an approved Chief’s Report and congressional authorization, to minimize impact as much as possible to this highly urbanized and important community economic engine for the area.  Renderings have been created for key areas to visually show heights relative to a person on the street, and are posted on this website.

 

  1. Will I still have access to the water?

Yes.  In the recommended plan 10% level of design,the team has included  walkovers which will allow access over or through the structures, at various locations, through a combination of walkovers and or deployable storm surge barriers for the landward structures. These walkovers are required for operation and maintenance, but would be available to the public to use for recreational opportunities and would maintain the current public accessibility and viewshed.   

 

  1. Will any existing recreational facilities be impacted by the project?

 

No, existing recreational facilities in the area will not be impacted.Temporary impacts to recreational activities during construction are anticipated. As a public safety measure, boating would be prohibited near the operating construction equipment.Recreational access to these areas would return to pre-construction conditions following completion of the project.Although short-term impacts could occur, no long-term adverse effects are anticipated. Commercial shipping would continue in the Federal navigation channel. Information would be provided to the USCG so they could issue a “Notice to Mariners” prior to initiation of construction and for each major change in the construction activities.This would alert public boaters of areas to avoid and the possibility of limited and restricted access.No significant adverse impacts to recreational boating are expected from the proposed project

 

  1. Will there be recreational opportunities associated with this project?

 

Yes, incidental recreation opportunities would result from this project, and are described by reach, below.

 

Condado Lagoon: The recommended plan proposes to construct an elevated living shoreline on the northern shoreline of the lagoon.  The elevated living shoreline would have a 10-foot top width and would be topped with crushed limestone with access intervals for the purposes of operation and maintenance.  This feature would be available to the community for incidental recreation opportunities where it could be used for running, biking, fishing, walking, and access to the lagoon, etc.  This feature would connect the existing southern and western walkways to create a full walking path around the lagoon. 

 

West San Juan Bay 1:  The recommended plan proposes to construct a levee on the southwestern portion of the reach.  The levee would have a 12-foot top width and would be topped with crushed limestone with access intervals for the purposes of operation and maintenance.  This feature would be available to the community for incidental recreation opportunities where it could be used for running, biking, fishing, walking, etc.  Access to La Esparanza park and along the shoreline for access to the water would be maintained through gaps in the floodwall, where deployable floodwalls would be used.  Access to parking would be maintained.  Existing recreational features in this reach, as described in Chapter 2, would not be negatively impacted.

 

West San Juan Bay 2: The recommended plan proposes to construct a levee on the western portion of the reach.  The levee would have a 12-foot top width and would be topped with crushed limestone with access intervals for the purposes of operation and maintenance.  This feature would be available to the community for incidental recreation opportunities where it could be used for running, biking, fishing, walking, etc. Existing recreational features in this reach, as described in Chapter 2, would not be negatively impacted.

 

West San Juan Bay 3: The recommended plan proposes to construct a seawall along the northern and eastern shoreline.  Access to the water along the shoreline for would be maintained through gaps in the floodwall, where deployable floodwalls would be used, or through walkover features such as boardwalks for the purposes of operation and maintenance; however, would be available to the public to use for recreational opportunities Some boat docks in La Puntilla could be impacted; the configuration of the floodwall will be further evaluated in PED to avoid impacts as much as possible. Although relocations of public facilities such as boat docks and boardwalks are not currently anticipated or identified, a more detailed analysis will be conducted during PED.

 

West San Juan Bay 4: The recommended plan proposes to construct a levee on the southeastern portion of the reach.  The levee would have a 12-foot top width and would be topped with crushed limestone with access intervals for the purposes of operation and maintenance.  This feature would be available to the community for incidental recreation opportunities where it could be used for running, biking, fishing, walking, etc.  There are no known recreational features in this area, and therefore none would be impacted.

 

 

  1. What are the benefits of this overall project?

 

The Recommended Plan uses key structural and natural and nature-based features in strategic locations designed to appropriate elevations which work together to effectively and efficiently reduce estimated damages due to coastal flooding by 98% to 100% in the San Juan Metro Area. The Recommended Plan provides average annual net benefits (AAEQ) of $57.6M each year of a 50-year period of analysis. The Recommended Plan is economically justified with a benefit to cost ratio of 4.8.

  1. What are the benefits of this project in Condado Lagoon reach?

 The Recommended Plan, which includes an elevated living shoreline, provides important and extremely effective coastal flooding damage reduction to the dense assets, including critical infrastructure, within the Condado Lagoon area.  The recommended plan in this reach will have some impacts to submerged aquatic vegetation (SAV) and mangroves, but would also construct an elevated living shoreline which will add native vegetation such as mangroves to the area, creating habitat, as well as contributing to potential incidental water quality improvements to the lagoon.  The recommended plan maintains life safety for residents while reducing damages, and provides a large incidental benefit in that the Recommended Plan will also reduce the frequent tidal flooding problems experienced by the communities.  The plan also increases incidental recreational opportunities in the area as the elevated living shoreline can be used by the community for hiking, biking, etc.  The elevated living shoreline will be constructed on the north side of the lagoon where there is currently not a sidewalk; therefore it will essentially close the loop to create a complete walking path, connecting the existing Riverwalk on the south side of the lagoon, and the existing bridge pathways on the east side of the lagoon.  The Recommended Plan could create a boost to the local economy through increased access to the lagoon for activities, and it ultimately provides resilience to the entire reach, allowing the communities to return to normal life sooner and with less economic impacts after an event.  More specifically, in this reach, the Recommended Plan would reduce risk from an event with an approximate 0.44% annual exceedance probability and would provide approximately 98% damage reduction under the intermediate sea level rise curve, and approximately 94% damage reduction under the high sea level rise curve. 

 

  1. What are the benefits of this project in WSJB 1B reach?

 The Recommended Plan which includes seawalls and a levee provides extremely effective coastal flooding damage reduction to the assets within the area, including critical infrastructure.  The recommended plan maintains life safety for residents while reducing damages. The Recommended Plan ultimately provides resilience to the entire reach, allowing the communities to return to normal life sooner and with less economic impacts after an event. Regionally, the Casa Bacardi Factory provides benefits to tourism and the ability to recover more quickly after a storm event would boost the economy. More specifically, in this reach, the Recommended Plan would reduce risk from an event with an approximate 0.18% annual exceedance probability and would provide close to 100% damage reduction under the intermediate sea level rise curve, and approximately 97% damage reduction under the high sea level rise curve. 

  1. What are the benefits of this project in WSJB 2 reach?

The Recommended Plan which includes a discharge structure and levee (connecting to the levee in WSJB 1B) has very minimal features and associated construction  compared to the other alternatives which were considered and provides extremely effective coastal flooding damage reduction to the high density of assets, including critical infrastructure, within the area.    The plan could also provide incidental water quality improvements to the freshwater wetlands located in the area.   The Recommended Plan ultimately provides resilience to the entire reach, allowing the communities to return to normal life sooner and with less economic impacts after an event.

More specifically, in this reach, the Recommended Plan would reduce risk from an event with an approximate 0.18% annual exceedance probability and would provide close to 100% damage reduction under the intermediate sea level rise curve, and close to 100% damage reduction under the high sea level rise curve. 

  1. What are the benefits of this project in WSJB 3 reach?

WSJB 3: The Recommended Plan which includes a breakwater and seawalls/floodwalls provides extremely effective coastal flooding damage reduction and wave action reduction to the high density of assets, including critical infrastructure, within the area.  The breakwater could potentially support mangroves and provide foraging habitat for fish on the landward side.  The recommended plan maintains life safety for residents while reducing damages, allows continued access and gathering along the important Cataño shoreline gathering area, and provides social cohesion for the entire West San Jun Bay area.  The Recommended Plan ultimately provides resilience to the entire reach, allowing the communities to return to normal life sooner and with less economic impacts after an event.  More specifically, in this reach, the Recommended Plan would reduce risk from an event with an approximate 0.18% annual exceedance probability and would provide approximately 99% damage reduction under the intermediate sea level rise curve, and approximately 99% damage reduction under the high sea level rise curve. 

  1. What are the benefits of this project in WSJB 4 reach?

 

WSJB 4: The Recommended Plan which includes floodwalls and a levee provides extremely effective coastal flooding damage reduction and wave action reduction to the assets, including critical infrastructure, within the area.   The Recommended Plan ultimately provides resilience to the entire reach, allowing the communities to return to normal life sooner and with less economic impacts after an event.  More specifically, in this reach, the Recommended Plan would reduce risk from an event with an approximate 0.24% annual exceedance probability and would provide approximately 99% damage reduction under the intermediate sea level rise curve, and approximately 92% damage reduction under the high sea level rise curve.

 

  1. Who will pay for this project?

The project first cost is currently estimated to be $365.2M (including a risk-based contingency), with a Federal cost of $237.4M and a non-federal cost of $127.8M, based on cost sharing percentages from the Water Resources Development Act of 1986 (Federal: 65%; non-federal 35%).

 

  1. What are the next steps?

 

If the recommended plan presented in the Final Report is supported by USACE decisions makers, it will receive an approved Chief’s Report recommending it for Congressional authorization for construction.The plan will then need to receive Congressional authorization and appropriations for construction and would be cost shared as appropriate between USACE and DNER.  Upon receipt of both, the project would continue to the preconstruction engineering and design (PED) phase where a more detailed analysis would be completed to 100% level of design  before construction of the project.  The project would be expected to be in PED phase for 2 years.  Construction is estimated to take 5 years.

 

 

 

Contact Information

Contact us at:  SJMBackBay@usace.army.mil

Documents

2018 Bipartisan Budget Act

The U.S. Army Corps of Engineers received disaster funds provided in Public Law 115-123, the Bipartisan Budget Act of 2018. The act provides nearly $17.4 billion to the Corps for disaster recovery.

Jacksonville District received $3.348 billion for long-term recovery investments in its area of responsibility, which includes Florida, Puerto Rico and the U.S. Virgin Islands. This funding will go toward 13 studies, and 22 projects that will reduce risk to communities damaged by storm events. The total Federal funding allocation for Jacksonville District recovery efforts so far exceeds $4 billion.

Additional information can be found here