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Home My WebLink AboutSubmittal-Tim Blankenship-USACE Back Bay Study PowerPoint PresentationSWIRE PROPERTIES 1 oo mbffdtl & nichcl 0106 377 Submittal -Tim Blankenship-USACE Back Bay St' Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk • STUDY AREA CONTEXT 5 BRICKELL BAY DRIVE PIP AI' .R35,7 , 0,1 • 5 NI SWIRE PROPERTIES —Hatt &niCh01 7 4 Submitted into the public record for item(s) DI.3, on 02-11-2021 City Clerk NI`JU G 2 2%I I S, 10 '411! 6 14 5 3 , - - 'u• "1134 0- 16ft 0419 6 4 1 3 18 ' 5 1,0 BRICKELL KEY 5 pp: '6-1' 2 3 2 6 E 2 3 a0 16f1 4M "63! S. BRICKELL BAY DRIVE 5 Fl as 7 L., 4 2 3.1 3 RISC A 4 — 2 Design Philosophy SWIREPROPERTIES hag moffott & nichol Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk • Multiple lines of defense • Hybrid storm surge/flood risk reduction for Back Bay & Brickell Key • Natural and Nature -Based Features as resiliency elements • Holistic, systems approach • Science -based • Sustainable • Adaptive • Probabilistic, Time Based Risk Analysis • Accessible waterfront • Overtopping and Stormwater considerations Build a system that operates together to provide an equivalent LOP and also provides environmental benefits that will be required for mitigation. And also add some additional social, access, and economic opportunities. 3 edsai 1 MI SWIREPROPERTIES ♦jli, maffott nic"1 edsai OPPORTUNITIES - 2030 / Revetments, seat walls, and localized building protection allows for adaptability and system adjustments upwards over time to match risk. REVETMENT & GREENWAY WETLANDS BOARDWALK OYSTER & MUSSEL REEF SEAGRASS L Submitted into the public record for item(s) DI.3, on 02-11-2021. City Clerk SEAWALL/FLOOD WALL PLANTER WALL/FLOOD WALL PERMEABLE PAVERS SIDEWALK BIOSWALE MHHWL +0.95' MSL: -0.16 MLLW_ -1.27' Final elevations TBD based on probabilistic water level assessment, risk tolerance, and allowable overtopping Oyster Reef Breakwater Mangrove Wave Absorption Revetment Armoring Near -Shore Berm and Pathway Seagrass and Wetland Storage & Water Quality Benefit Basin 1111111111.1 Segmented Seawall — Deployables Bioswale Stormwater Collection Permeable Pavement Promenade Planter Wall Overtopping and Stormwater Pumping System OPPORTUNITIES - 2079 Revetments, seat walls, and localized building protection can evolve upward through time to match risk REVETMENT & GREENWAY WETLANDS BOARDWALK OYSTER & MUSSEL REEF SEAGRASS SWIRE PROPERTIES 1d0011 moffofl & nlchol Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 106, f"r 1ZED FLOOD PROTECTION AT BUILDING —A �iSEAWALLIFLOO❑ WALL PLANTER WALL/FLOOD WALL PERMEABLE PAVERS SIDEWALK s BIOSWALE AIMIL f MHHWL +3.81' MSL: +2.70' MLLW: + 1.59' Final elevations TBD based on probabilistic water level assessment, risk tolerance, and allowable overtopping Oyster Growth Matches SLR Mangrove Growth Revetment and Dike Elevation Increase Basin Mangrove Growth Seawall Elevated to Bar Height Pump -Augmented Stormwater System Localized Building Deployable Protection Continues Monitoring of SLR and Science SWIRE PROPERTIES tail m o f f o tt n i c h o l PROMENADE PLAN VIEW Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsai k SWIRE PROPERTIES hjIkg mcffott & nichcl PROMENADE SECTION / Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsai 7 k SWIRE PROPERTIES hjIkg mcffott & nichcl PROMENADE SECTION / Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsai 8 DIRECT ASK Include in Final CSRM Study 1. Language that encourages the use of a hybrid structural and NNBF system. 2. Sample visual reference Submitted into the public record for item(s) D on 02-11-2021, City Clerk SWIREPROPERTIES hag moffott & nichol r— REVETMENT 6 GREETIWAY WETLANDS BOARDWALK OYSTER & MUSSEL REEF SEAGRASS 4 I,i/ DFLOOD PROTECTION ATBUILOINO- '"" • EA' ALL/FLOOD WALL PLANTER WALL/FLOOD WALL PERMEABLE PAVERS SIDEWALK RIO SWALE • r. STORMWATER PUMP AUGMENEATIO'N 9. edsai 1 MHHWL +381' MSL: +'TTh'__. MLLW. r 1.59 Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 1 SWJRE PROPERTIES hail m °"°" & niCh I Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsa OPPORTUNITIES - 2030 .100 YEAR WL: +7.74' WATER DEPTH. 5.9' OYSTER & MUSSEL REEF REVETMENT & GREENWAY (EL: +61 WETLANDS BOARDWALK GEOTUBE HYDRAULIC/TIDAL CONNECTION WETLAND DEPTH: -4.4' SEAGRASS SWIREPROPERTIES hag moffoft & niChol SEAWALL/FLOOD WALL EL: + 10' PLANTER WALL/FLOOD WALL EL: +10' PERMEABLE PAVERS SIDEWALK EL: +7' BIOSWALE 1 edsai 1 MIIHWL +0.95' MSL: •0.16` MLLW- -1.27' Oyster Reef Breakwater Mangrove Wave Absorption Revetment Armoring Near -Shore Berm and Pathway Seagrass and Wetland Storage & Water Quality Benefit Basin Segmented Seawall — Deployables Bioswale Stormwater Collection Permeable Pavement Promenade Planter Wall Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk OPPORTUNITIES-2079 100 YEAR WL: +10.6 WATER DEPTH: 7.9' OYSTER & MUSSEL REEF Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk REVETMENT & GREENWAY (EL: +9') WETLANDS BOARDWALK GEQTUBE HYDRAULIC/TIDAL CONNECTION WETLAND DEPTH: -4.4' SEAGRASS SWIREPROPERTIES hag moffott & nichol rr:f2ED FLOOD PROTECTION AT; EA ALL/FLOOD WALL EL: +12' PLANTER WALL/FLOOD WALL EL: +10' ttPERMEABLE PAVERS SIDEWALK EL: +7' BIOSWALE MHHWL +3.81' MSL: 2.70' MLLW: 1.59' Final elevations TBD based on probabilistic water level assessment, risk tolerance, and allowable overtopping edsai 1 Oyster Growth Matches SLR Mangrove Growth Revetment and Dike Elevation Increase Basin Mangrove Growth Seawall Elevated to Bar Height Pump -Augmented Stormwater System Localized Building Deployable Protection Continues Monitoring of SLR and Science SWIRE PROPERTIES hail m a" & n h I edsa Submitted into the public record for item(s) on 02-11-2021, City Clerk OYSTER REEFS SWIRE PROPERTIES tail moffoil & n;Ghal Submitted into the public record for item(s) D on 02-11-2021, City Clerk edsa 15 REVETMENT & MANGROVES Ni SWIRE PROPERTIES woo moffofl & nIchol Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 16 NI SWIRE PROPERTIES WOO m o f f a f l & n i c h o l WETLANDS / WATER FLOW Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 17 Ni SWIRE PROPERTIES woo moffofl & nIchol REVETMENT & SEGMENTED WALL/ Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 18 SWIRE PROPERTIES tail -.Hatt n i c h a l PROMENADE PLAN VIEW Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsai 19 BRICKELL KEY HI SWIRE PROPERTIES hag mof 1 aft & nic hal OdSa Submitted into the public record for 11..111(.) SWIRE PROPERTIES hail m °"°" & niCh I Submitted into the public record for item(s) DI.3, on 02-11-2021 City Clerk edsa k SWIRE PROPERTIES hjIkg mcffott & nichcl PROMENADE SECTION / edsai Submitted into the public record for item(s) DI.3, 22 SWIREPROPERTIES hdlIkg mcffott & nichcl PROMENADE SECTION edsai Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk! STORMY CONDITION 23 SWIRE PROPERTIES hail m a" & n h I edsa Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk USACE ALTERNATIVE USACE "High" Sea Level Rise Scenario — 2079 Storm Waves and Surge (90% confidence level)* Stormwater-overtopping design deferred to future phase Significant marine -based construction and dewatering SWIREPROPERTIES tail -.Hatt & n;Chal WALL ELEVATION - 2079 Level (with 100-Year Storm): +10.6 NAVD88 2030 Level (with 100-Year Storm): +7.74 NAVD88 Today's Level (with 100-Year Storm): +7.31 NAVDSS Today's Level (No Storm): +2.5 NAVD88 EXISTING OCEAN BOTTOM NEW FILL BASE WIDTH (VARIES) 30'-0" to 35%0" edsai EXISTING BULKHEAD TYPICAL PILES Submitted into the public record for item(s) 01.3, on 02-11-2021, City Clerk 25 AVER SAMPLE LANGUAGE Natural and nature -based features (NNBF) are included in the Mid - Rockaway HFFRRF design as a cost effective erosion control measure which improves natural resiliency. The NNBF include the placement of a stone toe protection and rock sill structures off the existing shoreline to attenuate wave action and allow tidal marsh to establish between the rock sill; and the berm. In some locations, the eroded/degraded shoreline will be regraded or filled to allow for the development of low marsh. XNE W row( Department of State Ni SWIREPROPERTIES lag moffoft & nici,ol Note. for iqustratpurposes oar edsai \ it marsh plants SLOW WATER MOVEMENT ;;;;.44.11,afigithilliiii Submitted into the public record for item(s) on 02-11-2021, City Clerk SAMPLE LANGUAGE NNBFs, or living shorelines, can help reduce the risk of smaller, more frequent coastal storms. They have the added benefit of being inherently resilient, and can fare better and recover on their own more than traditional hard structures in many instances (Gittman et al. 2014). For this reason they are an excellent measure for managing risk from high frequency flooding, if they can be sited appropriately. To meet the objective of improving the system's natural resiliency to storms, the PDT used the following criteria to site NNBFs: The bent must be free at woody vegetation like trees and Phriangekwhich have root systems that can compromise the integrity of the berm_ Howevernative grasses and upland vegetation will help prevent erosion. SWIREPROPERTIES tail" moffotl & nichal Coastal Shoreline Profile & Living Shoreline Treatments rrrequwty flawed ---Flooded - TIDAL MARSH UPLAND BUFFER BANKFACE OOA STA& VAT LA NOS& BEACK STRAND rirpanan Vegc€anon Managerrery Bank Grading fiimr Logs Sown, H,nh Tides & SRenns �..�H19111Twe Lev Tele SAV edsai Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk LIVIRG BREAKWATER SUBTI0AL \EATERS Trdal Marsh Enhancement Tidal Marsh Creation Beach Nourishment & Dune Rsbraton Marsh roe F2er011ent Marsh Sill Marsh MSer Greens Wig Breakwater OBYtore l#rsakwater Systwn dY r Reel Gracri•c coi,leetY Note Err ie:lem rse, Aeeosiekn • Addresses identified clusters of high frequency flooding —because this project has the objective of managing coastal storm risk, not ecosystem restoration, the NNBFs were sited in the areas where they would help manage risk for communities. Traditional restoration projects will restore wetlands and site those efforts based on the ability to maximize the functional habitat values per dollar invested, which can result in restoration being targeted in less developed areas. For NNBFs, the placement is made with consideration for how to best manage risk from coastal storms. ❑ Existing bathymetry and lateral space —a desktop analysis was performed to assess whether there was enough space and appropriate underwater bathymetry offshore to fit an NNBF. If the depths dropped off quickly once offshore, then the bathymetry was not considered to be suitable for the NNBF concept envisioned ❑ Site suitability —consideration was also given to whether the site conditions lent themselves to the appropriate NNBF type being able to persist. If the site has a heavy presence of anthropogenic infrastructure along shoreline (e.g. docks, piers), then that was also not considered a suitable site since it is not feasible to maintain a wetland in conjunction with docks and piers and the heavy traffic that they typically produce. ❑ Wave attenuation and erosion control—NNBFs were particularly considered as a cost effective means for attenuating wave action and thus reducing erosion on a proposed berm. Since the HFFRRFs are designed to be overtopped frequently unless the proposed storm surge barrier is built, they must be designed to withstand the wave action and overtopping they will encounter. Earthen berms, which are made of erodible material, particularly benefit from a wetland and rock sill complex in front of them to help reduce erosion and the required maintenance over time. The NNBF design shown in Figure 5-10 was demonstrated to be more cost effective than a comparably sized floodwall, which is less erodible (Table 5-29). The NNBF design has additional incidental benefits when compared to floodwalls in that they provide habitat, improve local aesthetics, and even improve water quality since wetlands help to filter water. Where berms are the proposed measure, the wetland and rock sill components are integral design features of the overall HFFRRF. SAMPLE LANGUAGE - MBB NiSWIREPROPERTIES lag moffaft & nichol Natural and Nature -Based Features (NNBF) work with or restore natural processes with the aim of wave attenuation and storm surge reduction. For this study, NNBFs considered include mangrove and native vegetation plantings at the Cutler Bay Site (east of Old Cutler Road and south of 184th street extending to southwest 188th street and extending to Biscayne Bay), enhancements or additional construction of dredged material spoil islands in Biscayne Bay, restoration of Submerged Aquatic Vegetation (SAV) in Biscayne Bay, and restoration of Bird Key in Biscayne Bay. Living shorelines and coral reefs were considered as well as possible NNBFs, however, no site -specific locations for these types of NNBFs were identified during plan formulation or during the Environmental Interagency Meetings so these NNBFs were not selected as potential NNBFs for this study and therefore, are not further discussed. Native vegetation plantings were determined to be the most feasible and cost-effective NNBF measure for this project. Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk edsai USACE ALTERNATIVE The Miami -Dade County Back Bay CSRM consists of measures that include structural, nonstructural, and natural and nature -based features (NNBF). An alternative plan is comprised of one or more measures functioning together to address one or more planning objectives. The substantive height of the floodwalls (up to approximately 20 feet from ground surface elevation) at the Brickell Floodwall would obstruct views from Miami to the Biscayne Bay resulting in permanent, significant adverse effects to the visua landscape. Submitted into the public record for item(s) DI.3, on 02-11-2021. City Clerk SWIREPROPERTIES h111114 mcffott & nichcl edsai TEMPORARY CONSTRUCTION IN WATER BASE WIDTH (VARIES) 10' - U' 3Q'-0'ta w FLOOD SIDE AS REQUIRED TO MOT ADVERSELY AFFECT EXISTING BULKHEAD 1110104111,1 11I1IPR-IO�I=E1ICaTElIlSilIIDE —ll 1L 11 111111111 1)1 'K TYPICAL PILES EXISTING BULKHEAD US ARMY CORPS OF ENGINEERS DESIGNED BY: ISSUE DATE: CONTRACT NORFOLK DISTRICT DestIner NO.: 803 FRONT ST.. NORFOLK, VA DRAWN BY: SOLICITATION FILE NUMBER: 23510 Author No.: MIAMI-DADE BACK BAY CSRM CHECKED BY: US MITI Checker i _ 1 STUDY FLOODWALL IN WATER Cor)�s of Engineers 0 . , s Ian lrro aY_ SWIRE PROPERTIES hag moffott & nichol edsai 1 USACE ALTERNATIVE / Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk Structural CSRM measures are man-made, constructed engineering solutions to manage flood risk and reduce damage from coastal storms by physically limiting flood water inundation. This includes measures such as storm surge barriers (which can include miter gates, sector gates, etc.), levees, and floodwalls/ringwalls that are implemented to protect people and property. Structural measures would have any associated pump stations that may be required to ensure there is no flooding being induced as a result of any measure Natural and Natural -Based Features are either natural or constructed features that mimic natural features that provide coastal storm risk reduction benefits such as wave attenuation and storm surge reduction. In addition to more traditional structural and nonstructural features, NNBFs were evaluated to determine if they could potentially be used as stand-alone features or be used in tandem as a multi -dimensional feature with other structural or nonstructural features (measures) to help achieve project objectives. 1 SWJRE PROPERTIES hail m °"°" & niCnni Submitted into the public record for item(s) DI.3, on 02-11-2021 City Clerk edsa Design Considerations + Precedents SWIRE PROPERTIES hag moffott & nichol Design Philosophy • Our NNBF Lens • Holistic, systems approach • Science -based • Sustainable • Adaptive • Probabilistic, Time Based Risk Analysis Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk • Hybrid storm surge risk reduction for Back Bay Area (excluding Miami River) • Brickell Key • Accessible waterfront • Stormwater considerations • Nature based resiliency elements • Performance • Nature -based system to provide equivalent protection over time • Enhance ecological performance — self mitigating • Increase multiple benefits on environmental and social factors 32 edsai 1 OPPORTUNITIES COASTAL RESILIENCY SEA LEVEL RISE RATES IPCC, USACE, High, Medium, Low TIDAL LEVELS When does the storm hit? MMLW? MHHW? WAVE HEIGHTS Return Periods - 50? 100? STORM DIRECTION Direct. Oblique STORM DURATION Overtopping Volume, Pumping Capacity SIMULTANEOUS EVENTS Rain and Waves DETERMINISTIC VS. PROBABILISTIC ANALYSIS OVERTOPPING CRITERIA Zero, Minor, Pumping Capacity ENVIRONMENT HABITAT REGENERATION OR ENHANCEMENT WATER QUALITY IMPROVEMENTS STORMWATER MANAGEMENT GROUNDWATER PROTECTION PROTECTIVE V5, ADAPTIVE APPROACH k SWIREPROPERTIES hag moffott & nichol FUNDING & COMMUNITY FINANCING MODEL PUBLIC ACCESS OPPORTUNITIES SIGHT LINES PROPERTY VALUE CHANGES Park Space and Wetlands vs. Wall edsai Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk 33 CASE STUDIES HUNTER'S POINT SOUTH PARK combines state -of -the art, resilient, and ecologically -sensitive edge treatments with people -focused spaces that engage the waterfront. It uses elevation change to create dynamic experiences above and on the water through observation decks, boardwalks, and sloped lawns. The site couples typical revetment conditions with sustainable planting design tied to the waterfront. LOCATION: Long Island, New York SIZE: 10.3 acres PHOTOS 1 Marsh trail offers visitors an escape from the hustle and bustle of the city. 2 The park's riprap water edge sculpts the shoreline. Existing inflll was re -purposed and moved to the water's edge. 3 Pathways snake along the site's contours and In between newly re -introduced wetlands and the water's edge. Plantings engender a sense of Immersion in nature. 4 Marsh Trail invites visitors to stroll and experience a closer connection to nature, the river, and the shifting views staged with the angular trail layout. 5 A dramatic. cantilevered overlook offers visitors expansive views and the perfect setting for a stroll. chat and photo. Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk SWIREPROPERTIES 1d0011 moffatl & Withal edsaI 34 CASE STUDIES The CHICAGO RIVERWALK is a good example of resiliency incorporated with pubic space. Varying levels of floodable promenades with terraced seating and seat walls all provide flood resilience, and wetlands work to cleanse and infiltrate runoff to improve the water quality of the Chicago River. LOCATION: Chicago, Illinois SIZE: 5.0 acres PHOTOS 1 The .jetty's floating wetlands provide a healthy habitat for the Chicago River's diverse native fish population, as well as educational and recreational opportunities far visitors to observe and interact with the aquatic ecosystem. Elegantly -detailed arid custom high-backed teak benches provide a great place to observe the river and create a dramatic edge to the new Riverwalk promenade. 3 Steps descend to nearly river level in the Marina Plaza providing users direct access to the water. 4 Plantings in the lower tiers are tolerant of inundation; the space was designed to be flooded during a storm event. S Restaurants and outdoor seating provide views of vrhrant life on the water. Submitted into the public record for item(s) DI.3, on 02-11-2021, City Clerk SWIREPROPERTIES hag moffott & niehol edsal 35