Hunts Point Landing, Bronx, New York Sustainable Shorelines in an Urban Environment John Roebig, PhD. HDR Engineering, Inc. John.Roebig@hdrinc.com Promoting Resilient Shorelines along the Hudson River Estuary: Sustainable Shorelines Project - November 7, 2012
What you will hear Project Background Hardened Shorelines vs. Living Shorelines Functions and Values of Salt Marshes Data collection and Site Constraints Salt Marsh Elements Lessons Learned
Hunts Point Landing, Bronx, NY
Project Background Hunts Point as it appeared in 1952
South Bronx Greenway
South Bronx Greenway
EXISTING PROPOSED
EXISTING PROPOSED
Existing Conditions Hunts Point Landing
Existing Conditions Hunts Point Landing
Coastal Wetlands Living Shorelines Tidal Salt Marsh dominated by grasses-spartina
Functions and Values of Wetlands-Salt Marsh Annual gross and net primary productivity High productivity-subsides in the form of tides, nutrient imports and abundance of water. Water Quality Improvement Nutrient removal Fish and Shellfish Habitat Spawning areas Wildlife Habitat Food, Shelter, Nesting Sediment and Shoreline Stabilization Stabilization of shorelines against erosion.
Shoreline Protection Sediment Stabilization Tidal Salt Marsh
Sediment Stabilization Sediment Stabilization
Values of Wetlands Recreation Fishing Hunting Observing wildlife Education and Research Educational opportunities Scientific studies Open Space and Aesthetics Visual enjoyment; great diversity and beauty Hurricane Protection
Flood Reduction Hurricane Protection Reduction in the depth of flooding as hurricanes Hilda and Betsy swept inland across coastal marshes in Louisiana.
Native Marsh vs. Hardened Shorelines Diversity and Abundance of Benthic In Fauna Adjacent to Shoreline Types
Data Collection Site Constraints I. Water Quality Data Bronx River CSO Study Intensive Surveys NYCDEP Harbor Survey Data II. Velocity Data Bronx River CSO Study Velocity Survey
Observed Velocity Measurements in Bronx River
HUNTS POINT SALINITY ANALYSIS Resulting salinity in lower basin (ppt) Winter Summer Spring Tide 15.5 18.7 Mean Tide 15.0 18.0
Plant Tolerances to Salinity Levels Scientific name Common name Location Optimum Salin ity Pannicum virgatum Switchgrass Above MHW Low salt tolerance Phragmites australis Common reed Above MHW High salt tolerance Scirpus pungens Common three square Intertidal (upper 50% or mid-tide to MHW) Low salt tolerance Low salinities Salinity Tolerance <10 ppt. 10-14 up to 20 ppt Low salinities <10 ppt. Scirpus rubustus Saltwater bullrush Intertidal (upper 50% or mid-tide to MHW) Spartina alterniflora Smooth cordgrass Intertidal (upper 50% or mid-tide to MHW) High salt tolerance High salt tolerance up to 25 ppt 10-20 ppt up to 60 ppt Spartina cynosuroides Spartina patens Big cordgrass Above MHW Low salt tolerance Saltmeadow cordgrass Above MHW High salt tolerance <10 ppt. up to 26 ppt Typha angustifolia Narrow leaved cattail. Intertidal (upper 20%) Low salt tolerance <10 ppt.
Wave Analysis Hunts Point Landing
Fetch Analysis Open water fetches greater than 1.6 km (1.0 miles) need protection along with Maximum Wind Speed Evaluation.
Design Guidance Wave Protection Design Guidance: Protect against open water fetches by design or other protections
Hudson Raritan Estuary
Hudson Raritan Estuary
Salt Marsh Development over accumulated sediment on a sand flat and over upland under the influence of rising sea level. In high energy environments; Shoreline design needs to provide some wave energy protection along with the ability to accommodate sea level rise.
Turtle Cove
Pelham Bay
Rocks in the High Marsh Pelham Bay Salt Marsh
Accommodation of Sea Level Rise Pelham Bay Salt Marsh
Rocks in the High Marsh Pelham Bay Salt Marsh
Alley Park Restoration
Rocks on the High Marsh Placeholder slide Alley Park Fresh and Salt Marsh
Design standard 0 High Marsh Low Marsh Bay Spartina patens (salt marsh hay) Tide range= 7.2 ft MHW Substrate TSS, Metals Midtide MLW 100
Design Guidance Wave Protection HP Landing Shoreline Section Showing Hollow Block Option Hunts Point Site C First Operable Unit
Design
Recreational values
Recreational value
Educational values
Educational values
Recreational Values
Visual Values
Design for Extreme Events
Effects of Hurricane Sandy
Effects of Hurricane Sandy
Effects of Hurricane Sandy
Effects of Hurricane Sandy
Effects of Hurricane Sandy
Effects of Hurricane Sandy
Lessons Learned Field/Data Required Existing Conditions Establish Goals Design to Realistic Functions and Values Connect to Other Areas Maximize Soft Shorelines and Area Plan for extreme events. Urban areas will require maintenance.
Questions?