New Jersey Water Supply Authority 1 NEW JERSEY WATER SUPPLY AUTHORITY Dredging of the Delaware and Raritan Canal from Kingston to Amwell Road Public Open

New Jersey Water Supply Authority1

NEW JERSEY WATER SUPPLY AUTHORITYDredging of the Delaware and Raritan Canal from Kingston to Amwell Road

Public Open House

December 13, 2010

New Jersey Water Supply Authority

New Jersey Water Supply Authority Henry Patterson Ed Buss Sharmila Rahman

Urban Dredging Consultants Joint Venture Ram Mohan Robert DeLorenzo

Other Joint Venture Members Carol Beske – ACT Engineers Eric Rosina – ACT Engineers Lynn Brass-Smith – Amy S. Greene

Environmental Consultants, Inc.

URS Anthony McNichol

Introductions


Dredging of the Delaware and Raritan Canal from Kingston to Amwell Road

Introductions

Primary objective, goals, and critical elements

Dredging technologies evaluated

Sediment characteristics and beneficial reuse

Phasing of construction

Traffic control

Agenda

Cultural resource investigation

Permitting requirements

Environmental information document and public hearing

Public outreach

Project schedule

Open discussion



Project Objective Remove an estimated 250,000 cubic yards of

sediment from the Canal in order to restore its flow capacity

Project Goals Protect the historical integrity

of the Canal

Maintain technical quality

Maintain water supply

Critical Project Elements Develop dredging plan acceptable

to stakeholders

Focused outreach to public officials and stakeholders



Project Area



Dredging Technologies Evaluated

Dry Excavation Mechanical Dredging Hydraulic Dredging



Pre-Sediment Removal Activities Tree Trimming

Trimming trees to allow equipment access to sediment

Submerged Aquatic Vegetation (SAV) Removal Remove SAV to prevent clogging of

sediment removal equipment

Debris Removal Remove debris to maximize sediment

removal production



Dry Excavation Canal separated into reaches

varying in manageable lengths

Each Reach with Access Area and Truck Ramp

Flow Bypassed through Work Area (portadam or other structure with piping to convey flow into the Millstone)

Flow diversion structures to facilitate removal on short notice to safeguard against high flow (flood) events



Dry Excavation (cont.) Low-ground pressure excavators

and dozers used to excavate sediment

Sediment within the dewatered Canal section will be reworked and air dried prior to excavation

Allows for higher degree of accuracy during removal (increased volume control)

Requires intensive water management operations



Mechanical Dredging Conducted in the wet using

hydraulic excavator operating from shallow-draft barge or flexi-float system

Hydraulic clamshell bucket to be used on dredge to minimize turbidity (1-3 cubic yard bucket)

Dredge maneuvering with non-penetrative methods (anchors, guidelines, etc.)



Mechanical Dredging (cont.) Dredged sediment to be placed

into 10-20 cy scows or 20 cubic yard containers on flexi-floats

Scows unloaded to trucks or hydraulically pumped to dewatering area

Sediment dewatered by air-drying, stabilization, geobags, or mechanical dewatering system

Potential for multiple dredge units operating simultaneously



Hydraulic Dredging Conducted in the wet using

hydraulic cutterhead dredge

Requires separate Submerged Aquatic Vegetation (SAV)/debris removal operations prior to dredging to prevent clogging

Dredge maneuvering with non-penetrative methods (anchors, guidelines, etc.)

Booster pumps required to facilitate transport of dredged sediment through plastic pipeline to dewatering area



Hydraulic Dredging (cont.) Dredged sediment to be

dewatered using geobags or mechanical dewatering system

High comparative production rate

Water generation significantly more than other investigated removal methods

Requires extensive water treatment/water management operations



Sediment Dewatering/Stabilization Technologies evaluated:

Air-drying Stabilization Geotextile tubes Centrifugation (hydrocyclones) Mechanical presses (belt filter, plate and frame) Rapid dewatering



Air-Drying Allow dredged sediment to

passively dewater by gravity draining and evaporating water from stockpiled sediment

Small dozer to work sediment to increase speed of dewatering

Stabilization Blend dredged sediment with

portland cement or other material to absorb free water



Geotextile Tubes Pump dredged sediments through HDPE

pipeline directly to geotextile tubes

Dose polymers to increase dewatering efficiency

Following dewatering, cut tubes and excavate material

Produce “truckable” material

Centrifugation (Hydrocyclones) Quickly separate solids from a slurry

Typically only the initial step in a series of dewatering procedures



Mechanical Presses (Belt Filter, Plate and Frame) System receives sediment slurry

Use combinations of presses to extract free water from sediment

Produces “truckable” material

Rapid Dewatering System receives sediment slurry

Use multiple steps and dewatering polymers to rapidly separate solids and reduce water content of sediment

Produces “truckable” material



Sediment Characteristics and Beneficial Reuse

Frequently Detected Compounds/Constituents

32 individual samples Represent vertical

average at each location

Gravel = 6% Sand = 29% Silt/Clay = 63% Organics = 2%



Phasing of Construction Number of reaches

Reach delineation

Reaches dredged in Year 1 (2013)

Reaches dredged in Year 2 (2014)

Intermediate reaches (minimize disruptions to recreational boaters-canoe rental)

Signage Towpath and Road Detours



Conceptual Traffic Routes



Section 106 of the National Historic Preservation Act: Cultural Resources Investigations and SHPO Review



Section 106 Review of the NHPA – requires the consideration of potential adverse effects on cultural resources within the project areaAs the consultant, URS will conduct a Phase IA Background Research Investigation, identifying areas of potential sensitivity within designated project footprints

Phase IA report is submitted to the New Jersey State Historic Preservation Office for comment and consultation

The SHPO then makes recommendations to the client for the treatment of resources within a given Area of Potential Effect (APE)

These recommendations may include one or more of the following: No impact, limited subsurface testing, or on-site monitoring during

project implementation

URS carries out Phase IB Investigations within the Project Area



Potential Resources within the Dredging Project Area Features directly associated with the Canal:

Clay liner

Rip-rap

Armor stone

Waste weirs

Dams

Spillways

Wharves and dock features

Slips and scuttled vessels



Potential Resources within the Dredging Project Area Historic Structures and Archeological Resources



Potentially Required Permits U.S. Army Corps of Engineers

Delaware and Raritan Canal Commission

NJ Department of Environmental Protection Freshwater wetlands Flood hazard area No net loss reforestation Water lowering Fish stocking Water Quality Certification Section 106 consultation

Somerset-Union County Soil Conservation District NJPDES Construction Soil erosion and sediment

control



Level II Environmental Information Document Key Environmental Issues

Public use

Surface water

Floodplains and riparian zones

Biotic (plant and animal communities)

Forest

Wetlands

Threatened and endangered species

Cultural resources

Impact on water users


Staging Area and Site Access Selection Process Wetland Investigation Secondary source data

Preliminary field investigation

Wetland delineation and survey




Project Schedule



Public Officials Briefings: July, September, FebruaryMontgomeryRocky HillFranklin TownshipHillsboroughSouth BrunswickMillstone BoroughSomerset County

Coordination MeetingsNJDEPD&R Canal State ParkD&R Canal CommissionD&R Canal interest groups briefing



D&R Canal Interest Groups Mapleton Preserve Commission Millstone Valley Preserve Coalition Kingston Historical Society Kingston Village Advisory Committee Raritan Millstone Heritage Alliance Somerset County Cultural Heritage Meadows Foundation Griggstown Historical Society Griggstown Canoe Canal Society of New Jersey D&R Canal Watch

Future Meetings: February 2011 Public officials briefings Public hearing



http://www.njwsa.org/html/canaldredging.html

View NJWSA Website for Continuing Project Updates


Open Discussion

Documents

New Jersey Water Supply Authority 1 NEW JERSEY WATER SUPPLY AUTHORITY Dredging of the Delaware and Raritan Canal from Kingston to Amwell Road Public Open