Hydraulic Design Nome & Port Clarence, Alaska

108 Pages·2014·10.42 MB·English

Alaska Deep Draft Arctic Port System
Feasibility Study

Appendix A - Hydraulic Design

Nome & Port Clarence, Alaska

January, 2015

U.S. Army Corps
of Engineers
Alaska District

CONTENTS
1.  INTRODUCTION .................................................................................................................. 1 
1.1  Appendix Purpose ............................................................................................................ 1 
1.2  Project Purpose and Needs Assessment ........................................................................... 1 
2.  SITE SELECTION ................................................................................................................. 2 
3.  PORT OF NOME ................................................................................................................... 3 
3.1  Existing Facilities ............................................................................................................. 3 
3.1.1  Causeway .................................................................................................................. 4 
3.1.2  Seawall ...................................................................................................................... 5 
3.1.3  Main and Spur Breakwaters ...................................................................................... 6 
3.1.4  Entrance Channel and Turning Basin ....................................................................... 7 
3.1.5  Small Boat Harbor .................................................................................................... 7 
3.1.6  Harbor Bulkheads ..................................................................................................... 7 
3.2  Climatology ...................................................................................................................... 8 
3.3  Water Levels, Currents, and Waves ................................................................................. 8 
3.3.1  Tides .......................................................................................................................... 8 
3.3.2  Sea Level Rise ........................................................................................................... 8 
3.3.3  Storm Surge ............................................................................................................ 10 
3.3.4  Set-Down ................................................................................................................ 11 
3.3.5  Currents ................................................................................................................... 11 
3.3.6  Wave Climate .......................................................................................................... 12 
3.4  Hydrology....................................................................................................................... 14 
3.5  Ice Conditions ................................................................................................................ 15 
3.6  Sedimentation ................................................................................................................. 15 
4.  PORT CLARENCE .............................................................................................................. 17 
4.1  Climatology .................................................................................................................... 17 
4.2  Water Levels .................................................................................................................. 17 
4.2.1  Tides ........................................................................................................................ 17 
4.2.2  Sea Level Rise ......................................................................................................... 17 
4.2.3  Storm Surge ............................................................................................................ 18 
A-i
4.2.4  Set Down ................................................................................................................. 18 
4.3  Ice Conditions ................................................................................................................ 18 
5.  POINT SPENCER ................................................................................................................ 20 
5.1  Existing Facilities ........................................................................................................... 20 
5.2  Waves and Currents ....................................................................................................... 21 
5.2.1  Currents ................................................................................................................... 21 
5.2.2  Wave Climate .......................................................................................................... 21 
5.2.3  Hydrology ............................................................................................................... 24 
5.2.4  Coastal Flooding ..................................................................................................... 24 
6.  CAPE RILEY........................................................................................................................ 25 
6.1  Existing Facilities ........................................................................................................... 25 
6.2  Waves and Currents ....................................................................................................... 25 
6.2.1  Currents ................................................................................................................... 25 
6.2.2  Wave Climate .......................................................................................................... 25 
6.3  Hydrology....................................................................................................................... 26 
7.  DESIGN CRITERIA ............................................................................................................ 28 
7.1  Design Vessel and Fleet ................................................................................................. 28 
7.1.1  Oil and Gas Exploration .......................................................................................... 28 
7.1.2  Resource Extraction ................................................................................................ 28 
7.1.3  Search and Rescue .................................................................................................. 28 
7.1.4  Support .................................................................................................................... 28 
7.1.5  Research .................................................................................................................. 29 
7.2  Allowable Wave Heights ............................................................................................... 29 
7.2.1  Port of Nome ........................................................................................................... 29 
7.2.2  Point Spencer .......................................................................................................... 30 
7.2.3  Cape Riley ............................................................................................................... 30 
7.3  Channel and Basin Widths and Depths .......................................................................... 30 
7.3.1  Port of Nome ........................................................................................................... 30 
7.3.2  Point Spencer .......................................................................................................... 33 
7.3.3  Cape Riley ............................................................................................................... 34 
7.4  Circulation ...................................................................................................................... 35 
A-ii
7.5  Ice Forces ....................................................................................................................... 36 
7.5.1  Port of Nome Ice Forces ......................................................................................... 36 
7.5.2  Point Spencer and Cape Riley Ice Forces ............................................................... 37 
7.6  Life-Cycle Causeway Extension/Breakwater Design .................................................... 37 
7.6.1  Port of Nome Life-Cycle Design ............................................................................ 37 
7.6.2  Point Spencer and Cape Riley Life-Cycle Design .................................................. 38 
7.7  Dredging ......................................................................................................................... 38 
8.  MODEL STUDIES ............................................................................................................... 39 
8.1  Physical Modeling .......................................................................................................... 39 
8.2  Numerical Modeling ...................................................................................................... 40 
8.2.1  Elevation Data ......................................................................................................... 40 
8.2.2  Boundary Wave and Water Level Conditions ........................................................ 40 
8.2.3  Port Clarence STWAVE Model .............................................................................. 43 
8.2.4  Point Spencer STWAVE Models and Results ........................................................ 45 
8.2.5  Cape Riley STWAVE Models ................................................................................ 46 
8.3  Point Spencer Unprotected Site Availability ................................................................. 47 
8.3.1  Wind Analysis ......................................................................................................... 47 
8.3.2  Percent Availability Analysis ................................................................................. 47 
9.  ALTERNATIVES................................................................................................................. 49 
9.1  Port of Nome Expansion ................................................................................................ 49 
9.1.1  Outer Entrance Channel and Maneuvering Area .................................................... 50 
9.1.2  Wave Heights .......................................................................................................... 51 
9.1.3  Circulation............................................................................................................... 51 
9.1.4  Shoaling .................................................................................................................. 51 
9.1.5  Construction Dredging ............................................................................................ 51 
9.1.6  Dredged Material Disposal ..................................................................................... 52 
9.1.7  Maintenance Dredging ............................................................................................ 52 
9.1.8  Causeway and Main Breakwater Extension Design ............................................... 53 
9.1.9  Concrete Caisson Dock Design .............................................................................. 55 
9.1.10  Steel Sheet Pile Modified Diaphragm Dock Design ............................................... 55 
9.1.11  Uplands ................................................................................................................... 56 
A-iii
9.1.12  Entrance Channel Navigation ................................................................................. 56 
9.2  Point Spencer Harbor ..................................................................................................... 56 
9.2.1  Site Selection .......................................................................................................... 56 
9.2.2  Alternative Design .................................................................................................. 58 
9.2.3  Entrance Channel and Maneuvering Area .............................................................. 59 
9.2.4  Wave Heights .......................................................................................................... 59 
9.2.5  Circulation............................................................................................................... 59 
9.2.6  Shoaling .................................................................................................................. 59 
9.2.7  Construction Dredging ............................................................................................ 60 
9.2.8  Dredged Material Disposal ..................................................................................... 60 
9.2.9  Maintenance Dredging ............................................................................................ 61 
9.2.10  Causeway Design .................................................................................................... 61 
9.2.11  Concrete Caisson Dock Design .............................................................................. 62 
9.2.12  Uplands ................................................................................................................... 63 
9.2.13  Bulk Petroleum Product Storage Facilities ............................................................. 63 
9.2.14  Crew Facilities ........................................................................................................ 63 
9.2.15  Water Supply .......................................................................................................... 63 
9.2.16  Sewage Treatment and Solid Waste Management .................................................. 64 
9.2.17  Airport ..................................................................................................................... 64 
9.2.18  Road ........................................................................................................................ 64 
9.3  Cape Riley ...................................................................................................................... 64 
9.3.1  Site Selection .......................................................................................................... 64 
9.3.2  Alternative Design .................................................................................................. 65 
9.3.3  Entrance Channel and Turning Basin ..................................................................... 65 
9.3.4  Wave Heights .......................................................................................................... 65 
9.3.5  Circulation............................................................................................................... 66 
9.3.6  Shoaling .................................................................................................................. 66 
9.3.7  Construction Dredging ............................................................................................ 66 
9.3.8  Dredged Material Disposal ..................................................................................... 67 
9.3.9  Maintenance Dredging ............................................................................................ 67 
9.3.10  Breakwater Design .................................................................................................. 67 
A-iv
9.3.11  Concrete Caisson Dock Design .............................................................................. 68 
9.3.12  Uplands ................................................................................................................... 68 
9.3.13  Road ........................................................................................................................ 68 
10.  PROJECT IMPLEMENTATION ...................................................................................... 69 
10.1  Breakwaters and Causeways ...................................................................................... 69 
10.2  Dredging ..................................................................................................................... 69 
10.3  Caisson Dock .............................................................................................................. 69 
10.4  Local Service Facilities .............................................................................................. 70 
10.5  Aids to Navigation ...................................................................................................... 70 
10.6  Construction Schedule ................................................................................................ 71 
10.6.1  Port of Nome Schedule ........................................................................................... 71 
10.6.2  Point Spencer Port Schedule ................................................................................... 71 
10.6.3  Cape Riley Harbor Schedule ................................................................................... 71 
11.  OPERATIONS AND MAINTENANCE ........................................................................... 73 
11.1 Port of Nome Expansion ............................................................................................... 73 
11.2 Point Spencer ................................................................................................................. 74 
11.3 Cape Riley ....................................................................................................................... 74 
12.  RECOMMENDED FURTHER DESIGN STUDIES ........................................................ 75 
13.  REFERENCES .................................................................................................................. 76 
14.  Attachments (Figures) ........................................................................................................ 79 

A-v
A-vi
1. INTRODUCTION
1.1 Appendix Purpose
This appendix describes the technical aspects of proposed navigation improvements to the Port
of Nome, Point Spencer and Cape Riley, Alaska. It provides the engineering background
information for determining the Federal interest in the major construction features including
causeways, breakwaters, channel improvements, and support facilities. Existing data was
gathered and analyzed to determine site characteristics, and numerical modeling was performed
to determine the physical impacts of the wave climate and ice conditions for design of the
proposed navigation improvements.
1.2 Project Purpose and Needs Assessment
The following objectives were identified for navigation improvements at Nome, Point Spencer,
and Cape Riley.
a. Provide safe and more efficient improvements for the various design fleets.
b. Provide facilities for fuel barges, US Coast Guard vessels, oil and gas support vessels,
and resource extraction vessels for which current depths and facilities are not
available.
c. Reduce travel delays and increase port operation efficiencies.
The project purpose is to provide a safe and efficient arctic port facility in an environmentally
sound manner that satisfies the above objectives.

A-1
2. SITE SELECTION
This study encompasses three sites on the Seward Peninsula; the Port of Nome, Point Spencer at
the entrance to Port Clearance, and Cape Riley to the southwest of Teller as shown in Figure 1.
These sites were selected through a charrette process that included stakeholders at the Federal,
State and local levels. The charrette considered many sites in the region and settled upon the
three sites evaluated in this study. The study compares the potential use of these sites as stand-
alone projects or combination projects with multiple sites used to cover a range of missions and
economic activities. Only one alternative design was considered for each site or combination of
sites. In each case the alternatives were considered to be the optimal designs for their intended
use by the project delivery team (PDT). The selected alternative will be refined in further detail
during the preliminary engineering design (PED) phase.
TELLER
CAPE RILEY
POINT SPENCER
SEWARD PENINSULA
BERING SEA
NOME

Figure 1: Site locations. Detail from NOAA Chart 16200, Norton Sound to Bering Strait.
Annotation Added. The latitude lines on this chart are 30 minutes apart, equivalent to 30
nautical miles or approximately 34.5 statute miles.

A-2