Pacific Coastal Salmon Recovery Fund – 2008
Project Proposal Form
I.
Project Title: Sediment Transport in Lower Ship Creek, Anchorage
II.
Project Manager/Principal Investigator:
Thomas M. Ravens
Associate Professor
University of Alaska, Anchorage
School of Engineering
3211 Providence Drive
Anchorage, AK 99508
Phone: 907-786-1943
Fax: 907-786-1079
Email: aftmr@uaa.alaska.edu
III.
Project Start/End Dates [7/1/08 – 6/30/09]
IV.
Project Description and Strategic Importance
1. Introduction
Ship Creek has the largest salmon fishery in the Anchorage area and is very
popular among recreational fishermen and women. Recently, there has been
interest in removing 3 of the 4 dams on Ship Creek (Figure 1).
1 mile
Figure 1. Map of North Anchorage showing Ship Creek and two dam
locations.
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Removal of these dams would increase salmon habitat and aid the
development of a natural fishery in Ship Creek. The fourth (furthest upstream)
dam is part of a secondary water supply system for Anchorage and removal of
this dam is not under consideration. The three dams that might be removed or
modified (in whole or in part) include: the Knik Arm Power Plant (KAPP)
dam, the Elmendorf dam and the Fort Richardson dam. Preliminary plans for
“removal” of all three dams have been developed (Inter Fluve 2007a,b), and
there is funding available for removing the KAPP dam, which is the lowest
dam (Holly Kent, Anchorage Waterways Council, personal communication).
One obstacle to KAPP dam removal is scour/erosion concerns expressed by
the Alaska Railroad which has property and infrastructure on the creek bank
downstream of the dam. There are also scour concerns with respect to the
buttresses of the North C Street Bridge (downstream of the KAPP dam). This
project will examine in detail the proposed dam removal plans and determine
whether there is likely to be enhanced erosion/scour associated with dam
removal. Topographic and sediment data will be collected and flow velocity
and sediment transport models will be developed to gauge the impact of dam
removal.
This project is necessary because it will answer the question about the impact
of dam removal on scour/erosion that has been raised. By answering that
question, this project will allow the KAPP dam removal project to go forward.
More generally, this project would be of assistance in the development of a
Watershed Management Plan for the Ship Creek Watershed.
2. Project Summary
A 3-dimensional flow and sediment transport model (Environmental Fluid
Dynamics Code, EFDC, supported by the EPA) will be developed to
determine whether the hydrodynamic and sediment character of Ship Creek in
the vicinity of and downstream of the KAPP dam is likely to change
significantly as a result of dam removal. The EFDC model can address flow
and sediment transport in tidally influenced creeks (such as Ship Creek), and
it has been widely used throughout the U.S. Removal of the KAPP dam, as
well as Fort Richardson and Elmendorf dam removal/modification scenarios
will be considered. High resolution topographic and bathymetric data will be
taken of the lower portion of Ship Creek (from 400 m north of the KAPP dam
to the creek mouth) allowing a more detailed examination of that area. Output
from an existing 1-dimensional hydrologic model (HEC-RAS, Inter-Fluve,
2007) as well as USGS gauge data and Port of Anchorage water level data
will be used initial and boundary conditions for the model. Both steady state
and unsteady hydrodynamic models will be developed, covering the range of
hydrodynamic phenomena observed in the creek up to the 50 year storm.
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River bank and bridge buttress erosion/scour are directly related to the nearby
creek velocity (Julien, 2002). Examination of velocity distribution under
existing conditions and the velocity distribution following dam removal will,
in part, allow determination of whether dam removal will likely cause
increased erosion/scour of the river banks and bridge buttresses in the lower
reaches of Ship Creek. River bank erosion could also be enhanced if dam
removal leads to sediment deposition below the KAPP dam. Sedimentation in
this reach would tend to reduce the creek cross-sectional area leading to
widening (i.e., bank erosion). Hence, the fate of any dam impounded
sediments that might be mobilized following dam removal will be determined.
An alternative point of view is that scour could be reduced by dam removal as
sediment would be allowed to flow in the creek perhaps satisfying the
sediment carrying capacity of the creek.
This project will examine whether dam removal/modification will lead to
increased scour/erosion in the lower reaches of Ship Creek. Thus, it will
facilitate the proposed KAPP dam removal project as well as the other dam
removal projects. If potential erosion/scour problems are found, it will provide
guidance about what can be done to reduce the vulnerability to erosion/scour.
3. PCSRF Goal(s) and Information Need(s)/Action(s) Addressed by the Project –
This project addresses PCSRF’s Habitat Goal (Goal 1). More specifically, it
addresses information need/action 1B-1: “address fish passage that is
restricted due to culverts, roads and other structures”.
4. Project Justification
A preliminary plan/design for the KAPP removal project was prepared by
Inter-Fluve, Inc. (Hood River, Oregon) in 2007, entitled “Ship Creek – KAPP
Dam Fish Passage and Dam Removal – Preliminary Design.” In addition, an
analysis of alternatives for the removal of Fort Richardson and Elmendorf
dams, entitled: “Ship Creek – Anchorage, Alaska – Fish Passage Improvement
Alternatives Analysis Past Elmendorf and Fort Richardson Dams” was
conducted by Inter-Fluve Inc. The latter study was prepared for the Alaska
Department of Fish and Game. The former was prepared for the Anchorage
Waterways Council.
The proposed study is supported by the Anchorage Waterways Council and
NOAA staff (see attached letters of support). In addition, the study was
discussed with a number of Alaska Department of Fish and Game and
Anchorage Municipality staff who were supportive of the project. Erosion
concerns of the Alaska Railroad need to be met before the KAPP dam
removal project can go forward. This project addresses those concerns. It also
will provide a detailed sediment transport study that will be of general use for
managers of Ship Creek and its watershed.
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V.
Objectives and Methodology
1. Project Objectives
The objectives of the project are: (1) to obtain detailed
bathymetric/topographic data for the lower reach of the Ship Creek (from 400
m above the KAPP dam) to the Creek mouth in Knik Arm, (2) to obtain grain
size distribution data throughout reach, (3) to develop a 3-dimensional
hydrodynamic model of flow in Ship Creek for existing conditions and for
post-dam removal, (4) to estimate sediment transport, geomorphic change, and
scour/erosion throughout the lower reach.
2. Justification of Objectives
Sufficient bathymetric/topographic data and sediment grain size data
(objectives 1 and 2) are prerequisites for any sediment transport study.
Knowledge of the flow field, under the full range of conditions, for existing
conditions and for post-dam scenarios (objective 3), is also necessary to
develop a sediment transport analysis. For example, scour depth at bridge
buttresses is known to be dependent on flow velocity. Calculation of sediment
transport (objective 4) following dam removal is necessary to determine
whether bathymetric/topographic conditions will change in the creek. If
mobilized sediment deposits in the lower reach in significant amount, there
will be an enhanced tendency for creek widening and bank erosion.
3. Project Impacts/Outcomes
The project will generate a large amount of high quality data (on topography,
sediment, flow velocity, and sediment transport) that will be of use to anyone
who is studying flow, sediment transport, and ecology in Ship Creek. In
addition, the study will determine whether there will be any geomorphic
change following dam removal. In particular, the study will determine
whether existing scour/erosion problems will worsen or otherwise change due
to dam removal. It will also determine whether new scour/erosion concerns
are likely to arise.
The EFDC model that we will develop would be useful not only for flow and
sediment transport studies but also for contaminant transport (if there was a
future interest in contaminant transport studies).
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4. Methodology
Methodology for objective 1, surveying:
RTK-GPS will be employed to set up control points throughout the study site
as appropriate. Using the control points, a total station will be used to survey
the lower 1 km of Ship Creek from the Creek mouth to 400 m above KAPP
dam. The cross-creek spacing between grid points will be about 10 m. The
spacing will be about 25 m in the along creek direction. Adjustments will be
made to ensure that the major topographic features are captured by the survey.
Methodology for objective 2, sediment grain size analysis:
Surface sediment samples will be taken and analyzed for grain size
distribution in the lower reach of Ship Creek. Sediment samples will be taken
at 5 equally spaced points on about 10 predetermined cross-sections in the
lower reach. Provided that the sediment is sufficiently fine, grain size
distribution will be determined from sieve analysis.
Methodology for objective 3, flow modeling:
The EFDC flow model will be used to model flow under existing conditions
and following dam removal. The model will be constructed based on the
topographic and sediment data (objectives 1 and 2).
Flow velocity/water level calculations will be calibrated by making
measurements of these variables at various locations under particular flow
conditions. Flow velocity measurements will be made with Acoustic Doppler
Velocimeters (ADV’s), and/or an Acoustic Doppler Current Profiler (ADCP).
USGS gauge data, HEC-RAS flow model results, and water level
measurements at the Port of Anchorage will be used to develop boundary and
initial conditions.
Methodology for objective 4, sediment transport calculation:
The sediment transport module of EFDC will be used to calculate bedload and
suspended load transport. Water samples will be collected under particular
conditions to calibrate the sediment transport calculations. EFDC will
calculate scour and deposition throughout the model domain. All model
calculations will be checked by hand, taking advantage of the vast literature
on bridge and bank scour and erosion. In addition, we will paint and monitor
gravel and cobble in the stream bed to see if they are mobilized by particular
hydrologic events.
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VI.
Results/Deliverable Products
1. Deliverables
Deliverables include: a topographic survey of the lower reach of Ship Creek,
sediment grain size data, a calibrated flow model, a set of sediment transport
calculations, as well as a final report.
2. Outreach and Communication
We will be in communication with the Anchorage Waterways Council and the
Dept. of Fish and Game throughout the project. In addition, we will present
our findings to the Anchorage Watershed Task Force. The Watershed Task
Force is an inter-agency body including state and federal agencies and
stakeholders (e.g., the U.S. military, Alaska Railroad and Anchorage
Waterways Council). The Task Force reports to the Mayor of Anchorage. In
addition, we will present our findings at a suitable conference. A number of
dam removal projects have been undertaken in the U.S. and we will network
with the associated PI’s (e.g., Tim Purinton, Massachusetts Riverways
Program).
VII.
Benefits to Salmon/Salmon Fisheries/Salmon Fishers/Communities
This project will benefit salmon fisheries/fishers/communities by helping to
restore salmon habitat. The dams on Ship Creek are preventing salmon migration.
This project will help facilitate dam removal by helping managers understand the
consequences of dam removal.
VIII. Project Duration/Milestones/Timelines
The project has a one year duration, from July 1, 2008-June 30, 2009. Major
milestones are listed below:
Project start date:
July 1, 2008
Completed survey of the lower reach of Ship Creek:
Sept. 1, 2008
Completed sediment sampling:
Oct. 1, 2008
Completed sediment grain size analysis
Nov. 1, 2008
Flow model completed:
Jan. 1, 2009
Sediment transport calculations completed:
June 1, 2009
Final report:
June 30, 2009
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Each major activity is dependent on the successful conclusion of the previous
activity. Monitoring of progress will involve determining whether we are keeping
pace with the schedule indicated above.
IX.
Experience and Qualifications
1. Experience/Qualifications of Principal Investigator(s) and Key Project
Personnel
PI: Dr. Thomas M. Ravens
Dr. Ravens, Associate Professor, joined the University of Alaska, Anchorage
faculty in the School of Engineering in June 2007, after receiving tenure at
Texas A&M University.
Between 2000 and 2007, Dr. Ravens managed about $1 million in research
projects while an Assistant/Associate Professor at Texas A&M University,
Galveston. These projects were mainly funded by Texas Sea Grant, Texas
General Land Office, US Army Corps of Engineers, and Galveston County.
All of these projects were successfully and satisfactorily completed. These
projects included survey projects, as well as hydrodynamic and sediment
transport projects. For example, Dr. Ravens supervised and participated in
numerous large-scale survey projects such as the 60 km long, 2003 Galveston
Island (Texas) beach survey project for the U.S. Army Corps of Engineers and
Galveston County. This project involved the use of RTK-GPS (Real Time
Kinematic GPS) as well as a total station. In addition, Dr Ravens has
conducted numerous investigations of hydrodynamics and sediment transport
including studies of shoreline erosion (Ravens and Sitanggang, 2007; Ravens
et al., accepted with revisions), studies of hydrodynamics and sediment
transport in creeks, rivers, and estuaries (Ravens and Gschwend, 1999;
Ravens and Kushwaha 2005, Ravens 2007, Ravens and Thomas, in press),
and computational and laboratory studies of sediment transport (Ravens and
Jepsen, 2006; Ravens and Sindelar, accepted) . Dr. Ravens has supervised
numerous graduate and undergraduate research assistants.
2. Sustainability
The project objectives will be met during the duration of PCSRF funding.
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X.
Partners
1. Project Partners
We will work in cooperation with the Alaska Dept. of Fish and Game. We
have contacted several Fish and Game staff directly involved with the Ship
Creek dam removal issue (e.g., Matt Miller). In addition, we will work in
cooperation with the Anchorage Waterways Council who is representing the
community’s interest in dam removal. We will contact appropriate staff at the
Alaska Railroad to make sure that their concerns are being met.
2. Local Partnerships and Capacity Building
We hope that this project will develop new partnerships between the
University of Alaska Anchorage (UAA) and the Alaska Dept. of Fish and
Game as well as with the Anchorage Waterways Council and the Anchorage
Municipality. UAA is intent on being engaged with and responsive to the
needs of the community.
XI.
Budget [by line item, by fiscal year]
1. PCSRF Budget Request
Budget Summary Chart:
FY09
100 Personnel
200 Travel
300 Contractual
400 Supplies
500 Equipment
Total Direct Costs
Indirect Costs:
62,493
1,200
500
64,193
14,239
Total
62,493
1,200
500
64,193
14,239
Budget Narrative:
Personnel costs include the PI salary ($18,586 = 2.0 mo. @9293/mo), grad
student salary ($20,880, for 12 months), undergrad student salary ($8352 for 3
months), fringe benefits ($7831), and tuition for grad student ($7236).
Travel cost covers the cost of site visits for survey work ($200), as well as the
cost to attend a conference to present the research results ($1000).
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Supplies cost covers the cost of sample jars for sediment sampling and stakes
for surveying.
The indirect cost is 25% of the non-tuition direct costs.
2. Leveraging Non-PCSRF Resources
This project will require the use of survey equipment and velocity
measurement equipment for extended periods of time. Use of this equipment
represents an in-kind contribution of about $10,000.
XII.
Date Prepared [12/30/07]
References:
Julien, P. Y. 2002. River Mechanics. Cambridge University Press.
Inter-Fluve, 2007a. Ship Creek – KAPP dam Fish Passage and Dam Removal –
Preliminary Design.
Inter-Fluve, 2007b. Ship Creek – Anchorage, Alaska – Fish Passage Improvement
Alternatives Analysis Past Elmendorf and Fort Richardson Dams.
Ravens, T. M. 2007. Comparison of two techniques to measure sediment erodibility in
the Fox River, Wisconsin. J. of Hydraulic Engineering-ASCE, 133(1): 111-115.
Ravens, T. M., and P. M. Gschwend. 1999. Flume measurements of sediment erodibility
in Boston Harbor. J. Hydraulic Engineering 125: 998-1005.
Ravens, T. M., and R. A. Jepsen. 2006. CFD analysis of flow in a straight flume for
sediment erodibility testing. J. of Waterway, Port, Coastal, and Ocean EngineeringASCE, 132(6):457-461.
Ravens T. and Kushwaha, V. 2005. Design of Tidal Creeks for Beneficial Use Marshes.
MTS/IEEE Oceans 2005 conference, Washington D. C., Sept. 19-23.
Ravens, T. M. and M. Sindelar. Flume Test Section Length and Sediment Erodibility. J.
of Hydraulic Engineering (accepted).
Ravens, T. M., and K. I. Sitanggang. 2007. Numerical modeling and analysis of shoreline
change on Galveston Island. J. of Coastal Research, 23(3): 699-710.
Ravens, T. M. and R. C. Thomas. Ship wave-induced sedimentation of a tidal creek in
Galveston Bay. J. of Waterway, Port, Coastal, and Ocean Engineering (in press).
PCSRF Project Proposal Form
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Ravens, T. M., Thomas, R. C., Roberts, K. A., and P. H. Santschi. Causes of Salt Marsh
Erosion in Galveston Bay, Texas. J. of Coastal Research (accepted, with revisions).
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ANCHORAGE WATERWAYS
P.O. BoxCOUNCIL
241774  Anchorage, Alaska 99524-1774  272-7335  Fax:
277-9207
http://www.anchoragecreeks.org
Sue Aspelund
Alaska Department of Fish & Game
PO Box 115526
Juneau, Ak 99811-5526
Re: Letter of support for UAA grant proposal
Sediment Transport Study of lower
Ship Creek
Ms. Aspelund,
The Anchorage Waterways Council is a non-profit organization working to protect, restore, and
enhance the creeks, wetlands, and associated uplands of Anchorage. We have spent several years
and close to $1M collecting information, compiling data, educating citizens, and facilitating
interagency and stakeholder communication within the Ship Creek Watershed. We have always
advocated for the development of a Watershed Management Plan for the Ship Creek Watershed
and to that end we are happy to collaborate with Tom Ravens on his project to study the sediment
transport mechanisms for lower Ship Creek.
Our role in this project will be to provide background information and data on the resource,
facilitate participation and contributions from the federal, state, and local resource agencies, and
to help in dissemination of the project results to stakeholders and the general public. The AWC
has a long history of facilitating interagency discussions on watershed issues in Anchorage and
specifically for the Ship Creek Watershed. We feel that we would bring a very strong
communication component to this project.
The AWC is a member of the Mayor’s Watershed Task Force which meets monthly to discuss
watershed issues in our community. We will work with Mr. Ravens to coordinate a presentation
of project results to the task force.
Thank you for your consideration of this proposal to provide valuable information on the Ship
Creek Watershed that will be used in the future for development of a watershed management
plan.
Sincerely,
Holly Kent
Executive Director
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