Pacific Coastal Salmon Recovery Fund 2007

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: [email protected]

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.

PCSRF Project Proposal Form Page 1 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.

PCSRF Project Proposal Form Page 2 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.

PCSRF Project Proposal Form Page 3 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).

PCSRF Project Proposal Form Page 4 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.

PCSRF Project Proposal Form Page 5 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

PCSRF Project Proposal Form Page 6 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.

PCSRF Project Proposal Form Page 7 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 Total 100 Personnel 62,493 62,493 200 Travel 1,200 1,200 300 Contractual - - 400 Supplies 500 500 500 Equipment - - Total Direct Costs 64,193 64,193 Indirect Costs: 14,239 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).

PCSRF Project Proposal Form Page 8 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 Engineering- ASCE, 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 Page 9 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).

PCSRF Project Proposal Form Page 10 ANCHORAGE WATERWAYS COUNCIL P.O. Box 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

PCSRF Project Proposal Form Page 11 PCSRF Project Proposal Form Page 12