1. Project Title: Burns Harbor Major Rehabilitation - Submerged Breakwater Reefs
2. Contact
Philip B. Moy, Fisheries Biologist
Chicago District, US Army Corps of Engineers, 111 N. Canal Street,
Chicago, IL 60606-7206, USA
Tel.: (312) 886-0451; FAX: (312) 353-1271; E-mail: nccpdpbm@smtp.ncd.uace.army.mil
3. Agencies Involved
Chicago District Corps of Engineers
Burns Harbor Port Authority
Indiana Department of Natural Resources (IDNR)
Illinois Natural History Survey (INHS)
4. Restoration Goal
To increase the amount of spawning area available for lake trout which are known to spawn in the immediate vicinity.
5. Project Type
Breakwater improvement - to reduce the wave energy and increase navigation safety.
6. Background and Rationale
The submerged reefs will be 1ocated 22.8 m north (toe-to-toe) of the existing breakwater at Burns Harbor, Portage, Indiana (Figure 1). The primary purpose of the project was to reduce damages to shipping and maintenance costs by attenuating wave energy associated with waves greater than 5 m in height before they strike the existing breakwater.
The submerged reefs will be composed of large armor stone which will provide incidental fish habitat. The bedding stone, which separates the heavy armor stone from the underlying sand, will extend 3 m from the base of the reef. The size of the bedding stone was modified from the original proposal to provide better spawning substrate for lake trout.
7. Regulatory Considerations
The Chicago District Corps prepared an Environmental Assessment
including a section 404(b)(1) water quality evaluation and we
obtained section 401 certification from the IDNR.
8. Criteria
To benefit the lake trout we specified a bedding stone size of 10 - 25 cm. There was little leeway allowed in the depth of the bedding stone layer or in the distance it extends from the base of the reef.
9. Project Design
The project will place seven submerged breakwater segments 22.8 m (toe-to-toe) from the existing breakwater. The reefs will be placed in 13.7 - 15.2 m of water, with a top crest 6.1 m below low watcr depth (LWD). Six of the oval segments will be 114.3 m long by 45.7 m wide. The segments will be 7.6 m apart at each end. A larger single segment will be approximately 480 m long by 45.7 m wide. The bedding stone will be 0.45 - 45 kg, 0.06 - 0.30 m, the interior stone will be 45-907 kg, 0.30 - 0.81 m and the armor stone will be 0.907 - 4.54 tonnes, 0.81 - 1.38 m (Figures 2 and 3).
10. Implementation
The reefs will be constructed over a 3 year period from June 1995
to September 1997. The
project will be located at Burns Harbor, Indiana. The project
was undertaken to protect shipping. The submerged reefs were the
best, most cost-effective means of supplanting the existing breakwater
and protecting the harbor from wave impacts. The normal work season
extends from April to November; a work window was imposed on this
project to prevent disturbance to spawning and hatching lake trout.
Work will be permitted between 1 June and 15 October.
11. Degree of Environmental Intervention
Highly interventive project. Requires heavy equipment, barges, cranes for open lake construction. Use of quarried limestone for reef construction. Turbidity may be an adverse impact. Deep water placement of materials may prove troublesome with small diameter stone.
12. Cost
Estimated construction costs are about $14 million (US). Assessment
and monitoring estimated to be $8 000 annually.