Memorandum for Record12 Dec 2019

Subject: 2019 High Lake Levels, Indiana Dunes National Park – Trip Report

  1. On 10 Dec 2019 a shoreline erosion inspection was conducted of Indiana Dunes National Park in response to the National Park Service request for technical assistance under provisions of PL 84-99. Representing the National Park Service (NPS) were Messrs. Paul Labovitz and Christopher Pergiel, At the invitation of the NPS, representing the Town of Beverly Shores were Messrs. Geof Benson and Ed Bracken. Representing the Corps of Engineers were Messrs. Joel Schmidt and Timothy Flaherty (attachment 1). All parties convened at the Park Headquarters whereby the purpose of the site visit was discussed. Mr. Labovitz presented an overview of the shoreline erosion. The sites for inspection were selected by the NPS. Weather was clear with north winds of 20 mph creating 3 to 4 foot waves. Lake level was 581.9 IGLD.
  2. Each site was inspected for condition of the shoreline protection, flank and backshore erosion, risk of wave over-topping and/or street flooding, potential adverse impact on property, infrastructure and public safety. Discussions involved mitigation measures both long and short term.
  3. Summary of Observations and Recommendations:
    1. Lake Front Drive at Lake Shore Country Road: This site was selected as to a typical reach of stone revetment that is in good condition. The toe stone is 2-4 ton with a stone slope consisting of 20-50 pound stone. The slope has maintained a uniform profile with no signs of distress. There was no evidence of wave overtopping or back shore erosion. (Photo 1).
    2. Revetment Breach at Lake Front Drive: A large scallop has formed due to a revetment breach and partial loss of the revetment. The scallop is widening laterally and progressing towards Lake Front Drive, which lies 50 feet from the head cut. (Photos 2-4). Utilities (water, gas and sewage) for Beverly Shores lie below or adjacent to the road. If the breach is left unchecked the road and utilities maybe damaged. As a short term measure, it is recommended sand filled super sacks or armor stone be placed into the breach at the base of the scallop to prevent further head cutting towards Lake Front Drive. The recommended long term measures is to fill the breach, reestablish the original profile and rebuild the revetment to match the lines and grades of the adjacent intact revetment.
    3. Lake Front Drive at Hutchinson Ave (Hutchinson Beach): This location is a former home site. The concrete bulkhead is a remnant of the former structure. During recent storms it has failed allowing severe backshore erosion to occur creating a scallop (Photo 5). Significant flank erosion is occurring on both sides of the failed bulkhead creating scallops (Photo 6). A remnant wall perpendicular to the shoreline is overturning (Photo 7). When this wall fails the east flank scallop will coalesce. The scallop is progressing towards Lake Front Drive, which lies 50 feet from the head cut. Utilities (water, gas and sewage) for Beverly Shores lie below or adjacent to the road. If Lake Front Drive fails, five houses located on Hutchinson Ave will lose access. As a short term measure, it is recommended sand filled super sacks or armor stone (2 to 4 Ton) be placed into the breach at the base of the scallop to prevent further head cutting towards Lake Front Drive. The recommended long term measures is to demolish the bulkhead remnants, fill the breach, reestablish the original profile and rebuild the revetment to match the lines and grades of the adjacent intact revetment.
    4. Lake View Access Point: This location is a NPS beach access point. The revetment has failed allowing backshore erosion of the bluff and loss of a beach access staircase (Photos 8 and 9). The scallop is widening laterally to the east and progressing southward towards a NPS parking lot and Lake Front Drive, which lies 25 feet from the head cut. Approximately 100 feet to the east is a NPS pavilion and comfort station. If the erosion is left unchecked the parking lot and Lake Front Drive with its underlying and adjacent utilities could be lost. As a short term measure, it is recommended sand filled super sacks or armor stone be placed into the breach at the base of the scallop to prevent further head cutting towards park facilities and Lake Front Drive. (Note at this point the Town of Beverly Shores representatives departed).
    5. Century of Progress Homes: These homes are on the National Register of Historic Places. There is no shoreline protection fronting these houses. They lay below the bluff and the beach profile as a gradual incline (Photos 10 and 11). There may be potential for structure flooding if there is additional lake rise and a large wave event with significant wave runup. The western most house looks like it has a low opening on the beach side. Additional analysis would be required to determine flood vulnerability. Recommended short term protection measure are sand berms or sand bags to ring the homes.
    6. Portage Lakefront: This location is a NPS beach access point and Park Pavilion. Severe flank erosion on the west side of the Burns Waterway breakwater has led to the loss of two public “fishing piers” (Photos 12 and 13). The flank erosion is continuing southward and does not threaten any structures at this time (Photo 14). Flank erosion is continuing eastward and may destroy more of the walkways and the staircase access. The walkway to access the breakwater walkway has begun to slide lakeward (Photo15). As a short term measure, it is recommended sand filled super sacks be placed along the toe of the bluff to protect the walkways and staircase. Public access to the breakwater should be closed to the public where the walkway has begun to slide. Recommendations for full scale restorations is outside the scope of this Technical Assistance request.
  4. At the conclusion of the site visits an out brief discussion was conducted summarizing the findings and the above recommendations. NPS was informed USACE does not have any funding to perform shoreline restoration. An interagency agreement would be required for the USACE to design and/or construct shoreline restoration on a fully reimbursable basis. The NPS would like a shoreline drone flight conducted which USACE may be able to conduct on a reimbursable basis. NPS requested USACE prioritize the above recommended short term protection measures for their use to seek emergency funding. The sites are prioritized as follows using best professional judgment:
    Priority Site Impacts
    1 Lake Front Drive at Hutchinson Ave Breach Impact to Critical Infrastructure
    2 Revetment Breach at Lake Front Drive Impact to Critical Infrastructure
    3 Century of Progress Homes Impact to Historic Structures
    4 Lake View Access Point Impact to Critical Infrastructure
    5 Portage Lakefront Impact to Recreational Structures
  5. All designs for permanent structures must be performed by a licensed engineer. A permit may be required for work below the water level. NPS should consult with LRC’s Regulatory Branch at (312) 846-5530, lrcregweb@usace.army.mil.

Timothy L. Flaherty PG
Engineering Geologist

Insepction sign-in sheet
Inspection sign-in sheet
Revetment at Lake Shore County Road
Photo 1: Typical intact stone revetment
Revetment breach at Lake Front Drive
Photo 2: Revetment breach at Lake Front Drive
Head cutting at Lake Front Drive Revetment Brach (looking east)
Photo 3: Head cutting at Lake Front Drive Revetment Brach (looking east)
Head cutting at Lake Front Drive Revetment
Photo 4: Head cutting at Lake Front Drive Revetment
Lake Front Drive at Hutchinson Ave. failed concrete bulkhead and erosion
Photo 5: Lake Front Drive at Hutchinson Ave. failed concrete bulkhead and erosion
Lake Front Drive at Hutchinson Ave. east flank erosion.
Photo 6: Lake Front Drive at Hutchinson Ave. east flank erosion.
Lake Front Drive at Hutchinson Ave overturning wall
Photo 7: Lake Front Drive at Hutchinson Ave overturning wall
Lakeview NPS Beach Access Point, failed revetment repair (looking east)
Photo 8: Lakeview NPS Beach Access Point, failed revetment repair (looking east)
Lake Front Drive at Hutchinson Ave. failed concrete bulkhead and erosion
Photo 9: Lakeview NPS Beach Access Point, failed revetment repair with exposed geotextile (looking west)
Century of Progress Homes beach profile.
Photo 10: Century of Progress Homes beach profile.
Century of Progress Homes beach profile
Photo 11: Century of Progress Homes beach profile.
Portage Lakefront failed handicap access
Photo 12: Portage Lakefront failed handicap access.
Portage Lakefront failed access point
Photo 13: Portage Lakefront failed access point.
Portage Lakefront flank erosion
Photo 14: Portage Lakefront flank erosion
Portage Lakefront staircase access
Photo 15: Portage Lakefront staircase access.
Portage Lakefront progressive failure of public access.
Photo 16: Portage Lakefront progressive failure of public access.
Portage Lakefront progressive failure of public access.
Portage Lakefront progressive failure of public access.