At our community meetings, you asked questions for our coastal/structural engineers and for the Chicago Division of the U.S. Army Corps of Engineers (USACE). Here are their responses to your questions.

Question. The McLaren Condition Study rates the limestone revetment as pretty good for the Corps' purpose of erosion control. And McLaren's Vulnerability and Alternatives Design reports use the Corps' research to conclude that the revetment needs repair but is safe as is. Has the Corps considered doing nothing and just letting the revetment erode like a natural shoreline? Much like a natural shore on Lake Superior or in Maine? Has the Conservancy considered that alternative?

Answer. Brian Moody, McLaren: The intent of our Alternatives Design Study was to restore and preserve the existing, historic fabric of the structure at the Point. Allowing the revetment to continue to fall into disrepair would allow for the continued loss of upland park area, reduce safety for park patrons, and erode the connection and integrity of the historic structure. Repair and maintenance of the limestone block structure are called for.

Answer. Mike Padilla, Chicago USACE: The Corps studies always include the “do nothing” alternative.  In the case of the 1994 Chicago Shoreline study, that alternative was not selected, probably because it was recognized that the revetment “needs repair” as stated in the question.
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Question. The original Burnham Plan for the lakefront had islands acting as breakwaters to protect the Chicago shoreline. This seems like a very good solution for minimizing wave forces and erosion damage to the City’s lakefront parks and spaces. There are effective breakwaters left at Steelworkers Park. Has the Corps and the City considered breakwaters offshore these South Side parks like Morgan Shoal and the Point? Has the Conservancy considered this alternative? If not, why?

Answer. Brian Moody, McLaren: Offshore breakwaters could be an effective option at the Point, although not required. If the Corps and the City decided to build a breakwater, the limestone block waterfront structure would still require repair and rehabilitation as well as maintenance.
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Answer. Mike Padilla, Chicago USACE: The offshore islands were, indeed, part of the Burnham Plan.  However, in the 1994 study, whole islands were not evaluated.  Standard “High Crest” rubble mounds were evaluated in Plan II of the study but were not part of the selected plan.  Those type of rubble mounds, while being overall smaller than the islands of the Burnham Plan, are very large and were not seen to be cost effective.  The team knew by extension that the islands would not be cost effective either. 
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Question: If the U.S. Army Corps expects its plan to take 5 years for construction, how long would it take to complete repair and rehabilitation work at the Point?

Answer: Brian Moody, McLaren Engineering Group: A lot depends on how you define the start and end of the project. Assuming you’re only talking about the revetment, our plan presented in the Alternatives Design Study, reusing most of the stones in a rebuilt structure, could easily get between five and ten linear feet a day of production completed. (Maybe more, once the work gets rolling.) With 3,050 linear feet around the perimeter of the Point, that could be as quick as 305 working days. (The total linear feet at the Point is 3,150. One hundred linear feet is the concrete ADA ramp at the south most end of the Point at the 57th Street Beach.) So less than one year to complete repair and rehabilitation per our plan if you’re able to work year round. If work must be seasonal, then no more than two seasons. Also, it could be reasonable to perform the work in phases, allowing as much as 80% of the park to be open at any time.
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Question. In your design plans, please add an easy way for folks to enter the water on both the north and south sides of the Point. I know people aren't supposed to swim there, but we all know that many people do and access is limited for those who aren't overly athletic.

Answer. Promontory Point Conservancy: People have been swimming at the Point since the 1920s, before it was a park: that’s nearly 100 years of people deep water swimming from the north and south sides of Promontory Point. Lake Michigan continues to be Chicago’s best cooling station.

In our Alternatives Design Study, on pages 25-32, we offer Universal Design Access (ADA compliance) upgrades at three locations along the perimeter of the Point. We worked with our coastal and structural engineers McLaren Engineering Group and with Universal Access architect Frank Heitzman on these options.

At the south edge of the Point at 56th Street, the City has already put in an ADA ramp. It’s not particularly easy to get to and the slope is steeper than the preferred 1:20” grade but it does provide access now to the limestone promenade on the south side and the concrete at 57th St Beach. We are proposing some upgrades there to make it more useful for access to the promenade and the water.

At the east end where the coffin concrete platform is in place, we are proposing multiple options for accessibility with graceful ramps down to the promenade as well as for riser-long tread stairs (stramps) for those with walkers and canes. These ramps/stramps would be provide easy access for wheelchairs but also for strollers and children to the promenade and the water.

At the north edge of the limestone revetment, where it connects with the concrete revetment north of the Point, we again are proposing 1:20’, graceful ramps and stramps from the Lakefront trail down to/up from the concrete and limestone revetments. Again, these would be for those in wheelchairs, with canes and walkers, but also strollers and children. The ramps would make it easy for kids, dogs and their families to get down to the shallow swimming area on the north side of the Point.

Finally, in the Alternative Design Study, for example pages 8, 18, 22 and 23, show riprap toe scour protection and alternative toe protection of limestone block steps. These recommendations for toe scour protection in the water protect and strengthen the water facing edge of the revetment. The rubble mound restores the original 1937-1939 structure. But, for access into the water, more limestone block steps down into the water at various places might accommodate.

Right now, we are working with an illustrator to create visitations and renderings to make dry engineering drawings more comprehensible so stay tuned for these. I am attaching renderings the Conservancy did for its 2003 engineering study of the Point which are still viable options to give you some clues to what we’re talking about.

From what we know about the USACE/CDOT plan, access to the water would be prohibited. The concrete revetment would provide ladders into and out of the water but are really for someone who falls in, not for swimmers.

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Question. What are the advantages and disadvantages of constructing a revetment with limestone versus concrete?
Answer. Brian Moody, McLaren:
Advantages of limestone

• Limestone is the material on site which is a huge advantage. It is the preferred historic material and avoids demolition and sourcing and delivery costs for construction.
• The service life of limestone block revetment is typically 70 years whereas the service life of concrete is typically 40 years. Limestone seawalls have a proven record of use. We estimate that the use of stone material will provide almost double the useful life as compared to reinforced concrete. Current technology, such as micro textiles and marine mattresses, also allows for proper drainage of the subgrade, prevents the displacement of stones which is beginning to happen now due to erosion of the subgrade material and could extend the service life to 100 years.
• Limestone is more durable than concrete over time. Limestone blocks make a more flexible structure that expands and contracts with temperature changes and absorbs wave energy, thereby sparing the parkland the brunt of storms.
• Using small, pivoting cranes to reposition limestone blocks minimizes damage and removal of trees in the park.
• Limestone breakwater blocks have a more natural appearance making the Point look more like the coast of Maine or Lake Superior.
• Repair and rehabilitation of the existing limestone block structure ranges from $55m-$93m and is overall cheaper than demolition and replacement with concrete. And maintenance of the limestone revetment is cheaper than concrete.

Disadvantages of limestone

• There are a few dozen limestone blocks that need replacing with new in-kind materials. Although it is not known what inventory exists off the east coffins or at other locations in the City, sourcing new blocks and transporting them would be an additional cost. New blocks do NOT have to be quarried because the limestone breakwater blocks used at the Point are waste materials from limestone quarries in Southern Indiana. (The breakwater blocks are not the uniform, buff color blocks desired for buildings which constitutes about 20% of the stone quarried. Therefore, 80% are classed as breakwater blocks or for other uses.) These blocks can be sourced for as cheap as $240/block and transported for about $500/block, bringing the total cost per block under $1,000. (A typical buff block runs $2,000 before transport.)

Advantages of concrete

• Reinforced concrete as a building material can be constructed into almost any shape. This is an advantage for new construction were the limestone block revetment to be demolished.
• Near-universal availability and familiarity of the workforce with concrete.

Disadvantages of concrete

• The steel reinforcing in the marine environment will eventually corrode. The corrosion process of steel results in expansion of the corroded material and ultimately causes cracking and breaking of the surrounding concrete. Apparently, this is what has happened to the concrete revetments on the Northside where the concrete unraveled after the 2020 storms at half life.
• The service life of concrete is typically 40 years whereas the service life of limestone block revetment is typically 70 years.
• Necessity of building an exposed structure having many contact points between steel and concrete. If limestone cladding veneer is added to the concrete revetment, then it adds more points of contact for erosions and deterioration which more quickly compromise the concrete and require greater maintenance expenses.
• Concrete is a CO2 polluter and contributes to urban heat index. Concrete will discourage the fish life that currently thrives off the Point and, without fish, will drive away the night herons.
• Requires clearcutting of the trees along the revetment for demolition and construction, and some in the meadow for staging.
• The City estimates the cost of demolition, new construction with concrete with limestone cladding at $100m. This design is considerably more expensive than repair and rehabilitation of the existing limestone block structure.
• Monolithic form that cannot be modified. Uniformity of design and surface. Unnatural appearance.
• As evidenced by major repairs made to the Northside’s concrete revetments after the 2020 storm, mid-term and long-term maintenance and replacement costs are specific to the concrete design, and are greater than maintenance of the limestone revetment.

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Question. With water levels low, you can hear waves splashing underneath the concrete coffins. Is Promontory Point going to fall into the water? Is it going to wash away?
Answer. Brian Moody, McLaren: The coffin structure is massive (approximately 5 feet thick) and spans between rows of continuous timber piles. This reinforced concrete structure exhibits only minor deterioration and is stable even with the voids beneath the platform.We do recommend that these voids be filled. In our Alternatives Design Study, we offer a grout bag solution to fill the erosion cavity beneath the coffin platform. But Promontory Point is not going to fall into the water anytime in the foreseeable future.
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Question. Why did the existing structure fail? Is it the result of poor design, poor maintenance or some other factor?
Answer. Brian Moody, McLaren: The structure has not failed. McLaren and Wiss, Janney, Elstner Associates did extensive above water and below water analysis of the existing structure to determine that, in fact, it functions in overall good condition. Deferred maintenance has resulted in some erosion of the subgrade material under the promenade causing the settling of the limestone blocks. And the erosion in the parkland is caused by lack of adequate drainage of water from the blown spray of storm waves. Over time, this erosion of the parkland has not been replaced with new topsoil and grass seed. The revetment and promenade can be economically repaired using current technology and techniques which will increase the resiliency and useful life of the structure.
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Question. Is the settling of the stone structure related to wave action or to compaction?
Answer. Brian Moody, McLaren: Where settling of the individual stones is observed on the promenade portion of the structure and at the top of the stepped stones in the parkland, wave activity and stormwater runoff has made its way into the soil, under and behind the stones. As water returns to Lake Michigan, it carries fill material — whether the subgrade material under the promenade blocks or parkland — out slowly over time. This erosion process leads to displacement of the stones. Using filter fabric and properly sized gravel subgrade can allow for water to pass through the soil, under the stones, and back into the lake without causing similar erosion and undermining of the stones. Our Alternatives Design Study recommends use of these materials to stabilize and lengthen the life of the structure.
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Question. Is it possible to build a limestone revetment that will last?
Answer. Brian Moody, McLaren: The limestone revetment has lasted nearly 100 years with little or no maintenance. That’s pretty good. Any structure built on the waterfront will require maintenance and upkeep over time. Rebuilding the revetment as described in our Alternatives Design Study will provide a more resilient structure, which can last indefinitely with periodic maintenance.
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Question. Can the limestone revetment be structurally supported without the use of steel sheet pile?
Answer. Brian Moody, McLaren: There are several ways to reconstruct the Point that will provide the same look as was provided 86 years ago. The purpose of the piling, whether timber or steel sheet, is to keep the subgrade material in place under the promenade and protect it from wave force scour. With the piling protecting the subgrade material, the block promenade stays stable and interlocks into a strong structure. The Alternatives Design Study explores several options for the water facing edge of the promenade including replacing the timber piling, which is a perfectly good solution when protected, and reinforcing the existing timber crib with concrete. Another alternative in the Study uses steel sheet pile rolled out along the existing crib structure. All of our alternatives maintain the historic fabric of the limestone block revetment and promenade.
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​Question. Is there danger of flooding DuSable Lake Shore Drive from overtopping waves at the Point? Climate change would seem to predict bigger waves and bigger storms.
Answer. Brian Moody, McLaren: No. There is no evidence that overtopping waves have damaged the Drive or the Point. There is erosion damage from loss of subgrade material beneath the promenade and lack of adequate drainage in the parkland. From the publicly available materials from the Army Corps and CDOT, there is no evidence that these agencies see flooding danger or damage at the Point. Our Coastal Vulnerability Analysis of a repaired limestone block structure shows that the structure meets the USACE and the City’s extreme wave conditions of +6.8 (2020 storm) and a non-historic +7.7 design wave for coastal resilience.
Promontory Point Conservancy: It’s hard to predict the effects of climate change at the Point. Right now, water levels are below average and falling due to increased evaporation, possibly caused by warmer winters and less ice coverage. It’s difficult to predict.

A bunch of preservation organizations, including Promontory Point Conservancy, have been locked in negotiations for the past two plus years about the future of the limestone revetment at Promontory Point. We’re wrestling with the Chicago Army Corps, the Chicago Department of Transportation (CDOT) and the Chicago Park District to come up with a binding preservation agreement to govern the design and construction at the Point. It’s not going so well.

Once upon a time, back in 2006, we were just as stuck — going round and round in circles. When Obama was our State Congressman, he’d seen how passionate the community was about preserving the limestone. At an early community meeting at the South Shore Cultural Center, I was standing near the door when he walked in the room. As soon as he saw the huge, noisy crowd that had come to protest the planned demolition of the limestone, he expressed himself in characteristic eloquence, “Holy sh*t”. When he got to be U.S. Senator Obama, the controversy was still raging. He decided to take action.

The community had already shown that the limestone could be saved and for less money than concrete. We’d paid for three independent, unbiased engineering studies that said so. But the City wouldn’t budge. Obama and U.S. Rep. Jesse Jackson Jr. supported the community's plan for preservation and knew what had to be done. They put all the contending parties in the same room, about 20 of us, and locked the door. It was hot in there. But, when we finally came out, we had an agreement —  the 2006 Obama Scope of Work.

It was an agreement that baked preservation into the design and construction for the needed repairs at the Point. And it made the community a full partner. Thanks to Obama, all parties reached consensus, including the Army Corps, CDOT and the Park District. But, in 2007, Mayor Richard M. Daley refused to sign the document. So here we are again, back going around in circles with the government agencies. 

All our local elected officials — U.S. Congresswoman Robin Kelly, State Senator Robert Peters, Cook County Commissioner Bill Lowry and Alderman Desmon Yancy — stand in support of the community’s desire to preserve our piece of paradise at the Point. We’re now asking them all to "do as Obama"— turn up the heat on the agencies, close the door on demolition and concrete, and save the Point.

From the very beginning, this community has been rational, relentless, smart and, yes, someting adamantly insistent, but always peaceful. Now that means negotiating a strong preservation project agreement for any design and construction planned at the Point. We're about to release our fourth coastal engineering study that makes it harder and harder and harder for the agencies to back into demolition and replacement with concrete. The community's work is close to a climax.

Very best,

Jack Spicer
President and co-founder of Promontory Point Conservancy

FOR IMMEDIATE RELEASE
April 30, 2024
Contact: Jack Spicer
+1.872.226.2240
Debra Hammond
+1.312.285.476
Elected Officials, City of Chicago and the Community Agree: No Concrete At Promontory Point
Promontory Point Conservancy is pleased to announce that a statement from the Chicago Department of Transportation (CDOT), Chicago Parks District (CPD), and the Chicago Division of U.S. Army Corps of Engineers, addressed to 5th Ward Alderman Desmon Yancy, denies any plans to replace Promontory Point’s iconic limestone revetment and promenade with a concrete alternative. Although earlier governmental plans obtained by the Conservancy indicated otherwise, now “there is no intention of replacing the limestone with a continuous concrete revetment,” said the City on April 4, 2024. 
Speaking to community members on Thursday, April 4, Alderman Yancy read aloud the City’s statement, and called on the City to “listen to the community, let the community lead, and make sure Promontory Point is restored using natural limestone and not poured concrete.”
The City’s statement came in response to the release of an independent Condition Study released by the Conservancy concluding that the Point’s limestone revetment is both repairable and provides more-than-adequate storm damage and shoreline protection as it is. The City did not say it has changed its previous judgement that the limestone revetment had failed, or whether it would dispute the findings of the McLaren Engineering Group concluding it has not failed.    
The Conservancy also notes the City’s repeated commitment to restoring the Point according to the U.S. Department of the Interior’s preservation standards, a commitment which will require the full preservation of the existing limestone, and will not be compatible with even partial concrete replacement. 
State Senator Robert Peters (D-13) also spoke, announcing the introduction to the Illinois legislature of a resolution to “Save the Point”. He stated that the resolution is intended to “further organizing efforts to make sure the City does the right thing,” and raise awareness for the preservation efforts outside the Hyde Park area.
Friends of the Parks interim President Gin Kilgore also spoke, praising McLaren’s evaluation and credentials. “We have a legitimate study that will [help] save public funds, protect the shoreline, and maintain access.” She said. “Friends of the Parks urges our public agencies to be responsive to community priorities, and respectful of the historic spots that give Chicago character.”
Other speakers included Cook County Commissioner Bill Lowry (3rd District), Landmarks Illinois’ Kendra Parzen, and Preservation Chicago Executive Director Ward Miller. For additional quotes and highlights from each speaker, please find footage available here.
The Conservancy and elected officials look forward to collaboration with the City on a preservation plan to retain and repair the current limestone revetment in place.  McLaren’s forthcoming Alternative Design Study Report will provide strategies, design options and cost estimates for repairing and preserving the historic revetment without replacing it with new construction. To date, this will be the only plan that meets storm damage and shoreline protection criteria AND preservation standards.
The Conservancy urges the City, the Chicago Park District and the Chicago Corps to accept the elected officials’ call for community leadership and collaboration, full transparency, and legitimate preservation plans for saving the limestone revetment at Promontory Point. 
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Here is the statement from CDOT that Alderman Yancy read at our April 4th press conference:

"Statement for 4/4/2024"
"The Chicago Department of Transportation (CDOT), the Chicago Park District, and the U.S. Army Corps of Engineers, as partners in the implementation of the Chicago Shoreline Project, look forward to reviewing the report released today. Any data and input will be valuable during the planning and design process needed to meet the goals of reducing coastal storm damage while preserving the limestone and historic nature of Promontory Point."
"The project partners have publicly expressed their commitment to the preservation of Promontory Point in a manner that is consistent with the Secretary of Interior Standards for Historic Preservation. There is no intention of replacing the limestone with a continuous concrete revetment."
"No planning or design work has started on the Promontory Point section of the Shoreline Protection Project. We look forward to working closely with the community, elected officials, and other stakeholders on developing a rehabilitation plan that preserves the limestone and historic character of this beloved segment of shoreline for future generations."
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Erica Schroeder
Director of Public Information 
Chicago Department of Transportation 
office: 312-744-0707
cell: 312-520-8210

FOR IMMEDIATE RELEASE
Monday, February 26, 2024

Promontory Point Conservancy Holds the City To Its Preservation Commitment at Promontory Point

Promontory Point Conservancy appreciates the Chicago Department of Transportation (CDOT) and the Chicago Park District’s (CPD) public commitment to “taking a preservation-based approach” to new designs and construction at Promontory Point. A genuinely preservation-minded approach at the Point creates an easy win-win for the City of Chicago (City) and the community: the City, CPD, and U.S. Army Corps of Engineers get strong storm damage and shoreline protection, while the community continues to enjoy the limestone revetment and the lakeside park it loves so well.

The Conservancy and the community will hold these agencies to their promise of creating a plan for genuine preservation. Earlier this week, CDOT issued a statement on behalf of the City about their intentions for the Point and its preservation at the behest of 5th Ward Alderman Desmon Yancy. The Conservancy applauds their commitment to genuine preservation through adhering to the rigorous legal guidelines set by the Secretary of the Interior Standards for the Treatment of Historic Properties (SOI standards).

Yet, we remain vigilant on behalf of the community. The Conservancy has obtained a recent drawing by CDOT and its preferred contractor, SmithGroup, of a so-called “preservation-based approach” for the Point that, in fact, demolishes the historic limestone revetment, replaces it with concrete, and arranges non-functioning, ornamental limestone blocks in the parkland. (See attached.) This is emphatically not the legal, genuine preservation that the City now says it is committed to carrying out. CDOT and CPD’s public statements commit only to “repurposing”, “saving and reusing as much of the existing limestone as possible,” a commitment that by itself does not meet SOI standards. We are concerned that the City’s commitment goes only as far as to open up a loophole big enough for a fleet of concrete trucks.

In early April, the Conservancy will be releasing its own condition study of Promontory Point conducted by McLaren Engineering Group. Already completed in draft form, this study finds that the historic limestone revetment functions right now for adequate storm damage and shoreline protection. This study shows that all but a few dozen limestone blocks can be retained and repositioned. And if repaired and maintained, the historic limestone revetment has another 86- or more years of service

Although CDOT publicly states this project is “not even at square one, we’re at square zero”, CDOT has not only issued an RFP for the design study but is already negotiating a full-scope contract. CDOT has not explained why it quietly issued its RFP to prequalified firms in December by task order and selected a contractor with whom it is now negotiating a contract. CDOT had informed the Conservancy that the RFP would be posted on the City’s Procurement Services website: it is not there. They have also declined to answer for the design study’s sky-high $5 million price tag. The Chicago Corps costed a design study of Promontory Point at $450,000. The Conservancy hired its coastal engineers McLaren Engineering Group for a condition study, preservation design planning study and a cost-benefit analysis for $252,000.

We applaud the City and officials’ willingness to speak on the project, but the overall lack of transparency and communication to community members is disturbing. We look forward to further dialogue and the release of McLaren’s report, which we are confident will demonstrate viable alternatives for better preserving this local landmark.

For written inquiries please contact Promontory Point Conservancy at [email protected].

The City of Chicago is fully committed to the preservation of Promontory Point, which is designated as an official Chicago landmark, listed on the National Register of Historic Places, and is a beloved part of Chicago’s lakefront. The Chicago Department of Transportation and the Chicago Park District, as partners alongside the U.S. Army Corps of Engineers in the implementation of the Chicago Shoreline Project, are committed to saving and reusing as much of the existing limestone as possible, as part of a rehabilitation effort that is consistent with the Secretary of Interior Standards for Historic Preservation to protect Promontory Point for future generations.

The project approach to Promontory Point has evolved significantly since what was contemplated twenty years ago.  The project partners are fully committed to preserving the Point’s historic nature while protecting it against erosion.

The City of Chicago’s 2023 capital bond allocated $5 million to fund the planning and design of the Promontory Point segment of the Shoreline Protection Project on behalf of their project partners, the Chicago Park District, as owners of the property, and the Army Corps of Engineers, federal partners in the Shoreline Project. The City issued a Request for Proposals (RFP) in December for the planning and design work and the procurement process is ongoing, including cost negotiations. We expect the contract to be finalized in the next few months. The awarding of this contract does not finalize any changes at the Point. 

The study will encompass a broad scope of work over the next few years, including planning, preliminary design, a public engagement process, and the creation of detailed construction drawings and specifications. An extensive public process will be a critical part of this project, providing a platform for community input and collaboration.

The Army Corps’ third-party review will complement the study by ensuring compliance with historic preservation and coastal storm risk reduction standards. Coupled together, this process will help ensure the project moves forward with a plan that preserves the limestone and historic character of this important segment of shoreline."
— Erica Schroeder, CDOT


Received from Marc Monaghan, Hyde Park Herald, [email protected]