This is rip rap. Go buy some from the McCook quarry and be part of regional flooding mitigation.
A few things are pretty clear after three meetings of the advisory committee for Envisioning a Chicago Waterway System for the 21st Century, a cooperative effort of the Great Lakes Commission and the Great Lakes and St. Lawrence Cities Initiative to investigate the costs and benefits of separating the Great Lakes from the Mississippi River (see some reflections on the first and second meetings here).
First off, as if it wasn't obvious enough already, the Chicago Area Waterway System is extremely complex. Altering the system in one place generates a bevvy of reactions elsewhere, and without careful planning and mitigation steps, Positive Alteration X could pretty easily lead to Harmful Consequences A, B and C. The project team is currently assessing the upstream and downstream consequences of placing barriers, or combinations of barriers, at several strategic locations throughout the system.
Second, that complexity isn't all technical, it's temporal and political. For the project team studying hydrological separation, the status and eventual performance of the Metropolitan Water Reclamation District's (MWRD) Tunnel and Reservoir Plan (TARP, also known as the Deep Tunnel) is critically important. Hypothetically, if a physical barrier to impede the movement of invasive species were deemed warranted, and then constructed in the next few years, it could significantly increase the risk of flooding until TARP is complete. Other mitigation strategies would help—green infrastructure and increased floodplain storage would certainly play a role—but for the amount of water we're talking about, TARP gets you the biggest bang for the buck. Until TARP is finished and solutions for invasive species and flooding risks can be totally disassociated from each other, hydrological separation could be a tough pill for many to swallow. In many respects, the determinant of whether people line up in support or opposition of hydrological separation could be determined when it would be achieved, rather than if or how. That's not an argument against separation, but simply another reminder of the urgency of completing TARP as quickly as possible.
Completing TARP faster and more effectively needs to be a priority for the state and the region—combined sewer overflows are fare more common than they should be, damaging property and the environment. This spring we had sewer overflows with particularly alarming frequency, making any discussion of effluent disinfection almost totally irrelevant. When you you have raw sewage, street runoff, and lawn fertilizers (among other things) flowing freely into your rivers every other day, it really doesn't matter how well you treat the effluent at your treatment plant.
So let's get TARP done and done right. As detailed in a past post here, TARP is currently slated to be totally finished in 2029, with phases of it coming online between now and then. While the tunnels are complete, operational, and helping to reduce the frequency and severity of combined sewer overflows (CSO), the reservoirs are not yet done. The hold-up, but also the solution, is the market for the kind of materials dug out of the quarries at McCook and Thornton. Thornton is closer to being finished, so it's McCook that really matters. The quarries are dug at the speed at which Vulcan Materials can sell the material it extracts—with a slow construction market, that means less of a market for the material, and thus a slower speed of extraction.
In theory the material could be dug out and stockpiled, but that means moving it around multiple times, and that get expensive.
So let's buy it and use it instead. The material dug out of the McCook quarry is mostly dolomite limestone, and it's suitable for:
As you pull out your sand wedge, know that you are helping solve regional flooding problems.
- Asphalt and concrete aggregate. That gets used in sidewalks and streets, outdoor basketball courts and parking lots. Our region has lots of all those things, and fixes them all the time.
- Manufactured sand. Not all sand is the same, though it may feel that way when it's down your bathing suit after a trip to the beach. Manufactured sand can often be finer and nicer than mined sand, and it's often used in sand traps at golf courses, as well as at beaches. Our region has those too, and we're always buying more sand to replace sand that's blown or washed away (or been carried away in your shoes).
- Rip rap. This is rock used to stabilize stream banks, shorelines, bridge abutments, and so on. There's a lot of it around if one just pays attention. Our region has plenty of uses for this stuff too.
- Railroad ballast. This is the rock under the tracks. We have lots of tracks, and that means we need lots of rocks.
This is ballast under a railroad. Chicago is the rail hub of the nation... one would think that calls for a lot of rocks.
The point is, there are lots of projects out there that could use materials from the McCook quarry. Construction materials are heavy, and with that comes steep transportation costs. Generally speaking, one sources that kind of material from as close to the project as possible in order to reduce those costs. If someone isn't buying from the McCook quarry now, it's likely because they're closer to another source.
So the question is whether the benefits of finishing TARP sooner (e.g. reduced severity and frequency of flooding, improved water quality, better riverine habitat, etc.) are worth the additional incremental cost of purchasing material from the McCook quarry. I think they are. I think everyone in and around Cook County that cares at all about reducing the risk of flooding should be buying materials from the McCook quarry for every golf course and beach project, every street and sidewalk repair, and every state, county and municipal construction project, until we get that hole dug. It's called putting your money where your mouth is.
I know my colleagues at Openlands are going to be buying rip rap for a habitat restoration project they're doing, and I commend that decision. If the market is going to drive completion of TARP, and if consumers drive the market, then let's start consuming.