The one that wasn't

My other major early project at TAMS was the proposed South Suburban Airport near Chicago. Beginning in 1990, we analyzed five alternative search areas ranging up to 18,000 acres in size; full biological inventories of each, over a two and a half year period. While two of the sites were almost entirely agricultural, one included some woodlands of moderate to good quality, and two, the Gary Indiana and Lake Calumet IL sites, included remnants of significant natural communities such as nearshore dune and swale, mesic prairie, and marsh. A lot of experience that would later prove to be valuable came out of this project, not to mention the world-class team I was fortunate enough to work with for those first seven years.

After some political contortions far too complex to describe here, eventually the Peotone site was chosen. It was one of the greenfield, or  agricultural sites and the vast majority of it was in row crops. All of the headwater streams that crossed it were channelized. And therein I found an opportunity.

One of the streams was Exline Slough. Today it's a straight ditch. Where it crosses Beecher-Peotone Road it's as much as 10 feet deep. Each year we sampled fish from within an earthen canyon, unable to see over the sides for the entire 200-meter sampling reach. It had been dredged, probably before 1910, and the rich black dirt sidecast into low irregular levees on either side. it was located just southeast of the proposed airport, well within the noise contours where we'd need to create unpopulated buffer areas.

In spite of the massive alteration we got above average fish assemblages there most years, with IBI scores around 44 if I recall correctly. There was at least one fishkill associated with nutrient over-enrichment, followed by fairly rapid recovery. So it was a reasonably diverse if sometimes unstable assemblage.

The obvious clue came from the name; it had been called a slough for a reason. Standing atop the bank, one could see an elongated basin slowly rising off to either side to the surrounding Valparaiso Moraine.  A glance at a topographic map confirmed it; there was a quarter-mile wide abandoned floodway perched 10 feet above the modern elevation of the streambed. Finally, a look at the 1830's GLO survey notes and map provided additional confirmation. At that time, prior to channelization, Exline Slough had been a quarter-mile wide flowing marsh with a very narrow open channel in the center. It had been like this for miles, from the headwaters all the way to the edge of the higher gradient sloping down to the post-glacial Kankakee Torrent valley.

Exline Slough, we determined, originated from a series of drain tile outlets about a mile and a half north of our sample reach. Here a south facing shallow basin climbed gradually to the divide between the Mississippi River drainage... Exline Slough into the Kankakee River, to the Illinois, and finally to the Mississippi; and the Lake Michigan drainage, via Plum Creek and Thorn Creek and into the Calumet. On the north side of this divide, only a few hundred meters from the Exline Slough drain tiles, we discovered a previously unknown 30-acre prairie set well in from the section roads. It had been heavily grazed by horses, but was restorable.

We quickly developed a concept to grade several miles of Exline Slough back to something like original elevations, re-establishing the wide, shallow and slowly flowing marsh that had once been there. At least two section road crossings would have been removed entirely. The drain tiles would have been removed. The prairie would have anchored the northern end.

Unfortunately, two things got in the way. Most importantly, the FAA issued published guidance restricting wetland mitigation within 10,000 feet of an active runway, for wildlife hazard reasons. The northern part of our site fell within this radius, effectively killing it as potential mitigation. Also, the proposed airport bogged down in Illinois politics. It still hasn't been built almost 20 years later, although land for the first runway (of six originally proposed) and a small terminal has been acquired.

Still, it's worth sharing the concept because there are other places in the Midwestern and Eastern U.S. where it's applicable. Structurally it's obvious enough. What made it so possible though was the existence of a published analog, a reference site a century removed in time. The photo below is from Sherff (1914), based on work done in the Skokie Marsh north of Chicago in 1910-1911 and published by the State of Illinois.

The photo was taken west of Glencoe. Note the relatively narrow open channel, choked with submerged vegetation, and the bordering bands of what appear to be bulrush, dropping into a marsh and wet prairie complex with lower vegetation to either side. Topographically this marsh would have been similar to the one at Exline Slough before both were extensively modified. There's an extensive vegetation list included in the published article and while the two site are perhaps 60 miles apart and they certainly weren't identical, they would have had much in common. It wouldn't have been hard to develop a planting mix from the available information. There's also a surviving area in Barrington Hills, around Spring Lake and Mud Lake, that's similar in appearance and which could serve as a reference site.

This one wasn't to be. However it's an excellent example of how to use historic information and a bit of temporal imagination to re-establish what once was, when the circumstances allow.

concept and constraints

I spent much of this afternoon reviewing documents for a proposed small stream restoration project. Although my task is primarily endangered species review for a project that was designed by others several years ago and is now approaching construction, it's always enjoyable to see how others worked through their thought process; especially when I know some of the people involved. I really enjoy the conceptual design end, and this project is fairly elegant.

The concept report discusses four alternatives, all of which were reviewed by various technical folks as well as state and federal agencies and a local NGO. They range from a no action alternative to one that would attempt to put hydrology all the way back to pre-disturbance conditions, as nearly as possible.

That extreme build alternative is of course rarely viable. In this case it would flood large areas at high tide, including adjacent landowners not involved in the project. It would render large areas unusable for their present purposes, which would probably cost the support of landowners who are currently cooperating with the project. In short, it would most likely result in the death of the project because the economic and social costs would not be politically viable.

Instead, an alternative is moving forward that partially restores hydrology, but limits the inundation area. This meets the primary project goals of improving sensitive species habitat, improving sediment transport and water quality, and keeping flooding within acceptable limits. It would actually reduce precipitation related flooding by increasing channel width and storage area. It's more expensive, but still feasible.

This is the elegant part. The design accomplishes all of the project goals, which can be a challenge when some of them aren't necessarily mutually compatible. I'm impressed because the designers managed to restore enough of the ecological processes to allow the watershed to function with minimal long-term maintenance while keeping enough political support to be permitted and built; it's one of those permit processes, under Section 7 of the Endangered Species Act, that I'm currently working on.

The downside is that, as so often happens, there are areas in the upper watershed which are slated for future development and are outside the influence of the project team. So depending on how those places are designed and built, there's a risk of a restored stream increasing in function and quality for a while, and then slowly degrading in different ways as upstream watershed runoff rates and sedimentation increase and water quality input decreases.

Short of controlling an entire watershed, which is quite rare, I'm not really sure how to protect against this. I've seen a few examples of conservation easements being put in place early to buffer streams, but when upstream lands are privately owned, the stars really need to align for this to happen, it needs to somehow be in the interest of those landowners to cooperate. If there are a few larger landowners and all of them agree, it can work. If an area is already subdivided and there are hundreds of owners, the challenges multiply.

command and control

I'm learning more about Logan County, Ohio.

It turns out that there is public land adjacent to the Hine's emerald dragonfly type locality. Indian Lake State Park wraps just about all the way around the man-made lake, created about 1851. The state lands come very close to where the dragonflies were collected in 1929-1930, and they were state lands at that time. I've found only coarse-scale maps thus far, best guess is that the type locality is a few hundred feet outside the public land boundary.

Taking a closer look at Google Earth, it's evident that the dredged channel is now much wider than the 20 feet described by E. B. Williamson in 1931. It's more like 50 feet wide now, almost all the way up to the bridge. According to a newsletter I found, the North Fork is scheduled to be dredged again in 2011. Apparently, there are two dredges working pretty much every year in Indian Lake and vicinity.

Then, I found "Indian Lake State Park's Natural Resource Management Plan, 2007-2012" posted online. If I read it literally, it's a metaphor of everything wrong with natural land management practices in America.

I can't find any evidence that park management knows that a federally listed dragonfly was first described from their backyard. There's an appendix with species lists for just about everything except dragonflies, although it's much more thorough for some taxa than for others.

Resource management goal #2 is to "continue to use the Lake Management Plan and Lake Dredging Plan to monitor, control, and protect the lake and lakeshore areas." So basically, never-ending dredging is official policy. That's necessary because:

"Indian Lake, a shallow lake with a dirt or silt bottom, is the ultimate downstream destination of the 63,000+ acres of residential and agricultural land that comprise the watershed. Sediment entering the lake over the past 100 years threatened the future of the recreational value of Indian Lake and property values around the lake and surrounding community, not to mention the loss of productive farm ground. The Ohio Department of Natural Resources (ODNR) had operated a suction dredge in the lake, as money allowed, for nearly 30 years to remove sediment. The cost of this operation had risen to over $300,000 per year." (from Appendix 1 of the Resource Management Plan).

The situation improved somewhat after 1987 with the onset of no-till farming practices and reduced upstream erosion, and with formation of a "Development Commission" to help raise funds for dredging. Yet the dredging continues, and no cost is given.

Let's go back to the beginning, and look at the sequence of events and how things got to where they are.

Prior to Euro-American settlement, the North Fork of the Great Miami River meanders through swamp woodlands, it's dynamic course depositing sediment within the relatively low-gradient valley. Sediment loads would have been low relative to modern times because of nearly complete ground vegetation cover. Thus, the 1800s valley represented over 12,000 years of post-glacial sediment deposition.

1851, dam construction begins. By 1857 the lower North Fork and the confluence with the South Fork are inundated by the rising lake.

Surrounding lands are cleared for agriculture, greatly increasing erosion and runoff. Water quality suffers, and the North Fork in most recent accounts is rated as "non-attainment" by OEPA. The greatly increased sediment load begins to fill the already shallow Indian Lake, and eventually frequent dredging becomes necessary to support recreational use of the lake.

Dredging gradually extends up the North Fork. In 1929, a 20-foot wide channel extended to a quarter-mile below the SR 117 bridge, according to Williamson. In a 2006 air photo, the channel is closer to 50-feet wide almost up to the bridge, and at least 20 feet wide above the bridge. The channel is straightened, bypassing the sinuous historic meanders.

Channelization moves more sediment, more quickly and more efficiently, from the farm fields into the lake. Soon the dredging operations increase to keep up. When the North Fork itself begins to clog, it is dredged again, as it apparently will be next year. This will once again allow efficient sediment transport into the lake.

This is 1950s command-and-control thinking, tempered slightly by late 1980s no-till agriculture. And it's all being subsidized by the taxpayers of Ohio.

I suppose it could be argued that it creates jobs for a couple of dredge operators, a few truck drivers who transport the sludge tainted by agricultural pesticides to wherever it is they take it, and a few bureaucrats who handle the paper.

Natural ecological processes had addressed this by creating, over time, a wide floodplain where excess sediment was deposited by a meanding channel. The meanders and the lower gradient channel slowed floodwaters, allowing sediment to deposit. The adjoining swamp forest and resulting woody debris input further filtered sediments. If a channel began to fill, it migrated laterally. A dynamic equilibrium held for millenia.

The "efficient" humans came along, and messed everything up in less than 100 years. Now we're fighting a never ending battle to maintain that disequilibrium. Somewhere along the way, we extirpated a population of a rare dragonfly, and who knows how many other things.

If not for the subdivision in the way, and the stubborn human attitudes, this could all be put back for the cost of perhaps a decade of dredging. The road is no real obstacle, it could be raised or the bridge widened. The original channel course could be determined from old maps and photos, it could be re-established and the old straight channel filled, and wet-tolerant trees and shrubs planted or allowed to naturally regenerate. The sediment load into the lake would immediately drop dramatically, because it would instead deposit on the floodplain. Hydrology studies could determine how much the water would back up in a 100-year event, and if necessary some additional floodway capacity could be excavated to prevent damage to upstream property. The permits and design to do all this would be of moderate complexity at most. There would be a short term (a few years) creation of engineering, environmental, and construction jobs, and because of transportation costs local firms would likely do most of the actual construction work with direct benefits to the local economy.

But first, a little imagination and creativity is required. This is the key first step, the place where restoration starts.