On the Beach
Keeping Lake Michigan from eating Chicago
May 22, 1987
In the 1980s, Lake Michigan water levels rose to levels not seen since the city of Chicago took root on its shore. Debates about what to do about the result shore erosion—and not do about it—were noisy and ill-tempered. They also were interesting, at least to me, hence this 10,000-word exploration of the issues. Given one of hiss signature titles by editor Michael Lenahan, it ran on the Reader’s cover. It is newly relevant, lake levels being again very high.
In the early morning hours after the storm of February 8, while the radio was reporting the death due to drowning of breakwaters and seawalls up and down the Chicago lakefront, Charlie Shabica went out to see if his beach was still there. Shabica is a geologist at Northeastern Illinois University, chairman of the City Club's Task Force on Lake Michigan, and a member of the mayor's Lakefront Protection Commission. When not in meetings, he also does a little private consulting as a beach builder, and this visit was to one of his restoration sites on a ragged stretch of shore off Highland Park. It is a geologist's beach, not a bather's beach, made of big stones instead of sand. But what mattered was not what it looked like, but that it was still there. "Yesterday's storm threw as large a wave as the beach was designed for," Shabica reported proudly, back at his north-side office. "I think it's fair to say that the structures that came away least scathed by yesterday's debacle were soft structures."
That's soft as in "sand"—as in "subtle," as in "not cement and steel." Soft--according to traditionalist skeptics whose idea of stopping a wave means building a wall—as in "softheaded."
Paul Kakuris went beach-watching on March 9, after the second big storm of the season. "Our beaches soaked up those waves like a sponge." Kakuris is a Chicago-based coastal engineer, consultant, and inventor who has designed "soft" beach restorations at five major sites along the North Shore. One of his spongy beaches was built in the summer of 1985, when he combined advanced precast-concrete technology, in the form of a modular artificial reef of his own device, with a rather cruder technology—rocks—to rebuild 200 feet of shore off a Winnetka estate. During its first autumn in the water, when Lake Michigan beaches usually lose sand, his gained it; during storms, when other beaches shrank, his grew. "The shoreline has been converted from energy-reflecting [hard-shore] to energy-absorbing [soft-shore]," Kakuris would write later. That's engineering for "Eureka."
Kakuris and Shabica, with a few other experts working around southern Lake Michigan, are fervent soft-shore men, dissidents from traditional shore protection orthodoxies. In the war between Illinois and a rising Lake Michigan—and what else should we call a contest in which everyone is losing?—they are the arbitrators, the diplomats among engineers, who know that the way not to lose a war with a superior foe is to not start one.
Attempts to stem the loss to waves of beaches, bluffs, and shore structures have ranged from the antic—the offshore sinking of a derelict barge—to the merely expensive. Many—mos—of them will not work well, or for very long. Consider these familiar maxims from the lake erosion debate:
Seawalls stop big waves.
High water levels cause erosion.
Storms destroy beaches.
Stone and steel are harder than water.
The beaches are gone.
All wrong, according to the soft-shore ethic, or at least misleading. Seawalls, for example, do not stop big waves, they create big waves. Storms do not destroy beaches, though they do remodel and sometimes even relocate them. Erosion, or recession, is good for a shore, whatever its effect on property values. While stone and steel are harder than water, they are only harder than water for a while. And the beaches aren't gone—they're traveling incognito up and down the lake as sandbars and shoals and dunes.
Some of these new truths confound common sense. They certainly have confounded their share of shore protection experts over the years. Ignorance in the shore protection business, it seems, consists not of knowing nothing, but of knowing the wrong things.
To understand the soft-shore ethic you need to know what a shore is, and what it does. The words "coast," "shore," and "shoreline" tend to be used interchangeably, and incorrectly. The shoreline is exactly that, a line, the wavering boundary between water and land, so variable in its position that it exists on the charts as an average known as the mean still-water line. "Coast" has marketing as well as maritime meanings; to the real estate speculator, "coastal" is any property whose proximity to water adds to its sale price.
Coastal experts—engineers, geologists, limnologists (freshwater scientists), hydrologists—think more inclusively. They describe a coastal zone that is hundreds of feet wide within which are found three distinct (if itinerant) regions. The nearshore is the lake bottom beneath shallow water, ending at the mean water line. Fastland is the territory above and beyond the reach of high water. And shifting between the two is the shore proper.
Though the definition of "coast" is fixed, the coast itself never is. If you envision what the experts call "the coastal process" as a battle between lake and land for possession of the shore, you see that the spoils of victory are as temporary as the combat is constant. Like all of the larger inland seas, Lake Michigan is in many ways a more rigorous environment than the oceans. The waves buffeting its shores are smaller than those at sea, but there are more of them.
And the shore in most winters is freighted by ice, which buffers it against waves but also punishes the shore's rocky parts in much the way it punishes city streets. Lake waves during a storm (16 feet high in midlake) are formidable; city cleanup crews no doubt were moved to contemplate the wave energy needed to keep in suspension the football-sized rocks they found strewn on the beach between 47th and 49th streets in February.
Against such an importunate neighbor the shore would seem to have no natural defense. Dunes of loose sand (which once stretched around the south end of the lake and which survive in Indiana) are plainly vulnerable. And the bluffs that reach north from Chicago into Wisconsin are scarcely more durable; made of unconsolidated glacial deposits, they are about as resistant to water as an alderman would be to a prosecutor's offer of immunity.
"No one can stop erosion," says Kakuris. "You can use words like 'slow' or 'retard' but you can't stop it." Geologically immature, the lake is still smoothing its bluff-bound borders. Waves constantly worry the shore, piling up a beach here, chewing away a bluff there, in fluid response to storm surges, seasonal and climatic changes in water levels, and other perturbations.
The greatest erosion occurs during storms and high water. (Indeed, during low water interludes, waves actually rebuild the shore in places, pushing sand and other waterborne sediment up onto the shore and beyond—ergo dunes.) But while the scale and pace of the work vary, its direction does not; like all reformers, the lake works ceaselessly to reduce the irregular to the uniform.
Archaeologists have ways of measuring shore recession. In the 1800s, they estimate, the average rate was about five feet per year along the north shore between Chicago and the Wisconsin-Illinois line; unprotected stretches of that shore are expected to continue moving landward by three feet a year or so between now and 2000. At particularly vulnerable spots, however, recession might better be described as routs; one recent study predicts shore losses of 80 feet a year in parts of Illinois Beach State Park near Zion.
That's a lakefront land grab.
To keep the lake at bay, we have "hardened" the shore by deploying an array of structural defenses. Like all modern arsenals, this one is ingenious within limits. It is also expensive, vulnerable to assault by a persistent enemy, and—handled carelessly—a danger to friend as well as to foe. It includes:
Groins—low walls (usually of steel) that jut perpendicularly into the lake from shore, and serve mainly to keep sand from being washed off beaches by the currents that sweep downcoast.
Breakwaters, which stand roughly parallel to the shore some distance out in the lake and intercept (and thus weaken) the energy of incoming waves.
Revetments, the family name for shore armor. Revetments may take the form of seawalls, which, as the name implies, are solid concrete barriers built along the beach above and beyond the waterline. They may also consist of stone rubble, called riprap, or cut-stone blocks, placed at the water's edge. Dikes are the most massive form of revetment, solid walls built against water; whereas a seawall protects a shore, a dike is the shore—a man-made replacement for the vanished original. Dikes are probably the ultimate expression of the hard-shore approach to erosion (all kinds of erosion; the Berlin Wall is a dike). The power plant at Wilmette is being diked with sand, and dikes have been proposed as a remedy of last resort for such threatened Chicago facilities as McCormick Place, which might otherwise get the chance to stage a boat show the way a boat show really ought to be staged.
Each of these types of structure works, at least within the narrow expectations of their designers. The trouble is that they don't work for very long. Most coastal structures are designed to last a minimum of only 30 years, although a well-built one can last much longer if maintained. A 1940s survey counted more than 350 shore-protection structures on the Illinois shore north of Chicago; most are still there today—in the form of steel stumps and rubble; at low water that shore looks like a sculpture garden.
Once committed to, such temporary protections burden public and private budgets with permanent costs. Offshore breakwaters, for instance, cost roughly $2,000 per foot; officials of Chicago's Department of Planning have thus estimated that building a two-mile structure to protect the shore north of Hollywood Avenue would cost at least $20 million. "The new structures that will be installed in the next couple of years will be another infrastructure that needs to be maintained," points out Lee Botts, doyenne of Lake Michigan environmentalists and currently adviser to the mayor's lakefront commission. "Structures are very costly to build, and when they fail—and they always fail eventually—you have to add the cost of that structure to the loss of the property it was supposed to protect."
The same complaint can be made against anything built, from an interstate to an icebox. What damns traditional shore protection structures in the eyes of soft-shore advocates is not that they cost a lot or that they don't last, but that they don't protect the shore. Their arguments are as follows:
The lake moves, but its fastened shore cannot. A fixed barrier works well when the lake is relatively stable, or when the rising and falling of water is gradual and predictable. What happens if (as climatologists worry) future fluctuations in lake levels occur more quickly and over a wider range than during the past century or so? The heavy timber piles that support the elegant cut-stone revetments protecting Meigs Field and Burnham Park were built during a long-ago high-water period; exposed to air when the lake dropped unexpectedly low during 1963-65, they became infected by dry rot and are now crumbling.
Fixed onshore structures merely change erosion problems rather than solve them. Man-made structures generally deflect the destructive energies of waves rather than dissipate them. The wave energy striking a solid reflective surface like a seawall is not absorbed, merely redirected. Some of those formidable energies explode upward, some recoil to collide with incoming waves; each creates splash and spray, which in cold weather freeze by the ton onto the lakeward sides of buildings. Deflected wave energy also skids downcoast, curling around the ends of seawalls and similar structures in a process called flanking. If you've noticed how windblown litter tends to accumulate in the downwind "shadow" of a biggish building you've seen a drier version of it; the difference is that a flanking wind can remove a hat, while a flanking wave, landing on an unarmored shore, can eventually remove a house.
Wave deflection works most perniciously at the bottom of a fortified shore. There, unseen, energized water veers downward to chew at the foot of the seawall itself during high water, in a process known as toe scouring. Undeterred, toe scouring can undermine a wall's foundations, causing its collapse. (The collapse of the multilane thruway bridge in upstate New York in April is believed to have been caused by scouring.) The emergency work done this winter by the U.S. Army Corps of Engineers off Sheridan Road included dumping boulders at the feet of seawalls--in effect, armoring the armor against scouring.
Scouring may chew most hungrily at the base of reflective shore structures, but its appetite is indiscriminate. Churning currents bouncing off a seawall will lift beach sands and carry them lakeward. Beach loss from in front of revetments has been documented up and down the Lake Michigan coast. In Indiana, the rise in lake levels that began in the late 1960s was causing water to creep across natural beach ever closer to the bluffs at Beverly Shores, near the Indiana Dunes State Park. In 1973-74 authorities installed a 13,000-foot-long rock revetment at the foot of those bluffs. Since then the beach has disappeared, the result of what the Purdue University Great Lakes Coastal Research Laboratory has described as "a real loss of material."
High water does not cause erosion. "High water, high water, high water.' That's all you hear," complains Paul Kakuris. "The problem is not high water. Not only high water, anyway." Purdue's study of the Indiana shore confirms this, explaining that water levels are a complication, not a cause.
A distinction without a difference, one might say. But soft-shore advocates worry that high water obscures more than beaches. Dick Holmberg is a coastal consultant whose firm, Erosion Control Systems, Inc., is located in Whitehall, Michigan. "Everybody is saying that the problem is higher water," Holmberg says. "Well, yes, the water is up by two feet. But it's twelve feet deeper off some shores. Where'd that other ten feet come from?"
Holmberg insists that it came from the removal of shallow-water sediments by deflected shore currents--in effect, that the sediment wasn't pulled out into the lake but pushed out there by currents and waves bouncing off reflective shore structures. Purdue's researchers confirm, noting that on the lakeward side of one section of rock revetment a total of five vertical feet of lake bottom disappeared in a recent seven-year period.
When the water becomes too deep near the shore, waves are not tripped before they reach shore, but instead crash into it. The results were spectacularly visible off Chicago during this winter's storms. "You got offshore waves breaking right up onshore that have no business being there," Holmberg says. When seawalls are installed, seawalls become necessary.
Saving the shore often means losing it. There are revetments that are less reflective than solid seawalls, such as rubble, or riprap; they mitigate flanking and scouring to some extent. The problem is that they also mitigate both the use of the shore and its aesthetics. (Environmentalist writer William Ashworth, in his book The Late, Great Lakes, describes riprap as "petrified vomit"—clearly not a rock fan.) The deeper the water the bigger the waves, and thus the bigger the stones needed to withstand them (a child who wanted to play on the beach of multi-ton stones piled off La Rabida Children's Hospital at 65th Street would need crampons and climbing rope, not a toy bucket and shovel).
Fixing the shore, in short, does not fix the shore.
However modern their materials, structural approaches to shore protection owe their inspiration to an ancient desire to regulate nature. Geologists describe, but engineers prescribe. "In general, persons with a geological background are likely to take a soft-shore view," explains Paul Morhardt, planner for the Army Corps of Engineers' Chicago district office, "and those with engineering backgrounds take a hard-shore view."
Such generalizations are treacherous: one of the most ardent exponents of a hardened Chicago shore is geologist Charlie Collinson of the Illinois State Geological Society; and the soft-shore camp includes people like engineer Kakuris who see the choice as not between an engineered shore and an unengineered shore but between a crudely engineered shore and a subtly engineered one.
Assuming Morhardt's dichotomy to be largely correct, however, no outfit could be expected to better embody the hard-shore ethic than a whole corps of engineers. The Army Corps' historical hard-shore bias is indisputable; you can walk on it along much of the state's 60 miles of lakeshore. "The Army is the Army." says Kakuris. 'Armor. Entrench. Dig in. Bigger is better. Heavier is better.'"
The corps builds structures (mainly to protect public properties from flood) under a complicated set of federal programs. Lake Michigan being navigable water, it also has approval power (which it shares with the state's Department of Transportation) over structures built by both private owners of shore property and public entities, from the state of Illinois to village park departments. By design or default, the present lakeshore is the corps' creation.
Among environmentalists, "corps" is a four-letter word. The corps has not wreaked the comprehensive havoc on Lake Michigan that it has on, for instance, the Illinois River. In the 1830s, a nearly half-mile-long sandbar extended from North Water Street to Madison, blocking the entrance to the Chicago River—in every way a bar to progress. The Army dug a ditch through it to drain river water away from Fort Dearborn, but it clogged back up. In 1833, the corps plowed through it again and built a pier upcoast of its new, straightened river mouth to keep sediment from filling it up again. New sand spilled over from the end of the new pier, clogging the river mouth again. A new pier was built, this much longer than the original and jutting well into the lake toward the northeast. This is how wars begin. "The corps was created in 1824," sniffs Lee Botts, "and by 1833 they were already messing up Chicago."
To its critics, the corps seems the image of the drug pusher in the schoolyard, but it may be more helpful to see the agency as a retailer selling goods he knows his customers either don't need or might buy cheaper elsewhere. Historically the first in line have been the politicians.
To many local officials, a successful shore protection structure is one they can be photographed in front of, which is one reason the corps has put more pork in the water than a hundred slaughterhouses. (Lee Botts: "The corps is not a technical agency. The corps is a political agency.") Budget cuts have slowed these torrents of concrete, however. A big water-projects bill just passed was hung up in Congress for ten years beginning in the Carter administration, and shore protection in particular has not been a high priority of the Reagan administration. Charlie Johnson, an engineer with the corps' North Central Division, confirms this. "We in the federal government will go along with what the politicians tell us to do."
Soft-shore advocates counsel that it is wiser to go along with what nature tells us to do. They are practical environmentalists who believe that nature suggests good engineering as well as good ethics. Resisting nature, a la the military model, is usually futile; better to modify it according to its own model.
Nature's model shore protection system is the sand beach. As the term is used here, the beach consists not only of the wave-deposited sand and gravel that lie immediately above the waterline, but also includes a mound of sand landward of "the beach." On the lakeward side of the waterline the beach stretches underwater, sometimes for hundreds of feet. This submerged shore face is usually gently sloped and covered by sand and other sediment. This loose material is arrayed in itinerant sandbars or shoals, some close to shore, some not, all roughly parallel to it; such bars congregate like knots of talkers on a busy street, broken up by currents and moving on to reassemble farther downcoast.
In placid water, such a beach makes an ideal shore protection system. As an incoming wave rolls toward shore across the shallows, it begins to drag against the bottom. The wave's upper half eventually outpaces its lower half, distorting it until it collapses forward onto the shallows like a drunk stubbing his toe and falling on his face. The kinetic energy of the wave is thus dissipated in what has been described as "futile foam and turbulence."
When a beach is attacked by flood or storm, the genius of its design is revealed even more clearly. While beaches would seem to be as ephemeral as sand castles in the face of an agitated lake, they are remarkably durable. During a storm, big waves will overrun a beach, snatching sand from the berm in back of it. That sand will be dragged lakeward onto the shore face, stretching and flattening the offshore beach profile, piling up new sandbars farther offshore. Incoming waves thus are tripped sooner, the run up to the shore becomes longer, the waves spend themselves earlier. The beach under stress is self-correcting; given time, it is self-healing as well. Normal wave action tends to restore the disheveled beach, pushing sediment back up above the waterline. (A storm can undo a beach in only hours; rebuilding it occurs over a period of weeks or months.) Sand above and below the waterline is part of the same beach, deployed in what has been nicely described as a system of wet and dry sand storage.
During periods of stable or slowly changing water levels, the overall beach area varies surprisingly little--even though the shape of a beach changes as the lake swings between calm and storm. "Nature is incredibly ingenious at maintaining equilibrium," enthuses Charlie Shabica. Unimpeded, a beach can also adjust to longer-term changes in lake water level. As water levels rise, a beach will tend to back up, like a 19th-century stroller hiking her skirts and scampering away from the approach of a wave. The beach will replicate itself inland (actually, the lake, using materials at hand, will replicate it) at a higher elevation.
In nature, shore physiography sets limits to this accommodation. In places where the back-of-the-beach terrain is abrupt and blocks the easy inland migration of the beach, waves will refashion it where it stands, making it steeper and thus narrower. The beach that appears to the unschooled eye to have disappeared often has merely been reconfigured into a less familiar shape. Corps engineer Charlie Johnson notes that many "vanished" beaches today lie in wet storage as many as several hundred feet offshore, in eight or ten feet of water. When—if—lake levels drop, these beaches will reappear "spontaneously."
Along a developed coast, shore becomes property, and the impediments to beach movement are economic. While floods and erosion losses are typically seen as vagaries of the lake, they are less the result of water being where it shouldn't than of buildings and roads being where they shouldn't. (Indians who camped on the Great Lakes never built permanently in the beach zone, but then they dwelt here in the dark days before the income tax deduction for mortgage interest payments.) "If we didn't have development onshore, and the water level were to stabilize," says Morhardt, daydreaming out loud, "the shore will stabilize too."
When and where it can, in short, a beach stays the same by changing. This is not a new truth, just an ignored one. Even the corps' official Shore Protection Manual classes beaches as "shore protection structures." This is the corps' way of paying them a compliment.
Everything of beauty has its poet, and the poet of the natural beach is Orin Pilkey. Pilkey, a marine geologist at Duke University, wrote (with Wallace Kaufman) the essential book The Beaches Are Moving (1979). In it he explained that beaches are not stable in the usual sense, but persist in a state of "dynamic equilibrium." "Like a person constantly changing position in a large armchair, not everything will be in the same place at the same time." What is true of individual beaches is true of the lakeshore as a whole.
If waves provide the dynamism in the "dynamic equilibrium" of the natural beach, the equilibrium is supplied by a phenomenon called littoral drift. The Illinois shore is washed by wind-generated currents that slide parallel to the shore in shallow (20 feet or less) water, the so-called longshore currents. These shallows constitute the lake's littoral zone. Sediment—sand, silt, gravel, the occasional boat house after a storm—drift through the littoral zone aboard the longshore currents by the ton, tumbling down the coast north to south in front of the prevailing winds. This littoral drift consists of materials chewed away from exposed bluffs, dislodged from beaches by storm waves, or lifted from offshore bars. Littoral drift is often described as a river of sand, but the phrase misleads. The downcoast progress of any particular part of it is anything but continuous, less a matter of flowing than hitchhiking down the coast while stopping for an odd job here and there for a season--a beach this year, an offshore bar next year, a dune the year after that. A beach is always losing sand, but as long as the sand lost is replaced by an equal amount of new sand drifting onto it from upcoast, erosion and deposition balance. The sand changes, but the beach stays the same.
A century and a half ago drift tumbled past Chicago by the ton, with ambivalent results. Drift deposits kept clogging the river mouth where currents, staggered by their collision with a pier, dropped them. But drift also began to pile up behind the pier that stood in the mid-1800s, extending the shore eastward from its 1830s terminus at Saint Clair Street for hundreds of acres, creating today's Streeterville district. As a letter writer put it to the Tribune in 1851, "To the city, Lake Michigan is a terror and a source of taxation."
Today, alas, the western shore of the lake exists in a state of dynamic disequilibrium. Seawalls and bulwarks built upcoast have secured bluffs against erosion, cutting off drift supplies at the source. And, there being no catastrophe that human ingenuity cannot make worse, much of the drift material that does enter the longshore currents is either intercepted by obtruding coastal structures or diverted into deeper waters with confused currents.
Indeed, coastal experts sometimes classify shore structures according to how well they impede offshore sediment transport. "Primary" structures extend into the lake across the littoral zone into deeper water where sediment transport is negligible, thus becoming a total barrier to drift movement; primary structures include sizable landfills as well as big harbor breakwaters at places like Waukegan, Wilmette, and the Great Lakes Naval Training Station. "Secondary" barriers intercept from 25 to 75 percent of the drift passing a point of shore; they typically include smaller jetties, long revetments, or groins reaching into but not across the littoral zone from seawalls. "Tertiary" structures are distinguished from secondary ones less by their design, which they share with other perpendicular impedimenta, than by their size; usually built by landowners to protect local properties, they have only local effects.
Not all of these obtrusions ought to be considered evil. Some are preservative; the long-standing groin at Wilmette, for instance, helps retain a fossil beach that accumulated upcoast of a natural promontory long before there was anything to be a suburb of. The worst barrier, however, will stop virtually all downcoast movement of sediment while sediment losses below it continue unabated. The result is a net loss of beach material.
Erosion. Beach death by starvation.
Nowhere does this process show more dramatically than at Illinois Beach State Park in Lake County near Zion. Beach recession along this eight-mile stretch of shore is normal, even proper. (The park's dunes and wetlands were once the shore of a former, higher Lake Michigan.) A century ago the shore here stood 1,200 feet farther into the lake than it does today. But sand-catching harbor structures at Kenosha and Trident in Wisconsin, upcoast of the park's northern boundary, have gagged the flow of nourishing sediments. The park's so-called north unit, immediately downcoast of those structures, is being stripped away by storm waves. Recession has accelerated ominously, to 80 feet a year in places.
Ironically, the south unit of the park is growing, fed by sands stripped from the north unit. Aerial photos show how the park's overall shoreline, formerly straight, is protruding badly to the south, like a man left hollow-chested and potbellied by age.
The Illinois Department of Conservation is building a new 1,500-slip marina in the park at Winthrop Harbor, near the Wisconsin border, which will further complicate the shore's muddled mechanics. A new breakwater (to protect the harbor mouth from silting) will slow erosion of the north park unit by capturing drift materials that escape from upcoast. However, protecting the beaches immediately south of that entrance will require construction there of what project consultants call a "sacrificial feeder beach" to provide drift material to replenish beaches downcoast; the feeder beach will use as much as a half-million cubic yards of fine sand excavated from the harbor site.
Beach nourishment of this sort is a temporary solution, limited in this case by the amount of sand available at the site. Its efficacy matters less in the long run than its example. The Winthrop Harbor project is notable on the Illinois shore for the attempt to mitigate in advance damage to downcoast beaches resulting from interruptions of sediment movement through the longshore system.
In more enlightened states, this sort of thing was being done long ago, says Paul Kakuris. Many of our North Shore disaster areas might have been avoided had we been paying attention to the issue of littoral drift. "Projects like Waukegan Harbor would not have been approved," Kakuris says. "They [harbor planners] would have been told, 'You can have your harbor, but you'll have to resupply the downdrift beaches with the 100,000 cubic yards per year or whatever amount of material that you capture.'" In ocean-coast states such as Florida, California, and the Carolinas, damage mitigation is made a condition of construction permits. Backed by surety or indemnity bonds, the obligation to mitigate (usually by "bypassing" captured sand past the new obstruction by dredge, pump, or truck) survives as long as the structure does.
Most knowledgeable observers agree that the Great Lakes states are decades behind ocean-coast states in the rigor of their coastal development policies. Illinois, sadly, lags behind even other Great Lakes states. There is not much of a coast lobby in Illinois; by comparison, the corps' Charlie Johnson says, Michigan politicians are "very quick" to demand corps assistance in mitigating downcoast effects of new shore projects.
However, transporting sediment to nourish downcoast beaches is not unknown on the northern Illinois shore. Commonwealth Edison has moved substantial amounts of dredged sand from the cooling-water discharge channel at its Zion plant site to the south unit of Illinois Beach. ("An excellent demonstration," says Johnson.)
Might not accumulated sediments trapped above the larger harbor structures be similarly mined? Couldn't their sands and gravels be reintroduced into longshore currents for transport downcoast where they would replenish starving beaches. Johnson estimates that the longshore currents can move 16,000 cubic yards of material a year. At that rate, he says, you could dig enough sediments from the Waukegan beach alone to keep the whole north shore littoral system fed for "several decades."
The artificial nourishment of beaches is a tenet of the soft-shore creed, and oddly one that the Corps of Engineers has officially endorsed since 1971. The corps tends to use soft-shore methods in remoter recreational beaches. Residential shores are what spark its latent fort-building impulses. (It is worth remembering that the cavalry killed Indians on behalf of the settlers and not just the railroads or the generals.) Although most of the sand-dumping has been done along the ocean coasts, the Great Lakes have seen several such earth works, including projects in Indiana and Michigan.
The corps has been sued for its failure to take mitigative steps in other states, but such actions are notoriously tricky to document; demonstrating precisely which shore is damaged by which upcoast structure is like trying to prove which part of a dropout's decision to leave school is owed to poverty, which part to TV, and which part to Dad's drinking.
The inability to undo the past is no reason to repeat it, of course, and mitigation promises to become an increasingly fractious issue in shore development projects in Illinois. In this sense, anyway, coastal observers have seen the future, and it is Lake Forest.
When one hears the word "bypass" in Lake Forest, the conversation is usually about the arteries of its leading citizens, not their public beach. But the concept has figured conspicuously in the controversy over that suburb's soon-to-be-completed $8.5 million beach complex. Essentially it is the mechanical transport of sediment from the upcoast side of an obstruction to the downcoast side--a means of returning captured sediment to the littoral current.
The complex is of unusual design. A new man-made beach will be protected by a segmented rubble breakwater connected to shore by groins, creating a series of semiopen beach cells. The breakwaters caused a stir. ("Unproven," says Charlie Collinson. "Sort of a fad," comments Lee Botts.) Flanking effects were mentioned in grim tones. But it was the complex's impact on littoral drift that was most talked about: if there are significant amounts of drift off Lake Forest, it would be hard to devise a better machine to capture it.
Private owners downcoast of the site complained of the risk of damage to their beaches (one of which is a Kakuris site). Project engineers replied that there is no drift to catch (an opinion sustained by the corps, among others). There followed many weeks of impatient debate among village officials, interested landowners, corps staff, attorneys, coastal experts, and engineers. (TV miniseries have had duller plots.) Expertise was challenged, motives were impugned, and reputations were staked on the question of whether a facility that is not yet built would affect materials that were not incontrovertibly known to exist.
The result was a curious agreement by which Lake Forest pledged to monitor and mitigate a problem that it says will not occur. Aerial photos, soundings of the shore profile, and similar measurements will be taken upcoast and down from the site for two years to provide base data against which changes in the shore configuration might be gauged. The new beach itself may offer clues to the working of shore currents; its sand is a distinctive type, and additions to it (from drift) or losses from it (which would appear on downcoast beaches) should be as easy to trace as marked twenties.
The village has publicly explained its acceptance of the monitoring requirement as precautionary, in case of future litigation. Lake Foresters will get a chance to cavort this summer in what amounts to a real-life wave-tank experiment, thus confirming that science can be fun. More important to the rest of the state, the data may help answer questions that will be raised again and again along the Illinois shore to which there are not yet any good answers.
The historically unprecedented lake levels have revealed an all-too-precedented ignorance about the lake. Purdue researchers studying shore processes along 18 miles of Indiana dune country could find no "appropriate data" on waves in the area and very little on winds. Climatologists at the Illinois State Water Survey evaluating precipitation patterns are frustrated because no one really knows how much it rains on the lake. Also, higher water means more erosion, which means more sediment in lake water, yet no one is studying the effects of these clouds of goop on shallow-water plant and animal life.
No questions are more in need of answers than those that remain about drift. "Lakes adjust to higher water levels to a point," Kakuris explains, "if there is enough sediment around." But is there? The fate of a particular stretch of shore depends on the sediment balance at that spot, and offshore sediment flows are complex and variable. Drift amounts are assumed to diminish as the longshore currents move south toward Chicago along the north shore. But how much are they diminished? How much material enters the system from Wisconsin waters? How and how fast does it move? The mechanics of the transport system are understood in principle, but informed engineering demands detail.
In the absence of comprehensive real-life data, experts rely on computer models and similar extrapolations. A half-dozen studies since 1953 of drift movement past the state line above Illinois Beach—studies done variously by the corps, state agencies, and private consultants—have yielded estimates that ranged from zero to 140,000 cubic yards a year. Indeed, tracing the movement of drift in the shallow-water currents is a lot like trying to track the president's memory: responsible people agree that it's there, but everything else about it is conjecture. Drift estimates vary with the method used to calculate them (land accretion minus land loss, changes in shore profile) and are affected by all sorts of factors. Water levels make a difference (a deeper lake eats more beach), as does the amount of dredging being done, the rates at which sediment is naturally bypassed around obstructions by currents, wave angles, and current velocities, even (for all we know) the phases of the moon.
When not much is known, the opportunities for dispute among honorable practitioners are ample. "It's a young field," explains William Wood, professor of ocean science at Purdue and head of its coastal lab. Data is scant or contradictory. Wood notes occasions when his staff and the corps, using the same predictive computer model, have forecast not just different quantities of current-borne sediment moving past a certain shore, but sediment moving past that shore in opposite directions! Change your assumptions about the angle at which waves attack a beach by a mere one or two degrees, he adds, and you can alter quantitative predictions by factors of two, five, even ten. "Both the corps and private consultants," Wood concludes, "can honestly get clients any answer they want."
"We've misread so much of the drift problem," insists Dick Holmberg. Armoring of the shore has changed both the way currents flow and the shape of the nearshore lake bottom. Partly as a result, the littoral environment has attained a complexity that the research models cannot match. Currents are shaped by a pliant lake bottom, Holmberg says, but the wave tanks used in the labs have solid bottoms. "They can't create the currents," he scoffs. "Their answers aren't whole."
The Lake Michigan Program of the Illinois State Geological Survey proposed an ambitious study of the lake environment to the Illinois General Assembly that would have attempted to augment, perhaps even replace, computer-modeled data with actual on-site sampling to determine the nature and amounts of material moving through the littoral zone. It was not funded.
Whatever the actual amount, experts on both sides of the soft-shore debate agree that "some" drift materials are present along the North Shore, but there is a lot less than there used to be. As for Chicago--well, whatever else the longshore currents off Chicago may be polluted with, they are not polluted with sand. The evidence is largely anecdotal, and the disputes therefore all the more heated, as they tend to be when answers swing on philosophy as much as fact. Kakuris is adamant. "Yes, there is littoral drift. It's not plentiful but it exists." The corps' Charlie Johnson thinks the quantities are insignificant. A gravel beach installed off Highland Park by the corps in 1983 to protect a sewer line has acquired what Johnson describes as "a thin veneer" of sand a few inches thick. "That's the only evidence of littoral material we've seen south of Fort Sheridan."
The absence of littoral sand doesn't necessarily signify the literal absence of sand. Johnson explains that currents have rerouted a lot of it. "Mass is conserved," he notes of the huge tonnage already circulating in the lake. "The sand doesn't disappear." The culprit, he adds, may be high water levels, which produce high wave energies on the shore, which in turn push sediments farther offshore. "It's so far offshore that no traditional shore protection structure like those used on the North Shore can capture it." Where wave energies are softened mechanically—as they can be by various soft-shore beach restoration technologies—significant, even startling accretions of sand have been recorded. In Johnson's view, however, such accretions do not prove the presence of accessible drift material but the shoreward movement of sand already present in nearby offshore shoals.
A skeptical outsider may think that the corps' general there-is-no-drift stand reflects agency self-interest as well as science. ("It's an assumption," states Nancy Holm, limnologist with the Illinois State Geological Survey's Lake Michigan Program.) By asserting that there are no appreciable quantities of drift below Waukegan, the corps bypasses the bypass issue. This enormously simplifies its permit and review process, and not just in cases of individual shore structure projects. The corps is under a statutory obligation—admittedly seldom enforced, rather like the pedestrian's obligation not to jaywalk—to consider not only the effects of local structures on local shores but the cumulative effects of all structures on the entire shore system. Adding drift to the equation would complicate such calculations enormously.
Forget the flow of paperwork through the corps, however, and consider the flow of sediment through the lake. Assume that the Illinois shore can be softened by replacing reflective structures such as seawalls with more energy-absorptive ones, thus reforming delinquent currents. Assume further that beach-building materials are available in quantity, either from captured sediment, offshore sandbars, or (as Johnson suggests) from deposits in the Fox River Valley. Accept that they are introduced to the longshore current somewhere south of Waukegan (say, at Lake Bluff), from which point they would move downcoast to Wilmette and its harbor jetty. Sixteen thousand tons of it a year—and what do you get? Each particle of beach sand that washes ashore on a downcoast beach helps sustain that beach for a time before it is dislodged by waves, pushed downcoast, and redeposited on another beach segment where it performs the same service. As sands pile up at Wilmette they would be trucked back upcoast and reintroduced to the system.
And? The result would not be a miracle. "Even at current rates of transport you're not going to have recovery anytime soon," says Purdue's Wood. Much of the new sand would be deposited offshore, restoring the shore's original profile. "It's doing the system good, it's just that it's doing it in a place where people can't see it," Wood points out. Unless sand is added to the system in amounts larger than present losses to downcoast transport, he concludes, "the best you can hope for is to maintain the status quo." A modest hope perhaps. But life, remember, may be described as the maintenance of the status quo in the face of death.
The obstacles to any large-scale nourishment project along the North Shore are not hydrologic but human. Private beach owners typically balk at paying for beach nourishment projects when the sand will move on to grace the beach of their downcoast neighbor who cheats at bridge; taxpayers seem similarly loath to pay for sand for bathing beaches that will eventually add to the property value of some private home owner. Unfixed shore protection systems that move and change shape confound our expectations of property lines. Besides, the negotiations that would be required to craft a cooperative cost-sharing agreement among hundreds of owners, public and private, in an area distinguished by the distance between neighbors make arms talks look easy.
In trying to protect their particular stretch of shore, unfortunately, North Shore beach owners doom the whole of it. There exists no authority, political or moral, sufficient to compel good sense on the part of such disputatious and selfish interests. "It's an institutional problem," says Johnson, and it's hard not to hear in that remark the suggestion that lots of people who aren't in one ought to be.
"The corps," snipes coastal consultant Dick Holmberg, "has never reestablished a natural beach and held it." If that's true—and the corps' record is not very good—the corps may be the only U.S. military outfit never to have won a battle. Wood points out that whatever its temporary benefit—and that benefit is usually political--sand pumping cannot restore a beach unless the rest of the decimated shore system—shore face, berms, etc.—is healed. Sand dumped onto a damaged beach will look like a beach for a while, but it won't act like one—80 percent of 400,000 tons of fine-grained sand placed on a two-mile Michigan beach recently was gone by the end of its first summer. Currents bouncing off an armored shore will simply push new beach material off the shore. In effect, beaches don't disappear because the sand leaves; rather, sand leaves when the beach is gone.
"Why are we attacking the symptoms and not the disease?" demands Kakuris. Corps policy calls for nourishment "when conditions permit," but conditions on the Illinois shore seldom permit more than short-term relief. To soft-shore advocates, nourishing a damaged beach is like buying a broken-legged man crutches without first setting his bones. Simply dismantling existing seawalls and groins would be a disaster in most places. The need is for protection systems that are durable but nonreflective, intermediate technologies between nature and the concrete truck.
Imitating nature, it turns out, is not just flattery but efficient design; dozens of new soft-shore technologies were announced in the 1970s, each exploiting its resemblance to some natural part of the complex coastal process. They share a family resemblance, however, insofar as each was designed to absorb rather than reflect water energy.
A few such designs have appeared on the Great Lakes. Dick Holmberg, for example, uses cement-filled bags to make an underwater groin. "We try to encourage nature to be a building force, not a destructive force," Holmberg explains, quoting from the soft-shore catechism. "The system acts like a series of baffles. The currents are not deflected out into deeper water, like they are by the old groins. They are slowed down, so they drop their sand." At a typical Holmberg site off New Buffalo, Michigan, owners of depleted bluff properties have seen accretion of some three vertical feet of new beach material over several seasons, and offshore sandbars have begun to creep shoreward, restoring the scoured shore face.
A decade ago, Kakuris coinvented and patented a "modular pervious sill"—an imitation reef—consisting of a series of concrete prisms set in shallow water, in rows parallel to the shore. Each trapezoidal component has three openings that taper toward the shore; striking it, incoming waves are funneled into and through the slots. The energy of waves is thus sapped, but the movement of water up and down the beach face is not otherwise impeded. Sold under the trademark Surgebreaker, the system has been extensively tested, alone and in conjunction with other soft-shore restoratives, in Hawaii and on the Gulf Coast as well as in Lake Michigan off Illinois. The latter installations have encouraged significant accretions of beach material not just on the landward side of the device but on the lakeward side as well, where one would ordinarily expect to see scouring. At spots along one site, for instance, roughly six vertical feet of new beach appeared in as many months, building up a new beach that healed a wave-eroded bluff.
High water and steep beaches complicate the mechanics of restoration. The pull of swash, or the lakeward backwash of waves slipping down a steep beach face, is enough to strip a beach of even coarse sand. One answer is to rebuild the beach with something other than sand. Beach materials range in size from the familiar sands to gravels to cobbles (tennis-ball- to basketball-sized stones) to boulders (your serious riprap). (To the large end of that spectrum we might add high rises.) Heavier beach materials are not so easily transported as sands, which is why they tend to accumulate along shores where wave action is vigorous, such as the Riviera.
Gravels occur naturally on Lake Michigan beaches. So—rarely—do cobbles. Shabica uses cobbles exclusively in his experimental beach restoration in Highland Park; Kakuris has arrayed them at sites in Winnetka and Wilmette in conjunction with his reefs to function as a containing wall that both breaks waves and prevents the lakeward migration of the stones. The two disagree about details: Shabica thinks Kakuris's cobbles are too small to be stable--large sand grains. Kakuris thinks Shabica's are too big to be absorptive enough--mini-seawalls. The salient fact is that it is possible to soften wave impact, ease scouring, and permit the delivery and retention of water-borne sediments.
Just add water. Instant beach.
Last fall Shabica told an audience at Northwestern University, "Chicago has been at the forefront of shoreline engineering since the turn of the century." That's a little like praising Detroit for the efficiency of its product recalls. The city forestalled devastation on one side of its armored shore at the cost of more subtle devastation on the other, in the form of a scoured and denuded lake bottom. And as Shabica puts it, "Soft-shore technologies only work when there is something soft already." Along much of the North Shore, offshore slopes remain fairly gentle, while the Chicago shore has, Shabica says, "gone past that point." Kakuris agrees. "The shore in Chicago is so overdeveloped, so urban. Adding structures like groins ordinarily would not be acceptable, but here the damage has already been done."
Chicago's lakefront custodians for decades have thus planned according to a rule borrowed from criminal law, namely that you can't kill a dead man. Indeed, the point of most of their work has been to dress up the corpse. The stepladder series of beaches between North Avenue and Fullerton, for instance, consists of "perched" beaches, so called because their sand is held up above the waterline in what amounts to a series of giant sandboxes formed by sand-containing groins on the sides and walls of sheet steel sunk into the water.
That's right. A son of a beach. The perched beach technology was developed by the Park District in response to the loss of naturally replenishing drift material some 25 years ago. It is a technologically admirable adaptation to a bad situation.
Alas, the situation that gave rise to the perched beach has changed. High water is overrunning the familiar beaches and stripping them. "I don't think we can sustain all the beaches in the lake," says Charlie Collinson of the geological survey. The corps' Morhardt agrees, saying, "Professional opinion is tending toward the view that any beach on the Illinois shore will have to be artificially maintained." Kakuris, who agrees with Collinson and Morhardt about little else, agrees with them about this: "We will have to budget in Chicago for the regular nourishment of beaches." But how will the beach-nourishing budget be nourished? Park District engineers have estimated that as much as a million cubic yards of sand are needed to restore all the beaches to their glory, at a cost of $10-$12 a yard. And the job may have to be done again and again, if the lake stays up. The city's war with the lake may yet see Chicagoans fighting not on the beaches, but over them.
Sandbags, not sand, have been the worry of residents of lakefront high rises. A perched beach is as artificial a presence on the shore as a condominium tower, but protecting the latter requires more than a dump truck. The talk to date has mainly been about building islands or landfills—expensive ideas that owe less to engineering than to politics (an extended Lake Shore Drive for you, a wave barrier for me) or to the anxieties of condo dwellers who would rather, it seems, have waves breaking into their places than bathers.
Local coastal engineers are not enthusiastic about islands or landfills. "That's not solving the problem," insists Kakuris. "That's just making it more expensive." Any new land in the lake will still have to confront waves on its lakeward sides, and any new seawalls, riprap, or breakwaters will confront the same fates as their predecessors.
If a beach remains the cheapest and most adaptable shore protection structure, why not build beaches? Models are already in place. "I've pointed out to the Park District that they already have the most effective shore protection structure they could want in Loyola Beach," says Charlie Johnson of the expanse of gravelly sediment that lies cradled in the arm of a groin off Pratt Avenue. "It's quite possible to do it. We know a lot more about what goes on on the shore than we did the last time the lake levels were high."
Stone might be used to rebuild the grade offshore as a first step, and stone is available locally in quantity in the form of leftovers from Deep Tunnel and canal excavations. And the topcoat? Johnson says that there is still enough sand off the Chicago shore to keep rebuilt beaches fed, given a little ingenuity and a lot of money. Borings taken recently off Edgewater found deposits 15 feet thick, a finding that doesn't surprise Holmberg. ("Chicago should be buried in sand," he says. "People should be complaining about their feet getting burned because they have to walk across so much of it to get to the water.")
There is less sand off the south side, or rather the sand is on the wrong side of the revetments fronting Burnham Park, having been sucked off the lake bottom to make the park. Even so, argues Johnson, "There's no reason why you couldn't establish beaches south of McCormick Place." The engineering requirements could be satisfied by trucking in beach materials from inland quarries. The economic requirements may be even easier to meet. "Given the deteriorated nature of the timber seawall foundations that are there now," Johnson says, "the alternative to a beach will also be very expensive." And any purely traditional structural alternative would not add several thousand feet of recreational beach to the neighborhood.
"It's almost too late," worries Lee Botts. "We did not succeed in convincing people of the need to do something in the early 1970s, the last time the lake was up." Given the human tendency to make bad situations worse, the risk seems to be that people will do something. True, Chicago made its river run backward. But that project offers a dubious precedent. It was an impressive technological feat for its time, but it was also a stupid one, a no-brain solution to a complex problem of the city's own creation.
A soft-shore approach requires not only that people build differently but that they think differently--think for example that the lakeshore is the lake's shore, as well as ours. When Botts says, "There's no hope of returning to a natural shoreline in Chicago," her pessimism reflects the politics of the situation rather than its science.
That a crumbling shore may not be fixable by traditional methods may in fact be its salvation. Lack of means isn't necessarily a condition of wisdom, but it usually imposes a becoming modesty on the ambitious. The recently passed federal Water Resources Development Act raised the required local share of construction costs (to 10-50 percent, depending on the type of project), which will probably mean smaller projects. And the corps, as implementing agency, is now obliged to offer nonstructural alternatives as part of its feasibility studies--alternatives that recommend themselves increasingly to engineers anyway because of their low cost.
A few blocks from the corps' Loop office, in the headquarters of the Chicago Park District, similar ferment simmers. As is true of most government agencies, when something doesn't work the Park District does more of it. That may not do this time. The February 8 storm alone did a reported $7 million damage. Early estimates of the cost of minimal repairs to existing revetments along Park Distict property ran to $200 million and more--half again the size of the district's entire annual budget--with full restoration costs possibly running as much as a billion. All to replace a system that might be left literally high and dry the next time the lake recedes.
Restoring Chicago's shore to a more natural profile is usually dismissed as impractical, even by the people who think it a good idea. But "impractical" often does not mean that something doesn't work, only that it works in unfamiliar ways. Besides, what is more impractical than spending money the city can't afford to build structures that don't work very well?
If restoring all or any substantial part of Chicago's shore to something like its original shape is a daydream, then no agency is better prepared to undertake it than the Chicago Park District. Not just because the district owns most of the shore, but because in Walter Netsch it has Chicago's designated daydreamer. Back in November, at a conference at Northeastern Illinois University, Netsch pointed to the stretch of Burnham Park between 26th and 48th streets as being especially threatened by erosion. Seawalls are collapsing, and water threatens Lake Shore Drive not just by flooding over it but by eroding under it.
“We cannot go into grandiose plans," Netsch announced. What he proposed instead was the construction there of a restored, softer shore. It was, Netsch announced, the vision of Luke Cosme, a longtime Park District engineer, who sat in the audience looking like a proud daddy watching his child in a school play. Vulnerable lanes of Lake Shore Drive would be relocated to the west, and a quarter-mile breakwater installed offshore to protect a new series of beaches nestled between headlands or points armored by riprap. The new shore, promised Netsch, would look "the way it was in DuSable's day." That is not quite true; the shore would still be a patently artificial one, if more cunningly artificial than the stone battlements it is proposed to replace. However, it would function enough like a natural beach to make good Netsch's plan to turn that stretch of shore into a museum where the public might glimpse a lake environment long since banished from Chicago.
The idea has since gone unmentioned, most of the press coverage of the Park District dealing instead with the erosion of administrative authority during power squabbles. There was some reason to question how seriously the Burnham Park beach was intended; no estimates of costs were prepared and no timetable presented. Most of the reporters covering the unveiling seemed disappointed anyway, having come to see a plan for islands or similar extravagance. (There had been leaks to that effect earlier in the week.)
Like most people, reporters mistakenly measure the ambition of a project by its scale, and so missed the potential significance of the proposed re-creation. The beach, Netsch explained, would be a "primary study area" where long-range solutions to shore protection might be tested for application up and down the city shore. A way to look forward by taking an intelligent look backward.
Even the most ardent soft-shore advocates do not pretend that their new ethic fits every circumstance. Completely nonstructured shores are probably foolhardy in urban areas anyway, in spite of Orin Pilkey's injunction that any system to secure a status quo is doomed, no matter how benignly it secures it. But traditional shore protections don't work in every circumstance either, and they often fail at even higher environmental and economic costs. As Netsch himself stressed last November, experiments do not always provide a solution. They are, however, places "to begin to look for a solution." ■