ROCK CREEK PARK IS AN AMAZEMENT, A DREAM, A God-made artifact in a human-made domain, a miracle. It also is a dumping ground, a sewer, a speedway, a human-made compromise on God's green earth, a resilient giant. The woodland valley -- with its sharp descents, towering trees, rushing waters and quiet eddies and its fish, deer, beaver and birds -- is ages old, a connection to the wilderness that once was, and to all the romance that non-Native Americans have made of the wild in the last five centuries. On September 27 the park will be, precisely, 100 years old.

Like many a transplant to this city, I vividly recall my first encounter with the park. It occurred -- and this is all too typical -- in a car, and it was love at first sight. This, I suspect, is also typical. A solitary passenger in the back seat with no particular interest in direction or location, I was dreamily enveloped by the lush canopy of green without really noticing until the improbability struck: green speckled summer sky for miles, green ground, green escarpments, green reflected in the faces of companions in the car. We were in a place called Rock Creek Park, I was told offhandedly. I thought: Rock Creek Park!

In the quarter-century since, I have been a steadfast admirer if only a casual, passive user of the park -- a commuter, shortcut taker, stroller, sometime picnicker. I've been moved by gospel singers at the Carter Barron Amphitheatre and by art at the Art Barn. Bill Christenberry once installed a piece in the attic there -- one had to climb a ladder to see it, and it spelled out "Fox" in italicized blue neon. Every now and then I'll stop at Pierce Mill, one of the few 19th-century structures remaining in the park, mainly for the unique smell inside the building, a damp mixture of machine grease, whitewashed old stones and old wood.

My daughters have ridden horses on its trails. A biker friend regularly pedals miles up the valley, way, way into Montgomery County, and back. I've had tennis-playing

friends who use the courts there, and a golf-playing colleague at work who speaks disparagingly of the lumpy greens but lovingly of the longneck Budweisers for a buck and a quarter at its rolling, well-hidden 18-hole course. Recently I walked a trail into the deep woods north of Military Road, just to see if a point could be attained where even the faintest hum of automobiles does not reach. It exists, one of those spots park Superintendent Rolland Swain had told me about, a place "not too different from being dropped into the middle of the Smokies." There were a few dilatory midsummer bird calls, and not another human soul.

Rock Creek Park is a presence in the city, and in the county too, though the county part is different, a meandering sliver of tree-bordered meadow that follows the stream for most of the 22 miles to its origin near Laytonsville. Because of its length, the county park is bigger (4,193 acres) than the portion inside the District line (1,754 acres). But because of its bulk, the city park, which antedated the county extensions by about 40 years, looks larger on the maps -- it stretches nearly a mile from east to west in its upper reaches and bulges even wider before funneling

down to Klingle Road and on to Georgetown and the Potomac.

And the city park feels larger. Which is to say that both in fact and in the imagination, Rock Creek Park is one of the biggest city parks in the world. No conventional urban park, it's a magnificent anomaly, an almost pristine forest in the city. The stream and valley date back to pre-prehistory, to geological time, and were utilized gently for thousands of years by Native Americans, hunter-gatherers, then hunter-cultivators. The ecological balance remained exact and exacting -- when the land thrived, the people did; when it didn't, they didn't.

Since contact with European cultures, the valley has been subjected to more or less continuous exploitation, sometimes healthy, sometimes not. One of the profound ironies of the valley's existence, after it became a protected parkland, is the immense amount of effort it has taken to keep it, pretty much, as it was. A recurring theme of the park's first century has been the unremitting struggle against the pressures generated by population growth and increasing development on the park's periphery. The incursions range from minor to middling to major, from thoughtless littering, for instance, to contemptuous dumping to insidious and constant depreciation of the stream's water quality. At times, to those in charge, it almost seems a losing battle.

On one occasion, of course, a literal war was conducted in the valley, although actual fighting was limited. The artillery at Fort DeRussy, one of 68 armed outposts ringing the city during the Civil War, secured the Union garrison's left flank when Jubal Early's Confederate force appeared in front of Fort Stevens in July 1864. (This was the engagement in which President Lincoln came under fire.) The fort is a secretive place today, hidden in the deep woods just 200 yards from Oregon Avenue NW (near Military Road). Standing atop its still impressive, tree-strewn earthworks, peering into thickets beneath the tall trees, it's difficult to picture the great forest as nothing more than a clearing of tree stumps for miles around. But the image, haunting in more ways than one, is yet another reason to celebrate the birthday of the park, its creators, its caretakers . . . and its survival.

THE DRIVE TO PRESERVE THE ROCK CREEK VALLEY FOR public uses has a curious origin. In Reveille in Washington, her nonpareil account of the city during the Civil War, Margaret Leech tells how President and Mrs. Lincoln, like President Buchanan before them, would remove during the summer's heat to an isolated presidential cottage on the grounds of the Soldiers' Home, well beyond the city's then-northern boundary. Questionable on security grounds -- the president's aides worried constantly about assassination plots in the southern-sympathizing city -- the practice was understandable for reasons of health and comfort. The White House at the time backed up to the fetid malarial shallows of the Potomac, where the Washington City Canal disgorged its wastes every day.

Dissatisfaction with the White House prompted Congress after the war to propose "a park and site" for a new presidential home in or near the city "which shall combine convenience of access, healthfulness, good water, and capability of adornment." The agent selected to survey possible sites was Maj. Nathaniel Michler, Civil War veteran, officer of the Army Corps of Engineers and first hero of Rock Creek Park. As recounted by National Park Service historian Barry Mackintosh in Rock Creek Park: An Administrative History, Michler did an astonishing thing.

"Departing from the apparent intent of the Senate," Mackintosh wrote, "Michler chose to separate the subjects of the presidential mansion site and the park," and, while enthusiastic about the former, he lavished his "greater attention and eloquence" on the latter. The public park he had in mind was none other than the entire Rock Creek valley within the confines of the federal district created by Congress in 1790. Something of a pragmatist, Michler in his 1867 report proposed an ideal version comprising 2,540 acres and a lesser alternative encompassing 1,800 acres. The whole idea was considered too extravagant by a majority of the Congress at the time -- "Let us wait until the country is in a more flourishing position before we do it," argued one opponent, successfully. The proposal died in

the House. But Michler had planted the seed. In size and location if not in character, the park created 23 years after he submitted his report closely approximated his alternative plan.

Michler's was not the first great written appreciation of the natural beauty of the Rock Creek area. Historians consider it likely that in his explorations of the Potomac River, Captain John Smith passed beyond the mouth of the creek (then much broader than it is today), and his 1612 "A Map of Virginia," with its accompanying text, contains much valuable information on the Native American groups in the region. The spirit of the early European accounts of the area is apparent in the celebrated description of Henry Fleet, a young Algonquian-speaking English adventurer-entrepreneur said to be the first white man to set foot

on the land that became Washington.

"This place without all question is the most pleasant and healthful place in all this country," Fleet wrote in 1632, "and most convenient for habitation, the air temperate in summer and not violent in winter. It aboundeth in all manner of fish. The Indians one night commonly will catch thirty sturgeon in a place where the river is not twelve fathoms broad. And as for deer, buffaloes, bears, turkey, the woods do swarm with them,

and the soil is exceedingly fertile."

Though written more than two centuries later and focused specifically on the Rock Creek valley, Michler's account of "this wild and romantic tract of country" was scarcely less effusive. But unlike Fleet, Michler wrote not to promote the commercial exploitation of the

territory but to conserve the land, and he considered congressional action urgent in order to prevent its usurpation by "costly suburban villas." Conservation was Michler's starting point; the rest he left to "the taste of the artist and the skill of the engineer."

In Michler's day the very idea of urban parks as we know them was still new. Victoria Park in London's crowded East End and Birkenhead Park across the Mersey River from industrial Liverpool, products of the English reform movement in the 1840s, were the first truly public parks in the history of western civilization. Before these, observed landscape historian Norman T. Newton, although there were piazzas, commons and royal parks that common people were allowed to use, "there is no recorded instance of outdoor recreational space on land acquired and owned by the people themselves, developed with public funds and open indiscriminately to all."

Michler clearly was inspired by the progressive example of Frederick Law Olmsted and Calvert Vaux, whose Central Park in New York (influenced by, but far grander than, the English examples) was well on its way by the time he made his tours of Washington's wilds. Indeed, as William Bushong, another National Park Service historian, pointed out in his recent study of Rock Creek Park's historic resources, had Michler's vision prevailed, the park would have turned out to be very much a Washington version of the New York prototype. Among the improvements Michler proposed were dams to produce a sequence of lakes and ponds "for useful and ornamental purposes"; long vistas, "artistically arranged," to be cut through the forest; formal flower gardens; "charming promenades"; observatories; conservatories for exotic plants; zoological and botanical gardens; and "grounds for play and parade, and many other useful purposes."

THE DECADES FOLLOWING THE CIVIL War made up a great era of city park building in the United States, and most of the parks -- Philadelphia's Fairmount (begun in 1865), San Francisco's Golden Gate (1870), the transformation of Boston's Back Bay Fens (1878), to name just three of many -- followed the Olmstedian example (when not actually designed by Olmsted himself). The basic concept of the age was to construct an artificial, idealized version of nature within the increasingly crowded cities. This was seen as an antidote to the ills of urban existence. Michler's windy justification for his proposal reflected these pervasive ideas. Parks, he wrote, were "the most economical and practical means of providing all, old and young, rich and poor" with opportunities "to cultivate an appreciative and refined taste," to breathe "the free air of Heaven" and to meet "that greatest of all needs, healthy exercise in the open country."

Similar ideas were expressed in Washington when sentiment to transform the Rock Creek valley into a park surfaced again in the 1880s. But, other than the Capitol grounds, which Olmsted designed in the 1870s, Washington was not to have its grand Olmstedian park. Simple, clear-headed recognition that too much tinkering with natural conditions in the valley would ruin it played a role in that decision, but it was not until much later that Rock Creek Park benefited from a systematic assessment of its character and needs. Other, more pressing concerns than park designs were the driving forces behind the campaign to acquire the valley.

Foremost among these concerns were the deplorable conditions of the creek itself and the realization among park advocates that they were in a race with development. From the late 18th century on, the lower creek, navigable as far inland as P Street, had been a site for trade and fledgling industry. By the 1880s, however, it had been heavily silted by nearby development and become smelly with Georgetown waste. Editor Crosby Noyes in the Evening Star predicted that the valley would become "a dangerous nuisance in the shape of foul open sewer, lined with a succession of slaughterhouses, breweries, dye-houses, hog-pens, privies, & c., polluting the creek with their excrement." Things were sufficiently bad that in 1888 the D.C. Board of Commissioners had recommended covering the fouled creek from O Street to Pennsylvania Avenue with an arched tunnel.

Development, meanwhile, was beginning to spread north into platted subdivisions in the rolling farmlands bordering the valley. And even though park proponents often used the "worthless lands" argument to make their case -- most of the land was unbuildable "in its present condition," they carefully said -- it was clear that with improved roads it would not be long before Michler's "suburban villas" began to perch on the ridges and fill in the many attractive creek-side locations that had for years been used for farming and low-level industry. During the mid-19th century there had been at least eight mills on the stream.

Furthermore, the valley needed saving even from its ostensible friends. In 1883, the city government, seeking a reliable source of clean water, had proposed federal purchase of much of the watershed in order to dam the creek for a deep reservoir extending four miles north of Georgetown. It is hard to imagine what this radical transformation would have meant, although it's certain the city now would have a wholly different feel. The park around this impressive lake, it was noted at the time, would be of "great natural beauty." Maybe, but the thought only makes one treasure today's park even more.

The Rock Creek valley was thus poised on the brink of another great change, potentially the most damaging. Burial seemed a probable fate for the lower creek -- the city's tunneling proposal had strong support in Georgetown and in Congress. Inundation was a possibility for the gorgeous upper reaches. The certainty was that, left in private ownership, the upstream valley would in time become an unusual rustic subdivision for wealthy residents, many of them emigrants from the nation's industrial capitals, who were just then beginning to transform Massachusetts Avenue with their beautiful stately homes.

What saved the valley in a sense was the valley itself -- its beauty was incontestable and its rarity in an urban framework widely acknowledged. But people had to fight for it, and, fortunately, the political climate was amenable. This was dawning time for a nationwide conservation movement. Thanks to the enlightened agitation of Olmsted and others, Yellowstone, the country's first great natural preserve, had been created in 1872, but it remained an isolated case. At the time of the Rock Creek debate, however, other important additions to the budding national park system were being considered by Congress and would become part of the public domain -- Sequoia National Park on the very same day the Rock Creek legislation was approved and, four days later, Kings Canyon (then called General Grant) and Yosemite. Locally, a bill to create the National Zoological Park in the Rock Creek valley was sailing through Congress, establishing an important precedent.

As it sometimes happens, leaders emerged who were sufficiently savvy to take advantage of the opportunity. "A final and vital component" of the park movement, as Bushong wrote, was the united effort of the local business elite under the leadership of Charles C. Glover, president of Riggs Bank (then Riggs and Co.) and second hero of Rock Creek Park. Glover had been the chief political force behind the reclamation of the Potomac River flats -- he helped to save them from the railroads -- and he used the experience to effect in the Rock Creek campaign.

To demonstrate the beauty of the place, Glover organized an outing in the valley for a few of his powerful friends on Thanksgiving Day 1888. This was followed by a meeting at his Lafayette Square home to draft a park bill, and a public gathering at the Atlantic Building downtown to elect an executive committee to lobby for the bill's passage. The committee included the president of the American Security Bank and the editor of the Evening Star, among other well-connected souls, but the tenacious Glover was its chairman.

The result was far from a foregone conclusion, despite the bill's sponsorship by Republican Sen. John Sherman of Ohio, one of the leading figures of the 51st Congress. Sherman's prestige guaranteed Senate approval, but the House -- burial ground for many a local measure -- was altogether another matter. Anti-Washington congressmen, always tight with the District's purse strings, had the extra ammunition of conflict of interest -- Sherman owned huge amounts of land on the periphery of the proposed park.

In the end, though, the House adopted the bill, with the conditions that the park be named "Columbus Memorial Park" in honor of the upcoming anniversary of the discovery of America, that the District government pay half of the $1.2 million price tag for a park of up to 2,000 acres, and that adjoining landowners also be taxed on the appreciated value of their property to cover a share of the costs. The Senate reluctantly accepted the last two of these amendments. The compromise creating Rock Creek Park was passed by both houses on September 25, 1890, and signed by President Benjamin Harrison two days later.

A five-member commission was appointed to survey the land and arrange for its acquisition. To no one's great surprise, the price limit set by Congress proved too low for a 2,000-acre park. In the spring of 1892, the commission reported the purchase of 1,606 acres of land north of the zoo for $1,174,511, with most of the "missing" acreage lying northeast of the park, between 16th Street NW and the creek. Predictably, the attempt to tax adjacent property owners came to nothing -- there was no immediate escalation in land prices, although everyone knew that one fine day living by the park would be a privilege people would pay handsomely for.

SO, WASHINGTON HAD ITS GREAT PARK, paid for and maintained equally by the federal and District governments. (Not until 1933 did it come under stewardship of the National Park Service.) People began to use it right away. A man hired to watch over the reserve was submitting reports by 1892. "I find everything all right in the Park this week," he wrote. "There has been Picnics in the Park every day this past week. No damage done yet to the trees." Teddy Roosevelt was of course a great fan, before and during his presidency, leading sturdy friends (or underlings) on strenuous "point to point" walks, as he called them, and more than once to swims in the creek "when the ice was floating thick upon it."

But money was in short supply and the park's early governors moved slowly upon improvements. This was just as well. Although the legislation creating it stressed the need to "provide for the preservation from injury or spoilation of all timber, animals or curiosities within said park, and their retention in their natural condition, as nearly as possible," the vast tract of otherwise unoccupied land has proven a constant temptation through the years.

Some proposals were downright weird -- in 1898 a couple of solons on the Hill floated a bill to establish permanent state exposition grounds in the park, with each state being allotted from one to six acres for a building. Others were sensible sounding but basically mischievous. One of the lesser known facts of park history is that from 1911 to 1920 the United States Forest Service operated an experimental botanical garden in the park, planting 2,000 trees of 170 species, with intentions to expand. Fittingly, an Olmsted came to the rescue: From his seat on the Commission of Fine Arts, Frederick Law Olmsted Jr. objected acidly to the orchard-like reserve. "It does not now, and it never will, look like a part of the natural scenery," he wrote. Eventually his view prevailed. Park rangers today cannot say whether any of the exotic trees still stand.

Olmsted Jr. also was one of the four members of the McMillan Commission, whose famous 1901 report did so much to reestablish the ingenious clarity of Pierre L'Enfant's original plan for the city. The report's impressive contributions to the capital's monumental core have in fact obscured its wider scope, which envisioned a cohesive system of parks for the whole city. Though its recommendations in this regard were not fully carried out, it had a lasting influence. For instance, the acquisition of tributary "fingers" to Rock Creek Park -- Piney Branch Parkway and others -- was due in no small measure to the commission. (Obviously, it is not the commission's fault that so many of the "fingers" are too narrow and, in some cases, almost wholly disconnected from the body of the park.)

Concerning Rock Creek Park itself, the report was cautionary: This "principal park of a populous city," it said, "was a matter of great perplexity, requiring the most careful study." When time tardily arrived for such a study, it again was Olmsted Jr., this time in partnership with his brother, John, who carried it out. The Olmsted brothers' report of 1918 remains the basic guidebook for the park, and for good reason -- its thinking is fundamentally sound. It identified three basic landscape categories for the park -- natural forest, open woodland and open grassland -- and established principles for their preservation and enhancement, with the largely efficacious results we see today. It created thoughtful standards for architecture in the park, which by and large have been followed to good effect: Structures, it said, "should be so designed and located as to fall naturally into place as part and parcel for the scenery."

And, perhaps most importantly, it set down a basic rule. "The dominant consideration," it began, "never to be subordinated to any other purpose in dealing with Rock Creek Park, is the permanent preservation of its wonderful natural beauty, and the making of that beauty accessible to people without spoiling the natural scenery in the process."

IT HELPS TO KEEP THIS WISE MANifesto in mind, for today Rock Creek Park is besieged with problems. It suffers from an image crisis. Recreational users compete with cars, and despair at the difficulty of such simple-seeming operations as reserving large picnic groves (they're snapped up by companies the first week of every year). The park is coupled in many minds with crime, despite statistics proving the actual incidence of crime there to be quite low, in relation not just to city streets infested by the drug wars but to practically all regional jurisdictions. And, because it is a dividing line of sorts between predominantly black and predominantly white residential areas of the city, it has been too easily identified by many as a source of racial tension, as if the forest itself somehow were a cause.

Plus, the park suffers from a sort of nagging malnutrition. I recently sat at a table with Superintendent Rolland Swain and his division heads. All are experienced National Park Service hands, which is to say they are the sorts of people who choose their work mainly because they love it, and also that their idealism has been tempered over the years by realism. They're straight shooters. Sad to report, the mood at the meeting was fairly grim. Dave Newman's summary was, unfortunately, typical. He's in charge of maintenance, and he has 57 full-time people (compared with 125 in 1972) to clean, mow, cut, clear and repair all the woods, meadows, roads, trails and buildings in the park (plus quite a few nearby parks). "In reality we're not doing a job I feel comfortable with," he said.

No wonder that, in places, non-native vines -- kudzu, porcelainberry, Asiatic bittersweet -- seem to be taking over. Not exactly a comforting image for a birthday celebration, but a needed wake-up call, a reminder that most of the park's problems come from outside the park.

Take, for instance, the car. Fundamentally, the park is fortunate in its roads. What the early park managers did do, they did well. With a few major exceptions, the basic system of roads and trails in the park was completed in the first three decades, under the sensitive aegis of the Corps of Engineers following the sensible, Olmstedian principle that roads ought to disturb the natural terrain as little as possible.

Of course, the automobile was unforeseen when the park was created, and no major concern when Beach Drive and the other roads in the park's northern sections were laid out and, subsequently, paved. The basic idea then seems to have been that the car was a Sunday convenience, and that motorists would cruise slowly through the park sheerly for the pleasure of it. But the days of the pleasure drive were numbered, as any non-rush-hour driver knows who tries today to glide along Beach Drive at 25 miles per hour, the legal limit but still a bit too fast to take thoroughgoing notice of the green. It's no fun leading an impatient pack around the curves.

The story of the park and the automobile is one of fair-sized disequilibrium -- the roads north of the zoo were not designed as commuter arteries, and, as pleasant as the trips may be for the drivers, their use as such twice a day, five days a week, definitely discourages the use of the park as a recreational resource. Returning these roads to their intended purpose should be the goal of any sensitive long-term policy. (The parkway south of the zoo tunnel is a separate chapter; it was planned from the beginning as such, and it saved the lower creek from being buried alive.) There is comfort to be found in the knowledge that it could have been much worse -- a scheme to turn the upper reaches of the park into a multi-lane freeway, connecting to Interstate 270, lived a long life before being discarded in the 1950s.

Traffic at least is cyclical. It happens every day and goes away. The most intransigent of the park's many problems is its principal reason for being, the stream itself. This striking tributary is subject daily to pollutants from an impressive variety of sources throughout the watershed -- illegal sewer connections, legal sewer lines (there are 60 crossings in the creek), streets, sidewalks, parking lots, farms, houses, yards, oil tanks, septic tanks, cars, trucks, buses, animals, people. Above all people, the root cause, doing what we do.

And that's on normal days. On the inevitable abnormal ones, when the rains come fiercely down, all of these sources combine to create a big mess with lasting consequences. Some we can see for weeks, months, even years after really madding storms, the creek clotted with wreckage, its banks falling away. Some we can smell. Sludge settles in and goes to work.

Surprisingly, and perhaps encouragingly (one can't afford to be smug), the creek seems to be holding its own. The overall water quality was rated "intermediate" in a massive study completed in 1979, and by most accounts (plus a casual inspection with eyes and nose), it remains about the same, in part because many of the recommendations of that study have been carried out. "Intermediate" isn't good, of course, but it has to be counted as something of a victory, given the scope and complexity of the problem and the resources available to counteract it.

One notices some of the work the Park Service has done, and notices that it has been done well. The stone embankments (boulders with a splendid name: riprap) built in critical places to combat erosion are soundly constructed, and they fit, "as nearly as possible," just as the law says, into the natural surroundings. Bob Ford, the park's resource manager, points out that trouble was taken to quarry the stones in nearby Occoquan and Rockville, to make a match with the creek's existing rocks. There are Catch-22s in such environmental work. Shoring the creek banks encourages the water to dig deeper into the soil; erosion is stopped, but the deeper creek bed may eventually lower the water table and dry up the creek. "We're studying it," Ford says.

It is ceaseless labor, mental and physical, the task of keeping this urban forest "pristine." The old conundrum applies: Is the cup half full or half empty? It's a matter of perception. Rock Creek Park remains a stunning, stirring, quiet, useful place, a gift unique in the world. But it is indeed a besieged treasure, a gift in need of a gift. Perhaps its great birthday comes just in time.

Benjamin Forgey, the architecture critic for The Washington Post, last wrote for the Magazine on Washington National Cathedral.