In 1967, renowned landscape architect Ian McHarg presented a study -- "Toward a Comprehensive Landscape Plan for Washington, D.C." -- to the National Capital Planning Commission. McHarg observed that Washington's waterways, woodlands, hills, ridges and valleys had allowed "a most dramatic contrast between calculated artifice and nature."

Compared to many cities, the nation's capital is blessed ecologically. Its geology and topography are varied, ranging from nearly flat, silty river plains to uplifted tablelands, palisades and steeply carved rocky ravines. Its soils and vegetation are equally varied, allowing evergreen and deciduous plant species found in northern and southern climes to coexist.

Frederick Gutheim has written that "the ongoing process of man's interaction with natural resources characterized the city as a growing and adapting organism." Look conceptually at Washington's plan and you will see a parkland network that, indeed, resembles a tree.

Rivers and creeks sometimes flow placidly, almost imperceptibly, while elsewhere they cascade and froth over ledges or through narrow channels. Many cities have but two seasons, hot or cold. Temperate Washington clearly has four, each distinct in its coloration and weather. Much of the year, it is genuinely pleasant and preferable to be outdoors, whether gardening, hiking, biking, swimming, sailing, playing ball, eating or window shopping.

Given these natural circumstances, Washington has been wisely developed, for the city and its environs contain extraordinary park space, both in quantity and quality. Moreover, the city's parklands accommodate almost any activity and are well-knitted into the tight fabric of the central city and the looser fabric of its suburbs. Residents must travel only a few minutes before reaching one of these environments where they can be as active or as passive as they choose.

Most notable are the stream and river valley parks originally envisioned by L'Enfant and later more clearly delineated by Frederick Olmstead, his son, the McMillan Commission and the Park and Planning Commission.

Rock Creek Park stretches northward from its tiny mouth (marked by Thompson's boat center) at the Georgetown Channel of the Potomac all the way into Montgomery County. Its width and topography vary dramatically. With meandering drives unfathomable to the newcomer, it contains rolling woodlands, flat grassy flood plains, deep chasms and ravines lined with imposing rock outcroppings and thick vegetation, rapidly rushing water courses and idle ponds.

In Rock Creek Park, you may drive or bicycle through, have picnics, jog, horseback ride, play golf at the Rock Creek Golf Course north of Military Road, attend performances at Carter Baron Amphitheater, or visit the National Zoological Park, better known as "the zoo."

Many see Rock Creek Park as a bisector of the city, a green seam dividing west from east. But, intimately integrated into the heart of the city, it could be seen, instead, as an element of unification and commonality through its unambiguous role as a great and beautiful city park accessible to all.

To the east lie the alluvial and upper woodland parks of the Anacostia basin. Ancostia Park, flanking both sides of the river, offers boating clubs, athletic fields, a field house and pool, and the Langston Golf Course north of RFK Stadium. Slightly upstream are the Kenilworth Aquatic Gardens and the extensive National Arboretum. The undervisited Arboretum is another unique D.C. asset, a vast botanical landscape and outdoor museum almost the size of National Airport or the Mall.

At the District line, the Anacostia River Park branches to the northwest, where it in turn splits into two of Montgomery County's finest stream valley parks, Sligo Creek and Northwest Branch. The latter culminates at Wheaton Regional Park.

The other branch of the Anacostia system heads northeast to Greenbelt Regional Park, just east of Kenilworth Avenue. Like so many of Washington's parklands, its size and amenities are rarely appreciated by occupants of vehicles speeding along its boundary roads or bisecting it on the Baltimore-Washington Parkway.

East of the Anacostia lies a series of parks named for the 19th century forts that made use of their relatively high ground for defending the capital city -- Fort Mahan, Fort Chaplin, Fort Dupont (the largest and best known of the parks), Fort Davis and Fort Stanton. They generally meander from northeast to southwest until meeting the Suitland Parkway, one of the city's most scenic drives. To its south is Oxon Run and its parkway, which terminate at St. Elizabeth's Farm north of the Beltway/Anacostia Freeway interchange and east of Indian Head Highway.

East Potomac Park separates the river from the Washington Channel and contains a golf course, tennis courts and swimming pool. West of the Tidal Basin ringed by cherry trees, the reclaimed land of west Potomac Park and parts of the Mall near the Lincoln Memorial accommodate numerous field sports, including polo, rugby, softball, touch football and soccer. By contrast, Lady Bird Johnson Park and Arlington National Cemetery across the river are more passive and contemplative in nature.

Proceeding up the river is the George Washington Memorial Parkway, a spectacular linear park for automobile traffic on both Virginia's and Maryland's steep Potomac embankments. The C&O Canal and its tow path, beginning in Georgetown, serve pedestrians and cyclists as they parallel the river for dozens of miles. Above Georgetown, Glover Archibald and Battery Kemble parks angle northwardly from the Potomac valley into affluent Washington residential neighborhoods.

Farther upriver are the Palisades, Little Falls, Glen Echo and Cabin John parks. Like portions of Rock Creek, these parklands include unexpectedly some of the most dramatic and rugged natural landscape to be found in the region. Only exploration on foot reveals fully their beauty. On a clear spring day, the sights, sounds and smells of moving water, new growth, scurrying wildlife and refreshing breezes never cease to amaze urbanites whose workaholic city is only minutes away.

In addition to the thousands of acres of stream valley parks in and around Washington, there are hundreds of smaller public parks and playgrounds, private country clubs and school campuses that serve local, rather than regional, constituencies. Thus, the nation's capital provides open space in hierarchical fashion at the scale of neighborhoods, communities and the city.

In how many cities can you walk, cycle or drive in a continuous park space comparable to that which runs from Great Falls to Mount Vernon? Along the way, where can you see natural, urban and architectural events comparable to those lining the Potomac River Valley? And how many cities provide such incredible variety of parkland topography, vegetation and activities, not to mention their geographical association with two centuries of American history?

Today, most would agree that the waterways, flood plains and stream valleys, terrace lands, slopes and ridges, hills and escarpments seen by our 18th century predecessors constituted a wonderful site for building a city. But we are fortunate that, the choice of the city's site having been made, much of that natural setting has been so well preserved and utilized.

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