The Purchase Area Watershed Mapping Project is an effort to create a full-featured GIS Model for use by Community development practitioners, emergency management agencies, civic organizations, schools, libraries and other public entities. This document describes how and why the model is being created beginning with the locale of Paducah, Kentucky following the Tennessee Valley Divide to the southern border of the Jackson Purchase Region of Kentucky in the USA.

Rediscovering the land[]

Most people who live in, or are familiar with Paducah and McCracken are aware of its basic geographical form through traveling on roads and streets. Major waterways are fairly obvious from landmarks such as the I-24 bridge across the Ohio, the floodwall at the foot of Broadway and the the Tennessee River bridge into Livingston County on Highway 60.

The intersections of man-made roads and natural water courses is an interesting study in the fundemental relationship between the built and natural environments. For example, Bridge Street is named for the bridge across Island Creek, near Brown. This spot has a place to pull over on the right just past it as you're heading out of town. There happens also to be a benchmark there. If you think we need a picture, go ahead and snap a .jpg and use upload file to your left when you get back here.

The new bridge across Perkins Creek on Pecan Drive near the site of the future Paducah Bank building is another fine example. Elements of the built environment provide notable landmarks, making things handy for motorists and commerce. But, unless one is focused on less obvious features, these constructions can distract the student and might obstruct the view of the natural environment. The Watershed Mapping Project will blaze hiking and bike trails with a focus on Island and Perkins creek to draw attention to these very important natural assets.

This map begins with a visit to Paducah Blueprint Supply and the purchase of the Paducah East and West quadrangle maps produced in 1982 from old high altitude photos and field work by the USGS. We take it from there to a more current version, producing overlays that include new features like the example above, and ecological markup for the one above that.

An interesting feature about the foot of Broadway is that, geophysically, that point represents the "golden spike" for this mapping project. Not only does it represent the point of confluence of the Tennessee and Ohio, but it is also the lowest point of elevation on the Tennessee Valley Divide. The ridge-valley system heads basically South toward Lone Oak and exits The purchase area at the Tennessee border near Hazel, Kentucky. This Water divide is among the most important geographic features in Mid-America, stretching through eight states ending (or beginning, depending on how you view it) in West Virginia.

Lone Oak Road (U.S. 45) actually tracks the ridge for several miles between Lakeview Drive and beyond the edge of town. Both Island and Perkins creeks have tributary headwaters in Lone Oak near the water tower. The eastern watershed flows into the Tennessee via the Champion/Island Creek System while the western watershed flows into the Ohio via the King/Perkins Creek System. The central reference line for the first PAWMP map will be a line from the top of the Lone Oak water tower to the foot of Broadway.

Funding and support[]

The efforts of PAWMP volunteers, compensated cheifly by DucahDollars will provide a substrate for community development in Paducah and McCracken based on the ubiquitous understanding of geography, helping to build Human capital through our sense of place.

The project exists mainly in Cyberspace initially using web services provided free of charge by Wikia, Inc and the Kentucky WikiProject at Some academic studies are also being developed at the Wikimedia Foundation's new Wikiversity by Paducah2020 volunteers enrolled there in several disciplines. The Images and maps will be released under a Wikipedia:Creative Commons License and made available for use on Wikipedia and other open content projects.

The field volunteers will need a pickup truck, a rugged laptop computer, a couple of GPS-enabled hand-held computers (similar to the Garmin iQue 3600), basic digital cameras, a first-aid kit, some hiking gear and a lot of encouragement.

Building the model[]

PAWMP's first task is to create a three-diminsional software model around two spatial points:

  1. The tip • A point representing the tip of the obstruction light atop the Lone Oak water tower
  2. The anchor • A point representing an imaginary anchor dropped at the confluence point of the Tennessee and the Ohio near the foot of Broadway.

These points are the primary Georeferences and represent our first orders of approximation of the Tennessee Valley Divide. We shall continue modeling the ridge/valley sytem using a successive approximation method tempered toward a model compatible with the Keyline principle first described by the Australian engineer, P. A. Yeomans.

See also: Yeomans, P. A., The Keyline Plan (1954) | Wikipedia:Catography | v:Topic:Cartography | Wikiversity

The starting line[]

An imaginary line called the dropline is stretched between the tip and the anchor defining the highest and lowest elevations in the model. These points are mathematically represented in the software model relative to the standard latitude, longitude and elevation grid used on USGS topographical maps. Now we construct a database table with variable names used as primary keys for referencing the latitude, longitude and elevation value sets (georeferenced tuples):

DROPLINE Latitude Longitude Elevation
tip tiplat tiplong tipelev
anchor anchlat achlong anchelev

This table resides in the "upper lefthand corner" of our software database. The tip, dropline and anchor form a one-dimensional object called the prime vector. It has a magnitude and a direction relative to the standard Georeferences used in common Cartesian coordinate systems.

NOTE: Please do not confuse "position" in the context of object relational database tables with coordinates for points, lines and planes and spheres in physical space, even though the two contexts are "kin" in many ways.

A frame of reference[]

In further visualizing this model, think of a vertical rectangular plane formed by erecting lines upward from the anchor and downward from the tip. These are called the tipline and the anchorline. The bottom of the tipline is called the basepoint and the top of the anchorline is called the skypoint. These share latitude and longitude coordinates with the tip and anchor, but swap elevations. They can be thought of as aliases for anchor and tip.

Now we draw a horizontal line from the tip to the skypoint which we call the skyline, and a line from the anchor to the basepoint which we will call the baseline.We now have the defining edges of a two-dimensional object called the centerplane around which the model is built.

In our data table, our next order of approximation establishes a two-dimensional object via the next set of reference keys:

tip skyline skypoint
tipline origin anchorline
basepoint baseline anchor

The baseplane and skyplane extend out from the centerplane intersecting the base and sky lines. For the Lone Oak : Foot-of-Broadway Model we arbitrarily limit the top and bottom planes to a square shape. We now have all three dimensions in an object called the geoframe. Now we draw the centerline at the centerplane's midpoint. The point where the dropline intersects the centerline is called the origin of our model.

SEE: Object relational database | v:Topic:Databases

Back down to Earth[]

The Next feature in the model, called a ridgebone corresponds to the highest elevations nearest the central plane along the ridge..

Two USGS maps called the Paducah East Quadrangel and the Paducah West Quadrangel illustrate the ridge and its first two watershed systems beautifully. The Tennessee Valley Divide is shown by an obvious thick red dotted line. The ridgebone is a wavey plane plotted first from the USGS maps into the software model. It shows the crest of the main ridge continuously from the tip to the anchor.

Field volunteers will walk the ridge following the USGS line with their hand helds and cameras. USGS Benchmarks, points of historical interest, hydrological keypoints (and their resultant keylines), archeological sites, special wildlife sightings, are identified, located and logged into their corresponding tuples in the model and uploaded into the growing metamodel which resides on the laptop back at the truck. At the office, a GIS-aware server equipped with a docking station, holds the working copy of the main database which is backed up and replicated through regional academic networks and the global Internet.

After the Ridgebone is entered, field crews then venture down from the headwaters into the watercouses below on each side.

Assembly areas[]

The most obvious assembly area is of course the Foot of Broadway near the anchor. The tip is easily seen from the Lone Oak High School parking lot which happens to drain into a notable headwater feature of Perkins creek out that way.

After curving toward the west, The ridge intersects Broadway again at Joe Clifton Drive. It's not such a good place to assemble because of the traffic, but a nice spot to keep in mind. Paducah Middle School sits atop the divide near Lone Oak Road and Jackson. Next, the ridge passes through the football field at St. Mary High School. Nice.

Some points of interest[]

The old Walter Jetton School campus on the Island creek side of the ridge (Near Kentucky Avenue and Walter Jetton Boulevard) in Uppertown is a good spot for meeting. There happens to be an easy-to-find USGS Benchmark there at the corner.

On the Ohio River side of the ridge, both Stewart Nelson Park and Bob Nobel Park are situated squarely alongside the scenic main channel of Perkins Creek.

On the East side of the ridge, Island Creek's confluence with the Tennessee at the Flood Wall (believed to be the site of Chief Paduke's lodge) is currently an unfortunate example of an ongoing ecological disaster.

Journey through time[]

The Purchase Area Watershed Mapping Project is a long-term project. Not only are geospatial coordinates plotted, but a fourth dimension, time is introduced to carry us back and forth through time.

We will carefully examine the built environment and speculate how things will look in a hundered or five hundered years. Will The Mall get a second story? Will there be skyscrapers at I-24 and US 60? How about an elevated bullet train from Chicago through Western Kentucky to Gulfport? Where will the eight-lane Interstate 66 cross the Mississippi? We might should think about the Mississippi Embayment and the Reelfoot rift on those.

We'll turn the dial counterclockwise to see how our Eastern border, The Tennessee River was altered by the building of Kentucky Dam. Going on Back, We'll picture the "Plant Boom" of the Fifties, study the ruins of the Kentucky Ordinance Works plant where tons of conventional bombs dropped on Berlin and Dresden in WWII were made in the Forties.

We'll drop back and watch the '37 Flood and see how Paducah looked in the Roaring Twenties when street cars still clanged their way down Broadway in Paducah. Our retro-map will systematically unbuild Paducah, Mayfield, Benton ... through the Steam Age.

We'll watch our part of Kentucky in the Civil War from our virtual seat... catch Polk setting up Columbus as the "Gibralter of the South" and trace Forrest sneaking down the ridge from Tennessee to camp at Hendron before raiding Paducah. We'll follow Grant's gunboat around the river system that wraps around the Purchase area on three sides.

We'll take up the tracks and ties and put the trees back to watch the development of flatboat settlements Pekin (on Island creek) and Rowlandtown (on Perkins Creek). By this time, the project may get to see the 1811-12 and 2011-12 Earthquakes at the same time.

As we move up and down the ridge and through time, we will also strip away modern roads and bridges revealing the ancient sites of Lovelaceville and Florence Station, along with the overland route connecting them. We'll travel Clark Line Road, the original supply line blazed by William Clark and among the oldest roads in Kentucky.

Working with the Confluence History and Archeology Taskforce, we'll identify sites visited by Cherokee, Chickasaw and Shawnee hunting parties. We will go even further back and visit Mississipian centers of culture.

Then in 2020, when the whole map is finished, we'll climb a pristine Tennessee Valley Ridge with no dotted-line southern border as we climb its rising arc all the way to its crest in the Appalachian Mountains.