The United States portion of the Gulf Coast makes for an easily framed map, once you decide what to do about Florida. Florida's Atlantic Coast is not on the Gulf, but cropping it off looks awkward. Besides, the beautiful arcs of the Georgia and South Carolina coastline nicely balance the curving Texas coast. On the south, including the Dry Tortugas requires a boundary that also takes in the coast of Tamaulipas, Mexico. That brings a bonus by showing the narrow extent of the coastal plain.
THE GULF COAST & Lower Mississippi 32" x 44" $95
The northern boundary is not so easily defined. How far from the Gulf can you go, and still be mapping the Gulf Coast? We settled on “far enough to show most of the regional watershed”. But, the central feature of the Gulf is the delta of the Mississippi river, and the Mississippi drains most of the country. And the Arkansas rises in Colorado, well north of our limits. So does the Rio Grande, cut off by our western boundary along with the headwaters of all the larger Texas rivers west of the Trinity. Well, we still show MOST of the regional watershed, and all of it east of the Mississippi. “Easily framed” does not mean "entirely consistent with the literal implications of the title".
The Gulf Coast region, along with Florida and the South Atlantic Coast, is unavoidably shortchanged in elevation-tint maps of the United States, including Raven’s. The elevation range along the coast is such a tiny fraction of the range within the country as a whole that it merges into just one or two categories. The Raven Gulf Coast map employs a color scheme tailored specifically for the region, and it shows clearly just how little really flat country there is outside of the Florida peninsula. The notable exception is the inland Mississippi Delta, extending all the way north to the southern tip of Illinois.
Originally an arm (“embayment”) of the sea, the Delta has been endlessly planed flat by the ever-shifting meanders of the river, many of the most recent ones preserved in 19th century state lines. Levees confine the river, for now, to a single channel. The Mississippi Delta is not to be confused with the Delta of the Mississippi, the even flatter Southeastern Louisiana maze of swamps, bayous, and distributary channels. The river has shifted among innumerable mouths in the past, and a great deal of engineering has to be applied to keep it from shifting again into the Atchafalaya. That is a shorter route to the sea, therefore a steeper gradient, so the natural course for an unconstrained river.
And then there is sea level rise. Flat country is not without drama.
May 16, 2018