Amazing Detail

I recently put up a map put up an 1884 planning map for the expansion of the Croton water system north of New York. It turns out that was just an appetizer. Today’s map, from 1899, has much more detail and is amazing proof of what could be done with hand drafting: no GIS database, no CAD, and look at this:

Manhattan is on the left, with the street grid drawn to scale, north is to the right, along with the Croton River watershed with the fuzzy black border. The Old (original) and New Croton Dams are shown, along with the changes to the reservoir size and shape resulting from building the new dam downstreamof the old, almost at the Croton’s outlet into the Hudson River. The watersheds of the Bronx and Byram Rivers are also marked, for the sake of completeness as far as I can tell. The dark red line on the map is the new Croton Aqueduct, cutting a straighter line than the old aqueduct. The section on the upper left shows the topography of southern Westchester County, the Bronx, and Manhattan as far as the Central Park Reservoir – yes, it was a real working reservoir back then – made to look more jagged than it is because of the exaggerated vertical scale. The important thing to note in that section is how the underground aqueduct ignores the changes in ground elevation above.

The section on the lower left is through the main reservoir and shows the increased depth from the new dam. Finally, the big red blotch isn’t a place the drafter’s pen leaked while drawing the aqueduct line, it’s the Jerome Park reservoir in the Bronx.