A few weeks ago I visited a reservoir in Virginia, an artificial lake created to cool a nearby nuclear power plant. What the dam accomplished was to drastically raise the water level, creating a horizontal plane which cuts across the landscape and registers the topography as defined by the shoreline. As the water level rises it floods more of the hydrology, up the river and into all feeder creeks.
The reason I mention all this is to explain a small epiphany I had after spending an entire semester looking at and adjusting topographic lines. Topo lines are both incredibly precise and incredibly abstract, representing a line which, shorelines aside, are rarely if ever experienced. When designing land forms, manipulating the earth in some way, topo lines allow for the precise adjustment of the earth’s surface. Below left shows the same hillside as defined by a single surface (top) and topographic lines (bottom). The middle image shows the quarry site in Altavista, Medellin and defines slope as a gradient, with the darkest areas being the steepest slope. On the right is part of a diagram showing changes to topography, as most of the design work ended up being done via adjustments to existing topo lines.
Topography is a means of understanding how steep slopes are, where water will collect, and where valleys allow the land to look inward, providing spaces for public gathering (see Informal Site Strategy from Jan 5th).