RECOMMENDED LESSONS: Runoff Runoff is precipitation that did not get (infiltrated) absorbed into the soil, or did not evaporate, and therefore made its way from the ground surface into places that water collect. Runoff causes erosion, and also carry chemicals and substances on the ground surface along to the rivers where the water ends up.
Noun. 1. obelisk-a stone pillar having a rectangular cross section tapering towards a pyramidal top. pillar, column-a vertical cylindrical structure standing alone and not supporting anything (such as a monument).
In the Middle Ages, there remained a sole pair of obelisks at Heliopolis, often called the two Pharaohs needles, but the only one left today had to be raised by two meters in 1950 to get it out of reach of ground water. Originally, it stood about 20.4 meters high. Notable, it is the oldest of all the standing obelisks in Egypt.