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).
The base of the obelisk at the Washington monument is 55 feet 1Â½ inches (16.8 m). It tapers to the capstone, which has a base of 3 ft x 3 ft (0.91 m). The aluminum apex has aâ¦ square base of 5.6 inches (14 cm). The official height is 555 feet, 5â inches (169.294 m).