Definitions

flood    n.  a great flowing or overflowing of water over land not usually submerged.    

flash flood,    a sudden and destructive rush of water down a narrow gully or over a sloping surface: caused by heavy rainfall.    

floodplain    n.  any land susceptible to inundation by floodwaters from any source.    

100-year floodplain,    The area adjoining a river, stream, or watercourse covered by water in the event of the 100-year flood.    

encroachment    n.  any man-made obstruction in the floodplain which displaces the natural passage of flood waters. (e.g., a structure)    

discharge    n.  the amount of water that passes a given point in a stream channel per unit of time.    

cfs,    an acronym for cubic feet per second. The units used to measure stream discharge. (e.g., 1 cfs=7.5 gallons per second)    

high water mark,    any evidence that indicates how high the water was. This may include a mud line, water stains, seeds caught in the bark of a tree, grass or seeds in a line in the grass, etc.    

Introduction

The Fort Collins community is vulnerable to river and stream flooding, flash floods, and urban street flooding. Flooding along rivers is a natural and inevitable part of life. Some floods occur seasonally when spring rains, coupled with melting snows, fill river basins with too much water too quickly. Most flash flooding is caused by slow-moving thunderstorms or thunderstorms repeatedly moving over the same area. Urban street flooding occurs when land is converted from fields to roads and parking lots and loses its ability to absorb rainfall. Urbanization increases runoff two to six times over what would occur on natural terrain causing streets to become swift moving rivers during rainfall.

Definitions and Introduction | Flash Floods | Stream Flooding | Fort Collins Utilities | Historical Flooding | Survival Tips