0.2% Floodplain

The area of land that has a 0.2% chance of being flooded from a bayou, stream, or creek in a given year. It is commonly referred to as a 500-year floodplain.

Alternatives

A combination of one or more components that provide a complete plan to reduce flood damages.

1% Floodplain

The area of land that has a 1% chance of being flooded from a bayou, stream, or creek in a given year. It is commonly referred to as a 100-year floodplain.

0.2% Rainfall

An amount of rain having a 0.2% chance of being equaled or exceeded in any given year. Also known as a 500-year rainfall

1% Rainfall

An amount of rain having a 1% chance of being equaled or exceeded in any given year. Also known as a 100-year rainfall.

Appraisal

A written estimate of the value of an asset or property prepared by a qualified, independent party.

Base Flood

A flood that has a 1% chance of being equaled or exceeded in any given year. Also referred to as a 1% or 100-year flood.

Base Flood Elevation

The elevation above the average sea level that waters from a 100-year flood will reach along a creek or bayou. These elevations are mapped out to create floodplains.

Benefit-to-Cost Ratio

Represents the overall efficiency of a plan and is determined by dividing the value of the annual benefit by the annual cost.

BMP

Best Management Practices

Bridge Modification

The replacement, extension, or reinforcement of a bridge in order to remove an impediment to flow or accommodate a channel enlargement.

Buyout

The elimination of potential flood damages to nearby structures by acquiring and removing them.

Bypass Channel

The construction of a new channel in order to convey stormwater runoff around the area.

Capacity

The measure of water capable of flowing through a channel or how much water a detention facility holds.

Cellular Concrete Mats

A mat of interlocking concrete puzzle-type blocks that are placed as a lining on the sides and bottom of a channel. These mats increase the efficiency of the stormwater flow in the channel, while allowing vegetation to still grow.

Channel

A generic term for a course or passage where stormwater may be directed.

Channel Flow

The amount of stormwater flowing through a channel.

Channel Modification

A man-made change to the channel’s characteristics, typically to reduce flood damages.

Citizens Advisory Committee

A group of stakeholders who meet regularly to discuss items of importance relative to Harris County Flood Control District activities, such as a study, design, construction project or maintenance practice.