That which supplies air. In Northern’s case, an aerator is the fountain placed in ponds to supply fresh air to the water.

A plant or plantlike organism, generally of several different varieties commonly found in drainage lakes and waterways. Many varieties have the capacity for rapid growth, causing poor aesthetics and stagnant waterways.

The margins of a channel. Banks are called right or left as viewed facing in the direction of the flow.

A constructed terrace of earth, commonly used to control or to direct the flow of water. Berms can also be utilized for landscaping barriers around the perimeter of developments for aesthetic or sound enhancement barriers.

An interest-bearing certificate of public or private indebtedness issued at a specified rate of interest for a fixed duration of time. Bonds are issued as a funding method regarding capital improvements for the District.

An artificially constructed and maintained waterway designed for drainage and conveyance of drainage and surface water runoff.

(See “Drainage Basin”)

A cistern or vault at the point where a street gutter discharges into a sewer to catch bulky matter which would not pass readily through the sewer.

An artificial structure, specifically located within a water channel, for the purpose of regulating storm water discharge within any drainage basin. Control structures can be set at a fixed, predetermined elevation or have operable gates, allowing for manipulated storm water discharge.

A unit expressing rates of fluid discharge. One cubic foot per second is equal to the discharge of a stream of a rectangular cross section, 1 foot wide and 1 foot deep, flowing water at an average velocity of 1 foot per second.

“Detention Facility” means facilities designed to hold runoff and release the flows at a predetermined rate.

Unwanted or unmaintained vegetation established on the slopes of canal banks.

A delineated land mass consisting of a surface stream or a body of impounded surface water, together with a designed discharge point(s). Or, a term used to refer collectively to the amount of water in natural storage in a drainage basin.

This means a plan for collection, transport, treatment, and discharge of storm and nuisance water onto, within, and from the subject property.

Any vegetative plant (perennial and/or annual) that has a predominant leaf structure visible above the water surface, with a root structure anchored underwater.

The process of the wearing away of land masses by the action of water, wind, and/or abrasion.

Stage at which a stream first overflows its natural banks.

Storage of water in reservoirs to abate flood damage. 

“Functional Maintenance” means the maintenance, repair, and/or replacement of storm water control structures, including the cleaning of storm sewers, inlets, and catch basins, to preserve the functional utility of the structure.

The area in and adjacent to shallow freshwater where light penetration extends to the bottom sediments, giving a zone colonized by rooted plants.

This assessment is a fee levied on certain properties to defray all or part of the cost of a specific capital improvement or service deemed to benefit the property being assessed. Sometimes referred to as a Special Assessment, the property value is not taken into consideration when this assessment is calculated.

That point or area at which runoff leaves a site and may include streams, washes, closed systems, or other well-defined natural or artificial drainage features, as well as areas of dispersed overland flows.

“Outfall Structure” means a structure designed to control the volume and velocity of runoff discharged from the drainage basin over a specific length of time.

A percentage of the total bid which a contractor (or subcontractor) pays upon submitting a bid for work. It is considered insurance, and a “good faith” tool; a way for public institutions/general contractors to assure that a company they are entering into an agreement with is solvent, insured, and will be around for the duration of the project.

A shallow trough-like depression that carries water mainly during rainstorms or snow melts.

“Sediment” means rock, sand, mud, vegetation, and other material produced by erosion or urban surface runoff which is carried by floodwaters and deposited in lakes, ditches, and pipes.

Water naturally detained in a drainage basin, such as groundwater, channel storage, and depression storage.

“Storm Water Control Structure” means those pipes, storm sewers, siltation basins, lined channels, head walls, inlets, catch basins, end sections, spillways, and other appurtenances which are necessary, designed, and intended to manage storm water flow, detention, and/or retention. A storm water control structure does not include the surface conditions and contours of the property upon which the structure is located.

Surface maintenance is the normal and usual maintenance of the ground conditions in, over, and around storm water control structures. This includes mowing and removal of debris which accumulates over and around inlets, outlets, manholes, catch basins, and siltation basins. This also includes work to preserve or restore the aesthetic qualities and features of the storm water control structure.

A structure in a drainage, or other water management system, that conveys water, controls the direction or rate of flow, or maintains a desired water surface elevation.