[Ord. 520, June 1999; Ord. 996, July 2014]
The purpose of this chapter is to diminish threats to the public health and safety caused by the runoff of excess stormwater, to reduce the possibilities of hydraulic overloading of the storm sewer system, to reduce economic losses to individuals and the community at large as a result of the runoff of excess stormwater, and to protect and conserve land and water resources, while at the same time ensuring orderly development. The provisions of this chapter are specifically intended to supplement existing ordinances regulating the following:
(1) 
The subdivision, layout, and improvement of lands located within the City of Collegedale.
(2) 
The excavating, filling, and grading of lots and other parcels or areas.
(3) 
The construction of buildings, including related parking and other paved areas, and the drainage of the sites on which those structures and their related parking and other paved areas are located.
(4) 
The design, construction, and maintenance of stormwater drainage facilities and systems.
[Ord. 520, June 1999; Ord. 996, July 2014]
For the purposes of this chapter, the following definitions are adopted:
(1) 
BASE FLOOD ELEVATION
The elevation delineating the flood level having a one-percent (1%) probability of being equaled or exceeded in any given year (also known as the 100-year flood elevation), as determined from Flood Insurance Rate Maps (FIRMs) or the best available information.
(2) 
CHANNEL
A natural or man-made open watercourse with definite bed and banks which periodically or continuously contains moving water, or which forms a connecting link between two (2) bodies of water.
(3) 
CITY ENGINEER
The person formally designated by the City of Collegedale as the city engineer.
(4) 
CONTROL ELEVATION
Contour lines and points of predetermined elevation used to denote a detention storage area on a plat or site drawing.
(5) 
DETENTION FACILITY
A facility constructed or modified to restrict the flow of stormwater to a prescribed maximum rate, and to concurrently detain the excess waters that accumulate behind the outlet.
(6) 
DETENTION STORAGE
The temporary detaining or storage of stormwater in storage basins, on rooftops, in streets, parking lots, school yards, parks, open space, or other areas under predetermined and controlled conditions, with the rate of drainage therefrom regulated by appropriately installed devices.
(7) 
DISCHARGE
The rate of outflow of water from any source.
(8) 
DRAINAGE AREA
The area from which water is carried off by a drainage system, i.e., a watershed or catchment area.
(9) 
EXCESS STORMWATER RUNOFF
The rate of flow of stormwater discharged from an urbanized drainage area which is or will be in excess of that rate which represented or represents the runoff from the property prior to the date of this chapter.
(10) 
FLOODPLAIN
The special flood hazard lands adjoining a watercourse, the surface elevation of which is lower than the base flood elevation and is subject to periodic inundation.
(11) 
HYDROGRAPH
A graph showing, for a given point on a stream or conduit, the runoff flow rate with respect to time.
(12) 
ONE HUNDRED-YEAR STORM
A precipitation event of twenty-four (24) hours' duration, having a one percent (1%) chance of occurring in any one (1) year.
(13) 
PEAK FLOW
The maximum rate of flow of stormwater at a given point in a channel or conduit resulting from a predetermined storm or flood.
(14) 
STORMWATER DRAINAGE SYSTEM
All means, natural or man-made, used for conducting stormwater to, through, or from a drainage area to the point of final outlet including, but not limited to, any of the following: open and closed conduits and appurtenant features, canals, channels, ditches, streams, swales, culverts, streets, and pumping stations.
(15) 
STORMWATER RUNOFF
The waters derived from precipitation within a tributary drainage area, flowing over the surface of the ground or collected in channels or conduits.
(16) 
TIME OF CONCENTRATION
The elapsed time for stormwater to flow from the most distant point in a drainage area to the outlet or other predetermined point.
(17) 
TWO-YEAR STORM
A precipitation event having a fifty percent (50%) chance of occurring in any one (1) year.
(18) 
TWO-YEAR STORM RUNOFF
The stormwater runoff having a fifty percent (50%) probability of occurring in any one (1) year.
(19) 
UPLAND AREA
Any land whose surface drainage flows toward the area being considered for development.
(20) 
WATERCOURSE
Any natural or artificial stream, river, creek, channel, ditch, canal, conduit, culvert, drain, waterway, gully, ravine, street, roadway, swale, or wash in which water flows in a definite direction, either continuously or intermittently, and which has a definite channel, bed, or banks.
(21) 
WET BOTTOM DETENTION BASIN
A basin designed to retain a permanent pool of stormwater after having provided its planned detention of runoff during a storm event.
[Ord. 520, June 1999; Ord. 996, July 2014; Ord. 1085, Aug. 2020]
Before initiating any activity regulated by this chapter, an applicant shall be required to obtain an approval of the construction plans by the city which indicates that the requirements of this chapter 5 have been met.
Land disturbance permit fees:
Less than 10,000 sq. ft. disturbed
no fee
10,000 sq. ft. to 0.9999 acres
$100
1.0 - 4.9999 acres
$250
5.0 - 19.9999 acres
$1,000
20.0 - 49.9999 acres
$3,000
50.0-149.9999 acres
$5,000
150.0 + acres
$10,000
Resubmittal fees*
$500
*(for review of plans due to unaddressed comments)
[Ord. 520, June 1999; Ord. 996, July 2014]
In addition to meeting the requirements of Division 2 and before starting any activity regulated by this chapter, an applicant shall comply with the requirements set forth in all other related ordinances and state statutes and regulations, including but not limited to the Tennessee Department of Environment and Control Construction General Permit and the Hamilton County Water Quality Program.