(1) Any person who violates any of the provisions of this article, or rules or orders adopted or issued pursuant to this article, or who initiates or continues a development for which a stormwater plan is required, except in accordance with the terms, conditions and provisions of an approved plan, is subject to a civil penalty. Each day of a continuing violation shall constitute a separate violation. Additional fees may be charged for remedies and enforcement of this chapter.
(2) Violation of this chapter may subject the violator to a civil penalty to be recovered in a civil action in the nature of a debt if the violator does not pay the penalty within thirty (30) days after notice of the violation is issued by the stormwater administrator. Civil penalties may be assessed up to the full amount of penalty to which the county and municipalities with stormwater inter-local agreements with the county is subject for violations of its Phase II stormwater permit, or if no Phase II stormwater permit exists for the jurisdiction, civil penalties may be assessed up to the full amount allowed by law.
(a) In order to reduce drainage related damage and hazards, adequate natural drainage systems or stormwater management installations are required to collect and transmit stormwater flows into either existing drainage facilities or a natural drainage system.
(b) All storm drainage facilities shall be designed, constructed and maintained so that adjacent properties are not unreasonably burdened with surface waters as a result of such improvements. Specifically:
(1) Offsite areas which drain to or across a site proposed for development must be accommodated in the stormwater plans for the development. The stormwater management system must be capable of conveying the existing offsite flows through or around the development such that the volume and rate of flow from the adjacent property is not altered. If offsite flows are carried in the site system any detention system shall be sized to accommodate this flow. The flow must be released to the original drainage area.
(2) Storm drainage facilities shall be designed to limit the discharge from the site to the rate for the one (1) year, twenty-four (24) hour storm that existed prior to development of the site. For projects that are redeveloping a developed site, the discharge will be limited to that which occurs before any new development. The type and location of the discharge will be as occurred before the current development unless the discharge is to a manmade conveyance system.
(d) These goals for discharge can be accomplished by designing, constructing and maintaining all stormwater management installations to the extent practicable:
(1) Avoid increases in surface runoff volume and velocity by including measures which promote the infiltration of stormwater,
(2) Maximize the time of concentration of stormwater runoff, and
(3) Promote the filtration and precipitation of pollutants from stormwater runoff in order to protect the water quality of the receiving watercourse.
Sec 5.5-43- Stormwater Management Design Standards
(b) Design storm:
(1) The measures shall control and treat at a minimum the stormwater runoff from the first inch of rainfall volume leaving the project site. Runoff volume drawdown time shall be a minimum of forty-eight (48) hours, but not more than one hundred twenty (120) hours.
(2) All structural stormwater treatment systems used to meet the requirements of this ordinance shall be designed to have a minimum of eighty-five (85) percent average annual removal for total suspended solids (TSS).
(3) The design of drainage facilities in flood hazard areas shall be consistent with the requirements of county’s flood damage prevention ordinance.
(4) The computation of stormwater runoff shall follow established engineering practice. Acceptable methods of computation include the Rational Method, the Peak Discharge Method as described in USDA Technical Release Number 55 (TR-55), and USGS Regression Equations, where applicable. If an alternate method is proposed, the method should be described and justification for using this method should be provided. The same method must be used for both the pre- and post-development conditions.
(5) Runoff coefficients shall be based on full development of the project and of the watershed to the extent of the current zoning or land use patterns, and shall include the complete development of the site through build-out, including roof tops and other impervious areas that may be proposed.
(6) Stormwater detention shall be provided to insure that the rate of discharge for the one (1) year, twenty-four (24) hour storm does not exceed the pre-development rate of discharge. In order to demonstrate this, inflow-outflow calculations shall also be submitted for any stormwater detention ponds.
(7) All stormwater systems shall be designed and built to route at a minimum the twenty-five (25) year, twenty-four (24) hour storm safely.
