7 Del. Admin. Code § 7403-2.0
The following words and terms, when used in these Regulations, should have the following meaning unless the context clearly indicates otherwise:
"Best Management Practice (BMP)" means a system or procedure that has been determined to be an effective, practical means of preventing or reducing nonpoint source pollution. These include conservation practices or management measures which control soil loss and reduce water quality degradation caused by nutrients, animal wastes, toxins, sediment, and runoff.
"Buffer" means an existing or purposely established area of vegetation which protects water resources from pollution.
"Certified Service Provider" means an individual representative of a manufacturer/supplier who holds a Department Class E System Contractor or Class H System Inspector license, or a Class E System Contractor who is certified, through Department approved training, on the operation and maintenance of the advanced treatment unit or system, or a Class H System Inspector who has become certified through Department approved training on the operation and maintenance of the advanced treatment unit or system, or a homeowner who has obtained Department individual home service provider certification and has been through Department approved training on the operation and maintenance of their advanced treatment unit or system. The Department homeowner certification allows the homeowner to operate and maintain their advanced treatment unit or system at their primary place of residence.
"Clean Water Act (CWA)" means the Federal Water Pollution Control Act, 33 U.S.C. §§ 1251- 1387.
"Department" means the Delaware Department of Natural Resources and Environmental Control.
"Drainfield" means a system of open-jointed or perforated piping, alternative distribution units, or other seepage systems for receiving the flow from septic tanks or other treatment facilities and designed to distribute effluent for oxidation and adsorption by the soil within the zone of aeration.
"End of Pipe" means the location where effluent discharges from the end of the advanced pretreatment unit before ultimately dispersing into the soil drainfield. This is the location where nitrogen and phosphorus sampling may occur in order to determine compliance with the applicable performance standard.
"High potential for phosphorus mobility" means an area where:
. the site's soils have a Fertility Index Value (FIV) of greater than 100 for phosphorus or a soil test value of over 100 parts per million (ppm) by the Mehlich 3 soil test; and
. the groundwater phosphorus content is above 0.034 mg/l and there is an indication that groundwater is anoxic due to low dissolved oxygen or oxidation reduction potential below 200 mV; and
. the disposal area contains soils with a seasonal high water table above 27 inches.
"Indian River Watershed" means the lands that drain into the Indian River and its tributaries as illustrated by the Delaware watershed map available from the Watershed Assessment Section, Division of Water Resources, Department of Natural Resources and Environmental Control.
"Indian River Bay Watershed" means the lands that drain into the Indian River Bay and its tributaries as illustrated by the Delaware watershed map available from the Watershed Assessment Section, Division of Water Resources, Department of Natural Resources and Environmental Control.
"Innovative and Alternative (IA) onsite wastewater treatment and disposal systems" means anything other than a conventional onsite wastewater treatment and disposal system.
"Little Assawoman Bay Watershed" means the lands that drain into the Little Assawoman Bay and its tributaries as illustrated by the Delaware watershed map available from the Watershed Assessment Section, Division of Water Resources, Department of Natural Resources and Environmental Control.
"Major subdivision" means a subdivision of land involving a proposed new street or the extension of an existing street.
"Mean high water (MHW)" means the point on the bank, tidal flat, beach or shore, up to which the presence or action of the water leaves a distinct mark, either by erosion, destruction of terrestrial vegetation (non-aquatic), physical markings or characteristics, and known vegetation lines, and may be further identified by tidal gauge data, or any other suitable means of delineating the mean height reached by a rising tide.
"National Pollutant Discharge Elimination System (NPDES)" means the program prescribed by the Federal Water Pollution Control Act for point sources of pollution.
"Nonpoint source (NPS) pollution" means pollution originating from diffuse areas having no well-defined source.
"Nutrient" means any element or compound essential as a raw mineral for organism growth and development and, for the purpose of this regulation, is limited to nitrogen and phosphorus.
"Onsite wastewater treatment and disposal system (OWTDS)" means a conventional or innovative and alternative wastewater treatment and disposal systems installed or proposed to be installed on the land of the owner or on other land to which the owner has the legal right to install the system.
"Ordinary high water mark" means, for nontidal waters, the line where the presence and action of water are continuous enough during ordinary rainfall years to leave a mark upon the soil of the bed or banks of the waterbody.
"Performance Standard Nitrogen level 1 (PSN1)" means where total nitrogen levels achieve either:
. an average annual concentration of 5 mg/l (parts per million (ppm)) total nitrogen in effluent sampled at the end-of-pipe of the pretreatment unit; or
. a 90% reduction in the effluent total nitrogen concentration when compared to the influent total nitrogen concentration; or
. an average annual concentration of 5 mg/l beneath any permitted wastewater spray irrigation field as verified by monitoring in-field lysimeters, providing that the design percolate concentration does not exceed 5 mg/l on an average annual basis.
Discharge limitations are to be expressed as a mass, based on average design flows (221 gallons per day per unit for residential systems).
"Performance Standard Nitrogen level 2 (PSN2)" means where total nitrogen levels achieve either:
. an average annual concentration of 10 mg/l (parts per million (ppm)) total nitrogen in effluent sampled at the end-of-pipe of the pretreatment unit; or
. an 80% reduction in effluent total nitrogen concentration when compared to the influent total nitrogen concentration; or
. an average annual concentration of 10 mg/l beneath any permitted wastewater spray irrigation field as verified by monitoring in-field lysimeters, providing that the design percolate concentration does not exceed 10 mg/l on an average annual basis.
Discharge limitations are to be expressed as a mass, based on average design flows (221 gallons per day per unit for residential systems).
"Performance Standard Nitrogen level 3 (PSN3)" means where total nitrogen levels achieve either:
. an average annual concentration of 20 mg/l (parts per million (ppm)) total nitrogen in effluent sampled at the end-of-pipe of the pretreatment unit; or
. a 50% reduction in effluent total nitrogen concentration when compared to the influent total nitrogen concentration.
"Performance Standard Phosphorus level 1 (PSP1)" means where total phosphorus levels achieve either:
. an average annual concentration of 3.9 mg/l (parts per million (ppm)) total phosphorus in effluent sampled at the end-of-pipe of the pretreatment unit; or
. a 75% reduction in effluent total phosphorous concentration when compared to the influent total phosphorus; or
. an average annual concentration of 3.9 mg/l beneath any permitted wastewater spray irrigation field as verified by monitoring in-field lysimeters, providing that the design percolate concentration does not exceed 3.9 mg/l on an annual average basis.
Discharge limitations are to be expressed as a mass, based on average design flows (221 gallons per day per unit for residential systems).
"Performance Standard Phosphorus level 2 (PSP2)" means where total phosphorus levels achieve either:
. an average annual concentration of 7.85 mg/l (parts per million (ppm)) total phosphorus in effluent sampled at the end-of-pipe of the pretreatment unit; or
. a 50% reduction in effluent total phosphorus concentration when compared to the influent total phosphorus concentration.
Discharge limitations are to be expressed as a mass, based on average design flows (221 gallons per day per unit for residential systems).
"Person" means any individual, business enterprise, or business entity, including but not limited to, a trust, firm, joint stock company, partnership corporation (including government corporation), limited liability company or association, any state, municipality, commission, or political subdivision of a state, any federal agency, any interstate body, or other such entities as allowed by law.
"Point source pollution" means pollution discharged directly from a specific site such as a municipal sewage treatment plant or an industrial outfall pipe.
"Pollution Control Strategy (PCS)" means a document that specifies actions necessary to systematically achieve pollutant load reductions specified by a Total Maximum Daily Load for a given waterbody. The regulatory actions are included in these Regulations.
"Pre-engineered plan" means a design using packaged mechanical devices such as equipment of cataloged design which complies with all applicable regulations and approved by the Department, or listed by a third party testing authority for a specific application recognized and approved by the Department.
"Primary water features" means State-regulated wetlands and those waters depicted by the United States Geological Survey on the National Hydrography Dataset as perennial, and identified on maps developed by the Department and adopted as part of this Regulation in Appendix A. Such features may be adjusted in accordance with Section 9.2 of these Regulations.
"Rehoboth Bay Watershed" means the lands that drain into the Rehoboth Bay and its tributaries as illustrated by the Delaware watershed map available from the Watershed Assessment Section, Division of Water Resources, Department of Natural Resources and Environmental Control.
"Secondary water features"means those waters depicted by the United States Geological Survey on the National Hydrography Dataset as intermittent, and those forested ditches that flow within or are directly adjacent to forested lands, and identified on maps developed by the Department and adopted as part of this Regulation in Appendix A. Such features may be adjusted in accordance with Section 9.2 of these Regulations.
"Site plan" means a drawing illustrating proposed residential planned communities, conditional uses, dwellings, multiple family dwellings, townhouses, houses of worship, hotels, motels or motor lodges, docks or piers, footbridges or walkways, business and office buildings, commercial buildings or industrial buildings, mobile home parks, campgrounds, borrow pits, or amusement places, circuses, or carnival grounds.
"State-regulated wetlands" means those wetlands depicted on maps adopted pursuant to 7 Del.C. Ch. 66 or otherwise field verified or adjusted.
"Systematically eliminate" means to require the elimination of waste loading into the affected waterbody by point sources on a firm, fixed schedule as approved by the Department. This elimination must occur within five years of the expiration of the facility's current NPDES permit unless a longer period of time is provided for in a State or Federally enforceable Consent Order, Decree, or Administrative Order.
"Total Maximum Daily Load (TMDL)" means the amount of a given pollutant that may be discharged to a waterbody from point, nonpoint, and natural background sources and still allows attainment or maintenance of the applicable narrative and numerical water quality standards. A TMDL is the sum of the individual Waste Load Allocations (WLAs) for point sources and Load Allocations (LAs) for nonpoint sources and natural background sources of pollution. A TMDL may include a reasonable margin of safety (MOS) to account for uncertainties regarding the relationship between mass loading and resulting water quality. In simplistic terms, a TMDL matches the strength, location and timing of pollution sources within a watershed with the inherent ability of the receiving water to assimilate the pollutant without adverse impact.
"Treatment train" means a series of best management practices for stormwater.
"Watershed"means a region or area delineated by a topographical divide and draining ultimately to a particular watercourse.
7 Del. Admin. Code § 7403-2.0