

| BMP | Best Management Practice |
| Ecology | Washington State Department of Ecology |
| EPA | United States Environmental Protection Agency |
| ERU | Equivalent Residential Unit |
| ILA | Interlocal Agreement |
| MS4 | Municipal Separate Stormwater Sewer System |
| NOI | Notice of Intent |
| NPDES | National Pollutant Discharge Elimination System |
| Permit | Eastern Washington Phase II Municipal Stormwater Permit |
| RSPG | Regional Stormwater Policy Group |
| SIC | Standard Industrial Code |
| TMDL | Total Maximum Daily Load |
| WQIP | Water Quality Improvement Project |
AKART – All Known, Available, and Reasonable methods of control and Treatment
Best Management Practices (BMPs) – Best management practices are the schedules of activities, prohibitions of practices, maintenance procedures, and structural and/or managerial practices approved by Ecology that, when used singly or in combination, prevent or reduce the release of pollutants and other adverse impacts to receiving waters.
Co-permittees – Yakima County, City of Yakima, City of Union Gap, City of Sunnyside
DDD - Dichlorodiphenyldichloroethane
DDE – Dichlorodiphenyldichloroethylene
DDT – Dichlorodiphenyltrichloroethane
Ecology – Washington State Department of Ecology
ESA – Endangered Species Act
IDDE – Illicit Discharge Detection and Elimination
ILA – Interlocal Agreement or Intergovernmental Local Agreement
LID – Low Impact Development
Maximum Extent Practicable (MEP) – MEP refers to paragraph 402(p)(3)(B)(iii) of the Federal Clean Water Act, which reads as follows: Permits for discharges from municipal storm sewers shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques, and system, design, and engineering methods, and other such provisions as the Administrator or the State determines appropriate for the control of such pollutants.
Measurable Goal – Definable tasks or accomplishments that are associated with a performance measure.
Municipal Separate Storm Sewer System (MS4) – A conveyance, or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains): (i) owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to State Law) having jurisdiction over disposal of wastes, stormwater, or other wastes, including special districts under State Law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the CWA that discharges to waters of the United States; (ii) designed or used for collecting or conveying stormwater; (iii) which is not a combined sewer; and (iv) which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2.
National Pollutant Discharge Elimination System (NPDES) - The national program for issuing, modifying, revoking, and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements, under Sections 307, 402, 318, and 405 of the Federal Clean Water Act, for the discharge of pollutants to surface waters of the state from point sources. These permits are referred to as NPDES permits and, in Washington State, are administered by the Washington State Department of Ecology.
New Development – Land disturbing activities, including Class IV general forest practices that are conversions from timber land to other uses; structural development, including construction or installation of a building or other structure; creation of impervious surfaces; and subdivision, short subdivision and binding site plans, as defined and applied in Chapter 58.17 RCW. Projects meeting the definition of redevelopment shall not be considered new development.
NOI – Notice of Intent
O&M – Operation and Maintenance
Outfall – Means point source as defined by 40 CFR 122.2 at the point where a municipal separate storm sewer discharges to waters of the State and does not include open conveyances connecting two municipal separate storm sewers, or pipes, tunnels, or other conveyances which connect segments of the same stream or other waters of the State and are used to convey waters of the State.
PAH – Polyaromatic Hydrocarbon
Performance Measure – An activity performed to implement one of the eight permit program elements.
Point Source – Any discernible, confined, and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system, vessel or other floating craft from which pollutants are or may be discharged. This term does not include return flows from irrigated agriculture or agricultural runoff.
POTW – Publicly Owned Treatment Works
Program Element – One of the eight program components included in Sections S5.B.1 through S5.B.6, S7, and S8 of the Eastern Washington Phase II Municipal Stormwater Permit.
RCW – Revised Code of Washington State
Redevelopment - The replacement or improvement of impervious surfaces on a developed site.
Return Frequency or Recurrence Interval - A statistical term for the average expected time interval between events (e.g., flows, floods, droughts, or rainfall) that equal or exceed given conditions. Recurrence interval can be converted to probability by dividing the return frequency into one year. For example, a 100-year event has a one percent chance of occurring in any given year (1/100 = 0.01); a 5-year event has a 20 percent chance (1/5 = 0.20) of occurring in any given year.
RSL – Regional Stormwater Lead
RSPG – Regional Stormwater Policy Group
RSWG – Regional Stormwater Working Group
RSWMP – Regional Stormwater Management Program
Runoff - Water that travels across the land surface, or laterally through the ground near the land surface, and discharges to water bodies either directly or through a collection and conveyance system. Runoff includes stormwater and water from other sources (e.g. snowmelt) that travels across the land surface.
Stormwater Pollution Prevention Plan (SWPPP) – A documented plan to implement measures to identify, prevent, and control the contamination of point source discharges of stormwater.
TBD – to be determined
TMDL – Total Maximum Daily Load
TSS – Total Suspended Solids
UA – Urbanized Area
UGA – Urban Growth Area
UIC – Underground Injection Control
USEPA – United States Environmental Protection Agency
VE – Value Engineering
WAC – Washington Adminstrative Code
Waters of the State – Those waters as defined as waters of the United States in 40 CFR 122.2 within the geographic boundaries of Washington State and waters of the state as defined in Chapter 90.48 RCW which includes: lakes, rivers, ponds, streams, inland waters, underground waters, salt waters and all other surface waters and water courses within the jurisdiction of the State of Washington.
YCHD – Yakima County Health District