Anaerobic: Living in the absence of air or free oxygen; a situation in which molecular oxygen is absent (or effectively so) from the environment.

Annual: In general reference, appearing each year; in reference to biological life-cycles, organisms which reproduce and die within one year.

Anthropogenic: Effects or processes that are derived from human activities, as opposed to natural effects or processes that occur in the environment without human influence.

AQMP (Air Quality Management Plan): A plan prepared by an air pollution control district or air quality management district, for a county or region designated as a “nonattainment” area, for the purpose of bringing the area into compliance with the requirements of the national and/or California Ambient Air Quality Standards. AQMPs are incorporated into the State Implementation Plan (SIP).

Aquifer: A body of rock or sediment that is sufficiently porous and permeable to store, transmit, and yield significant or economic quantities of groundwater to wells and springs. (CDWR 2009)

Aquifer, well-defined: An aquifer between two distinct layers of earth that “confine” the aquifer of interest. Such an aquifer would be readily visible in a cross section obtained from multiple boring logs.

Aquifer, poorly-defined: An aquifer not having distinct layers of earth that “confine” the aquifer of interest. The boundaries of such an aquifer would not be readily visible in a cross section obtained from multiple boring logs.

Archaeological: Relating to the material remains of past human life, culture, or activities related to pre-European settlement.

Area of Shallow Flooding: A designated AO, AH or VO Zone on the FIRM. The base flood depths range from one to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

Area of Special Flood Hazard: The land in the floodplain within a community subject to a one percent or greater chance of flooding in any given 35.5.2year; sometimes referred to as the “Base Flood.” This area is designated as Zone A, AO, AH, A1-A30, AE, A99, VO, V1- 30, VE, or V on the FIRM.

Arterial: A major street carrying the traffic of local and collector streets to and from freeways and other major streets, with controlled intersections and generally providing direct access to nonresidential properties.