Development Intensity: A measure of the amount of development often expressed as the ratio of building floor area to lot area (floor area ratio) for commercial, business, and industrial development, or dwelling units per acre of land for residential development (density).

Disjunct: Distribution of populations that are widely separated from a main, coherent population or cluster of populations.

Diversion: The act of turning or changing the natural course of water for use in other purposes.

Domestic Water, Potable Water: Water that has undergone adequate treatment and is suitable for human drinking and cooking uses as defined by state and federal drinking water standards.

Drought: An extended period of months or years when a region notes a deficiency in rainfall affecting its water supply.

Dwelling Unit: One or more rooms in a dwelling designed for or occupied by one household for living or sleeping purposes and having only one kitchen.

Dwelling Unit per Acre (du/ac): Number of dwelling units per one acre of land.

Easement: A recorded right or interest in the land that belongs to someone else, which entitles the holder to some use, privilege, or benefit out of or over said land.

Entitlement: A permit granted to a landowner or other authorized party giving it the right to develop a property. Such right is usually expressed in terms of a use and intensity allowed under a specific plan, subdivision or tract map, use permit, variance, building permit, or other similar permit.

Ephemeral Streams: Streams that flow only during and for a short duration after precipitation events.

Erosion: The loosening and transportation of rock and soil debris by wind, rain, or running water.

Exposure pathway: The course a chemical or pollutant takes from the source to the organism exposed. A “complete” exposure pathway consists of four elements: chemical sources, migration routes (i.e., transport in the environment), an exposure point for contact (i.e., soil, air, or, water); and exposure routes.

Exposure route: The way a chemical or pollutant enters the organism after contact. Four exposure routes are recognized in risk evaluation methods: ingestion, inhalation, dermal (skin and eye), and injection.

Extirpated: Locally extinct.