Glossary

This glossary is copied from the Stormwater Manual of Western Australia Chapter 11: Further Information. References are available from this chapter.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

E

Ecological values: Particular values or uses of the environment that are important for a healthy ecosystem or for public benefit, welfare, safety or health and economic activities, and which require protection from the effects of pollution, waste discharges and deposits (ARMCANZ & ANZECC 2000) and from the effects of altered water regimes.

Ecological water requirements (EWRs): The water regimes needed to maintain ecological values of water dependent ecosystems at a low level of risk (Water and Rivers Commission 2000a). Also see ’environmental water provisions’.

Economic values: Includes water body uses, stormwater use, economic values of the receiving environment (e.g. fishing and tourism), values of land used for stormwater management and values of land adjacent to stormwater management devices.

Education and participation program: One of the five principal categories of non-structural BMPs for stormwater management. Examples include training programs and involving the community in the development and implementation of stormwater management plans.

Effective imperviousness: The combined effect of the proportion of constructed impervious surfaces in the catchment, and the connectivity of these impervious surfaces to receiving water bodies (adapted from Walsh et al. 2004).

Effectiveness: The extent to which project outcomes (see ’outcomes’) are achieving project objectives (Bullen undated).

Efficiency: The extent to which project outputs (see ’outputs’) are maximised for the given level of inputs. Efficiency is concerned with the processes (activities/strategies/operations) by which the project is delivered and which produce the outputs of the projects.
BMP Efficiency: Measures how well a BMP or BMP system removes or controls contaminants. Although ’percent removal’ is the most common form of expressing BMP efficiency (when used alone), it is a poor measure of BMP efficiency compared with alternatives such as the ’effluent probability method’. (US EPA 2002; Taylor & Wong 2003.)

Effluent: Sanitary, industrial or agricultural discharge from wastewater treatment plants or treatment lagoons (ARMCANZ & ANZECC 2000).

Environmental management systems (EMS): The part of the overall management system that includes organisational structure, planning activities, responsibilities, practices, procedures, processes and resources for developing, implementing, achieving, reviewing and maintaining an environmental policy (Standards Australia 1996).

Environmental water provisions (EWPs): The water regimes that are provided as a result of the water allocation decision-making process taking into account ecological, social and economic impacts. They may meet in part or in full the ecological water requirements. (Water and Rivers Commission 2000a.) See ’ecological water requirements’.

Erosion: The process by which the land surface is detached and transported away by the action of water, wind, ice or gravity.

Evaluation: A periodic but comprehensive assessment of the overall progress and worth of a project (Woodhill & Robins 1998). The term used for final assessment of whether a BMP has achieved its pre-defined objectives.

Event: A single precipitation and associated runoff occurrence (ARMCANZ & ANZECC 2000).

Event mean concentration: The average concentration of a contaminant over the period of an event discharge. It is normally determined by the sum of the concentrations (for multiple samples taken during the period of the event discharge) multiplied by the flow weighted volume of the sample, divided by the cumulative volume of the samples. (ARMCANZ & ANZECC 2000.)

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