Glossary beginning with I

terms for which definitions are available

impairment

weakening, damage, or instability, such as the effects caused by pollution

impervious

incapable of being penetrated, such as a surface that does not absorb water

infill

development that occurs on smaller parcels that remains undeveloped but is within or in very close proximity to urban or densely developed areas; usually relies on existing infrastructure and does not require an extension of water, sewer, or other public utilities

infiltration

movement of surface water into the soil, where it is absorbed by plant roots, evaporated into the atmosphere, or percolated downward to recharge groundwater

infrastructure

the basic system of utilities and services needed to support a society; structures such as culverts, pipes, bridges, dams, and flood control measures can cause instability of streams and affect aquatic habitats

inlet

the upstream end of any structure through which water may flow

insoluble

unable to pass into solution

invertebrates

animals, such as insects and crustaceans, that lack backbones (vertebrae)

IWMP

Ingetrated Watershed Management Plan