Goal 5: Safeguard Environmental Health

Forest land conversion: Total acreage over time. When forests are converted to housing and other developments, many environmental qualities will be negatively impacted.

Proportion of watershed covered by impenetrable materials such as roads, parking lots, and buildings preventing water from leaching directly into the soil. The greater the proportion of watershed with impervious surfaces, the greater the likelihood of geomorphic processes and conditions being degraded due primarily to modifications of stormwater runoff dynamics.

Proportion of watershed covered by impenetrable materials such as roads, parking lots, and buildings preventing water from leaching directly into the soil. Water quality is affected by impervious surface development in watersheds. The more impervious surfaces are developed, the greater the chance that water quality will be degraded.

An index of biotic community composition and structure, which respond to disturbance. This is a composite of several indicators of condition and can be applied using metrics for fish, algae, and benthic macroinvertebrates communities.

Inter-annual variability measures the variation in water supply between years. This indicator was used by the World Resources Institute in the Aqueduct 2.0 project.

Magnitude and timing of managed system flows suitable for native riparian habitats and geomorphic processes. Healthy aquatic, riparian, and floodplain ecosystems require periodic high flow events, not just minimum flows.

Mercury in fish tissue is an important measure of water and sediment quality. for mercury to increase in concentration in fish tissue, it must be available in the environment (water and/or sediment) and methylated, usually by bacteria in hypoxic/anoxic conditions.

Ratio of observed to expected native fish species in a waterbody or watershed. Fish indicators have been widely used and recognized as important tools to evaluate watershed and stream ecosystem health.

Sufficient and adequate direction of flows for maintaining historically-present native fish. Native fish are often adapted to certain hydrologic regimes and may not tolerate modified flow patterns or quantities.

The amount and extent of cover of algae attached to the benthos and other underwater surfaces. Excess algae can harm aquatic ecosystems and reflects a combination of effects of land and water use on aquatic ecosystems.