Being an informed citizen and an effective steward of urban streams and wetlands requires a basic understanding of the natural processes that sustain life. This page highlights many of these important processes.

Hydrologic Cycle
Water is life. Literally. Earth is the only planet in the solar system with liquid water and is (as far as we know) the only planet with any form of life.

The hydrologic cycle describes the movement and storage of water around the globe in its various forms (solid, liquid, gas). This diagram (below) was sourced from the pollution prevention website of the City of Boca Raton, FL.
external image WaterCyclebig.jpg

Nitrogen Cycle
Nitrogen (chemical symbol 'N') is an important building block of living tissues, including DNA. It is found in many forms on Earth, including as a gas (N2, 78% of our atmosphere) and as compounds of nitrates (NO3-) and nitrites (NO2-) with other elements. The nitrogen cycle, like the hydrologic cycle, illustrates the flow through the environment of materials critical for life. The image below was sourced from the wikipedia page for the nitrogen cycle. The wikipedia page describes the nitrogen cycle in far more detail than is practical here and also includes more links to further reading.

external image 720px-Nitrogen_Cycle.svg.png