Different streams have different sources of water, and this will impact water quality and levels.
Groundwater: Water seeps into the earths surface to a certain depth where the ground is saturated with water (the water table). Where the water table meets the surface, we get natural springs. Spring-fed streams tend to be clean and cold, with stable water temperatures and chemistry throughout the year.
Runoff: Rather than seeping into the ground, some rain and snowmelt waters flow over the land and into waterways. The runoff waters pick up sediments and pollutants as they flow over the land and this influences the water chemistry. Runoff streams tend to be warmer and can have water quality issues.