Sources of Freshwater Inflow

Available freshwater is a very limited resource in comparison of all of the water on Earth. About 97% of all water on Earth is in the oceans, the other 3% is freshwater that is mostly stored in glaciers and unavailable for human use (USGS 2013b). Less than one percent of the world’s freshwater is in streams and rivers where it is available for human use (USGS 2013b). Freshwater use must be appropriately managed because there is such a small amount in streams and rivers. To properly manage fresh water, the sources of fresh water are important to identify because they affect the amount, timing, and frequency of fresh water (Montagna et al. 2013).

Rivers are constantly flowing and changing patterns. The changes in rivers and streams can be influenced by climate or human activities. Water in river seeks the lowest point of gravity, flowing downstream until it reaches this point. The drainage slopes that instream flows follow are called watersheds.