5

Watershed

Overview

Everyone's home is located in a watershed, but what is a watershed? Well, it is a land area that drains water to a central shared location, such as a lake, river or ocean. It may be helpful to think of it like a tub, where you live would be the rim and the drain would be the central water body. In real life the rim would be a hill or a place of higher elevation, everyone, even people who live across the tub from you share the watershed because water is draining to the same location, we are connected by our watersheds. What is done on one part of the rim affects the rest of us, since they are connected by a shared water source. As water runs downhill to the water source, it carries pollutants from our cities, fertilizer from farms, waste from plants, animals and humans. Watersheds can be very small, the size of only one neighborhood or very large, draining water from several states. Contamination is a concern for watersheds, since human activities nearby will always reach the water supplies. Pollutants can come from pavement, farmland, roofs or cars. When it rains, all of these contaminants can be washed into a stream or water system. Trees and plants can help to filter sediment and harmful nutrients as they sink into soil before they reach aquifers.

Main Concept

Watersheds involve two types of water, Groundwater and Surface water. Surface Water is exactly what it sounds like, water that we can see: puddles, lakes, ponds and streams. Groundwater is water that takes up open spaces underground, between the soil and rock layers. These natural water storage areas are called aquifers, and they store and filter water until it is released back out into surface water sources. In this module we will learn about the parts of a watershed and model the movement of water to understand how watersheds work.

Definitions

River Source: The headwaters of a river or stream is the farthest place in that river or stream from
its estuary or downstream confluence with another river

Upstream: in the direction opposite to the flow in a stream, river

Downstream: the direction where the fluid is going to.

Main River: Main rivers are usually larger rivers and streams.

Tributaries: A tributary is a freshwater stream that feeds into a larger stream, river or other body
of water.

Floodplain: A floodplain (or floodplain) is a generally flat area of land next to a river or stream.
It stretches from the banks of the river to the outer edges of the valley.

Watershed Boundary: Is elevated terrain that separates neighboring drainage basins.

Meanders: Turns, or windings in the channel of a river, stream, or other watercourse.

Wetlands: A wetland is a distinct ecosystem that is flooded by water, either permanently or
seasonally.

River Mouth: A river mouth is the part of a river where the river joins into a larger body of water,
such as another river, a lake/reservoir, a bay/gulf, a sea, or an ocean.

Point source pollution: toxic chemicals that enter a body of water from many sources.

Nonpoint source pollution: pollution from a single, identifiable source.
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Launch Watershed Activities