Surface Water Notes
What is a River System?
1. What causes streams to flow downhill?
GRAVITY
2. What happens to the size of a stream or river as it meets up with other streams and rivers?
FORMS LARGER STREAMS
Tributaries
1. What do rivers finally spill into?
OCEANS
2. Tributaries are the __streams______ and smaller __rivers______ that feed into a main
__river________.
3. A __river_____________ and all the streams and smaller rivers that flow into it together make up a
river system.
Watersheds
1. A watershed is the __land_____ area that supplies __water_______ to a river system.
2. How much of the U.S. does the watershed of the Mississippi River cover?
1/3 of the United States
Divides
1. A divide is what separates one ___watershed________ from another.
2. Streams on each side of the divide flow in __different_________ directions.
What are Ponds and Lakes?
1. Ponds and lakes contain __still_________ water.
2. Where does the water in a pond or lake come from?
RAIN, MELTING SNOW, ICE, AND RUNOFF
3. Ponds and lakes form when water __collects______ in hollows and low-lying __areas_______ of land.
Exploring a Pond
1. Because water is __shallow________ enough for ____sunlight_______ to reach the bottom, plants
grow ___throughout________ a pond.
Exploring a Lake
1. Lakes are usually ___larger_________ and deeper than ponds, so little ___sunlight_____ reaches
the bottom of a deep lake.
2. Fewer plants __live________ in the deep, _____dark______ depths of such a lake.
Lake Formation
1. What are the natural processes that can form a lake?
DEPRESSIONS, MOVEMENT OF EARTH’S CRUST, VOLCANOES
2. How can people create lakes?
BUILDING A DAM
3. A reservoir is a lake that _stores______ water for ___human___ use.
How Can Lakes Change?
1. Natural processes and ___human______ activities can cause lakes to ___disappear_____.
Eutrophication
1. As lake organisms die, __bacteria_______ break down the bodies and release
___nutrients_________ into the water.
2. Eutrophication is the process of __nutrients________ building up in the lake over time.
3. What are the steps that can cause eutrophication to change a lake?
1. Bacteria break down dead organisms and put nutrients back into the water.
2. Algae use the nutrients and spread forming a layer on the lake’s surface.
3. The layer of algae is so thick it blocks the sunlight preventing plants from making food
(photosynthesis). Plants and animals die.
4. Dead organisms pile up making the lake shallower, so plants begin to grow.
5. Over time a meadow replaces the former lake
The Human Role
1. How can human activity increase eutrophication?
HUMANS USE FERTILIZERS. THE FERTILIZERS FROM FARMS RUNOFF INTO PONDS, LAKES, AND
STREAMS.