Surface Water

Surface Water

Workbook pages 29-32

Multiple Select

Enlarge and look at the map that shows part of a river system. Select ALL of the rivers that are tributaries.

• Missouri River

• Mississippi River

• Ohio River

Multiple Choice

Looping curves in a river are called

• oxbow

• meanders

• delta

• divides

Multiple Choice

All fresh water comes from precipitation.

• True

• False

Multiple Choice

People can make lakes by building a dam across a river.

• True

• False

Multiple Choice

In deep parts of a lake, many organisms can live.

• True

• False

Multiple Choice

Ponds and lakes contain salt water.

• True

• False

Multiple Choice

Reservoirs were made by melting glaciers.

• True

• False

How Lakes Can Change

Lake Turnover

Lakes change as the seasons change. For example, the water is warmer in the summer than in the winter. Temperature changes through a year cause water to sink and rise in lakes. In the fall, the water mixes and spreads nutrients through a lake. This refreshes the lake so organisms in a lake can use the nutrients.

How Lakes Can Change

Eutrophication

This process occurs over a long period of time (years). Nutrients build up in a lake which causes algae to grow over the surface of a lake. Plants under the algae do not get enough sunlight for photosynthesis, so they die. The animals that eat those plants die too. Dead material fills up the lake, making it shallower. After a long time, the lake dies and a grassy field takes over.

Multiple Choice

Which process happens over many years?

• Lake Turnover

• Eutrophication

Multiple Choice

Which process cause a lot of algae to grow on the surface of the lake?

• Lake Turnover

• Eutrophication

Multiple Choice

Which process involves nutrients mixing throughout a lake?

• Lake Turnover

• Eutrophication

Multiple Choice

Which process leads to the death of a lake?

• Lake Turnover

• Eutrophication

Multiple Choice

Which process happens in the fall?

• Lake Turnover

• Eutrophication