1. Surface Water
Streams, rivers, ponds, lakes and wetlands.

2. Surface Water Productivity in a lake:
Oligotrophic- low amounts of nutrients such as phosphorous and nitrogen.
Mesotrophic- a moderate level of productivity
Eutrophic- high levels of productivity

3. Oligotrophic and Eutrophic Lakes
Fig , p. 257

4. Altering the Availability of Water
Levees- an enlarged bank built up on each side of the river.
Dikes- similar to a levee but built to prevent ocean waters from flooding adjacent land.

5. Altering the Availability of Water
Dams- a barrier that runs across a river or stream to control the flow of water.
Reservoir- the area where water is stored behind the dam.

6. Tradeoffs of Large Dams and Reservoirs
Large losses
of water through
evaporation
Flooded land destroys forests or cropland and
displaces people
Migration and
spawning of
some fish are
disrupted
Downstream cropland and estuaries are deprived of nutrient-rich silt
Provides water
for year-round
irrigation of
cropland
Reservoir is useful for
recreation and fishing
Can produce
cheap electricity
(hydropower)
Downstream
flooding is
reduced
Fig. 11-8, p. 243

7. Altering the Availability of Water
Fish ladders- a set of stairs with water flowing over them that have been added to some dams to help migrating fish such as salmon get upstream.

8. Altering the Availability of Water
Aqueducts- canals or ditches used to carry water from one location to another.