Post on 26-Dec-2015
transcript
PHYSICAL HYDROLOGY
All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither theyreturn again”
(Ecclesiastes 1:7)
PHYSICAL HYDROLOGY
• Why should we be concerned with the complexity of the many relationships that affect various phases of the hydro. cycle?
• Arguably, hydrologic science wasn’t as
important 20 years ago, so why is it now?
PHYSICAL HYDROLOGY
“Multiple demands for the use of the same gallon of water and prospects for even greater demands tomorrow indicate that more and more people of different disciplines need to have a knowledge of hydrology”
PHYSICAL HYDROLOGY
PHYSICAL HYDROLOGY
Employment of environmental scientists is expected to grow about as fast as the average for all occupations through 2014, while employment of hydrologists should grow much faster than average. Job growth for environmental scientists and hydrologists should be strongest at private-sector consulting firms. Demand for environmental scientists and hydrologists will be spurred largely by public policy, which will oblige companies and organizations to comply with complex environmental laws and regulations, particularly those regarding ground-water decontamination, clean air, and flood control.Job opportunities also will be spurred by a continued general awareness regarding the need to monitor the quality of the environment, to interpret the impact of human actions on terrestrial and aquatic ecosystems, and to develop strategies for restoring ecosystems.
PHYSICAL HYDROLOGY
PHYSICAL HYDROLOGY
Agriculture
Undeveloped
Existing Development
Undeveloped
UnderConstruction
Developed
Developed
Center for Watershed Protection
Impervious Cover Can Transform a Watershed in Just a Few Years
1940s1950s1960s1970s1990s
PHYSICAL HYDROLOGY
More Frequent FloodingCenter for Watershed Protection
Higher Flood Levels
The large amount of stormwater runoff in the stream system can cause:
PHYSICAL HYDROLOGY
PHYSICAL HYDROLOGY
“Today’s student will be tomorrow’s water management decision maker”
PHYSICAL HYDROLOGY
• The spatial and temporal variations of water substance in the terrestrial, oceanic, and atmospheric compartments of the global water system
• The movement of water on and under the earth’s land surfaces, the physical and chemical processes accompanying that movement, and the biological processes that conduct or affect that movement
What Is a Watershed?
A watershed is the area of land that drains to a particular point along a stream
Center for Watershed Protection
PHYSICAL HYDROLOGY
PHYSICAL HYDROLOGY
• Many hydrologic processes are non-linear
0
500
1000
1500
2000
2500
0 50 100 150 200 250
Time (seconds)
Infi
ltra
tio
n (
mm
/hr)
PHYSICAL HYDROLOGY
• e.g. preferential flow
PHYSICAL HYDROLOGY
• e.g. turbulence
PHYSICAL HYDROLOGY
• Conditions vary enormously in space and time and it is difficult to obtain data to characterize this variability
00 100 200 300
FIELD A
Sep Oct Nov Dec Jan Feb Mar Apr May
1992 1993
Frozen ground
010203040
-1R
ainfall (mm
day )
Vehicle wheeling
Time (days)
Soi
l moi
stur
e (g
g
)-1
10
20
30
40
50
PHYSICAL HYDROLOGY
PHYSICAL HYDROLOGY
18 oct 19 oct
22 oct
< 80%
80-90%
90-100%
Saturated