1. PHYSICAL HYDROLOGY All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again” (Ecclesiastes 1:7)

2. 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?

3. 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”

4. PHYSICAL HYDROLOGY

5. 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.

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8. Agriculture Undeveloped Existing Development Undeveloped Under Construction Developed Center for Watershed Protection Impervious Cover Can Transform a Watershed in Just a Few Years 1940s 1950s1960s 1970s1990s

9. PHYSICAL HYDROLOGY More Frequent Flooding Center for Watershed Protection Higher Flood Levels The large amount of stormwater runoff in the stream system can cause:

11. PHYSICAL HYDROLOGY

12. “Today’s student will be tomorrow’s water management decision maker”

13. 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

14. What Is a Watershed? A watershed is the area of land that drains to a particular point along a stream Center for Watershed Protection

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16. Many hydrologic processes are non-linear

17. PHYSICAL HYDROLOGY e.g. preferential flow

18. PHYSICAL HYDROLOGY e.g. turbulence

19. PHYSICAL HYDROLOGY Conditions vary enormously in space and time and it is difficult to obtain data to characterize this variability 0 0100200300 FIELD A SepOctNovDecJanFebMarAprMay 19921993 Frozen ground 0 10 20 30 40 Rainfall (mm day ) Vehicle wheeling Time (days) Soil moisture (g g ) 10 20 30 40 50

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