# GEOG 3511: Introduction to Hydrology

Fall Semester 1997

Instructor: John Pitlick

## Introduction:

Are you a visual learner? If so, then your vision of what hydrology is all about probably looks something like this:

This, of course, is a schematic view of the hydrologic cycle (from Dunne and Leopold, 1978). It's a useful diagram because it shows the interaction among various hydrologic processes, and thus, it provides a conceptual framework for where we're going in this course.

Another view, espoused by many people in the field, is that hydrologic processes can be reduced to a set of equations, the simplest of which might be the continuity equation:

ds
q = i - ------ (1)
dt

where i is the rate of input (e.g. of precipitation), q is the rate of output (e.g. of runoff) and dS/dt is the rate of change in storage (e.g. of a lake). I present both the schematic view of the hydrologic cycle (Fig. 1) and the continuity equation (1) to remind you that both are necessary.

#### Hydrology is

both about learning concepts and physical principles as well as learning techniques that can be used to understand a particular phenomena. In practice, hydrologists have to quantify the rates at which water is exchanged between the atmosphere, the ground and the ocean, and this often involves manipulating data and solving sets of equations. As you'll soon see, it's fairly easy to lose sight of the conceptual part of the problem once you enter into the realm of techniques. Thus, my goal in this course is to give you a balanced view of hydrology - one that includes both a description of the basic processes as well as a coherent presentation of the theories and techniques that are used.

## Text (required):

S.L. Dingman, 1994, Physical Hydrology, Prentice Hall, New Jersey, 575 pp.

Another reference that' I'll put on reserve in the Geology library is:

Dunne, T. and Leopold, L.B., 1978, Water in Environmental Planning, W.H. Freeman, New York, 818 pp.

## Lab:

A 2-hour lab session will be held every Tuesday.Attendance is mandatory and please be on time. We may take a field trip depending on people's interests and schedules, but the majority of the labs will be techniques oriented. Hydrologists use a variety of techniques that require skills in statistics, mathematics, remote sensing, cartography, computers, and in my case, rafting and surveying. We won't go into great depth in developing skills in all of these areas, but my goal in the lab portion of this course is to give you a basic understanding of these skills and show you how to apply them to specific hydrologic problems.

## Grading:

Your course grade will be determined as follows:

- 1st midterm 20 % (tentatively scheduled for Sept. 27)
- 2nd midterm 20 % (tentatively scheduled for Nov. 1)
- Lab 20 %
- Final 40 % (tentatively scheduled for Dec. 12)

The exams will cover material from the lectures and your textbook. Test questions will be short answer and essay. No make-up exams will be given. If you miss a midterm exam and have a legitimate excuse, I will give you a score equal to your grade on the other midterm. If you canÕt explain your absence, youÕll get a score of zero. As some of you may know, my upper division courses are relatively rigorous. This means that I set high standards and you will have to work relatively hard to earn an 'A'. However, if you put in the time and show an interest in learning the material, I guarantee that you will come away with a thorough knowledge of hydrology.

## Course Outline

Week Topics Reading 8/28 Introduction, general principles Chapt. 1, 2 9/4 general climatology, global water resources Chapt. 3 9/11 precipitation I: sources and measurement Chapt.4 9/18 precipitation II: spatial & temporal variability Chapt.4 9/25 snow and snowmelt Chapt. 5 9/27 1st Midterm 10/2 water in soils: infiltration and redistribution Chapt. 6 10/9 evapotranspiration I: physical processes Chapt. 7 10/16 evapotranspiration II: approaches for estimating Chapt. 7 10/23 groundwater I: Darcy's law; local vs. regional flow Chapt. 8 10/30 groundwater II: effects on surface runoff and water balance Chapt. 8 11/6 catch-up and review 11/8 2nd midterm 11/13 streams I: flow in channels; flood routing Chapt. 9 11/20 streams II: networks; response hydrographs Chapt. 9 11/24 Thanksgiving Break 11/27 streams III: floods and droughts; frequency analysis Chapt. 9 12/4 watershed and regional hydrology Chapt. 9 12/11 catch-up and review 12/18 Final Exam

## Lab Exercises

1. basic statistics
2. introduction to computers & more statistics
3. precipitation measurements; areal estimation, frequency analysis
4. energy balance in snowmelt runoff
5. infiltration measurements
6. developing a simple model of infiltration
7. approaches for estimating evapotranspiration
8. groundwater
9. flow in channels
10. unit hydrographs
11. flood frequency analysis
12. watershed and regional hydrologic analyses

* we may not have lab every week, e.g. on Aug. 29 (during 1st week of semester), on days before midterms, on Nov. 21 before Thanksgiving break, and on Dec. 12 before the last day of classes.