Environmental Engineering Reference
In-Depth Information
1 Introduction
1.1 HYDRO-ENVIRONMENTAL ANALYSIS, OR WHAT IS IN A NAME?
The title of this text is Hydro-Environmental Analysis . So, the irst obvious question that the reader
may have is what exactly is “hydro-environmental analysis?” What is the topic area and is this a
new ield of study? The phrase is not new to this topic and its usage is becoming increasingly com-
mon. Other topics and journals are devoted to hydro-environmental studies. We are sure that we
could provide some concise, valid, and very esoteric deinitions. But we will not do so. Instead, we
will provide a discussion of the purpose of this topic, which may hopefully indicate why Hydro-
Environmental Analysis is an apt title for the content.
All a man needs is Conidence and Ignorance, and he will be sure to succeed in life.
Mark Twain (Figure 1.1)
The topic is intended primarily for undergraduate and graduate students of engineering, while
it is hoped that students in other disciplines will also ind it useful. Engineering is, in large part,
based upon the premise that we can predict things. For example, much of engineering is based
upon Newton's laws of motion, or laws of conservation, or laws of thermodynamics, etc. Engineers
have successfully used these laws, principles, or theories in order to make predictions about what
happens to a system, or to relationships between cause and effect. In order to design engineering
structures, some idea of the relationships between cause and effect is necessary for predictions,
whether they be predictions of the impact of wind loads on a building or the impact of high lows
on a dam.
There is something fascinating about science. One gets such wholesale returns of conjecture out of such
a triling investment of fact.
M a r k Tw a i n
A basic question is the degree to which we need to understand a system in order to make pre-
dictions about it. Engineers, by deinition, deal with the art of applying scientiic knowledge and
theories to practical problems, with the emphasis on the “a” word—applied. So, to what degree do
engineers need to understand these theories or that knowledge in order to apply them correctly? Or,
what are the consequences if the scientiic theories or “conjectures” are wrong? For example, under-
graduate engineering students often learn speciic computational techniques, and then often only as
graduate students do they ind out how limited the knowledge base is on which those computations
are based. But, if the limitations are not known and methods are applied inappropriately, there may
be consequences in terms of human or environmental health.
A quote often attributed to George Box (one of the most inluential statisticians of the twentieth
century) is that while “all theories are wrong, some are useful.” One could argue then that at a
minimum, we need to know enough about a system to know when the laws, theories, or knowledge
that we use to establish cause and effect relationships and make engineering predictions are wrong.
For example, Newton's laws on are not universally applicable. There are natural phenomena that
Newton's laws cannot explain, particularly as one approaches the speed of light. For most engineer-
ing structures though, where the design is based on Newton's equations, hopefully that is not a
major problem. There are many similar theories and laws in other disciplines, which are useful but
 
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