Are you precise in discribing a....Various forms of running water.

[Boasun]

Looking in Lexicons, dictionaries, an Encyclopedias, I've never found a decisive way of explaining the differences between;
A Brook
A Creek
A Rivulet
A stream
or a River.
So when does one of the above deffinitely becomes one of the other??
Can you discribe each one of the above in words to actuately give an understanding of what each is? When can that body of water could be either one of the names above. I.E. A brook is a creek or a rivulet?
Is there a wordsmith who can help us out on these minor details of discription?

So go for it.

[jaschrumpf]

Well, my degree is in geology with an emphasis on geomorphology, so I'll have a go at answering your question.

Basically, a river is any natural watercourse filled with fresh water that flows toward another body of water. All those categories you list are actually just common names for small rivers, and there really is no "official" demarcation between a "rivulet," "creek" (or "crick" where I'm from), "stream" and "river."

Hydrologically, rivers are rated according to their Strahler number, which is a numerical measure of a river's branching complexity. A river with no other rivers flowing into it has a Strahler number of 1, and is called a first-order river, or stream. when two rivers with a Strahler number of 1 join, their number changes to two and it becomes a second-order stream. A first-order stream joining a second-order stream does not change the second-order stream into a third-order; only two of the same order can do increase the number. The Amazon River is a twelfth-order stream -- that'll give you some idea of its size and complexity.

So really, you can name the little guys however you like. There is no official list that can call you wrong.

[catamount]

All of these terms are defined in the "Glossary of Hydrology" by Wilson and Moore, 1998.

They don't give quantitative cut-offs, and there is A LOT of overlap, but there does seem to be some agreement on the relative ranking of these terms:

Rivulets are generally the smallest -- I think of them as being the small overland flows that only develop during rain storms (see rill flow).

Brooks are often considered smaller than creeks, but there is a lot of overlap. I think the terms may be interchangable depending on where you're from. Using the Strahler terminology, I think of them as only ever first or second order...(not counting any rivulets that might contribute).

Stream is a generic term that describes any flow of water, but it can also be used in the sense that Streams are generally larger than brooks or creeks, but smaller than rivers, although again there is a lot of overlap.

Rivers are almost always larger than streams, creeks, brooks, and (especially) rivulets.

[paulk]

You're pushing it if you think I'm taking my boat up a rivulet, creek, brook, or stream. Even then, there are navigable and non-navigable rivers.