Check out this:
沧浪亭，为苏州现存最古老的园林，占地面积1.1公倾。北宋庆历年间(公元1044年)诗人苏舜钦遭贬谪流寓来苏，因感其原址高爽静僻，野水萦洄，遂以四万钱购得，始在水旁筑亭，取“沧浪之水清兮，可以濯我缨；沦浪之水浊兮，可以濯我足”之意，名亭曰“沧浪亭”。

Plus it gives me an excuse to dust off my camera every once in a while.

The “cang 沧” does mean blue or azure blue as Chris noted though according to the Hanyu Dacidian the “lang 浪” generally means “waves” or “breakers.” The locus classicus for 浪 in the dictionary is a poem by Du Fu (712-770 C.E.): “源水无非浪, 他山自有春.”

I guess one translation goes with the first character and the second translation looks at the second character. But that’s just a guess.

Thanks for the post, I’ve enjoyed your virtual tours of the sites of Suzhou.

(for the record, we’ll call you “expert” around these parts.)

Cānglàng Tíng (沧浪亭), better known in English-speaking circles as Surging Wave Pavilion (though the name translates as Blue Wave Pavilion – any experts know why?)

I’m not an expert, but here’s the results of my ten minutes of research. This character “沧” does mean “blue”, but it’s special, and really means “deep sea-blue”. It’s only used in a bunch of idioms (成语) together with “海 hǎi sea”, as “沧海 cānghǎi” which would best be translated as “the deep blue sea”.
Some of these idioms are really cool, like, for example, “沧海桑田cānghǎi-sāngtián” which means, literally, the deep-blue sea changes into mulberry fields — i.e. time changes everything; “沧海一粟cānghǎi-yīsù a drop in the ocean”; or, my favorite, “沧海遗珠 cānghǎi-yízhū”, literally, “a pearl left behind in the deep blue sea”, i.e. “undiscovered talent”.
So here, I’m convinced that “沧浪 cānglàng” is an abbreviation of “沧海波浪 cānghǎi bōlàng – a wave from the deep blue sea”, and (taking into account the idioms mentioned above) connotes great changes, like “the turning of the tide”. So, just translating it as “blue wave” doesn’t do that justice at all, does it. “Surging wave” is a little better, but not much.