Long Island Canals. Who built them, and when?

Stumbled into this Reddit thread. Technically speaking this is not the Long Island itself, but rather a group of smaller islands in the South Oyster Bay located to the south of Long Island. Apparently this group of islands is... well, you can see for yourself.

• Map Link

KD: A quick search produced nothing for me. Who and when built these canals?

And question #2. Who and when bombed this area to pulp?

• Circular lakes: evidence of the War of Gods?

Do you think this here is a plausible explanation?

• Under the direction of economic-rebuilding “New Deal” initiatives, the Civilian Conservation Corps dug an estimated 562,000 miles of parallel ditches in ≈90% of the coastal salt marsh from Maine to Virginia. Ditches were intended to control mosquito production by draining shallow pooled waters called pannes where mosquito larvae commonly develop and by allowing fish to feed on mosquito prey during high tides.
• Answer: What are those lines in the bay?

562,000 miles. Where are the digging process pictures?

• The length of the Earth Equator is 40k miles. This combined mosquito ditch is 14 times that.

Looking at these small canal lined islands, it appears that the canals, or ditches if you will, came before small lakes and streams within these same very islands.

• The only photographs pertaining to this mosquito ditching I found, reflect people doing some shovel digging. I doubt the manual way can account for 562,000 miles.

Any opinions?