Often people think about hunter-gatherers as primitives. "Dark Emu" book is a great example of popular history book that refutes those beliefs. Aboriginal constructions could be quite impressive: Brewarrina - 1800 meters of dams for fishery, Toolondo 1200 m channel, Condah eel traps - 2 km of channels, Bulloo water storage dam that stored 700 m^3 of water during arid season, 7 m deep water wells caved in stone.
"Dark Emu" concentrates on Australia. What about the rest of the world?
I found some info about Comox Harbour(Canada) or Iijoki River(Finland) fish traps but they look much less impressive than Brewarrina Complex.
What are examples of African/European/American hunter-gatherer's record sizes for dams, canals, wells?
Are there equally impressive examples of African/European/American hunter-gatherer's constructions?
It'll be best if you can narrow down this criteria for a bit, and perhaps offer a definition for "impressive" since that feels subjective. Physical scale perhaps? You could ask for the biggest hunter-gather construction outside of Brewarrina.