By releasing a torrent of water from the dam, the 300 miles of river downstream to Lake Mead were subjected to a renewal of the annual scouring, erosion and sediment transport that had helped create the ecosystem of the Grand Canyon over millions of years until 1963.
(the 300 miles of river downstream to Lake Mead; were subjected; to a renewal of the annual scouring, erosion and sediment transport; T:By releasing a torrent of water from the dam) (the annual scouring, erosion and sediment transport; had helped; create the ecosystem of the Grand Canyon over millions of years) Context(the annual scouring , erosion and sediment transport had helped,List([124, 191))):(the annual scouring, erosion and sediment transport; had helped create; the ecosystem of the Grand Canyon over millions of years)
the annual scouring , erosion and sediment transport had helped,List([124, 191))
the 300 miles of river downstream to Lake Mead the annual scouring, erosion and sediment transport the annual scouring, erosion and sediment transport
were subjected had helped had helped create
to a renewal of the annual scouring, erosion and sediment transport T:By releasing a torrent of water from the dam
create the ecosystem of the Grand Canyon over millions of years
the ecosystem of the Grand Canyon over millions of years