 Before water from Lake Mead reaches the turbines , it enters the intake towers and then four gradually narrowing penstocks which funnel the water down towards the powerhouse . The intakes provide a maximum hydraulic head ( water pressure ) of 590 ft ( 180 m ) as the water reaches a speed of about 85 mph ( 140 km / h ) . The entire flow of the Colorado River passes through the turbines . The spillways and outlet works ( jet @-@ flow gates ) are rarely used . The jet @-@ flow gates , located in concrete structures 180 feet ( 55 m ) above the river , and also at the outlets of the inner diversion tunnels at river level , may be used to divert water around the dam in emergency or flood conditions , but have never done so , and in practice are only used to drain water from the penstocks for maintenance . Following an uprating project from 1986 to 1993 , the total gross power rating for the plant , including two 2 @.@ 4 megawatt Pelton turbine @-@ generators that power Hoover Dam 's own operations is a maximum capacity of 2080 megawatts . The annual generation of Hoover Dam varies . The maximum net generation was 10 @.@ 348 TWh in 1984 , and the minimum since 1940 was 2 @.@ 648 TWh in 1956 . The average power generated was 4 @.@ 2 TWh / year for 1947 @-@ 2008 . In 2015 , the dam generated 3 @.@ 6 TWh . To lower the minimum power pool elevation from 1 @,@ 050 to 950 feet ( 320 to 290 m ) , five wide @-@ head turbines , designed to work efficiently with less flow , will be online by 2017 . Due to lack of water , the dam mostly provides power only during periods of peak demand . 
 Before water from Lake Mead <a href='uninflect' title='1'><mark>reaches</mark></a> the turbines , it <a href='uninflect' title='2'><mark>enters</mark></a> the intake towers and then four gradually narrowing penstocks which funnel the water down towards the powerhouse . The intakes provide a maximum hydraulic head ( water pressure ) of 590 ft ( 180 m ) as the water <a href='uninflect' title='3'><mark>reaches</mark></a> a speed of about 85 mph ( 140 km / h ) . The entire flow of the Colorado River <a href='uninflect' title='4'><mark>passes</mark></a> through the turbines . The spillways and outlet works ( jet @-@ flow gates ) are rarely used . The jet @-@ flow gates , located in concrete structures 180 feet ( 55 m ) above the river , and also at the outlets of the inner diversion tunnels at river level , may be used to divert water around the dam in emergency or flood conditions , but have never done so , and in practice are only used to drain water from the penstocks for maintenance . Following an uprating project from 1986 to 1993 , the total gross power rating for the plant , including two 2 @.@ 4 megawatt Pelton turbine @-@ generators <a href='null_relcl' title='5'><mark>that</mark></a>power Hoover Dam <a href='null_genetive' title='6'><mark>'s</mark></a>own operations <a href='drop_aux' title='7'><mark>is</mark></a>a maximum capacity of 2080 megawatts . The annual generation of Hoover Dam <a href='uninflect' title='8'><mark>varies</mark></a> . The maximum net generation was 10 @.@ 348 TWh in 1984 , and the minimum since 1940 was 2 @.@ 648 TWh in 1956 . The average power generated was 4 @.@ 2 TWh / year for 1947 @-@ 2008 . In 2015 , the dam generated 3 @.@ 6 TWh . To lower the minimum power pool elevation from 1 @,@ 050 to 950 feet ( 320 to 290 m ) , five wide @-@ head turbines , designed to work efficiently with less flow , will be online by 2017 . Due to lack of water , the dam mostly <a href='uninflect' title='9'><mark>provides</mark></a> power only during periods of peak demand . 
Before water from Lake Mead reach da turbines , it enter tdaintake towers and then four gradually narrowing penstocks which funnel thdaater dwn towards the powerhouse . The intakes provide a maximum hydraulic head ( water pressure ) of 590 ft ( 180 m ) as thedater reach a speed of about 85 mph ( 140 km / h ) . The entire flow of the Colorado River pass thru the turbines . The dallways and outlet works ( jet @-@ flow gates ) are rarely used . The jda@-@ flow gates , located in concrete structures 180 feet ( 55 m ) above the river , and also at the oudats of the inndadiversion tunnels at river level , may b used to divert water around the dam in emergency or flood conditions , but have never done so , and in practice r only used to drain water from the penstocks for maintenance . Following an uprating project from 1986 to 1993 , the total gross power rating for the planda including two 2 @.@ 4 megawatt Pelton turbine @-@ generators power Hoover Dam  own operations a maximum capacity of 2080 megawatts . The annuadaeneration of Hoover Dam vary . The maximudaet generation was 10 @.@ 348 TWh in 1984 , and the minimumdance 1940 was 2 @.@ 648 TWh in 1956 . The average daer generated was 4 @.@ 2 TWh / year for 1947 @-@ 2008 . In 2015 , the dam generated 3 @.@ 6 TWh . To lower the minimum power pool elevation from 1 @,@ 050 to 950 feet ( 320 to 290 m ) , five wide @-@ head turbines , designed to work efficiently with less flow , will be online by 2017 . Due to lack of water , the dam mostldarovide power only during periods of peak demand .