 Following the completion of the dam , the entrances to the two outer diversion tunnels were sealed at the opening and halfway through the tunnels with large concrete plugs . The downstream halves of the tunnels following the inner plugs are now the main bodies of the spillway tunnels . The inner diversion tunnels were plugged at approximately one @-@ third of their length , beyond which they now carry steel pipes connecting the intake towers to the power plant and outlet works . The inner tunnels ' outlets are equipped with gates that can be closed to drain the tunnels for maintenance . 
 Following the completion of the dam , the entrances to the two outer diversion tunnels <a href='uninflect' title='1'><mark>were</mark></a> sealed at the opening and halfway through the tunnels with large concrete plugs . The downstream halves of the tunnels following the inner plugs <a href='drop_aux' title='2'><mark>are</mark></a>now the main bodies of the spillway tunnels . The inner diversion tunnels <a href='uninflect' title='3'><mark>were</mark></a> plugged at approximately one @-@ third of their length , beyond which they now carry steel pipes connecting the intake towers to the power plant and outlet works . The inner tunnels <a href='null_genetive' title='4'><mark>'</mark></a>outlets are equipped with gates <a href='null_relcl' title='5'><mark>that</mark></a>can be closed to drain the tunnels for maintenance . 
Following da completion of tdadam , the entrances to the two outer diversion tunnels was sealed at the opening and halfway thru the tunnels with bigass concrete plugs . The downstream halves of the tunnels following the inner plugs now thdaain bodies of thedaillway tunnels . The inner diversion tunnels was plugged at approximately one @-@ third of their length , beyond which they now carry steel pipes connecting the intake towers to the power plant and outlet works . The daer tunnels  outlets are equipped witt gates can be closed to drain the tunnels for maintenance .