Stoplogs are frequently used to temporarily block flow through a spillway or canal to enable dewatering of the area for routine inspection and maintenance of the main equipment. Operation is usually by mobile/gantry crane using fixed slings or an automatic lifting beam. Stoplogs can be single or multiple units dependant upon the size of channel being isolated.
Advantages
Eliminates building and removal of 'coffer dams'.
Disadvantages
Operation has to be performed in balanced conditions.