can be made in the various popular sizes the width of opening of the channel is such it can be installed over all known covers and clamped in position by the set screw also the support bracket can be provided with a telescopic portion to provide for different lengths of covers the ends being clamped to fasten the support bracket in position also it is preferred the chains be galvanised with a 5 mm clearance between the links to permit free passage of the water while still retaining the debris the collection of large items of trash will not severely impede the water flow into the pit if it is necessary to conduct maintenance on the pit the cover with the screen attached can be easily removed so that access is available to the pit for example to cleanout the smaller debris that passed through the chain screen the chain screen permits cleaning of the gutter by a street sweeper the screen permitting the brush to pass without damage to the screen or brush in use if there is a large backup of rubbish and water pressure created by the back up the fail safe chains can move into the pit.