Ball screw swinging gate mechanism - GIF

[jdurand]

Look at each top corner and you will see the studs for the cover.

In my experience any box below grade even with a "water tight" cover will fill up with water.

[NortonDommi]

Have you by any chance experienced the wonders of modern polysulphide adhesive sealants? : ) Looking at the video the box is above ground level but perhaps a good few Silicon absorbent sachets tossed in before sealing would not go amiss huh?