A fiberglass Packaged Metering Manhole measuring effluent from a cheese making operation in upstate New York. As the manhole is away from vehicular traffic, it is provided with a domed fiberglass top.  Domed tops provide excellent operator access and are designed to fail-open (open when not secured).  Openchannelflow's fail-open design means that at a glace an operator can know if a site has been secured.