JÄRVA DAGVATTENTUNNEL ERFARENHETER AV FEM ÅRS DRIFT / Järva Urban Storm Water Tunnel Experiences from five Years of Operation
Storm water from 1,520 acres of Järvafältet north of Stockholm is treated by means of sedimentation in a 12 km long tunnel system with a volume of 275,000 m3. Storm water is thus given a long detention time before it is pumped out into Edsviken. Earlier a report has been given of one year’s pilot operation in part of the tunnel system. The finished installation is in full operation since April 1, 1981. Studies have shown that the quantity of water pumped out has been less than was originally assumed. Similarly, the contents of most of the impurities in the treated storm water have been lower than was expected on the basis of the earlier pilot operation. Pumping of the treated water is controlled fully automatically by the water level. Operating experience indicates that sedimentation takes place rapidly. “Complete abstract not presented.”