My question went thru 3 managers at NPS in Yellowstone until one of them forwarded it to a the civil engineering contractor hired by NPS;
...from our memories the connections were raised to keep infiltration from surface water runoff from entering the services, the maintenance staff wanted to keep them up off the ground to keep rocks and debris out if possible, there was also some talk from maintenance about putting the bends in the wyes above ground because garbage was getting placed down the pipes directly into the mains. The connections are actually more like 6-8” except for the couple of sites at the far east end where the mains are shallow and there wasn’t enough room between mains and the fittings required. Hope this answers the question.
