The Colorado Experiment Station 
36 
occasions we have had it fill the ditch section so that the water ran 
over the sides of the ditch on top of the ice. What takes place in¬ 
side the pipe is only surmised, but we believe that the ice floats in 
the upper half of the pipe until it accumulates sufficiently to form 
a plug, and this plug is forced out after the water backs up in the 
approach to the pipe and increases the pressure sufficiently to break 
the plug.” 
Table 9 shows the factors of flow in these siphons under con¬ 
ditions found in them during August, 1913. 
REDLANDS MESA SIPHONS, GRAND JUNCTION. 
These are of 48-inch bore throughout, buried beneath about two 
feet of earth, except at the lowest points where a few feet are ex¬ 
posed. (Eigs. 28 and 29.) As there are no blowoffs, it is be¬ 
lieved that the velocity of 1.6 feet per second, which was found in 
the test made June 15, 1913, was hardly sufficient to prevent some 
Fig. 28. Siphon (a), Redlands Mesa Canal, Grand Junction. 
deposition of the red sandy sediment characteristic in that region 
of the water diverted from the Gunnison River. No doubt, how¬ 
ever, when the canal is carrying its full capacity, sufficient velocity 
is developed to remove this deposit of silt, though coarser material 
may still remain. One instance is reported of a dead cow having 
been carried through the siphon which would indicate sufficient 
