44 BULLETIN 194, U. S, DEPARTMENT OF AGRICULTURE. 
some grass on the lower water edge. Second third of distance much roughness, with 
cobbles over most of bottom. Last third, in condition intermediate first and second 
thirds. Coefficient n=0.0262. 
No. 252, Expt. S-10, Upper Canal from Big Cottonwood Creek, Utah. This reach 
of canal follows a gentle contour curve on a very gravelly hillside. The sides are 
nearly vertical and lined with trees and willows whose rootlets extend into the water 
prism. The bottom is completely covered with cobbles up to two-fist "size. Like 
nearly all ditches of this character the sides are irregular in outline, as the cobbles do 
not break into an even bank. Coefficient n=0.0277. 
No. 253, Expt. S-15, Logan and Northern Canal, Utah. This is a fine example of 
a ditch following a gravelly hillside contour near the mouth of a canyon, a condition 
typical of many canals near the mountains. The sides are densely fringed with 
willows and bushes whose rootlets hold silt and form nearly vertical banks. The 
bottom is completely covered with well-packed gravel and cobbles up to two-fist 
size. Coefficient n=0.0270. 
No. 254, Expt. S-51, Keno Ditch of the Reno Light & Power Co., Nevada. This 
reach of canal was originally excavated in an old river bed containing innumerable 
bowlders up to 5 cubic feet in size (PL XVIII, fig. 3). About a year before this test 
the sides and bottom of this channel had been paved with a hand-laid riprap of these 
bowlders, the sides being laid about J to 1, and the bottom flat. Many of the 
bowlders at the top of the walls have rolled into the canal, as no cement or other bond 
was used, but the general condition of the walls appears to be good. The reach 
tested was straight with the exception of a gentle curve in the last 200 feet. Coeffi- 
cient 71=0.0291. 
No. 255, Expt. S-43, Sullivan and Kelly Ditch, Nevada. This reach follows a gentle 
contour on a rocky hillside (PL XIX, fig. 1). The bowlders have been hand laid in 
a nearly vertical wall on the lower side while the bottom and upper side are rough and 
irregular with projecting large bowlders. A slime of mud from the Truckee River 
water covers all rocks below the water line. Vegetation is negligible. Coefficient 
n=0.0324. 
No. 259, Expt. S-89, Beasley Ditch, Colorado. This canal on a straight reach with 
a curve about 100 feet below the lower end. At the time of test it was carrying but 
about one-fourth its capacity. The bottom and sides are a mass of unpacked gravel 
and bowlders up to 2 cubic feet in size. Coefficient n=0.0383. 
SIDEHILL CUTS, WITH RETAINING WALLS. 
No. 261, Expt. H-23, Hedge Canal, Montana. This test was made on a short reach 
excavated in granite hillside, with the lower bank formed of a random rubble masonry 
wall, well plastered with mortar on the nearly vertical water face. The reach is 
straight except for a slight curve in the last 50 feet. The bottom is covered with 
granite gravel, most of which would pass a £-inch screen, with occasional pieces one- 
fist size. The excavation is quite true to line for a rock cut. Coefficient n=0.0185. 
No. 262, Expt. H-27, Hedge Canal, Montana. This reach is about 500 feet below 
that in No. 261. The upper side is excavated quite true to line in earth and disin- 
tegrated granite. The lower side is a vertical concrete wall laid against board forms. 
The floor is concrete with from 1 to 2 inches of fine, sharp ravelings from the hillside. 
In scattered spots the floor shows. The reach is 450 feet long. Station 1 to 2 is about 
a 20° curve, on 12-foot chords. At station 3+40 is a rather sharp bend. The rest is 
fairly straight. Coefficient n= 0.0225. 
No. 263, Expt. H-9, Cove Ditch, Montana. This reach is cut from a sandstone 
hillside (PL XIX, fig. 2). The lower bank is a rubble masonry wall plastered with 
concrete on the water side. The bottom is also overlaid with concrete. The align- 
ment is wavy with some 20° curves. From stations to 2 there is some gravel; from 
stations 2 to 4, clean bottom, the rock on upper bank being smooth but the width 
