20 BULLETIN 87, U. S. DEPARTMENT OF AGRICULTURE. 
consideration the possibilities of such features being needed when 
locating the general line along which bis flume is to be constructed. 
Where such features are carefully looked up before the final location 
of a flume line is settled and flume construction has begun, it is some- 
times possible slightly to vary the location of the proposed flume line 
so as to bring it to the desired grade to be successfully operated in 
connection with a cheaply constructed holding reservoir, without in 
any way decreasing the transporting capacity of the flume. It is also 
sometimes advisable to construct a small reservoir or "catch basin" 
at the foot of an unavoidably long and very abrupt grade, so that 
when the material being shipped leaves the flume or slip it will strike 
into a pond of water and thus avoid being split or broomed. Some- 
' times the reservoir and its additional feeders will furnish enough water 
to permit the flume line to be carried on an even grade from the point 
of the "catch basin" or small reservoir at the foot of an abrupt 
descent to its destination. In such cases the reservoir and feeders act 
as equalizers of the volume of water in the flume. 
It has been found necessary in some instances to have small storage 
reservoirs, provided with a small gate that could be quickly closed or 
opened, located at different portions of a flume where no feeders were 
available, in order to obtain a sufficient volume of water to carry the 
material being handled to the next station or reservoir, or to its desti- 
nation. Where conditions obtain that make this kind of an operation 
necessary, it is usually advisable to have the mouth of the "intake" 
considerably wider than the flume, which permits the water to go into 
the flume opening in a wide unobstructed flow. 
When operating under such conditions it is always advisable to let 
the water in the flume run for a short time before any material is 
shipped. Otherwise the material receives a strongly accelerated 
movement on the rapid descents, and is therefore carried by its own 
weight and momentum into the slower moving volume of water in the 
flat grades at a greater rate of speed than the water is moving, and 
consequently runs slightly faster than the water. For this reason 
the water should always be allowed to run in the flume for a sufficient 
time to be sure that the latter will be filled its whole length, or at least 
to the next station below, before any material is started on its way 
from the shipping point above. 
RESERVOIR PONDS AT HEAD OF FLUMES. 
It is advisable and oftentimes necessary to make a small artificial 
pond or reservoir at the upper end of a flume in which to "land" or 
"bank" the material to be shipped, especially when handling logs, 
railroad crossties, or heavy unmanufactured material of any kind. 
Conditions sometimes make it possible to use the ice on a pond of this 
