NATIONAL HYDRAULIC LABORATORY
1 Measuring basin of Bureau design is entirely outside the building proper. It must therefore be covered with a roof (or floor) which will serve no other useful purpose. No
portion of the north, south, or west walls of the Bureau design for measuring basin is so located as to serve as foundation walls of the proposed future extension of the laboratory in
Useful clear area.
that direction. The proposed future enlarging of the Bureau measuring basin is not a feasible thing to do, because of extreme difficulty of making new concrete joints water-tight
where new walls and floor join the old structure.
2 Bureau's concrete forebay is subject to serious cracking and consequent leakage. It is more expensive to construct than the steel cylinder. It also is not as adaptable as the
circular steel forebay to the many demands for attaching pipes for supplying water to experimental set-ups or for attaching pump discharge pipes.
3 The purpose of the large cross-section of the Freeman flume is to give convenient space and "elbow room" for fundamental research on large depths on many forms of weirs,
dams, baffle piers, and Venturi meters, under both normal and disturbed or turbulent flow.
The greater depth of the Bureau return flume makes the use of this flume for experimental purposes more difficult and inaccessible.
It's primary purpose is to return water to the supply basin from small experiments using not over 40 or 50 cubic
feet per second. A pipe line 36 inches in diameter would serve equally well. The inclusion of this high-level return flume in the Bureau design requires that this portion of the
5 The Bureau's high-level return flume is a needless expense.
laboratory building be about 8 feet wider than would otherwise be necessary. The space thus involved above the first floor (8 feet wide by 31 feet high by 203 feet long) (50,400
cubic feet and costing probably upward of $5,000) is of little, if any, practical use.
6 For water measurement purposes this is less accurate and precise over a wider range than the measuring basin or special forms of weir.
7 The second floor in J. R. Freeman's study No. 4 for the entire length of the narrow portion of the building and north of the central building columns, can be inexpensively
extended to the south edge of the main flume wherever desired, for increased width (as for a crooked river flume) supported on steel columns 20 feet apart, so arranged as not to
Bracket supports can be provided on the columns along the north side of the building so that, to any extent desired,
interfere materially with the operation of the main flume.
second floor area over the main flume can be extended by removable flooring.
• Extension of second floor to south edge of main flume has been considered.
Useful for floor load of 50 pounds per square foot over entire area and is available for experiments on roof.
12 Timber gates are much more practical, durable, and cheap; more convenient for attachments. Similar timber gates are in almost universal use for 50 years past in the large
10 Not durable and not strong; can not be used for out-of-door experiments on roof.
water-power developments in New England. Mr. Freeman has designed many, such timber gates which have been long in successful use.
18 Space is provided for adding these tanks in future if desired.
19 Great height desirable for photographic records.