The Washington times., 1924-03-22
PLAN ON
HYDROPLANT
FAVORED
Use Of All of Potomac's Avail
able Energy Contemplated
Under This Development.

Continued from First Page.)
stage would be required. During
this period the accumulated revenue
from the sale Of current would
amount to q large sum. which 1t Is
proposed to apply on the cost Of
the required additional construction.
Compromise Suggested.
A compromise or combination
plan, making use Of the most
economical features Of the two plans
Of Tyler and Cranberry. should give
better results, rather than following
out in detail that Of the former in
its entirety.
The Potomac river, with a drain
age basin Of 1850 square miles in
area above the tidal limit at Chain
bridge, is quite variable in its flow
or volume of discharge in the diff
ferent seasons of the year. This
glashy feature Of the stream in
vites the most careful consideration
in the formulation Of any plan
looking toward development Of
power.
! It is necessary that a dependable
minimum volume of flow be fixed
| upon for continuous power genera
| ton in every day of the year, and
Of an amount that will meet the
current demands. Gauging records
of the Potomac's daily discharge
have been carefully kept by the
| United States Geological Survey
more than thirtyfive years.
A close study of these records
develops the fact that a minimum
discharge Of a value sufficient for
adequate power output is Nafforded
| during ten months Of the year.
During the remaining two months
to complete the years cycle the
ten months minimum value OF
natural stream flow could be at.
forded through regulation.
Through Storage Basins.
This regulation would be MAIDS
by means of storage basins, located
in the valleys of upstream tribu-
taries, with surplus water kept In
reserve. Reserve water storage is
that conserved during the seasons
Of the year when the rivers dis
charge is excessive and consider.
ably beyond the amount determined
as adequate for the operation OF
the hydro-electric project.
In other words, provision IL to
be made to withhold, in the upper
valley basins, surplus waters that
have come with the spring. and
summer rains, in turn to be rer
leased to the upper river, making
up for the natural deficiency in
times of drought or lessened stream
discharge, which usually occur dur.
ing several weeks of the fall.
The initial element, or first stage
of development as planned, in the
Tyler method, is to be made with
the construction Of a gravity dam
at point about one mile above the
Government water supply dam at
Great Falls. This dam, forty.thres
feet in height, is to divert the water
from the bondage so created to an
open flume or canal, constructed
along the side hill on the Maryland
side Of the river and extending to a
point opposite the locality known as
Cupid's Bower. about a mile and
one-half down stream from the falls.
At the base Of the hill at this
point a power house is designed for
construction and connection between
flume and power house made by
penstocks of riveted steel plate.
146-fOOt Head.
The total normal hydraulic head
between water surface in the fore
bay or flume and the tail water level
in the river, Immediately in front
of the power house, would amount
to 146 feet. All allowances have
been made for the necessary grading
of the flow line of the flume and the
| friction head due to the velocity of
the water in the conduit, in calcu.
lating the net hydraulic head.
The dam referred to is to be Of
the gravity type, Of cyclopean con-
crete, with a spillway 2,40O feet in
length crosswise of the river. Pro-
vision has been made for mechani-
cally operated gates to be located
on the crest in order to conserve a
large depth of bondage during ne.
RODS Of low stream flow.
Pondage from this dam viii be
afforded in a length of slack water
extending upstream to a distance
Of thirty-four miles, to about the
locality Of Point of Rocks. The
Baltimore and Ohio Railroad tracks
fringe the river at this point, and
accordingly this locality determines
Ahe limits to which the pond may
extend.
The section Of the Chesapeake
and Ohio Canal between the dam
site and Point Of Rocks will be
submerged, but the pond will serve
as a waterway for boat transporta.
ton following the construction of
the dam. Lockages are designed at
downstream end Of the pond to pro-
vide for the necessary boatway con.
nection to the present canal leading
to Georgetown.