The Alexandria herald. [volume] (Alexandria [Va.]) 1811-1826, 1823-03-26
POTOMAC RIVER.
Report Of tho commissioners appointed
to examine the navigation Of the Po-
sOmac river (Confi,,us1

| :omac river. Continued.
Lock and Dam Navigation.
Another mode is by some relied up
on, to improve the navigation OF the rive
in consequence of its supposed create
cheapness, than canal properly so cell
ed. and consists in deepening the waite
in the bed of the river, sufficiently for tn,
purposes OF navigation by high dams %
large stone and solid Construction, with ;
lock or two LOCKS TO each dam, and
| short canal for She purposes of descend
Ing and ascending each level.
| This mode has many great inconveni
ences insePerable from it; the mos
important objection to il is the create,
expensiveness of the kind of navigation
which alone it affords, that is, in boat.
managed by men, instead of boats drawn
by horse besides this general obiec-
ton, many reasons may be sdduced tc
to shew Why IL cannot be advan,ageously
adopted on the Potomac river; the gene.
raj width OF this river is too great, the
fall is also too considerable, and the allu>
vial margins which alternate from the
right TO the left bank OF tie rivers the
whole length OF its course to tide water,
and which vary in elevation from fifteen
to thirty feet would in high water, with
out enormous exp, nse form insecure
attachments Of the dam, this kind of mar
gin being formed Of loose earth, OF com
2arative recent formation, would when
distractions are placed in the bed OF the
river, be liable to be forced and washed
away at the eXtremities ofthe dams the
dams themselves although ever so sold,y
built, would require frequent repairs !;
the fall in the river from Cumberland 10
tide water being about 5S7 feet, would
require about53 dsms,as The banks would
not admit of a greater elevation being Ell
vento the dams than | 0 feet, without great
risk of damaging the marginal property, *
cf increasing the liability to frequent in
Iu'ies to the dams themselves ; (a) each
dam would require lock of the same
lit as the dam end also an entering ca
nal with guard lock, of considerable eie-
yation, to be used in high water add to
these the danger of being thrown by the
>rr---ut cyrrfhe flAsp- .i.csseyer ipdieip,sss
iy located, below the guard LOCK and
their Inconvenience, which would Use
in high water taking all these disad-
vantageous circumstances into the &C
count, consider tie number of dams,
locks, &c. and their great length from 100
TO 800 yards, and the necessary soiidity
required in their construction, and then
calculate the other incidental expenses,
The whole amount would be nearly equal
TO the cost of regular canal, and the I'd.
vantsges would be infinitely less. Unon
foil view of the different plans therefore,
it cannot for moment be doubled, but
that the adoption of regular canal out
OF the river, though following its ravine.
will! be the most useful and durable i'm
proVement, and when the advantages
and cost Of each mode are relatively con.
sidereds incomparably the cheapest
The canal which, under all circums,an>
ces, the commissioners have thought bes,
calculated to suit the localities Of Polo
mac river, on which our estimates are
is one so feet wide at top, 90
feet at bottom, and feet deep; the
earth TO be thrown ont next to the river,
to form tow>path elevated two feet OF
above the level of the water
in the caBal,snd the track of the tow path,
to be ten feet wide. The level Of the ca.
nal to be generally elevated above the
highest foods, except when it is found
necessary to take in supply of water
from the river, or to pass expensive
ground along rocky shore thirty feet,
it is supposed, is the necessary width to
admit the passage Of two boats of suf-
ficient size to carry 25 tons, and to admit
of a small platform on the bow Of the boat,
sufficient TO take horse in upon, as
that in two places would be necessary,
where it has been found expedient to
cross the river by means Of dam to a.
void too expensive cutting OF walling.-
In order to ascertain the practicabllity
and cost of this plan, commissioners have
had the assistance Of the late engineer Of
the state Of Virginia, on whose sound
practical judg ,EeDt and knowledge en-.
tire reliance may be placed, more espe-
cially after the test his estimates have un.
dergone on that part of the james river,
where part Of the canal he had designed,
has been completed. (6) And it has
been there found, that contractors and
underwriters in sufficient numbers can be
obtsined from various parts of the UDited
States, to undertake the works at the es-
tlmated cost, whenever the states think
proper to authorize the cutting of canal.
The report and calculations on the plan
made from Mr.. Moore's field notes, by
dr.isaac Briggs, who has been appointed
MS successor, as far as we proceeded be.
tore the adjournment, occasioned by the