Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1881-02-23
SAN FRANCISCO EIARBOR.
The Causes Tending to Diminish
It's Tidal Area.
REPORT OF COL. GEO. H. WENDELL.
Drainage System of the Rivers
Employing Into the Bay.
ESPECIAL BY TELEGRAPH TO The nrooRDusos.l

WASHINGTON, February 22d.-The Score
tary of War to-day transmitted to the House
of Representatives an elaborate and highly
interesting report, prepared by Col. George
| ID. Mendell, Of the United States Engineer
| Corps, in response to Horace Davis resolu
ton calling for information as to the causes
tending to diminish the tidal area of San
Francisco bay and lessen the tidal scour on
the bar, and thereby decrease the depth Of
the water upon said bar, and diminish the
| value of San Francisco as a commercial har.
Dor. Colonel Mendell first specifies the
natural causes, which are practically not sub.
Ject to control. He describes the
DRAINAGE SYSTEM OF THE RIVERS
Implying into San Francisco bay,
and shows how the rapid fall of
their tributaries and the violence of
the rains favor the erasion and transportation
OF earthly matter from the mountains and the
steady conversion of the marshes into dry
land. The present extent of the marshes in
San Francisco bay, including Suisun and San
Pablo bays, is stated at 800 square miles,
Mention is next made Of the similar tenden
cies of hydraulic mining, and the report then
proceeds to consider the artificial causes. such
as the construction of piers and jetties, and
the utilization of State and city grants of
submerged lands.
Referring to the piers and training walls at
Oakland, Co. .Mendell says: THE tendency
OF these structures is to hold the material de-
posted along tie shore, and therefore TO con-
centrate in a small area the effect which 9TH
erwise would have been distributed over
larger areas. This effect can never take great
dimensions He reports in regard to
THE APPREHENDED sHoALING OF THE BAR
Outside the entrance to San Francisco bay,
that comparison of the survey made in 1855
with the one last made in 1873 shows that the
bar has not retreated, and that the depth of
water on its crest has not been diminished.
He therefore says it is safe to state that the
bar was as good in 1873 as in 1855. No sur
vey has been made since 1878. After dis
cussing the various features of the problem
suggested Colonel Mendell concludes his re-
pJEt lOAioWo. hO ioiCSoibS oSoSiApehoh
o. the bar demonstrates that it is able to lose
a great part of its advantages and yet remain
an admirable channel for commercial pur-
poses. At present this channel is eleven
miles wide. If we suppose the bar to move
shoreward until it is shortened to half its
present length, it is apparent that largely
diminished tidal prison might be able to
maintain over the shorter line the depth it
now maintains over longer. The depth of
the crest might be reduced to much narrower
limits than the one last named, and yet remain
an excellent channel and be maintained by a
tidal area only small fraction of that which
now contributes to this result. If we sup
pose the crest of the bar to maintain its
present position instead of retreating, the eff
feet would be diminished channel, result
ing from the filling of the interior of the bays,
to encourage the growth of existing shoals
and to form new shoals These shoals would
shorten the crest and lessen the area of the
channels to be maintained. The result would
be practically equivalent to that to be pro-
duced by the retreat of the bar shorewards
and between these shoals one or more chan
nels would remain.
THE ACCESS TO THE HARBoR