Rogue River courier. (Grants Pass, Or.) 1886-1927, 1904-06-02

in 1890, the height of tha water will
be proportionately increased under
the bridge, and as q consequence
the water may rise to level of Sixth
Street.
1t is from these facts that ! have
drawn the conclusions, that the pres
ent bridge structure should be raised
six feet higher to accommodate any
such emergencies, and render the
bridge safe, that an additional span,
of 1870 feet or more. should be built
on the same level as the raised
structure, and rest upon an abutment
pier, which will protect the end OF
the ill. The said I'll should not be
less than 30 feet wide ON top, and
should extend to the south ON a very
light grade to some point between
400 and 500 feet south Of the bridge,
so that any high water the bridge is
aimed to accommodate, will not find
its way around the south end of the
bridge in any way to destroy the tll
a 20-foot roadway would not be
sufficiently wide to allow two loads
of hay to pass. or accommodate the
usual heavy tesming that the road is
subjected to.
would call your attention to the
fact, that it is a very important mat
ter in structures of this kind, to pro-
vide sufficient safeguards against
wrookage, by giving all the clearance
possible that can be seen to be neces-
sary from the conditions that exist
or that you have any reasonable belief
will occur at any time in the life Of
the structure. 1t must be borne in
mind that when stream Of water is
obstructed by a dam, or anything
else, and the velocity of the flow of
the water diminished above any such
obstruction, as it must be, that the
cross section of the stream above such
dam is increased in direct proportion
to the diminished velocity, so if you
cut the velocity in two, it double:
the area of cross-soo,ion Of the stream.
The fiji and method recommended
by Mr.. Grondahl, would be totweer
two and three feet higher than the
high water mark of 1908, which or
the account of the increased height
of water under the bridge, because o.
cutting off tie flood area, would not
leave the fill over two feet higher
than the water of 1908.
In this examination, Mr.. Grundah
has taken my figures as to the height
= of water and bridge. He has taken N
? observations himself, otherwise thai
3 super fetal view of the bridge, dam
} etc. The observations as to the heigh
r of the dam and grade of the river
were taken subsequent to Mr
70 Grundahps report. and submitted t
| i'm but he does not consider them Q
d any importance. Mr.. Grundahl ad
5 mitted when ON the ground with mt
u that the difference Of level Of the hig
Il water of 1903 and 1890 at the PowC
c house was not far enough away frol
& the influence of the dam to indicat
e the true difference.
u am not bridge specialist al
have not been requested to pass upC
the structure, but as have been "a
) cused Of such and credited with co
tain recommendations, which ! ha'
=. not made a few words on the matt
will not be amiss. From an eng
neering standpoint there is conside
able fault to be found with the bridg
J. 1t rests upon two-thirds of the su
Oh port that the first bridge Of two spa
did, doubling the load of the piel
The piers are not properly brac
n. together, aud If the South pier
ne not strengthened and braced, anoth
.ss high water may wreck it. The brid
J.. is too narrow for its height a
of length. The bridge is subject
We to excessive strains and tensions,
ms cause of its great loxibility fro
to its narrowness 1t is not possible
set tighten the bridge up any moro
it is frightened to the limits uroyid,
bo And you cannot pronounce a brid
.o, safe from the borings of two or thI
- :4. -. nm. IDfagtiva /
.ho ber will wreck it, As a matter
v future economy to the county, il
oir my opinion, being taxpayer, u
no the bridge is better suited for So
sco other point on the river where
,o, traffic is not SO heavy or liable
a. such rapid increase. The timh
10 in the bridge have been in place
,a, long, in the practice Of Railroad
,Lo gineering, as it Is considered "a
ma Therefore from the facts hcrctoi
,ho stated, ! cannot concur with
No Grundahl as to the width or hcigh
,ho tne FIJI; hut believe that for a
bod manent proposition, that my conf
,ho sions are not in the least oyerdr.
tho or excessive.
= 60 respectfully submitted,
40. WILLIAM II. HAMP|Ol
Grants Pass, Oregon, May 27, d
W. To the Honorable County Court
~, Josephine County.