One hundred and twelve miles of State roads have been surfaced with
broken stone and gravel macadam. Practically all of this surfacing is
sixteen feet wide; there are, however, a few short stretches of
nine-foot width necessitated by the coming on of wet weather before the
full sixteen-foot width could be completed. The total quantity of broken
stone and gravel placed in these 112 miles of surface was 247,925 cubic
yards, an average of 2,210 cubic yards per mile, which quantity of
material per mile gives an average loose thickness of eight and one-half
inches for macadam sixteen feet wide. The Department's specifications
call for a minimum thickness of six inches. In many places, however,
particularly on the lower Columbia River work it was found necessary to
place as much as eighteen and twenty-four inches of rock before a
satisfactory foundation could be secured.
The sections upon which broken stone or gravel surfacing was placed are
as follows:
Clatsop County-- Miles
Astoria to Columbia County Line 24.4
Columbia County--
Clatsop County Line to Goble 27.2
Deschutes County--
Bend-Lapine Section (cinder macadam) 12.5
Douglas County--
Divide to Leona 7.0
Gilliam County--
Condon to Thirty Mile Creek 6.7
Hood River County--
Cascade Locks to Hood River 18.0
Jackson County--
Siskiyou Mountain Section 6.5
Lake County--
Lakeview-Paisley Section 4.0
Lane County--
Divide-Cottage Grove Section 1.0
Wheeler County--
Cummins Hill Section 4.5
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Total miles of macadam surfacing 111.8
A complete description of each of the above sections will be found in
the chapter devoted to the county in which the work was performed.