Historic Resource Evaluation Project - Tuolumne Utilities District

ditch had been absorbed into the TCWC system; it was thereafter associated with the
TCWC and its successors, one of the largest and most important entities in Tuolumne
County from 1852 to the present.
Under Criterion C, although paralleling the earlier 1850s ditch in places, the Roach’s
Camp Ditch retains its integrity to its period of significance (ca. 1850s-1967) along about
80% of its length, and embodies the distinctive characteristics of its type, period, and
method of construction. Although the active ditch was truncated after about one and onehalf
miles, instead of continuing southerly to Roach’s Camp and the Tuolumne River, the
extant operating segment conveys its integrity of location, design, setting, feeling, and
association, and conveys water in the same manner as when it was first constructed. The
lower section, although no longer in operation and outside of the project boundaries, also
appears to be a contributor as an archaeological property.
San Diego Ditch (P-55-006538)
Description. This resource is a water conveyance system consisting of earthen berm
ditch, siphons (pipe), and two tunnels. From a dual junction box along the Columbia
Ditch, the San Diego contours along a side hill north of Italian Bar Road to a siphon that
crosses Yankee Hill Road, continuing in earthen berms on contour to San Diego
Reservoir, about 3.5 acres in size. The ditch continues, flowing around Kennebec Hill
first in a pipe and pipe-in-tunnel to its terminus near the end of Damin Road at Hippie
Pond. This system is somewhat rural, set in a mixed conifer-oak woodland along
hillsides that were heavily mined during the Gold Rush.
The total length of the ditch is 19,369 linear feet that conveys water managed by the
Tuolumne Utilities District from the Columbia Ditch to the end of Damin Road. There is
5,355 feet of pipe, 289 feet of tunnel, and 13,892 feet of open ditch. Forty-one percent
(41%; 5,710 ft.) of the open ditch is lined with gunite. Segments of the operating ditch
were previously recorded, including those abandoned when the Kennebec tunnel was
constructed. The USGS-mapped ditch is inaccurate in many locations.
Thirteen features were recorded. Only one spillgate with crossgate; four small
archaeological branch ditches/flume channels leading off from the San Diego; a random
replaced by an inverted siphon; a tunnel now with pipe laid in it; a dry-laid rock
reinforcement feature; a lengthy discontinuous segment of similar rock reinforcement; a
formerly flumed segment of ditch through blasted rock; a dry-laid limestone rock
embankment that retains the bank below the ditch; San Diego Reservoir, about 3.5 acres
in size; and a junction structure known as the Tower.
History. The San Diego Ditch was one of the first distribution ditches to be completed
by the TCWC in 1852 and is depicted on Wallace’s 1853 and 1862 maps of the system
(Figures 10, 12). It carried water southerly from Matelot Reservoir to San Diego
Reservoir, from where water was distributed to Copeland’s and Byrd’s reservoirs,
westerly around Kennebec Hill, down Columbia Gulch, through Red Gulch to Saw Mill
Flat, and to numerous placering and hydraulicking claims along its route.
Foothill Resources, Ltd. 4.38 TUD Ditch Sustainability Project
Francis Heritage, LLC
Historic Resource Evaluation Report