The San Francisco call., 1908-03-10
TURNS SACRAMENTO
SWAMPS TO FARMS
Joint Survey by State and Fed
eraI Government to Re-
claim Valley
Three Million Acres Viii Be
Added to Finest Lands
in the World

! WASHINGTON. March s.-In the Sac
ramento valley of California there is
being conducted the greatest geograph-
I ical survey of its kind in the United
States-the cooperative state and fed
eral survey of 100000 acre tract OF
reciaimable swamp and desert land,
conducted by the United States geologi-
cal survey.
The first concrete result of this sur
vey is the Orland irrigation project.
which the reclamation service already
/ has well under way. This is small
enterprise as compared to the whole
| embracing but about $4,000 acres, yet
| II Is important In that IL is considered
a starting point for the reclamation of
| the entire valley. This land. when re-
claimed. Is valued at from 5000 to 1900
an acre, probably representing the
| highest value for raw farm land in the
country.
! The quick achievement OF the reclaim
alton service in this instance Is an ex-
ample of the Importance and necessity
| for accurate and detailed topo-
| graphic survey, without which any
such engineering construction Is I'M
possible. The United States geological
survey has been working on this great
topographic survey OF the Sacramento
/ valley for the last five years and has
! already completed and mapped nearly
| 100000 acres. Shortly following the
completion of the topographic survey
| embracing the Orland district the
reclamation engineers appeared on the
ground, took the topographic map OF
the geological survey as a base and
began the work of construction. Or
| land Is what is known as unit
| project; that is. Ii 10 a complete
project; but IL may be extended almost
| indefinitely and become a part of the
entire great system which will be con-
structed.
LIKE EXPLORING JUNGLE
! Surveying In the Sacramento valley
is carried on in many cases in the
! face of almost insurmountable difficult
| ties. Fully a million acres Of the sur
vey comprise the tule swamps, where
1 giant rushes grow to a height OF 15
feet, necessitating the use by the sur
veyors of buckboards and tripods with
| spliced legs, so that the instrument will
stand at least 10 feet high. In the
dense jungle growths bordering the
| water and marshes all sorts Of ex
pedients are resorted to to obtain the
necessary sites for making levels. the
men frequently planting their instru-
ments on the elevated limbs of some
| great tree or huge snag that has been
swept down by the floods, or climbing
| up into the forks of a growing tree. or
! obtaining a precarious footing on
stump overhanging some deep slough.
In other situations, while the topog
raphers are stationed with their in
struments on narrow strip of tule
| land between sloughs, the flood OF the
/ incoming tide will submerge the entire
locality, and they must stand quite
still for some minutes with the water
| flowing above their knees. until the
ebb begins, in order-to determine where
| to step and not TO pitch off into deep
water in the various channels. along
which the tide flows as in a millrace.
/ Just what, it is often asked. is a
topographic survey or map? The
topographic map is simply the highest
type of an accurate geographic map.
and the topographers of the geological
survey who make these surveys are
| in reality geographers. The old maps
and biographies showed depressions.
hills and mountains, by means of what
are known as hachures-fine penmarks
representing the reliefs-as they would
be shown in photograph; but the
height of a hill or mountain for in
stance, judged from hachured map,
simply indicates graphically in very
general terms the physical character
| istics of the country, whether fat
rolling, hilly or broken or very noun
tainous-as 1t would be viewed from
| a high elevation. The contour map.
while not representing to eye such
a graphic picture of the country. yet
shows by the means of the contour
| lines the almost exact physical char
acteristics of the section surveyed
USE OF CONTOUR LINE
The contour lines follow the same
level. Take for instance a point in
some large valley or basin which point
| Is 500 feet above the mean sea level
From this point contour line would
start and ramify the entire valley
fpassing In and out through every 500
foot point. At the $40 foot elevation
| the. next contour line would be run
and pass through every $40 foot point
in the valley. and so on. the contour
| line showing ever elevation from the
lowest point to the highest. A man
walking long the course of one of these
contour lines would always be on the
same level.
Wherever on Topographic map
these lines are close together it is
evident that the slopes are steep, but
where they are far apart the slopes
are gentle So that an examination
of contour map shops every physi-
cal inequality of the country. With
one of these as guide it would be
possible actually to build clay model
which would be an exact physical re-
production of the area portrayed In
addition the topographic maps of the
/ United States geological survey show
all the developing works OF man.
] The state of California has already
contributed s65,000 TO this cooperative
topographic survey OF the Sacramento
valley, the geological survey spending
an equal amount in making the sur
vey. The maps show five foot con-
! tours and are the most detailed works
| of the kind in the country. The work
has been under the direction of Robert
B. Marshall, recently appointed chief
geographer of the United States. In
charge of the topographic branch of
the United States geological survey
| The entire project for the reclama-
tion of the Sacramento valley. through