Page 17 - lopezrobert1974

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!coast; and secondly by the fact that the Piru Creek Drain-

lage Basin experiences drastic se&sonal changes in temp-

lerature from warm, dry summers to damp, roj_ld winters ..
!
i Generally, precipitation is moderate with 90% of the
I
!total annual rainfall occurring during the period between
i
!October to April. In the course of my research I was

1
able to compile a table of precipitation relating the
iPiru Creek Drainage Basin for the period from 1769 to

1972. (Figure 1)~ This came mainly from early historical

journals, the records of Fort Tejon, the records of

Missions San Buenaventura and San Fernando and from the

records of the various agricultural service agencLes in

the area. While not 100% accurate, this table does reveal

some interesting facts; for instance the average annual

rainfall since 1769 has been 17.01 inches~ The Sandberg

weather station, located in the northeastern quarter of

the basin at an altitude of 4~517 feet or about 400 feet

higher than the mean altitude for the whole basin, at

present has the only known long term precipitation and

temperature profiles for the area. (Figures 2 & 3)~

At Sandberg, annual precipitation ranges from 12 in-

ches at the station to about 24 inches at the Temescal

;station, in the southwestern portion of the basin~ Mean

annual rainfall for the entire basin based upon informa-

!tion collected since 1933 supports the previously stated

figure of 17 .. 01 inches. (Figure 4) .. 'rhe data collected