BOARD01250

• Board Meeting Date: 12/9/1964
• Description: Minutes
• Board Meetings - Doc Type: Meeting

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MR. MOORE:

MR. LONGENBAUGH:

MR. MOORE:

4133

with this year, that we use about l/lOOth of
a foot per day of water in the phreatophyte
zone, if we have 4,000 acres and take and
multiply it by l/lOOth of a foot, this might
come out to be about 40 acre-feet per day or,
essentially, 20 second feet.

My question to John is, on the left hand
side here you have a May situation in which
the trees had ~ot leafed out - excuse me, on
the right hand - on the lower one here in
July you have a situation in which the trees
have leafed out and using at the maximum rate
in the month of July, and then we find one in
October. October 20th is about a date on which
the leaves have fallen from the trees. Would
the 20 second foot decline in July be reflected
in the use by phreatophytes and therefore no
decline in May and October?"

"Part of the decline is due to phreato-
phyte use - a small part - but the major part
is due to ground water pumpage. I don't know
whether that will answer your question or
not.1I

nYes.t.

"The use of water in an area that has
less than five feet of water that is covered
by phreatophytes is about 3.5 acre-feet per
year. I think y.ou pointed this out. But the
major cause for the changes as shown on the
change map are ground water pumpage. The area
close to the streambed shows little or no
decline. The decline takes place very gradually
and very slowly over a long period. In fact,
we cannot even detect except with very sensi-
tive recorders these changes.

You are right. One of the most important
parts of the study and one of the hardest ones
to put your finger on is the amount of water
consumed by phreatophytes and not only the
water consumed by the phreatophytes, it's not
only the phreatophytes, it's just evaporation
in the areas where depth of water is less than