WMOD00479

• Title: Design and Field Testing of a Remote Ground-Based Liquid Propane Dispenser
• Weather Modification - Doc Type: Report

<~
..... :...

.-

r./
. ..,
~-{
f&" .U; -. {

Figure 8 Closeup view of nozzle after 14 hours of
operation on Jan. 30, 1990. Methanol added to propane
taGk has prevented nozzle and temperature probe from
icing.

The seeding log for the 1989-90 winter season is
shown in Table 1. Tne table shows that both dispensers
were operated for about 80 hr. However, various nozzles
were tested on each dispenser so that seeding rates
varied slightly. Thus the volume of liquid used is slightly
different. Several tests were performed to see how well
release rates could be matched using identical nozzles
on each disper.ser. These tests were run on 1/12, 1/30,
1/31-2/1, and 3/4. Very consistent seeding rates were
foand be1\veen the two dispensers and within a few
tenths of 9 L/hr (2.5 gal/hr). The 1\\'0 dispensers
operated without faihIre from January 8 through April
30, 1990. One hundred percent of the data were
recovered from each site during this time period.

2.3 Further Design Considerations for 1990-91

As mentioned above, a few minor design changes
were needed before dispensers were installed this

D2te

r'C.
: l~e II!"' '-:r~

r;';:'=

Tota 1

Pi>-;-

T'~",

;-'~I

ii' 2;98
L "319(;
1/~c/9::

~2:35

3.5hrs

Gg:~G ..

...;,,:

L. ::'r,~s

G7:"S ...

~~t:rs

L-:2e/9C

..:::.. ... =
~V_ ,...

4;-;rs

1/3:/9G
1,31-2/1

'5.S3~rs

;,]4: -:, .:.

~ "7 . ~2;- rs

season. Tne first was the addition of a 5 V regulator to
operate the temperature sensors. This has been
completed and tested and has eliminated tac problem of
artificially low temperature values \\'hen a solenoid is on.
Secondly, the supply line has now been installed inside
5-cm-square tubing (the tower had 7.6-cm tubing, buL it
was reduced in size to reduce weighL of the tower)
running from the base of the tower to just below the
valve box. [The supply line hooks external!y to the valve
assembly.] The tube is filled with foam insulation. A
second supply line comes from the Lank to :he bottom of
the tower and is wrapped in foam ir.sulation and
reflective tape. Tank level sending units are not being
used as they were found to be unreliable. More reliable
units are available but were not purchased to keep cost
down.

It is believed that the current design should
perform satisfactorily. However, at this 'WTiting, operation
of the dispensers is being delayed until appeals to the
environmental documentation submitted by the State of
California and the U.S. Forest Service (for obtaining use
permits to operate the dispensers on Forest Service
land) can be adequateiy addressed. It is anticipated that
seeding will not be permitted this winter.

3.0 Acknowledgments

This work was sponsored by the California
Department of Water Resources (DWR) through
Cooperative Agreement B-57788. Without the dedicated
efforts of ~1r. Bruce Gillette, Mr. Conrad Lahr and Mr.
Jim Hespen of DWR and the continued encouragement
of Mr. Larry ~fullni.", Deputy Director of DWR, this
work would not have been possible.

4.0 References

Reynolds, D. W., 1989: Design of a ground-based
snoYipack enhancement program using iiquid propane. 1.
Weather Mod..21,29-34.

t:Ge.,lcr.s

HP2
C~f

::Ga.-;-ons

-:-(:~al

"::;:--2 C!1

Prc::::are J......;

PET

: ":w"?- :"rc.p-2~e

,2.8

...-- ~.-.-,.
"" ~ ....... .::

1:' '7

12: 15

~7:2G

5.9

"'-='. .~
v:,:.' ~......:

'"-"1..""....
.........v

2.2~rs

&::4.1:.

07:-;:;

~ "; . 1:::_
.:. .....

10hrs

9. 5 i.~~. r-_

~o: ;5

"::--:':-5

1~.35

J9.o

04.: '"-5

:::O:G5

1~.83

.HL.5

2J:G5

: i 4~':

"!3:~O

-1.5~~~s 07? G4:3G

.::.::...-.....

;j1.~-Gf~

04:30 ~

3/.~..:-gO

~4;5::! /'

6.e:;;-:!'""s

3/1J!9G

06:~G

~i~~5

eO.L5hrs. 2C2.5sa-

':'.~L ga:;h~.

A_g.

: c.: v~.:;

2~:. 02

15.9

~ 4: 5(;

2': ..to

c.~...;

,c ")

"7 '"l

Ga: 1C

17: ~C

ZG.46r.r 235.27;~i.

-:,. ~'!

ga:!nr

Table I Seeding log for 1990 for two dispensers
operated on Haskell Peak.