# Water Collection Project - Page 2

Posted by Curbie on January 27, 2011, 1:28 am

Oh, boy.

The normal rain fall for the rainiest month (August) in Tampa is 7.6".

7.6" / 31 Days = less than .25" per day for the rainiest month of the
year in which it rains almost every day around 4:00 to 5:00Pm due to
convection.

@ .25" of rain fall, collecting 1000 gallons normal day would require
a single-story house footprint of 8,400ft2.

Good message, shaky messenger.

For anyone interested in this idea, get your average rain/snow fall
and plug them into this spread-sheet:

Curbie

Value    Unit    Note    Expression
Location Rain & Snow Falls            1
Average (AVErain)    0.25    Inches    2
Average (AVEsnow)    0.00    Inches    3
Factor of Normalization (Fnorm)    80%        4
Factor of Concentration of Rain (FconR)    75%        5
Normal (NORrain)    0.20    Inches    6    =AVErain * Fnorm
Normal (NORsnow)    0.00    Inches    7    =AVEsnow * Fnorm

Roof Catchment            8
Length (RCl)    200    Feet    9
Width (RCw)    45    Feet    9
Roof Capture of Rain (FRCrain)    90%        10
Roof Capture of Snow (FRCsnow)    10%        11
Area (RCa)    9000    Feet^2    12    =RCl * RCw
Roof Catchment of Rain (RCrain)    1010    Gallons    13    =NORrain *
(CuFt2Gal / In2Ft) * RCa * FRCrain
Roof Catchment of Snow (RCsnow)    0    Gallons    14    =NORsnow *
(CuFt2Gal / In2Ft) * RCa * FRCsnow * Fsnowpack
Roof Catchment of Both (RCboth)    1010    Gallons    15    =RCrain +
Rcsnow

Ground Catchment            16
Diameter (GCd)    35    Feet    17
Factor of Ground Catchment (FGC)    60%        18
Factor of Snow Pack (Fsnowpack)    30%        19
Area (GCa)    962    Feet^2    20    =PI() * (GCd / 2)^2
Ground Catchment of Snow (GCsnow)    0    Gallons    21
=NORsnow * (CuFt2Gal / In2Ft) * GCa * FGC * Fsnowpack
Ground Catchment of Rain (GCrain)    72    Gallons    22
=NORrain * (CuFt2Gal / In2Ft) * GCa * FGC
Ground Catchment of Both (GCboth)    72    Gallons    23
=GCsnow + GCrain

Cistern            24
Height (Hcist)    7    Feet    25
Roof Cistern Volume (RCVcist)    101    Feet^3    26    =(RCboth /
CuFt2Gal) * FconR
Roof Cistern Diameter (RCDcist)    4.3    Feet    27    =SQRT(RCVcist
/ Hcist / PI()) * 2
Ground Cistern Volume (GCVcist)    10    Feet^3    28    =GCboth /
CuFt2Gal
Ground Cistern Diameter (GCDcist)    1    Feet    29
=SQRT(GCVcist / Hcist / PI()) * 2
Combined Volume (CVcist)    111    Feet^3    30    =RCVcist +
GCVcist
Combined Diameter (CDcist)    4    Feet    31    =SQRT(CVcist /
Hcist / PI()) * 2
Total Harvest of Both (Harvest)    1082    Gallons    32    =RCboth +
Scboth

1 Cubic Foot of Water (CuFt2Gal)    7.481    Gallons    33
Inches to Foot (In2Ft)    12    Inches    34

Footnotes
[01] Care must be taken with the term "precipitation" which is any
form of water falling to the earth (rain, snow, hail, sleet, or mist).
I separate rain
& snow because snow accumulates all season, but is collected
as water all at once in the spring melt, where as rain collects as it
falls
during a location's rain season.
[02] Average rain fall includes the odd wet and dry years which may
[03] Average snow fall includes the odd wet and dry years which may
[04] Adjusts the percentage of average yearly rain and snow fall to
excludes the odd wet and dry year which may lead to improperly sized
system.
[05] Adjusts the percentage of rain season "concentration", short rain
seasons concentrate the yearly rain into a short period of time, where
long
rain seasons distribute the rain over the entire season. This
can be a major consideration in sizing a cistern, selecting a higher
concentration
percentage (short rain season) will increase cisterns storage
capacity, a lower concentration percent will decease storage capacity.
This
factor only effects rain, snow falls all snow season and
accumulates as standing snow, but melts all at once into the cistern.
[06] Normal rain fall is what "normally" falls in an area excluding
the odd wet or dry year, and can be adjusted by the "normalization"
factor.
[07] Normal snow fall is what "normally" falls in an area excluding
the odd wet or dry year, and can be adjusted by the "normalization"
factor.
[08] Building roof structures are generally square, thus so are roof
catchment areas.
[09] This are the total "length" and "width" of the roof catchment
area, if you're using the areas of more than one structure, calculate
each
structure separately, then add these individual areas together
for a total area. Lastly choose any "length" and "width" values that
equal the
combined total area.
[10] Adjusts the percentage of rain fall that is "captured" by a roof,
some bounces away and some is forced off the gable side of the roof.
[11] Adjusts the percentage of snow fall that is "captured" by a roof,
most snow slides off roofs in sheets during it's accumulation period.
[12] This is the total roof catchment area.
[13] This is the total harvest of rain fall by the roof catchment area
in gallons.
[14] This is the total harvest of snow fall by the roof catchment area
in gallons.
[15] This is the total harvest of both rain and snow fall by the roof
catchment area in gallons.
[16] Again care must be taken with the term "precipitation". Catchment
takes place on the ground, generally in a buried cistern.
rain fall which takes place on a structure where snow can slide
off roofs in sheets.
[17] Ground catchment area is better measured by the diameter around a
buried cistern. This is the diameter where rain falls or snow falls or
is
piled-up.
[18] Adjusts the percentage of rain or snow fall that is "captured",
some will seep into the ground around the cistern without being
captured.
[19] Adjusts the percentage of snow fall "pack", from 10% for powder
up to 40% for piled-up or packed snow is typical.
[20] The total catchment area in feet^2 for the diameter of a ground
buried cistern given.
[21] This is the total harvest of snow fall by the ground catchment
area in gallons.
[22] This is the total harvest of rain fall by the ground catchment
area in gallons.
[23] This is the total harvest of both rain and snow fall by the
ground catchment area in gallons.
[24] For structural reasons, cisterns should be round, rain and snow
cisterns may be separate or combines, a rain cistern may be by your
house
and a snow cistern may out close to a garden or livestock. It
all depends on someone's needs and resources.
[25] The height is used for BOTH rain and snow cisterns,
considerations given to frost line depth (water freezes), soil type
and pack, and water
table depth will help determine height for buried cisterns.
[26] Roof cistern volume in cubic feet as determined by the water
harvested by the specified roof catchment.
[27] Roof cistern diameter needed to store the volume of water
harvested from the roof catchment.
[28] Ground cistern volume in cubic feet as determined by the water
harvested by the specified ground catchment.
[29] Ground cistern diameter needed to store the volume of water
harvested from the ground catchment.
[30] Combined rain & snow cistern volume in cubic feet as determined
by the harvest of both catchments.
[31] Combined rain & snow cistern diameter in feet as determined by
the harvest of both catchments.
[32] Combined rain & snow cistern volume in gallons as determined by
the harvest of both catchments.
[33] Constant for gallons of water in a single cubic foot.
[34] Constant for inches in a foot.

Posted by Jim Rojas on January 27, 2011, 1:55 am

So what you are saying that it is impossible to collect 1000 gallons of
rain water in just one day of rain? You obviously never been Florida.

I am only collecting water from the back end of my house. I haven't
installed any gutters on the front or side. Doing that would double my
collection efforts. I really don't need anymore than what I am using now
for the moment.

It hasn't rained here for 2-3 months. My pool lost 18 inches due to
evaporation. The pool is 15x4. If the pool holds 5000 gallons, my
guesstimate of 1000 gallons collected is very under exaggerated. In the
past 2 weeks it has rained 3 times. My pool is overflowing.

My setup is basically temporary. I have a spare metal roofing panel
acting as a 36 inch wide gutter. I have a total of 10ft of PVC gutter
installed. I have a 1 inch PVC pipe running from the pool to the end of
the metal roofing panel. A 3 ft piece of gutter is used to connect the
whole thing. The other 7ft of gutter I temporarily installed it over my
back french doors. The house is under construction, so things will

It rained pretty hard yesterday. For the most part, the gutter kept
overflowing, so I am losing a good part of what I am collecting. I know
I should be using real gutter downspouts, but like I said, its just
temporary. Maybe I should drain the pool completely and see if one of
our normal rainfalls would fill it up in a single day. I don't see why
it wouldn't.

I also have a 60 gallon rain barrel directly underneath my roof panel. I
added a hose fitting to slow down the amount of water to be stored in
the barrel. I use this water for the inside plants and for both my fish
tanks.

I will see about taking some pictures of it, and posting it on my web
server.

Jim Rojas

Posted by Curbie on January 27, 2011, 3:56 am

I'm just saying .5" of rain isn't a normal day's rain and to convert a
normal day's rain (in August the rainiest month of the year for Tampa)
of .25" you or anyone else would need an 8,400 ft2 house footprint!

I'm also saying you should try to get facts straight so you don't
interested in this idea, they get a lot further along doing the
numbers.

Your view of what is obvious, is about as factual as most other things
you've said, I lived in Deerfield Beach FL for about 30 years.

Good message, shaky messenger.

Curbie

Posted by Jim Rojas on January 27, 2011, 9:10 pm
Curbie wrote:

On our first day of rain we got close to 2 inches fo the entire day.

Rain does not seek its own level when its falling. Some areas get no
rain, others get twice as much rain as officially reported.

I left a 5 gallon pail in the yard that day. It had 6 inches of water in
it. Does that mean we got 6 inches of rain? Of course not.

I stated that my pool lost 18 inches of water. According to an online
pool calculator, that is over 1000 gallons easy. The total roof area of
water collection is about 950sq ft, give or take. So it must have rained
alot more that day than what was officially reported.

Jim Rojas

Posted by Jim Rojas on January 28, 2011, 9:39 pm
Curbie wrote:

I went to 3 different online pool volume calculators. Each one stated
that a 15ft round pool that is 18 inches deep (amount of rain I
collected) comes out to 2000 gallons. That's alot more that I expected.
So one normal .5 inch of rainfall is all I need in a month to keep my
pool topped off. Though I may need more due to summer heat evaporation.
I will keep you all posted.

Jim Rojas

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 Re: Water Collection Project Jim Rojas 01-26-2011
 Re: Water Collection Project Jim Rojas 01-27-2011
 Re: Water Collection Project Jim Rojas 01-28-2011
 Re: Water Collection Project Jim Rojas 01-27-2011
 Re: Water Collection Project Jim Rojas 01-27-2011
 Re: Water Collection Project Jim Rojas 01-28-2011
 Re: Water Collection Project Jim Rojas 01-29-2011
 Re: Water Collection Project Jim Rojas 01-29-2011
 Re: Water Collection Project Jim Rojas 01-29-2011
 Re: Water Collection Project Daniel who want... 01-29-2011
 Re: Water Collection Project Jim Rojas 01-29-2011
 Re: Water Collection Project Jim Wilkins 02-04-2011
 Re: Water Collection Project Jim Rojas 01-29-2011
 Re: Water Collection Project Daniel who want... 01-30-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-31-2011
 Re: Water Collection Project Jim Rojas 01-31-2011
 Re: Water Collection Project Jim Wilkins 01-31-2011
 Re: Water Collection Project Jim Rojas 02-01-2011
 Re: Water Collection Project Jim Wilkins 02-01-2011
 Re: Water Collection Project Jim Rojas 02-01-2011
 Re: Water Collection Project Morris Dovey 01-31-2011
 Re: Water Collection Project Jim Rojas 01-31-2011
 Re: Water Collection Project Morris Dovey 01-31-2011
 Re: Water Collection Project Steve Ackman 02-07-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-30-2011
 Re: Water Collection Project Jim Rojas 01-31-2011
 Re: Water Collection Project Michael B 01-31-2011
 Re: Water Collection Project Jim Rojas 02-04-2011
 Re: Water Collection Project Jim Rojas 02-06-2011
 Re: Water Collection Project Jim Rojas 02-06-2011
 Re: Water Collection Project Jim Rojas 02-07-2011
 Re: Water Collection Project Jim Rojas 02-08-2011
 Re: Water Collection Project Jim Rojas 02-08-2011
 Re: Water Collection Project Jim Rojas 02-02-2011
 Re: Water Collection Project Jim Rojas 02-02-2011
 Re: Water Collection Project Jim Rojas 02-02-2011
 Re: Water Collection Project Jim Rojas 03-29-2011
 Re: Water Collection Project Jim Rojas 02-02-2011
 Re: Water Collection Project Jim Rojas 02-02-2011
 Re: Water Collection Project Jim Rojas 06-26-2011
 Re: Water Collection Project Morris Dovey 06-26-2011
 Re: Water Collection Project Jim Rojas 06-27-2011