Eric's Catchment Water System Thoughts


Topographic Map with House - Each Line is Five Feet
Topographic Map with House
Each Line is Five Feet
Water meter and electricity currently on lot, catchment
water tanks and possible wind turbine for agricultural use.
North-most 20,000 gallon tank uses 5,580 sq. ft.
roof water from house and optional storm drain runoff.
A second 6,000 gallon tank near workshop is fed
from 1,250 sq. ft. workshop and lath house roof.

Agricultural water sources:
1. House Roof catchment
2. Barn Roof catchment
3. Road runoff (filtered, used only for emergencies)
4. Kahakuloa Acres Private Water (via float valve in water tank)

Kahakuloa Acres Private Water Company (KAPWC) provides a maximum of
311,000 gallons potable treated well water per year ($6.00 / 1000 gallons)

Catchment sources for agricultural use (House):
Horizontal roof projection: 5500 sq. ft.
One inch rainfall / sq. ft = 5/8 gallon
e.g. 40 inches rain / year on 5500 sq. ft. = 137,500 gallons / year
Assume 80% efficiency (losses due to evaporation, absorption, gutter spill, etc,) = 110,000 gallons / year (agricultural use only)

Catchment sources for agricultural use (Barn):
Horizontal roof projection: 1250 sq. ft.
Assume 90% efficiency (metal roof) = 28,125 gallons / year (agricultural use only)

Second source:
Easement for road storm drain (agricultural use only, minimal use of street - only four houses on street above lot.)
Aprox. 14,000 sq. ft. road between storm drain and next highest storm drain
40 inches rain / year on 14,000 sq. ft. = 350,000 gallons / year
Assume 70% efficiency (losses due to evaporation, absorption, etc,) = 245,000 gallons / year (agricultural use only)


Average Rainfall (inches):House Roof (gal)Barn Roof (gal)Street (gal)
January6.217,0504,35937,975
February4.412,1003,09426,950
March4.813,2003,37529,400
April4.412,1003,09426,950
May2.15,7751,47712,863
June0.92,4756335,513
July1.54,1251,0559,188
August1.74,6751,19510,413
September1.43,8509848,575
October3.08,2502,10918,375
November4.412,1003,09426,950
December5.214,3003,65631,850
Yearly Total40.0110,00028,125245,000

Catchment water stored in 20,000 and 6,000 gallon tanks.
Top of tank 14 ft. below house and 10 ft. below storm drain outlet.
Gravity fed irrigation with automatic timers and rain sensors to areas below tanks.
Pumped with solar-powered 12V Shurflo Aquajet ARV Variable Speed
RV demand pumps
(5.3 GPM, 10 Amp., 80 PSI [184 ft. head])
with automatic timers and rain sensors to areas above tanks.

Battery Operated Controller  Rain Sensor 

Pump Schematic
Catchment Tank and Pump Schematic

Remote Automatic Irrigation from Cistern / Pond and Pump Schematic
Remote Automatic Irrigation from Cistern / Pond and Pump Schematic

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Grading for First 20,000 Gal. Water Tank
Grading for First
20,000 Gal. Water Tank
Blue Rock Culvert Under Construction
Blue Rock Culvert
Under Construction
20,000 Gallon Agricultural Water Tank Installation
20,000 Gallon Agricultural
Water Tank Installation
20,000 Gallon Water Tank Viewed from Below
20,000 Gallon Water Tank
Viewed from Below

20,000 Gallon Water Tank With New Shed
20,000 Gallon Water
Tank With New Shed
20,000 Gallon Water Tank Full and Backfilled
20,000 Gallon Water
Tank Backfilled
20,000 Gallon Water Tank with Superferry in Background
Water Tank with Superferry
in Background
20,000 Gallon Water Tank and Shed for Pump
Water Tank and
Shed for Pump

Water Pump Shed with Solar Panels
Water Pump Shed
with Solar Panels
Water Tank, Retaining Walls, and Bird Feeder
Water Tank, Retaining Walls,
and Bird Feeder
Water Tank, Retaining Walls, and Hibiscus
Water Tank, Retaining Walls,
and Hibiscus
Water Tank and 160W Solar Panels
Water Tank and
160W Solar Panels

Charge Controller for Solar Panels
Charge Controller
for Solar Panels
Tank with Retaining Wall and Solar Panels
Tank with Retaining Wall
and Solar Panels
Tank with Retaining Wall and Solar Panels
Tank with Retaining Wall
and Solar Panels
Water Tank with Drip Irrigation Controller
Water Tank with
Drip Irrigation Controller

Battery Operated Drip Irrigation Controller
Battery Operated
Drip Irrigation Controller
Water Tank Filler<br>Filter Nylon Sock.  January 19, 2009
Water Tank Filler
Filter Nylon Sock
Trenching Agricultural Water Pipe from Tank.  Mar. 1, 2009
Trenching Agricultural
Water Pipe from Tank
20,000 Gallon Water Tank and Solar / Battery Operated Pump.  Mar. 6, 2009
20,000 Gallon Water Tank and
Solar / Battery Operated Pump

1.5 inch Gravity Fed PVC Pipes From Water Tank.  March 21, 2009
1.5 inch Gravity Fed
PVC Pipes from Water Tank
1.5 inch PVC Pipes From Water Tank.  March 21, 2009
1.5 inch PVC Pipes
from Water Tank
1.5 inch PVC Pipes From Water Tank to Sheds.  March 21, 2009
1.5 inch PVC Pipes from
Water Tank to Sheds
1.5 inch PVC Pipes From Water Tank to Hose Bib.  March 21, 2009
1.5 inch PVC Pipes
to Hose Bib

Trench for Six Inch Gutter Pipe to Catchment Water Tank.  June 11, 2009
Trench for Six Inch Gutter
Pipe to Catchment Water Tank
Six Inch Gutter Pipe with Valve and Overflow.  June 11, 2009
Six Inch Gutter Pipe with
Valve and Overflow
Solid Copper Gutters on Roof. June 16, 2009
Solid Copper Gutters
on Roof
Water Tank Automatic Float Valve. June 11, 2009
Water Tank Automatic
Float Valve

Plumbing for Water Tank Automatic Float Valve. June 11, 2009
Plumbing for Automatic
Float Valve
Automatic Float Valve Inside Water Tank. June 11, 2009
Automatic Float Valve
Inside Water Tank
Pressurized Tank and Domestic Water Lines and Hose Bibs. June 11, 2009
Pressurized Tank and
Domestic Water Lines
Pressurized Tank and Domestic Water Lines and Hose Bibs. June 11, 2009
Pressurized Tank and
Domestic Water Lines

Fence Structure Around Second Water Tank, Oct. 23, 2009
Fence Structure Around
Second Water Tank
Starting Screen Around Second Water Tank, Oct. 28, 2009
Starting Screen Around
Second Water Tank
Lath on Second Water Tank Screen, Oct. 31, 2009
Lath on Second
Water Tank Screen
Second Water Tank Screen Painted, Nov. 5, 2009
Second Water Tank
Screen Painted

Gutter Catchment in Back of Barn, June 2, 2010
Gutter Catchment
in Back of Barn
Gutter Catchment in Back of Barn, June 2, 2010
Gutter Catchment
in Back of Barn

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Location of First Water Tank
Location of First Water Tank
Video of Grading for 20,000 Gallon Water Tank, August, 2008
Video of Grading for Water Tank
Video of Water Tank Installation, September 2008
Water Tank Installation
Video of Water Tank Retaining Wall
Water Tank Retaining Wall

Video of Water Tank, Pump, and Solar Panel Installation
Water Tank and Pump
Video of Water Tank and Pressurized Water Line
Water Tank and Water Line
Video of Water Tank and Plumbing, Jan. 18, 2009
Water Tank and Plumbing
Video of Pipes from the Water Tank, Mar. 4, 2009
Pipes from Water Tank

Hose Bibs Near Sheds.  March 23, 2009
Hose Bibs Near Sheds
Water Tank Filler and Pipes.  June 10, 2009
Water Tank Automatic Filler
Water Tank Filler with Water Meter Bypassed.  June 12, 2009
Water Tank Automatic Filler
Front Irrigation.  September 2, 2012
Front Irrigation

Front Irrigation.  September 7, 2012
Front Irrigation
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Rain Totals:
[Last Year Rain Totals]  [January]  [February]  [March]  [April]  [May]  [June]  [July]  [August]  [September]  [October]  [November]  [December]

[Last 24 hours]

[Rainwater Catchment Systems for Hawaii (PDF)]

Farm Plan
Farm Plan

Workshop and 6000 Gallon Water Tank
Workshop and 6000 Gallon Water Tank

Building the Maui House

Agriculture Thoughts


Eric Newman * Copyright © 2006 - 2012, Eric Newman *Revised 9/7/2012