Living off Rainwater, Even in a Drought

Steve and Betty ClyburnTexas Master Naturalist – Hill Country

ChapterOctober 24, 2012

       “Water is the driving force in nature.” ― Leonardo da Vinci

The prime root causes of most wars:

• Race• Religion• Resources (water, food, fuel) "Whiskey is for drinking; water is for fighting

over” – Mark Twain

1) WHY COLLECT RAINWATER2) HISTORICAL3) THE COMPONENTS OF A RAINWATER

HARVESTING SYSTEM WORK4) WATER QUALITY5) HOW MUCH WATER DO YOU USE? 6) HOW MUCH WATER CAN YOU

COLLECT? 7) CODE AND SAFETY ISSUES 8) COST CONSIDERATIONS9) CONSERVATION

How Much Water is Available~70% of our Planet is Water

“When the well is dry, we learn the worth of water.”

Benjamin Franklin, Poor Richard's Almanac (1746?)

Rainwater harvesting has been around for thousands of years.

One resource can date rainwater harvesting tanks back to 2600 BC

in India.

Historical

Portuguese Cistern of El Jadida in Morocco. Circa 1542

Cisterna Basilica Junto a Santa Sofia Istanbul 6th Century CE

Rainwater Harvesting Tank – IndiaGravis

Carrington-Couvert HouseAustin TX ~1857

Why would Anyone In their Right Mind Want to Collect Rainwater?

• Conserve water resources to help preserve water levels in the aquifer

• Superior water quality – softer water means less detergent, no lime/calcium buildup on shower walls and appliances

• Plants and landscape prefer rainwater• May be more dependable than a well• Save money if using city water –

30-50% of total water used by a typical home is for landscape watering

• No chemicals or additives necessary

Why would Anyone In their Right Mind Want to Collect Rainwater?

• 90+% of rain evaporates• To avoid drilling a well.• To be able to water plants during water

restrictions. • Does not require a water softner• By using rainwater you can limit storm water

pollution by catching water that would otherwise wash over land, streets, cow pastures and into waterways.

Circa 1800’s

Catchment Surface• Rainwater harvesting can be done with any

roofing material if it is only for non-drinking use.• For potable use, the best roof materials are

metal, clay, and cement although all roof material types have been used(except asbestos). Asphalt shingles can contribute grit to the system and need a pre-filter for the water before it enters the cistern. Lead materials in any form should not be used in the system (i.e. lead flashing and soldered joints).

Barn Roof for Water Catchment3,300 SQF

200 Meter Rainwater Harvesting TowerChile

Water harvesting structure utilizing condensation,

Trans-en-Provence, France. Circa 1927

How Much Water Can I Catch?

• 0.623 gallons per square foot of roof per inch of rain (Roof area calculated from parimeter of roof – slope of roof is not considered)

• A one inch rain falling on 1000 sq ft of roof area will give you 623 gallons.

• A 3,300 sq ft roof captures 2055 gallons for every inch of rain…..in an average rain year (28”s) that would be about 57,500 gallons!

Gallons Collected per Square Feet of Roof Area for 0ne Inch of Rainfall

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Conveyance to Storage

Conveyance to 2 X 20,000 Tanks

Initial Filtration/First Wash

First Wash System – rain barrel

First Wash System – the EliminatorTank Town

Cost ~$1200

First Wash System – Filtration box

Fiberglass box with removable filters – $600-$800

Wisy Vortex Filter

First Wash System – Wisy Vortex Filter

Storage

Tanks/Cisterns

Should have • Cover to prevent mosquito breeding and

algae growth due to sunlight• Inlet - generally at the top• Outlet - ~ 6” above floor of tank• Overflow - larger than inlet and

screened• Bottom drain valve for cleaning• Covered man way - 24”• System to prevent agitation of the tank

while it is filling to minimize the stirring of any settled solids in the bottom of the tank.

• Two or more tanks permit servicing one of the units without losing the operation of the system.

Polyethylene tanks

Fiberglass

Galvalum w/ vinyl liner

Pioneer tanks from Australia

Conveyance to Purification or End Use

Quick-Connect Valve for Firetruck

Grundfos MQ Constant Pressure Pump

~$575

Shallow Well Jet Pump 1 HP w/ Pressure Tank

Jim Stanley

Purification

Filters

UV light

UV Light has been used for disinfection since the 1900,s and has now become common practice in public utilities

Pump, Filtration and UV Light

~$2000

http://www.rainwatermanagement.com/

Digital Tank Volume

What happens if it doesn’t rain?

• It is important that the system is sized to meet the water demand throughout the dry season. In general, the size of the storage tank should be big enough to meet the daily water requirement throughout the dry season. In addition, the size of the catchment area or roof should be large enough to fill the tank.

How Much Water Do I Need?

Kerrville Average Monthly Rainfall~Average 28” per Year

Kerrville Rainfall – 8 yearsYear Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

2005 2.86 2.80 1.66 1.46 4.63 1.24 2.75 2.03 3.27 1.91 1.91 0.00 26.52

2006 1.02 0.55 1.87 1.49 4.41 1.08 1.30 0.11 5.25 3.00 0.07 1.41 21.56

2007 3.27 0.11 9.65 2.42 9.81 7.68 6.91 6.05 2.76 1.02 1.06 0.36 51.10

2008 0.44 0.19 2.40 1.88 1.69 0.50 1.82 2.84 0.47 2.17 0.09 0.23 14.72

2009 0.62 0.05 3.70 2.96 2.32 0.97 2.80 0.24 9.21 5.27 3.29 1.29 32.72

2010 3.21 2.88 2.50 3.94 1.88 3.86 4.78 0.04 5.160.84

0.06

0.98 30.13

20111.30

0.56

0.07

0.94

1.17

0.78

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0.21

2.06 0.79 2.06 3.00 13.10

2012 2.30 2.10 3.75 0.00 4.35 0.17 2.00 0.75 3.80 1.60 20.82

2005-2011 Avg 1.88 1.16 3.20 1.89 3.78 2.04 2.82 1.53 4.00 2.08 1.22 1.04 26.33

How Much Do I Need to Collect?

• Figure approximately 50-75 gallons per day per person

• For 2 people: 3000-4500 gallons/month requires an average of 1”-1½” rain/month

• 25,000 gallons = 7-8 month supply• 1996 – summer 2011: never below 14,000 gallons• To calculate capacity needed, figure on historic

maximum number of days with no rain

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Rain in Inches Gallons in Tanks Linear (Gallons in Tanks)

Clyburn Rainfall vs. Storage

Emergency Backup Plan• What to do if you lose all of your water?

DroughtLine Break or LeakContamination

• Where do you get water?WellRiver, Stream or LakeNeighborHow do you transportPurchase Truck Load

Water Quality?Is Rainwater Really OK to Drink?

• 25-micron fiber sediment filter • 1-5 micron fiber sediment filter• UV light• pH 6.0 – 7.0• Testing for Heavy Metals, E coli and coli-

form testing available through UGRA

Stephen F Austin Univ.Data from 5337 Fiedler Rd Storage Tank

• Riverside Nature Center 10,000 gallon system collecting off ~4,500 sq ft – takes only a 4” rain to fill

• Hunt School District – 20,000 gallons• Willow City Volunteer Fire Department –24,000

gallon system: gravity flow dispensing system can fill a 400-gal tank on a brush truck in 2 minutes

• Lady Bird Johnson Wildflower Center in Austin – 70,000 gallons

• Peterson Memorial Hospital – 130,000 gallons• Kroc Center in Kerrville – 135,000 gallons• Boerne Champion High School – 224,250

Commercial Applications(All for Irrigation Only)

Cost of Rain Water Harvesting Components

• Technology:• Fairly well-developed; new products are being

developed. Rainwater harvesting is an old tradition practiced in all parts of the world including Texas.

• COST:• Rainwater harvesting systems are costly

compared to a city hookup. Compared to a well, they are approximately equal

Clyburn Rainwater Collection System  Brand Where

2005 Cost

2 20,000 gal tanks PioneerWhitaker

Tanks $16,130.00

1Pump and pressure

tank FlotecHome

Depot $419.00

1UV purification

system Wedeco Internet $800.00

 Pre Filtration

Equipment WISY Austin RW $814.00

 

Cartridge Filter system

And 1u and 25u filters

Big Blue Type  Internet $150.00

  Plumbing parts   Ferguson's $1,000.00

         

  Total Rainwater Costs     $19,313.00

Maintenance• Monitor tank levels - weekly• Inspect tanks for light leaks - monthly• Clean first wash system after each major rain• Measure pH or buffer tank water with baking

soda – after major rain• Change filters quarterly/annually as needed

~$25/yr• Clean gutters as needed with mild bleach –

annually• Replace UV bulb every 12-14 months ~$100• Sample water to certified test lab ~annually ~

$20

PUBLIC ACCEPTANCE:

• In the Hill Country area, there are is an increasing number of rainwater harvesting systems. • A small segment of the population desires

rainwater catchment systems for indoor water use.

• A larger portion of the population feels there is an advantage of using captured rainwater for irrigation.

.

REGULATORY:

• At present, there is no Texas regulation for rainwater for indoor or outdoor household use unless the system is backed up by publicly supplied waterlines. If a backup system is used, to avoid any cross-connection, an airgap must exist between the public water and rainwater. (An example is a city water line feeding into a rainwater cistern.) This airgap must exceed two diameters of the city line in width.

• The Health Department will require that the rainwater system does not contribute to mosquito breeding by having an uncovered cistern.

Conservation

Ways to Conserve Water• Check all faucets, pipes and toilets for leaks.

• Take shorter showers.

• Install water saving showerheads and ultra-low-flush toilets.

• Turn off the water while brushing teeth or shaving.

• Rinse vegetables in a full sink or pan of water.

• Fully load dishwasher.

• Rinse dishes in a full sink or pan of water.

• Wash full loads of clothes.

• Waiting for hot water (hot water recirculation loop or water heater at point of use)

• Plant drought tolerant plants

HOW MUCH WATER DO WE USENon-Conserving Pre 199280 – 100 gallons per day per

personCurrent Conserving w/Efficient

Appliances30-50 gallons per day per person

Shower(5 minutes)

Old shower head30 gallons

2.2 GPM @ 60PSI Limit9-11 gal per shower

Toilet Flushing Conventional toilet4-7 gallons per flush

Ultra-low flush toilet 0.9 -1.5 gallons per flush

Brushing Teeth Tap running - 10 gallons Wet brush, rinse briefly 1 cup or less

Tub Bath Full - 20 gallons Minimal water levelLess than 10 - 15 gallons

Shaving Tap running - 2 gallons or more

Fill basin½ -1 gallon

(Running Water Till Hot)

Washing Hands Tap running - 2 gallons or more

Soap and rinse1 gallon or less

Dishwashing Tap running - 30 gallons Wash and rinse in sink5 gallons

AutomaticDishwasher Full cycle - 15 gallons

1.6 – 2.9 GPLDo not rinse dishes before

putting in dishwasher

Washing Machine

Full cycle, top water level - 40 gallons 13 – 15 GPL

Fountain/Birdbath

Evaporates ~ 5 gallons/day in summer

The Fix

Grey Water Collection Irrigation System

ReferencesThe Texas Manual on Rainwater Harvesting - Texas Water ...www.twdb.state.tx.us/.../rainwaterharvestingmanual_3rdedition.pdf

Rainwater Harvestingrainwaterharvesting.tamu.edu/

Rainwater Harvesting for Drylands and Beyond by Brad Lancasterwww.harvestingrainwater.com/

Tank Town - Rainwater Collection Since 1994!www.rainwatercollection.com/

The Rainwater Harvesting Community : HarvestH2o.comwww.harvesth2o.com/

RAINWATER HARVESTING MANUAL - Virginia Department of ...www.dcr.virginia.gov/documents/stmrainharv.pdf

Harvested RainwaterSustainable Sources: 18 years of online Green Building informationhttp://rainwater.sustainablesources.com/

Present Day• Currently in China and Brazil, rooftop rainwater harvesting is being practiced for providing drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. Gansu province in China and semi-arid north east Brazil have the largest rooftop rainwater harvesting projects ongoing.

• In Bermuda and U.S. Virgin Islands the law requires all new construction to include rainwater harvesting adequate for the residents.

• In the United Kingdom water butts are often found in domestic gardens to collect rainwater, which is then used to water the garden. However, the British government's Code For Sustainable Homes encourages fitting large underground tanks to new-build homes to collect rainwater for flushing toilets, washing clothes, watering the garden, and washing cars. This reduces by 50% the amount of mains water used by the home.

• Until 2009 in Colorado, water rights laws almost completely restricted rainwater harvesting; a property owner who captured rainwater was deemed to be stealing it from those who have rights to take water from the watershed. Now, residential well owners that meet certain criteria may obtain a permit to install a rooftop precipitation collection system (SB 09-080).[6] Up to 10 large scale pilot studies may also be permitted (HB 09-1129).[7] The main factor in persuading the Colorado Legislature to change the law was a 2007 study that found that in an average year, 97% of the precipitation that fell in Douglas County, in the southern suburbs of Denver, never reached a stream—it was used by plants or evaporated on the ground. In Colorado you cannot even drill a water well unless you have at least 35 acres.

• In New Mexico, rainwater catchment for irrigation is mandatory for new dwellings in Santa Fe.[8]

• In Australia rainwater harvesting is typically used to supplement the household mains supply. In south east Queensland, households that harvested rainwater doubled each year from 2005 to 2008, reaching 40% penetration at that time (White, 2009 (PhD)).