rainwater catchment & filtration presentation for charleston, wv
TRANSCRIPT
Catch the Rainwith Jeremiah Kidd
San Isidro Permaculture
In an animal or plant, 99 molecules in 100 are water…An organism is a pool in a stream of water along which metabolites and energy
moves through ecosystems.W.V. Macfarlane
Why catch rainwater? Primary Source Naturally distilled Saves energy and
chemicals Recharge aquifer Reduce erosion and
runoff Water security
Human Impacts Institute. 2012
Why catch rainwater Store for dry season Multiple Uses Self Reliance Plants benefit Contains N and P Remote areas Free Conserves aquifers
Benefits to the Environment
EPA ranks urban runoff and storm sewer discharge as second main source of water quality impairment in estuaries and fourth in our lakes
James, William “Green roads: Research into Permeable Pavers” 2002
“…have shown that up to 70% of the pollution in our streams, rivers, and lakes is carried there by stormwater,”
(Raingardens.org)
Benefits to the Environment
“contributes to a yearly loss of rainwater infiltration ranging from 57 to 133 billion gallons. If managed on site, this rainwater—which could support annual household needs of 1.5 to 3.6 million people—would filter through the soil to recharge aquifers and increase underground flows to replenish rivers, streams, and lakes,”
Paving our Way to Water Shortages (American Rivers, Natural Resources Defense Council 2002.
Misconceptions No recharge Too little Mosquitoes Deprives lakes Eyesore Too complicated/
expensive Must use tanks
Bill Abell 2009
Physical Properties of Rain Water
Water seeks the lowest point and path of least resistance
Conserve energy by storing at highest point possible for pressure, .43 psi per 1’ elevation,
1 psi=2.31 feet of elevation One gallon of water weighs 8.3 lbs, 3.8 kg One liter of water weighs 2.2 lbs, 1 kg There is 7.48 gallons per cubic foot of water There is 1,000 liters per cubic meter of water Lower pH than groundwater in the arid areas
Qualities of Rain Water Precipitation is the primary source of fresh water within
our planet’s hydrological cycle. Precipitation is naturally distilled through evaporation
prior to cloud formation, and thus is one of our purest sources of water.
Rain is considered soft due to the lack for calcium carbonate or magnesium in solution and is excellent for cooking, washing and saving energy.
Rainwater is a natural fertilizer – picks up N & P Rainwater has the lowest salt content of natural fresh
water sources so it is a superior water source for plants.
Water Harvesting Principals
Begin with long and thoughtful observations.
Start at the top (highpoint) of your watershed and work your way down.
Start small and simple. Slow, spread, and infiltrate the flow of
water.
Brad Lancaster: www.harvestingrainwater.com
Water Harvesting Principals
Always plan an overflow route, and manage that overflow as a resource.
Maximize living and organic groundcover. Maximize beneficial relationships and
efficiency by “stacking functions”. Continually reassess your system: the
feedback loop.
Brad Lancaster: www.harvestingrainwater.com
Design starts with observation
What is the rainfall patterns: wet, dry seasons
How much average rainfall in your area? Where are there catchment surfaces? What is the elevations of the catchment
surfaces in relation to point of use? What is the vegetation growing above
and below catchment surfaces? Taste and smell experience difference
from city or well supply
Planning a water harvesting system
1. What will the water be used for?
2. How much rain falls in a year?
3. How much water is consumed?
4. The area of roof or other catchment available?
5. What size storage can be built?
6. Where to place the storage relative to the catchment and point of use.
7. Budget/resources available
Parts of a system
Collection Surface – Roofs, Patios, etc Conveyance – Gutters, Downspouts, Piping Filtration – Screens, First Flush Storage Containers – Tanks, Ponds, Soil Other Parts – Pumps, Pressure Tanks Overflow – Rain Garden, Swales, Pond Water Usage – Domestic, Toilet, Irrigation
Collection surfaces
Preferable Surfaces Acceptable roofing materials are slate, terra-cotta
tile, copper, untreated wood shingles, concrete, and metal painted with an epoxy paint.
Unacceptable materials are asphalt shingles, older concrete tiles (which can contain asbestos), tar, or treated wood shingles.
Asphalt shingles are by far the most common roofing material. Unfortunately, they leach toxins into the water that runs off them.
If you have asphalt shingles, think of other options or apply acceptable surfaces on some or your home.
Roof Catchment
Shingle Conversion
Conveyance Gutters, Downspouts, Piping
Roof to Tank
Catch Boxes
First Flush ExamplesCourtesy of HarvestH2O.com
First Flush Sizing 1-2 gallons per 100 sq.
ft. of roof area. 5-10 gal per 1000 sq. ft. A 1’ length of 3 inch
pipe holds approximately 0.74 gallons
A 1’ length of 4 inch pipe holds approximately 1.30 gallons
Pre Tank Filtering
Storage Containers – Tanks
Water Wall Tank
Above Ground Tank
Partially Buried Poly Tank
SIP 2011
Buried PE Tank
SIP 2011
Linking Cisterns in Parallel
PE Tank in Parallel
SIP 2011
Access Risers & Venting
Ferro-Cement Tanks
Ferro-Cement Tank Uganda
Finished 79,800 liter Tank!
Post Installation Inspection
Tank Parts
Monthly PrecipitationCharleston, West Virginia
Jan3.00”
Feb3.31”
Mar3.91”
Apr3.24”
May4.80”
Jun4.29”
Jul4.94”
Aug3.74”
Sept3.25”
Oct2.67”
Nov3.73”
Dec3.27”
Total: 44.15”
The driest month is October with 2.67” of precipitation, and with 4.94” July is the wettest month.
Calculating CatchmentCharleston, West Virginia
Average Annual Rainfall ~ 44.15”Method 1:
1000 sq. foot house X44.15” rainfall (average annual rainfall) /
12 (12 inches per cubic foot) = 3,679 cubic feet of water
3,679 (cubic feet) X 7.48 (7.48 gallons per cubic foot of water) =
27,519 gallons per year
Calculating CatchmentCharleston, West Virginia
Total Annual Rainfall ~ 44.15”Method 2:
Catchment Area (square feet) X Average Rainfall (ft) X
7.48 (gallons per cubic foot) = Total Rainwater (gallons)
1,000 square feet X3.679’ (44.15” / 12) X
7.48 (gallons per cubic foot) = 27,518.92 gallons per year
CATCHMENT AREA in square feet
28’x33’=924 f2X
RAINFALL 44.15” /
feet = 3.8 f3 X
7.48 = 26,264Gallons per year
Calculating StorageCharleston, West Virginia
October 2.67” Average Rain Fall – Average Low.
1000 sq. foot house X2.67” rainfall (average monthly rainfall) /
12 (12 inches per cubic foot) = 222.5 cubic feet of water
250 (cubic feet) X 7.48 (7.48 gallons per cubic foot of water) =
1,664.3 gallons in January
1,664.3 / 4 = 416 gallons per family member (family of 4)
416 / 30 (average days per month) = 13.9 gallons per day each
Calculating StorageCharleston, West Virginia
July 4.95” Average Rain Fall – Average High.1000 sq. foot house X
4.94” rainfall (average monthly rainfall) / 12 (12 inches per cubic foot) =
411.7 cubic feet of water
411.7 (cubic feet) X 7.48 (7.48 gallons per cubic foot of water) =
3,079.5 gallons in January
3,079.5 / 4 = 769.9 gallons per family member (family of 4)
769.9 / 30 (average days per month) = 25.7 gallons per day each
Calculating StorageCharleston, West VirginiaAverage Water Use in the USA
Bath – A full tub is 36 gallonsShower – New heads 2 gallons per minute / 5 gallons with
the oldBrushing Teeth - < 1 gallon
Washing Hands & Face – 1 gallonFace & Leg Shaving – 1 gallon
Dishwasher – 4 – 10 gallons per loadDishwashing by Hand – 20 gallons
Clothes Washing – 25 gallons per loadToilet Flushing – 1.6 – 3 gallons per flushDrinking Water – 8 – 24 8oz cups per day
(1/8 – 3/8 gallon per day)
*A Santa Fe Family Uses 23 gallons Per Person Per Day For the Household
Calculating StorageCharleston, West Virginia
Potable water at 2 gallons per day for family of 4 is 240 gallons per month – a 500 gallon
tank sufficient
For whole house would suggest at least 2,ooo gallons – 67 gallon per day
Pumps: Choose the right one for the job
Pump Characteristics
Water pumps are designed to push water not pull Whenever possible locate pumps so water flows into
the pump by gravity - Foot Valve Suction Head is the pressure required to pull water into
the pump housing, most pump not more than 10 feet Match needed flow rate with pump output GPM Sprinklers or flood irrigation uses much more GPM than
Drip Irrigation Prescreen to 1/8” for inlet of pump
Pressure Tank or On Demand Pump
Pressure tank keeps extra water available so small demands do not trigger pump start Prolongs the life of a pump by reducing on/off Provides water that is under pressureOn Demand Pumps-cycles on/off as demand requires- Does not require a pressure tank- May have built in dry protection- Usually has shorter life
Floats for On, Off & Auto Filling Pressure Switches Irrigation Computer Smart Controllers
Pump Controls
Materials - Vinyl, Aluminum, Steel, Stainless, Copper
Slope – 1/16” per 1’ to 1/16” per 10’ Tilt Out – ½” to prevent water seeping into
walls Expansion Joints for runs over 40’ Sufficient Support Downspouts – 1 per 1,000 sq ft surface 1 sq inch of outlet per 100 sq ft surface Screen to reduce debris entering conveyance Prune Branches Snow Cleats – reduce damage, increase
catchment
Gutters
Catch Boxes Drain Grates Patio Drains
On Ground Catchment
Preventative Care & Health Risk Realities
Keep vegetation and animal nests away from the catchment surface - First Flush Diverters
Leaf Screens – make them accessible Good Things – Water improves with age –
Biofilm Many people around the world live on rainwater.
Dilution reduces load on immune system Simple & Economical Filters Available
Sanitation
Be cautious but not paranoid, filter for needs Don’t clean your tanks unless emergency-Biofilm Pollutants that can be found in rainwater:
Microbiological: Parasites, Bacteria, Fungi, Organic - Bird Droppings, Insects – UV Sterilization
Chemical Contaminants: Volatile Organic Chemicals (VOCs) – Solvents – Carbon Filter
Synthetic Organic Chemicals: Usually only around heavy industrial areas – Carbon Filter
Minerals/Metals: Copper, Lead from roofs or gutters -
Sanitation: Microbes Viruses: smallest 20 to ~100 nanometers in size. Most difficult
to remove Bacteria: larger (0.5 to 3 micrometers) also can not be
removed by plain sedimentation or settling Protozoan: next largest (3 to 30 micrometers) largest ones
likely to gravity settle at appreciable rates. Can filter out some waterborne pathogens are often associated with larger
particles or they are aggregated (clumped). Aggregated or particle-associated microbes are easier to remove by physical processes
Coagulation-flocculation
WHO 2012
Treatment of Stored Rainwater
If going to do it, do it right Chlorination Filters Boiling Sunlight Additional Treatments
Chlorination
Effective, but conduct with care
Shock with 1 Tablespoon (.5 ounce or 14g) swimming pool calcium hypochlorite (60-70%) per 530 gallons (2000 liters)
Stir and let stand 24 hrs for chlorine to dissipate
Maintain with 1/7th of the above amount - stir in and let stand 2 hrs
Mix chlorine into water NOT water into chlorine webelements
Sediment/Screen 80-100 micron
Carbon – Best for VOC’sWhole house 10 micron can be found for $200
Ceramic – for smaller particles – viruses
Reverse Osmosis (RO)Finest yet wastes 1-5 x filtered
Filters
“Biofilm” provides the effective purification in potable water treatment with 90-99% bacterial reduction
Courtesy of Clean Water for Haiti & National Drinking Water Clearing House
Sand Filter
Filtration - Ceramic
Katadyn Ceramic Filtration System$295.00 - $318.00 www.katadyn.com
The Gravidyn is a microporous ceramic filter element with an inner core filledwith activated carbon granulate.
99.9999 % removal of harmful Bacteria and Parasites 99.99 % removal of Cryptosporidium and Giardia
General: Removal of organics (this will include: organic contaminants,pesticides, micropollutants, humic acids, detergents) and free chlorine
Sanitation
Berkey Filtration System$228.00 - $625.00 www.berkeyfilters.com
Viruses: 99.999% reduction MS2 - Fr Coliphage*Exceeds purification standards Pathogenic Bacteria, Parasites, and Cysts100% reductionE. coli, Klebsiella terrigena, Pseudomonas aeruginosa, Giardia, Cryptosporidium*Exceeds purification standards Trihalomethanes: Removed to below detectable limits - 99.99999% reduction Bromodichloromethane, Bromofore, Chloroform, Dibromochloromethane
Sanitation
Katadyn Hiking Carbon System$50.00 - $150.00
Boiling
2-3 minutes A lot of fuel Take a while to cool Not always feasible Solar Cookers
Dr. Kundapur
Low-Tec Sedimentation
Simple and low cost: storage vessels - pots, buckets
Clays and smaller microbes do not settle Do not disturb sediment particles at bottom Unreliable to reduce pathogens Remove solids and clean regardless of
storage vessel type Good pre-treatment to remove turbidity
before UV or chemical disinfection
S.O.D.I.S. Solar Disinfection 6 hrs full sun – UV
starilization
SequenceCombining Filtration and
Purification Strategies for Potable Water
SequenceCombining Filtration and
Purification Strategies for Potable Water
Corrosion Control pH Rainwater naturally
Acidic: 4.5-6.3 – usually not a problem
Affects Copper – raise with Baking Soda (sodium bicarbonate) periodically to pH of 7.4
In-line Filters Available – Calcium carbonate (limestone) pellets, Sodium oxide (lime) pellets – these must be downstream of UV units
Water Quality Enhancers
Calmed Inlets – Minimize the disturbance of sediment on bottom of tank and Biofilm
Floating Valve Out-take – Remove water from the “sweet spot” when possible
Thanks to
Aaron Kauffman Brad Lancaster Chelsea Green Publishers John Gould & Erik Nissen - Peterson
Resources Rainwater Harvesting for Drylands www.HarvestingRainwater.com Virginia Rainwater Catchment Manual
http://www.cabellbrandcenter.org/Downloads/RWH_Manual2009.pdf Simple explanation and diagram
http://www.chelseagreen.com/content/free-your-water-fundamentals-of-a-rainwater-harvesting-system/
Supplier in Salem, Virginia http://rainwatermanagement.com Supplier in Maryland offers all parts needed for a system http://
www.conservationtechnology.com Supplier in Georgia http://www.rainharvest.com Contech Engineered Solutions 700 Tech Dr, Winchester, KY
www.conteches.com First Flush Design
http://cals.arizona.edu/cochise/waterwise/first_flush_diverters.pdf