1. Rainwater Harvesting Mike Kizer OSU Extension Ag. Engineer Gutter Downspout

2. Rainwater Collection Issues How much rainfall can I expect?How much rainfall can I expect? –Annual total –Seasonal distribution How much rainwater can I collect?How much rainwater can I collect? –Collection area –Storage How much water do I need?How much water do I need? –Household use –Irrigation –Livestock

3. Oklahoma Annual Precipitation (30-year Average: 1971-2000)

4. Oklahoma Precipitation What is Normal? OCS 1990 Annual Summary

5. 1998 Annual Percentage of Normal Precipitation Oklahoma Rainfall What is Normal? OCS 1998 Annual Summary

6. OK Monthly Rainfall Distribution Month Percentage of Annual Rainfall January 4% 4% February 5% 5% March 8% 8% April 9% 9% May14% June12% July 8% 8% August September11% October 9% 9% November 7% 7% December 5% 5%

7. Rainwater Volume D= rainfall depth (1 in) W= catchment width (12 in) L= catchment length (12 in) Volume of water collected = L x W x D 12 x 12 x 1 = 144 in 3 1 gallon = 231 in 3 1 in rain = 144/231= 0.62 gallons / square foot of roof Not all will make it into the rain barrel (  70%)

8. Roof Catchment Area USE THE VERTICAL PROJECTION OF THE EAVE LINE, NOT THE SLOPED ROOF AREA SQUARE FOOTAGE BASED ON THESE MEASUREMENTS

10. Roof Catchments- Potable Water Preferred MaterialsPreferred Materials –Steel (galvanized, painted) –Tile (clay, cement) –Wood (untreated) –Fiberglass –Composition Undesirable MaterialsUndesirable Materials –Tar –Asbestos

11. Rainwater Conveyance Structures (from Sustainable Building Sourcebook) Slope gutters 0.5% (1 in/16 ft)Slope gutters 0.5% (1 in/16 ft) Place gutter hangers 3 ft on centerPlace gutter hangers 3 ft on center Use expansion joints in gutters 60 ft or longerUse expansion joints in gutters 60 ft or longer 1 downspout per 50 ft of gutter length1 downspout per 50 ft of gutter length 1 in 2 of downspout area per 100 ft 2 of roof area1 in 2 of downspout area per 100 ft 2 of roof area Slope horizontal conveyance pipes 2% (1 in/4 ft)Slope horizontal conveyance pipes 2% (1 in/4 ft) Horizontal conveyance pipes should have cleanouts every 100 ftHorizontal conveyance pipes should have cleanouts every 100 ft Limit horizontal conveyance pipe bends to 45ºLimit horizontal conveyance pipe bends to 45º

12. 16’ Long Level Line 1” Fall Proper Rain Gutter Slope

13. 3 ft Spacing of Gutter Hangars

14. Roof Area & Downspout Size 1 square inch of downspout cross-section for every 100 square feet of roof area 32 ft 12 ft 32 ft x 12 ft = 384 ft 2 /100 = 4 in 2 2 in x 3 in minimum size

15. Gutter Guard to Remove Roof Debris ¼ to ½-inch wire mesh Slide This Side Under Shingles Clip This Side to Gutter

16. Roof Washing Before Filling Storage Tanks Manually operated diverter allows initial rainfall to be wasted while roof is being washed free of sediment. Overflow hose 2-4 ft above downspout end with small weep hole allows initial runoff and sediment to collect in bottom of downspout. After initial washing period, cleaner water overflows into collection tank.

17. Roof Washer

22. Rainwater Storage (from Sustainable Building Sourcebook) Cisterns may be above or below groundCisterns may be above or below ground Preferred materials: concrete, steel, fiberglassPreferred materials: concrete, steel, fiberglass Smooth interior surfaces preferredSmooth interior surfaces preferred Use water-tight, non-toxic joint sealantUse water-tight, non-toxic joint sealant Cover to prevent mosquito and algae growthCover to prevent mosquito and algae growth Manholes should be  24 inches wideManholes should be  24 inches wide Buried cistern manholes should 8 inches or more above original ground surfaceBuried cistern manholes should 8 inches or more above original ground surface

23. Large Capacity Above-Ground Cisterns

24. Small Capacity Above-Ground Tanks New polypropylene rain storage barrels Recycled barrels Food-grade polyethylene Oak New 50-60 gallon Rain Barrels (2009 Prices) (2009 Prices) Plastic: $100-150 Plastic: $100-150 Oak: $350-300 Oak: $350-300

25. Household Water Requirements Typical Usage: 50-100 gallons/person-day Toilets: 0.6-1.6 gallons/flushToilets: 0.6-1.6 gallons/flush Washing Machine: 30-50 gallons/loadWashing Machine: 30-50 gallons/load Dishwasher: 7-15 gallons/loadDishwasher: 7-15 gallons/load Bathtub: 30-50 gallons/useBathtub: 30-50 gallons/use Shower: 2.5-3.0 gallons/minuteShower: 2.5-3.0 gallons/minute Kitchen/Bath Sinks: 1.0-1.5 gallons/minuteKitchen/Bath Sinks: 1.0-1.5 gallons/minute

26. Summer Irrigation Water Requirements (Adequate for flowers & vegetable garden) Eastern OK: 0.20-0.25 inch/day (20 gallons/100 sq. ft.-day)Eastern OK: 0.20-0.25 inch/day (20 gallons/100 sq. ft.-day) Western OK: 0.25-0.30 inch/day (25 gallons/100 sq. ft.-day)Western OK: 0.25-0.30 inch/day (25 gallons/100 sq. ft.-day) The storage volume required makes rainwater irrigation makes impractical for large, water-intense landscapesThe storage volume required makes rainwater irrigation makes impractical for large, water-intense landscapes

27. Livestock Water Requirements Beef Cattle:8-12 gallons/head-dayBeef Cattle:8-12 gallons/head-day Beef Calves: 1-1.5 gallons/100 lb-dayBeef Calves: 1-1.5 gallons/100 lb-day Horses: 12 gallons/head-dayHorses: 12 gallons/head-day Sheep & Goats: 2 gallons/head-daySheep & Goats: 2 gallons/head-day Chickens: 9 gallons/100 head-dayChickens: 9 gallons/100 head-day

28. Appropriate Pipe Sizing Flow Rate (gallons/minute) Nominal Size PVCPE RecommendedMaximumRecommendedMaximum ½-inch ½-inch 12.5 12.5 ¾-inch ¾-inch 25 24 1-inch 1-inch 49 49 1 ¼-inch 1020 813 1 ½-inch 15301221 2-inch 2-inch25502450

29. Units Conversions 1 acre-inch = 27,154 gallons1 acre-inch = 27,154 gallons 1 cubic foot = 7.48 gallons1 cubic foot = 7.48 gallons 1 cubic foot of water = 62.4 pounds1 cubic foot of water = 62.4 pounds 1 gallon of water = 8.34 pounds1 gallon of water = 8.34 pounds

30. Rainwater Harvesting Information Green Building Program: Sustainable Building Sourcebook www.greenbuilder.com/sourcebook/Rainwater.html Texas A&M Rainwater Harvesting Site http://rainwaterharvesting.tamu.edu/

31. Oklahoma Annual Precipitation (30-year Average: 1961-1990)

32. Pressure Requirements 0.43 psi for every 1 foot of vertical lift0.43 psi for every 1 foot of vertical lift 10-15 psi for point-source drip emitters10-15 psi for point-source drip emitters 6-12 psi for drip tape6-12 psi for drip tape 30-50 psi for impact and rotor sprinklers30-50 psi for impact and rotor sprinklers 20-40 psi for spray head sprinklers20-40 psi for spray head sprinklers 0.5-1.0 psi/100 feet of PVC/PE supply line0.5-1.0 psi/100 feet of PVC/PE supply line

33. Water Pumps Dayton 1/3 hp, 115 v. Centrifugal Pump Price: $238 (Grainger.com) 18 psi Max. Pressure 10 gpm@ 15 psi Little Giant 5/8 hp, 115 v. Submersible Pump Price: $195 (Plumbingstore.com) 13 psi Max. Pressure 22gpm @ 10 psi

34. Rainwater Collection (Irrigation) Waste initial runoff to wash off sedimentWaste initial runoff to wash off sediment Screen organic matter (leaves) to prevent fermentationScreen organic matter (leaves) to prevent fermentation

35. Rainwater Collection (Drinking Water) Waste initial runoff to wash off sedimentWaste initial runoff to wash off sediment Screen organic matter (leaves) to prevent fermentation and disinfection by-productsScreen organic matter (leaves) to prevent fermentation and disinfection by-products Filtration by coarse sand recommendedFiltration by coarse sand recommended Disinfection by chlorination, ozonation, or ultraviolet light is necessaryDisinfection by chlorination, ozonation, or ultraviolet light is necessary

36. Net Irrigation Water Requirement Location Warm Season Turf (inches/season) Small Vegetables (inches/season) Altus18.48.6 Ardmore17.48.4 Elk City 16.98.2 Enid14.87.5 Guymon14.28.2 Hugo15.16.4 McAlester14.46.8 Oklahoma City 15.07.2 Tulsa13.67.0 Woodward13.98.0

38. Homemade Roof Washer

39. Water Metering Household water meters 5/8-inch meter: Approx. $110 ¼- gpm – 20 gpm capacity Auto shut-off meter 100-1600 gallons Approx. $25

40. Large Capacity Below-Ground Tank (2009 Prices) 600 gal: $598 1700 gal: $1313 2500 gal: $2361

41. Circular Tank Capacity (Tank Dimensions: feet – Capacity: gallons) HeightDiameter68101214161820 612701690211525402960338538104230 822553010376045105265601567707520 103525470058757050822594001057511750 125075677084601015011845135351522516920 1469109210115151381516120184252072523030 16902512030150401804521055240652707030080 181142015225190352284026650304553426038070 201410018800235002820032900376004230047000

42. Square Tank Capacity (Tank Dimensions: feet – Capacity: gallons) Height Base Size 68101214161820 6x66x66x66x616202160270032403780432048605400 8x88x88x88x828803840480057606720768086409600 10 x 10 450060007500900010500120001350015000 12 x 12 64808640108001296015120172801944021600 14 x 14 882011760147001764020580235202646029400 16 x 16 1152015360192002304026880307203456038400 18 x 18 1458019440243002916034020388804374048600 20 x 20 1800024000300003600042000480005400060000

45. http://www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition.pdf

47. Annual Rainfall