Harvesting Rainwater for Animals Ginger Easton Smith Emily Moench Texas AgriLife Extension
How to Collect Rainwater P 0.6 gallons per square foot of roof per 1 rainfall
Gutters and Downspouts
Weight 8.33 lb/gallon 7.5 gallons per cubic foot
Rainfall is captured off a small barn into 300 gallon recycled containers and used to water chickens, ducks and Guineas
These watering pans are connected to the 300 gallon containers by a water hose.
Deciding Factors for Water Needs Kind of animal Number of animals Annual rainfall and length of time between rain events (longest usual dry period) Whether or not wildlife have access to the water
Example: Water demand for 2 horses I have 2 mature horses and live where the average rainfall is 31 inches of rain per year and most dry spells are not 2 months long. How much roof surface do I need and How large a catchment tank do I need?
Average Daily Consumption of water by various Livestock Species Species Cattle Horses Sheep and Goats Gallons of Water per Day 7 to 18 gallons 8 to 18 gallons 1 to 4 gallons General rule: Provide 2 gallons of water per 100 pounds of body weight daily.
Water needs for 2 horses Daily maximum water requirements 18 gallons x 2 horses= 36 gallons/day Monthly requirement 30 days x 36 gallons = 1,080 gallons/month Storage needed for dry spells 1,080 gals. x 2 months supply = 2,160 gals. minimum storage needed, so at least a 3,000 gallon tank
How Much Water Can You Capture? Rainfall x Catchment Area x Conversion factor = Supply (Inches) x (Square Feet) x 0.623 = (Gallons) Example: 1 inch rain falls on a 10 by 20 roof 1 x (10 x 20) = 200 sq x.6 (0.623 rounded off) = 120 gallons
Catchment area Footprint of the building
Roofs and Collection Surfaces
Is my barn big enough to catch needed water? If the roof measures 20 x 60 (footprint) how much will I catch per 1 rain?
Reminder: Rainfall x catchment area x conversion factor = supply 1 rain x 1,200 sq.ft. (20 x 60 ) roof area = 1,200 1,200 x.6 (conversion factor) = 720 720 gallons per inch of rainfall If the average monthly rainfall is 2.5 then how much will I catch? 720 gals. x 2.5 = 1,800 1,800 gallons could be captured in an average month So barn roof is big enough to catch needed 1,080 gals. water
How Big A Storage Tank Do I Need? Average monthly rainfall: 2.5 or for the 20 x 60 barn = 1800 gallons The dry spells seldom last 2 months but we need to store a minimum of 2 months supply to protect us from extended drought So, 2160 gallons would be sufficient (2 months x 1080 gals. = 2160 gals.) Rounded up to 3000 gallon tank
Just to be on the safe side Other considerations: Efficiency of roof and collection system Evaporation from watering device or trough Water that might be diverted in a first flush, if attached Water used to wash horses, water pets, wash hands or for other needs So, 4,000 gallons of storage or more would be preferred.
How Much Rain Will It Take To Fill The 4,000 Gallon Storage Tank? Roof area 20 x 60 = 1,200 sq 1,200 x.6 = 720 gallons per 1 rain 4,000 gallon tank divided by 720 = 5.6 5.6 of rain would fill the 4,000 gal. tank
Dry Line vs. Wet Line
Dry Line
Minimum of 18 inches difference in height required from the bottom of the gutter to where the water goes into the storage tank.
Wet Line
T he O ther P ar ts P Gate valve and faucets P.434 lb of Pressure/column ft.
The overflow allows water to run out of the tank when it is full rather than backing up into the gutter Overflow Pipe
Pump and Pressure Tank Shallow well pump and Pressure tank or On-Demand Pump
Screens
Rainwater Collection System
Texas State University s Freeman Ranch Wildlife Water Guzzler 20 x 20 Roof And Two 1500 Gal. Tanks. The Fence Keeps Livestock Out.
The Larger Tub May Attract Mosquitoes Unless Mosquito Dunks Are Used. The Cover Over The Float Prevents Raccoon From Damaging The Guzzler.
When animals drink the water the float drops down and allows water to run just as in a commode Donkeys drinking from a watering trough with a float connected to it to keep it full of water.
http://rainwaterharvesting.tamu.edu/ The calculator on the website provides average monthly rainfall for each location marked Thank you to Mr. Billy Kniffen for use of slides