Water Use Efficiency in Hydroponics and Aquaponics Water Conservation is a Topic of Increasing Concern Especially in the drought-ridden west, water conservation is a topic of increasing concern. You’ve recently heard about water in the news, across social media, and among friends – not just from farmers. Drought conditions and lack of water impacts agriculturalists, municipalities, industry, and individuals alike. How can hydroponic and aquaponic systems reduce water loss, increase water use efficiency, and use water more sustainably?
Hydroponic and Aquaponic Systems Recirculate Water In most hydroponics or aquaponics systems, water is recirculated. Excess, run-off water not taken up by the plants is captured. Nutrients are constantly added by fish waste or fertilizer, and water returns to the plants. Every bit of water is reused over and over again, an impossibility in traditional, soil-based agriculture.
How is Water Lost in a Hydroponic or Aquaponic System? Since it is recirculated and recycled, water is never discharged in hydroponics or aquaponics. Water loss occurs in two main ways:
Water Loss: Evapotranspiration Evapotranspiration is the use and evaporation of water through the plants. There is no way to eliminate evapotranspiration; it is a necessary function of living plants!
Water Loss: Leaks Leaks sometimes form in the greenhouse irrigation system. Careful, frequent monitoring of the system is the best way to identify leaks. Make repairs as quickly as possible.
Total Water Loss in Our System Altogether, total water loss in Bright Agrotech’s aquaponic system, using ZipGrow Towers, is only 1.5% per day. Other leading hydroponic system competitors have water losses of 7% per day. The difference from traditional systems is hardly comparable.
Water Loss in Traditional Systems
Traditional gardening requires 20 times the water use of a recirculating system. Agricultural flood irrigation in large fields loses water to simple evaporation, run-off, and dispersion beyond the reach of plant roots. About 50% of flood irrigation water is lost. The agricultural industry is changing its practices to be more water-wise, but even the best drip irrigation only cuts flood irrigation losses by about one-fourth, nothing close to hydroponics.
How Much Water do I Need for my ZipGrow Tower System? At Bright Agrotech’s farm, we run a 4,000 gallon system in our 2,000 square foot greenhouse with a little over 200 towers. We replace 40 – 60 gallons of water each day due to loss. Water needs for your ZipGrow Tower system depend on whether you are a hydroponics or aquaponics producer. Scaling of needs as system size increases is fairly constant. Dig Deeper >> Learn More About Flow Rates in ZipGrow Towers
Hydroponics Water Requirements For a hydroponic system, plan for a 50 gallon sump plus an additional 0.5 gallon of water per ZipGrow Tower. Hydroponics sump size (in gallons) = 50 gallons + (# towers * 0.5 gallon) So, for a 200-tower hydroponics system, plan for 150 gallons of water.
Aquaponics Water Requirements Aquaponic systems have slightly more complicated water requirements. For each pound of mature fish, allow 8-10 gallons of water. Each linear foot of tower requires 0.3 – 0.5 lbs. of fish. Aquaponics sump size (in gallons) = (lbs. of fish)*(8 – 10 gallons) Lbs. of fish = (# towers)*(tower size, in feet)*(0.3 – 0.5 lbs.) So, for each 5-foot ZipGrow tower in the system, plan for approximately 2.5 lbs of fish and 20-25 gallons of water. A 200-tower system would require 4000-5000 gallons of water.
If You Find Yourself Concerned About Water Conservation, Try Our Systems Water use efficiency in a hydroponic system using ZipGrow Towers is drastically lower than that of traditional agriculture and other leading competitors, with only 1.5% water loss. This not only lowers water bills, but allows water to be used much more sustainably.
(Information in this blog was provided via personal interview with Dr. Nate Storey unless otherwise linked.) For more information, visit http://verticalfoodblog.com/water-useefficiency-hydroponics-aquaponics/