Performing A Greenhouse Water Audit

1
Performing A Greenhouse Water Audit
By Paul Thomas, and Forrest Stegelin, The
University Of Georgia
Cooperative Extension Service
2
Adverse Water Use Legislation Is Inevitable

• 1). 27 counties in Georgia currently have
  year-round water
• restrictions in place that limit landscape
  watering.
• Birmingham, Alabama landscapers, greenhouse and
  nursery
• owners are desperately trying to prevent city
  officials from
• shutting down nurserys and landscapers.again.
• 3). Most of Florida is in a Stage 2 drought.
  Water tables are
• dropping and water use legislation is popping up
  everywhere.
• 4). California, Texas, Oregon, Washington and
  most other
• western states have new and more extensive water
  use
• legislation. You do not own water in these
  statesyou pay
• for the right to extract it.

3
Adverse Water Use Laws Are Preventable
The drought is forcing legislators to take
action. They are in a tough spot! They cannot
control the weather, and yet answer to the
citizens. They need facts to make the best
decisions. The question is not if
restrictive legislation is to be proposed at the
local level, it already has been and will be
again! If things dont improve, its only a
matter of time before national legislation is
proposed that will limit water use for all
farmers and growers. Doing nothing will result
in legislators justified in their beliefs that
they must act given what facts are known and
what they see.
4
Why Do A Water Audit?
The large volumes of irrigation water used, and
the high visibility of our industry, puts our
industry at risk of losing control over our
water resources. Worse, our industry is being
viewed as a major water waster! Legislators
want to know how much water we use, so they can
assess if steps need to be takenbut we have no
clue! Our lack of interest greatly concerns the
people who regulate water usage in our state.
We must become pro-active.
5
Our Image? What Can We Do?
6
Will A Greenhouse Audit Really Help? Yes, The
greenhouse industry is probably the most
efficient water user group of all commodities in
agriculture. The greenhouse industry is
efficient compared to car washes and industrial
firms. The trouble is, we dont have the
proof. What proof? Facts! Figures, Ratios,
Comparisons! Water conservation
documentation Drip tubes, etc. Gallons of
water per dollar of tax revenue
generate. Gallons of water per square foot /
acre / year. Gallons of water per dollar
wholesale farm-gate value. We need to get
this information soon!
7
Water Audit Procedures
Carefully audit (measure), review and then
document commercial water use in your
operation. Identify potential problem areas, and
then explore methods to improve water use
efficiency. Develop short and long term
management tactics to reduce water use.
8
Water Audit Procedure
The following are some important questions you
should ask. Once answered, develop a summation
of your findings, and document all the
improvements you made. This information will
help you explain your water use policy and use
history to legislators.
9
Whats In A Water Audit?
Audit Information Current Best Management
Practices (BMPs). Crop inventory organized by
water need. Pesticide and chemical
inventory. Expansion, storage and recycling
options. Water conservation technology
implemented.
10
Goals Of A Water Audit
Reduce luxury water consumption! Eliminate
non-target water use (waste). Reduce current
fertilizer and pesticide usage. Minimize
legislative problems through consistent education
efforts. Restore legislators confidence in our
water use policies, and our industry.
11
The Audit
Greenhouse Water Use Is Different Than Field
Agriculture
12
Part 1. Water Source Assessment  ________________
________________ Do you have multiple sources of
water? Do you store water for emergencies?
  Do you have a manditory water restriction
plan? How long can your operation do without
water? What would be the financial loss if water
was cut off?
13
Is Your Water Source and/or Pump Capacity Up To
The Challenge? If your pump provides only 30
gallons per minute (GPM), you can easily see that
it will not be capable of irrigating a large
field of perennials and eight greenhouses at the
same time. You would likely have to water one
house or one zone at a time. A member of your
crew would likely be watering all day, most days.
Your pump would run all day, every day. Hot
weather labor costs would skyrocket!
14
What If Things Were Different? ?
If you had that one days supply of water stored
in a 30,000 gallon storage tank. with a
distribution pump, and a capability to deliver
several hundred gallons per minute and you
automated the delivery system.. and used
efficient drip irrigation or ebb and flow
benching. ..you could water your entire
facility in a few hours for just pennies in labor
!!!
15
The Solution Water Storage! YES! You
can! At 30 GPM, would you have enough water
replaced in the storage tank each day to allow
full watering schedules? If we assume the pump
cycles on 45 minutes per hour, then 45 x 24 hours
in a day 1080 minutes. At 30 gallons per
minute, we would have 32,400 gallons of water
pumped per day. If watering was automated,
youd save the labor cost, and complete all your
watering in a few hours. If you had a three day
supply, youd never have a direct use shortage,
and you may use less electricity as the tank
would rarely be drawn down and require a full day
of pump activation. The labor savings would be
significant!
16
Part II. Water Use Assessment and Storage Do
you know your greenhouse operations maximum
daily water demand in summer?
Do you know your greenhouse operations maximum
weekly, monthly or yearly water usage in cubic
feet or gallons?
Do you know your greenhouse operations maximum
daily water demand?
Do you know which crops have maximum daily water
demand? Which have the least?
17
Part II. Water Use Assessment and Storage
There are three basic methods to determine water
usage over time!
1. Endpoint Flow Rate 2. Volumetric
Calculations 3. Flow Meter Reading
18
Flow Meters Are Your Best Choice!
Accuracy Continuous Measurement Data
Acceptability Is Good Low Maintenance /
Permanent Low Long-term Cost Simple To Install
19
An In-Line Flow Meter
20
And easy to read
21
Part III. Water Use Labor Cost Assessment
 Are your employees watering efficiently? Do
you periodically observe your employees watering
skills? Do you know how much the application
of water is costing you per hour?
On what basis do you decide to water? Need?
Schedule? Do you have a daily time period set to
water within?
22
Part III. Water Use Assessment Do you
record daily, weekly or monthly water use?
Do you test your water quality on a monthly basis?
Do you keep the results of your water tests to
show the absence or presence of ground-water
contamination
23
Knowing True Costs Can Generate Significant
Savings
You can save up to 70 of water used for pot
crops and 35 for bedding plant production by
updating your watering system to include drip
irrigation, ebb and flow benching or flood floor
systems.
Automation would save hundreds of hours / month.
The estimated labor savings is significant. If
you pay the average of 8.40 / hour, you can
save just over 7300.00 per Quonset house or
large bay per year.
24
Part IV. Application Technology   Do you know
if your pressure is correct for that particular
system component?   Do you have particle
filters and properly calibrated injectors or
proportioners? When did you last test the
system?   What percentage of your total crop
variable cost does watering take up?  
25
Back-Flow Prevention Selection Back-flow
prevention is the law in Georgia!    Are you
connected to a municipal water source controlled
by a water authority? Pumping from a well?
Pumping from a stream? Do you or any neighbors
live within a mile of the greenhouse?   How are
you applying the water? Using drip irrigation?
Injecting fertilizer, pesticides or chemicals?
If so, you are required to have a back-flow
prevention system    
26
Back-Flow Prevention Guidelines
Consult with the Local, State, County or on some
cases the Federal agency that may monitor water
quality and safety. They have specific
guidelines as to the type of back-flow prevention
needed.
However, if you are connected to a local water
authority (LWA), their rules supersede all
others. If the State requires only a single stage
check valve and the water LWA requires a double
check reduced pressure device, you must go with
the more expensive LWA requirements. The most
effective and cheapest back-flow prevention
measure is a 12 air-gap between the top of a
storage tank and the incoming water line. Water
cant jump up-hill in open air!
27
   
REDUCED PRESSURE ZONE BACKFLOW PREVENTERS  
PROS      Two IN-LINE INDEPENDENT CHECK VALVES
with intermediate relief valve .     For use
in hazardous CROSS-CONNECTION situations.     If
both check valves fail, BACK SIPHONAGE IS
DIVERTED TO THE ATMOSPHERE.
28
REDUCED PRESSURE ZONE BACKFLOW PREVENTERS
    They have low pressure drains incorporated
into their design.     Test port cocks are
provided for testing back siphonage.     Can
be installed below irrigation sprinkler head,.
CONS    Expensive in the SHORT RUN     Must
be installed one foot above the ground.

29
Part V. Water Recycling   Do you recycle any
portion of the water used in your growing
operation?   Can you accurately measure the
amount of recycled water?   Could you report
with some accuracy how much water you saved per
year by recycling? Have you attended a water
recycling lecture or meeting in the last year to
update your understanding of the new technology,
standards and methods being used?
30
Water Collection
There are many ways to recycle water, but all
systems require you to plan on how you will
Collect and reuse or of the water. Cisterns,
and ponds are suitable for large or
small operations. Getting the water to that
holding are can be a challenge.
Drainage Channels
Holding Ponds
31
Storage Tanks and Cisterns
32
Potential Rainfall
33
(No Transcript)
34
(No Transcript)
35
Part VI. Water Release - Pollution
Prevention   Do you know how much water you are
releasing from your operation? Do you have a
bio-remediation site (a catch-pond with
established plants such as cattails) to reduce
free nutrients and act a s a bio-filter prior
to releasing the water. Do you have a
scouting or evaluation program to monitor water
release quality and quantity Do you know the
acceptable limits for nitrate or phosphorus
release in your local community or
water district?
36
Part VII. Monitoring water use legislation
and local water use regulations   Do
you know if your county or city has a commercial
water use ordinance? Are there water use
restrictions in effect in your community?   Is
your region currently in a drought or low-water
supply situation?    
Have any operations near you been asked to
conserve or cease watering use due to a
municipality shortage?
37
Part VIII. Planning For Future Expansion
Do you have a site-specific water use fact sheet
for local legislators or regulatory personnel to
inspect upon demand? Is your growing
facility within 5 miles of a subdivision or city?
Are you familiar with your state regulations
regarding water release, well contamination and
groundwater contamination?
38
Part VIII. Planning For Future Expansion   Is
your current water supply sufficient for your
potential expansion needs over the next ten
years?   What are the impediments to
expanding your water supply?  
39
Part VIII. Planning For Future Expansion
Could conservation and new technology negate the
need for a new well or expanded usage?   Would
you consider changing crops grown to include more
drought tolerant plants.   Would changing over to
a water efficient application method pay for the
new well or additional water source costs in the
next five years?
40
Automating Your Irrigation System Is a Great
Investment!
Automating your irrigation system proves to be a
very good investment. Payback (breaks even)
for 4778.00 is under 1 ½ years with 79 return
on investment _at_ 6 interest over 10 yrs, this is
greater than a 22,000 net present value, or a
65 internal rate of return with a benefit cost
ratio of 5.8. That is a fantastic benefit ratio.
Net labor savings is over 3,712 per house
over the next 10 years !!!!! .
41
Automating Your Irrigation System Is A Great
Investment!
Non-monetary tangible benefits More uniform
plant growth, Scarce labor now freed up Labor
for planting or loading trucks, Hire less
staff More management time for planning! Dont
forget the real conservation benefit of using
between 30 and 70 less water .and the public
relations benefit gained by being efficient and
aware!
42
Read Your Greenhouse Water Audit Handout
If you have questions, The University of Georgia
has faculty that specialize in Irrigation
Technology, Crop Production, Agricultural
Economics, Regulatory Compliance and
Environmental Assessment. See your county
agent to access these resources.
43
Acknowledgments The author would like to
thank Ben Bradshaw, Progress Growers Inc, Dr.
Don Wilkerson, Texas AM University, Dr. Maryann
Rose, formerly at The Ohio State University,
and Dr. Tom Yeager, University of Florida for
the use of their previously published
materials, tables and figures.