Agriculture is the largest user of groundwater in the United States. Ground water at dairies used for cow drinking, milking parlor clean-up and crop irrigation is produced from wells that often are often improperly designed and completed. Inefficient well design results in increased pumping costs and increases the frequency that wells and/or pumps have to be replaced. Inefficient wells require significantly more energy to pump lesser amounts of water than properly designed wells. Significant operational cost savings (power, pump replacement) can be realized through properly: Selecting screen size/geometry, Locating screened intervals, Selecting filter pack size, Developing the well, Testing the well, Maximizing pump efficiency, Sizing pipelines and Minimizing pipe runs where possible.

1. Design of High Capacity Energy
Efficient Wells
Jay Lazarus, Jim Riesterer, P.G.
Glorieta Geoscience, Inc.
PO Box 5727
Santa Fe NM 87502
www.glorietageo.com
Waste to Worth Conference April 2-4, 2013
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2. Efficient Water Use At Dairies
 Agriculture is the largest user of groundwater in the
United States
 Ground water at dairies used for cow drinking, milking
parlor clean-up and crop irrigation is produced from wells
that often are often improperly designed and completed.
 Inefficient well design results in increased pumping costs
and increases the frequency that wells and/or pumps
have to be replaced.
 Inefficient wells require significantly more energy to
pump lesser amounts of water than properly designed
wells.

3. Well Drilling
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4. Types of Wells
 Domestic
 Municipal
 Commercial
 Irrigation
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5. Types of screen
 Torch cut
 Plasma cut
 Saw cut (PVC)
 Mill slot
 Wire wrapped
 Louvered
Photo from
johnsonscreens.com
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6. Well Efficiency
Inefficient well: Efficient well:
•Limited open area •Maximize open area
•Incorrect/no filter pack •Proper filter pack
•Screens get dewatered •Screens are not dewatered
•Pumps sand and/or air •Does not pump sand and/or air
•Oversized pump motor •Properly sized pump motor
•Artificially high total dynamic head •Minimizes total dynamic head

7. Why is Well Efficiency Important?
 Energy cost savings
 An efficient, sand-free well will save a
farmer significant money on energy costs
to produce the water and the well and
pump lifetime will be extended
significantly.
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8. When Does a Pump Fail?
 When you need it the most…..
 During the hottest time of the irrigation
season…..
 When the pump contractor is servicing a
municipal well for a bigger client…..
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9. Why Does a Pump Fail?
 Old Age
 Excessive sand production
 Excessive drawdown
 Water not cooling the pump effectively
 Air entrainment  Cavitation
 Other…
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10. What Causes Sand Production?
 Improper
screen/filter
pack sand
sizes
 Casing failure
(bad welds,
corrosion)
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11. Screen Placement
 Best production intervals
 Allow sufficient water column above
screen to prevent dewatering screens
 Include margin for long-term drawdown
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12. Well Screen Design
 Slot size
 Slot geometry
Total open area
 Filter pack
 Sized in conjunction with sieve analysis of
formation material and screen slot size

Increases hydraulic conductivity, reduces
(eliminates) sand production
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13. Well Development
 Removes drilling fluid from filter pack and
formation (increases production)
 Removes fines from filter pack, properly
grades filter pack and formation for long
term sand-free production
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, Photo from Driscoll, 1986

14. Specific Capacity
 Defined as production rate per unit of
drawdown (Q/s)
 Typically expressed as gpm/ft
 The bigger the number the better the well
 Allows well to be designed in a manner
that will avoid dewatering screens
 Often must estimate Q/s in design phase
based on nearby wells or lithologic
analogues

Confirm actual Q/s with test pump
prior to selecting permanent pump GL IE A GE
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15. Specific Capacity
 Directly impacts pumping costs

16. Maximizing Specific Capacity
 Proper screen and filter pack selection
 Proper screen locations
 Proper well development
 Up front costs associated with these items
can easily be recouped in power savings
and pump longevity
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17. Maximizing Pump Efficiency
 Must have good specific capacity (step
drawdown) test at a minimum to select
best pump for the job
 Select permanent pump AFTER step test
is conducted
 Oversizing the pump requires choking
back flow, creating artificial and
unnecessary head (and increased
pumping costs)
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18. Step Drawdown Test

19. Using the Step Test Results

20. 7 Day Drawdown Test

21. Maximizing Pump Efficiency
800 80
~71 % eff.
700 70
50 hp ~62 % eff.
600 60
40 hp
500 50
Assumed
400 30 hp 40
%
n
e
y
c
)
(
Eff
i
300 30
20 hp Step test
m
Result
H
D
To
d
e
n
a
c
y
)
(
f
t
i
l
200 20
10 hp
100 10
0 0
0 100 200 300 400 500 600
Capacity (gpm)
If pump is selected based on the assumed flow and head, the pump will be
oversized and actual operation will be ~9% less efficient and discharge will
have to be choked back creating an additional ~80 ft of artificial head.

22. Maximizing Pump Efficiency
 In our example*, a 9% reduction in pump
efficiency and an extra 80 ft of head
translates to a cost increase of
approximately $9200/year for one pivot.
*Q = 500 gpm, Q/s = 15 gpm/ft, Pipe diameter = 6”, pipe length = 1000 ft,
power cost = $0.10/KWH
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23. Other Considerations
 Well location
 Geohydrology
 Distance from pivot (pipeline friction loss)

Elevation change to pivot
Note: All other factors held
Constant: Q = 500 gpm, Q/s
= 15 gpm/ft, pipe diameter =
6”, elevation change = 0, energy
Cost = $0.10/KWH
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24. Other Considerations
 Pipeline sizes
 Properly sized pipes can significantly reduce
friction loss/pumping costs
Note: All other factors held
Constant: Q = 500 gpm, Q/s
= 15 gpm/ft, pipe length =
1000’, elevation change = 0,
Energy cost = $0.10/KWH
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T OSCIENCE INC.
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25. Summary and Conclusions
 Significant operational cost savings (power, pump
replacement) can be realized through properly:
 Selecting screen size/geometry
 Locating screened intervals
 Selecting filter pack size
 Developing the well
 Testing the well
 Maximizing pump efficiency
 Sizing pipelines
 Minimizing pipe runs where possible
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T OSCIENCE INC.
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26. Questions?
www.glorietageo.com
lazarus@glorietageo.com
riesterer@glorietageo.com
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