Subsurface Drip Design Calculator

Design SDI lateral layout from crop spacing, emitter specs, and peak ET to determine tape length, flow rates, and run times.

Inputs

Field size (acres)

Field length (ft)

Crop row spacing (in)

Lateral spacing (in)

Emitter spacing (in)

Emitter flow rate (GPH)

Peak crop ET (in/day)

Tape burial depth (in)

Tape cost ($/ft)

System efficiency (%)

Tab to move between fields

Results

Number of laterals

1,056

Application rate (in/hr)

0.32

Peak run time (hr/day)

Field width (ft)2,640

Total tape length (ft)1,393,920

Total tape (miles)264

Total emitters1,393,920

System flow rate (GPM)11,616

Meets capacity? (1=Yes)1

Total tape cost ($)$111,514.00

Tape cost per acre ($)$1,394.00

Est. wetted diameter (in)23

Lateral overlap (%)0

How to Use This Calculator

Enter Field size (acres), Field length (ft), and Crop row spacing (in).
Set Lateral spacing (in), Emitter spacing (in), and Emitter flow rate (GPH).
Adjust Peak crop ET (in/day), Tape burial depth (in) as needed.
Review Number of laterals, Application rate (in/hr), and Peak run time (hr/day).
Use Field width (ft) and Total tape length (ft) to inform your decision.

How the result changes with Field length (ft)

Field length (ft)	Number of laterals	Application rate (in/hr)	Peak run time (hr/day)
618	2,256	0.32	1
1,913	729	0.32	1
3,467	403	0.32	1
4,762	293	0.32	1

What each input means

Field size (acres): Total field area for SDI installation.
Field length (ft): Length of field in the direction laterals run (quarter-mile = 1320 ft).
Crop row spacing (in): Distance between crop rows.
Lateral spacing (in): Distance between drip laterals. Often matches row spacing or every other row.
Emitter spacing (in): Distance between emitters along the drip tape.
Emitter flow rate (GPH): Individual emitter discharge rate at design pressure.
Peak crop ET (in/day): Maximum daily crop water demand during peak growth.
Tape burial depth (in): Depth of drip tape below soil surface.
Tape cost ($/ft): Cost of drip tape per linear foot.
System efficiency (%): SDI application efficiency (typically 88-95%).

What each result means

Field width (ft): Calculated field width from area and length.
Number of laterals: Total drip laterals needed across the field.
Total tape length (ft): Total linear feet of drip tape required.
Total tape (miles): Total tape length in miles.
Total emitters: Total number of emitter points in the system.
Application rate (in/hr): System application rate in inches per hour.
Peak run time (hr/day): Hours of operation needed to meet peak ET demand.
System flow rate (GPM): Total flow required for the entire system.
Meets capacity? (1=Yes): Whether system can meet peak ET within 22 hours/day.
Total tape cost ($): Cost of drip tape material only.
Tape cost per acre ($): Tape material cost per acre.
Est. wetted diameter (in): Estimated wetted soil diameter from each emitter.
Lateral overlap (%): Estimated overlap between adjacent lateral wetting patterns.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Field size (acres) = 80, Field length (ft) = 1320, Crop row spacing (in) = 30, Lateral spacing (in) = 30 = 10 input(s) provided
Calculate Number of laterals
Number of laterals = ceil(fieldWidthFt / lateralSpacingFt)
1056 = 1056
Calculate Application rate
Application rate = (emitterFlowGph * 1.604) / emitterAreaSqFt
0.321 = 0.321
Calculate Peak run time
1 = 1
Calculate Field width
2640 = 2640
Calculate Total tape length
Total tape length = numLaterals * fieldLengthFt
1393920 = 1393920

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