Understanding Sprinkler Types
Different sprinkler types are designed for specific irrigation needs and coverage patterns.
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Rotary Sprinklers
Rotating stream sprinklers that cover 20-50 feet radius. Flow rates: 2.0-6.0 GPM. Best for large lawns and sports fields. Distribution uniformity: 70-80%.
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Spray Heads
Fixed spray pattern covering 5-15 feet radius. Flow rates: 1.0-2.0 GPM. Ideal for small to medium areas. Distribution uniformity: 60-70%.
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Impact Sprinklers
Mechanical arm creates rotating spray. Coverage: 20-60 feet radius. Flow rates: 2.0-8.0 GPM. Good for large irregular areas. Distribution uniformity: 65-75%.
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Drip Systems
Low-flow emitters at 0.5-4 GPH. 90% water efficiency. Perfect for gardens, shrubs, and trees. Minimal water loss through evaporation.
Technical Specifications
Pressure Requirements
- Spray Heads: 20-30 PSI
- Rotary Heads: 30-50 PSI
- Impact Sprinklers: 25-45 PSI
- Drip Systems: 10-30 PSI
Coverage Patterns
- Full Circle (360°)
- Half Circle (180°)
- Quarter Circle (90°)
- Adjustable Arc
Overlap: 100% head-to-head coverage recommended
Precipitation Rates
Inches per hour (in/hr):
- Spray: 1.5-2.0 in/hr
- Rotary: 0.4-0.8 in/hr
- Impact: 0.3-0.7 in/hr
- Drip: 0.1-0.5 in/hr
Spacing Guidelines
- Square: Equal to radius
- Triangle: 1.15 × radius
- Rectangle: ≤ 50% of width
- Head-to-head: Essential
Advanced Irrigation Concepts
Water Requirement Calculations
Weekly Water Need = ET₀ × Kc × Area
Where:
- ET₀ = Reference Evapotranspiration
- Kc = Crop Coefficient (lawn ≈ 0.8)
- Area = Irrigation zone size (sq ft)
System Flow Rate
Total GPM = Σ(Sprinkler GPM × Count)
Runtime Calculation
Minutes = (Inches needed × 96.3) ÷ Precipitation Rate
Distribution Uniformity (DU)
DU = (Average of Lowest Quarter) ÷ (Overall Average) × 100
- Excellent: > 80%
- Good: 70-80%
- Fair: 55-70%
- Poor: < 55%