Irrigation in the Pacific Northwest

General Design Calculators

Field Area: Determines the area of rectangular, triangular, circular and trapezoidal fields.

Irrigatable Area: The land area that can be irrigated with a given flow of water.

Irrigation Frequency: The maximum interval allowed between irrigations.

Irrigation Run Time: Determine the length of time that an irrigation system must run to apply enough water to replace the water lost to evapotranspiration.

Season Operating Hours: Calculate the number of hours per season that you irrigation system will typically need to run to keep up with crop water use requirements.

Required Water Pump Horsepower: Estimate the size of pump that you need (brake horsepower) and the total power (hp) requirements of the pump drive motor for your irrigation system.

Irrigation Water Costs: How much is your irrigation water really costing you? How much can you save by trying to conserve?

System Pumping Requirements: Calculate the system capacity (flow rate) required to meet the demands of a field.

NPSHA: determines the absolute pressure at the pump impeller.

Total Dynamic Head: This calculator finds the pressure required at the pump, and the head that the pump must generate.

Pipe Size Estimate: Determined by measuring the circumference of the pipe with a string or a flexible tape measure.

Pipe Velocity and Diameter: Calculate the velocity of water in a pipe and calculate the diameter of a pipe required for 5 fps pipe velocity.

Pipeline Pressure Loss: Calculates the pressure or friction loss along a given length of pipeline with a specified inside diameter and the minimum pipe size to limit pressure loss to a specified value.

Pressure Loss with Outlets: Calculates friction loss in a pipe with equally spaced outlets and the minimum pipe size for a pipe with equally spaced outlets.

Fitting Pressure Loss: The equivalent feet of pipe to add to the pressure loss equation.

Pipeline Pressure Rating: Calculate the maximum operating pressures at 74 deg F (23 deg C).

Required Maximum Flow Rate: Flow rate onto a specified area to meet the maximum water use rate requirements.

System Capacity: Calculate the system capacity (flow rate) required to meet the demands of a field.

Water Application Rate: Water application rate using the flow rate on an area.

Water Depth: Depth of water applied to a specified area over the specified time span based on the given flow rate onto the field.

Water Hammer: Surge pressure due to a sudden shutting of a valve, or water hitting the end of a pipe.

Irrigation System Capacity: Estimate of the water flow requirements to replace water lost to evapotranspiration.

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