CPED: Center Pivot Evaluation and Design
Authors: Dale F. Heermann, Kristine M. Stahl
Platform: WIN2000 WINXP
CPED models water distribution under a Center Pivot or a Linear Move sprinkler system. Water distribution is modeled using the sprinkler inventory, the pump characteristics, and terrain changes in the field. The output from CPED can be used to replace can tests when calculating system uniformity. It assumes no wind conditions.
Pump - A second order regression equation describing the pump curve is used. Alternately, a constant head with an estimated discharge, or a constant discharge can be used to describe the pump.
System Inventory - Most of this information is provided by the manufacturer. It should include the length, inside diameter, and Darcy Weisbach resistance coefficient for each pipe; the tower locations; and the sprinkler inventory for the system. The individual information on each sprinkler should include: the model name, the distance from the pivot, pattern shape, range and spreader diameter, pressure regulators, start and stop part circle angles, and right and left offset distances.
The model gives a summary of the sprinkler inventory. It is expanded to include hydraulic characteristics such as pivot pressure and system discharge based on both the pump curve and the depths, and the line pressure, nozzle pressure, discharge and pattern radius of each sprinkler. Results include the effective irrigated area, the mean depth, the uniformity coefficient, and the individual depths at the specified distances.
Windows 2000 with a pentium processor 32 megs of memory and 5-10 megs of free disk space.
Documentation and Availability:
A users manual is provided with the program. Both the manual and the program can be downloaded from the FTP site. Contact Kris Stahl for permission to download.
References: Available upon request.