Off-campus South Dakota State University users: To download campus access theses, please use the following link to log into our proxy server with your South Dakota State University ID and password.

Non-South Dakota State University users: Please talk to your librarian about requesting this thesis through interlibrary loan.

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Agricultural Engineering


Irrigation loads, being seasonal in nature, can cause high peak electric demands during the summer which may last for one or more months. Costs of supplying electric power rise with peak demand as short term peaks require generation and transmission facilities that are often underutilized during most of the year. A computer simulation program was developed to assist in the evaluation for using earthen storage reservoirs as a means to moderate peak electric energy demands caused by addition of irrigation loads. Seasonal reservoirs, having the capacity to store annual irrigation water requirements, and daily reservoirs, storage capacity for one day requirements, were used in the analysis. The proposed Forest City Irrigation Project near Gettysburg, SD was used as a basis for the study. Electric demands for the Forest City Project would cause a peak summer demand three to four times that of the average yearly demand. These high peak demands can be reduced with seasonal and daily reservoirs. The daily load curve for the Forest City Substation was relatively flat, with only a 28% difference between maximum and minimum values. Seasonal reservoirs had the most significant impact of moderating peak electric demands. Maximum reduction in peak demand for all conditions investigated in the study was 36%. A more variable daily load curve allowed daily reservoirs to have a greater impact on the reduction of peak demands. The use of a more variable daily load curve, showing a 50% difference between maximum and minimum values, reduced peak electric demands by an additional 50% over the flatter daily load curve. Pumping periods or "schemes" for seasonal reservoirs had an influence on system load factors. A five-month variable pumping period had a load factor of 44.5, a 40% increase over the load factor produced by the Forest City Project, 26.7, with no load management.

Library of Congress Subject Headings

Electric power systems -- South Dakota -- Computer simulation

Irrigation water -- South Dakota -- computer simulation

Reservoirs -- South Dakota -- computer simulation



Number of Pages



South Dakota State University