Shirish Bhat

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering


Thirty-two flow gaging stations from South Dakota, Minnesota, and Iowa were chosen for the low flow frequency analysis. A common base period of 68 years (1930- 1997) for the flow records of South Dakota streams was developed. Thirty-two gaging stations located in the Big Sioux River Basin were fit for the record extension. The flow records for 32 gaging stations were extended using Maintenance of Variance Extension Type 1 (MOVE.1) method. A new approach, the nonparametric method, is introduced to analyze low flow frequency for South Dakota streams. Low-flow frequency analysis was performed with log-Pearson Type III and nonparametric approaches. Seven-, 14-, and 30-day low flow magnitudes were determined for recurrence intervals of 1.25, 2, 5, 10, 20, 50, and 100 years for 32 gaging stations. The flow magnitudes for different recurrence intervals determined from log-Pearson Type III were slightly higher than those from nonparametric method were. The expected flows for different recurrence intervals from both the methods were compared with the observed flow magnitudes and recurrence intervals. Seven-day low-flow characteristics were presented graphically. Overall seasonal low-flow statistics for selected gaging sites were also presented. Total Maximum Daily Load (TMDL) for ammonia, waste load allocation, and load allocation for the Big Sioux River near Brookings were determined. Both 30-day average and daily maximum loads were determined to maintain the surface water quality standards for ammonia.

Library of Congress Subject Headings

Stream measurements -- Big Sioux River Watershed (S.D. and Iowa) Stream measurements -- South Dakota



Number of Pages



South Dakota State University