To provide a consistent, long-term estimate of discharge from select tributaries to the lower Boise River, two datasets of daily discharge records were harmonized. Differences between a discharge record compiled by the Idaho Department of Water Resources (IDWR) and one compiled by the U.S. Geological Survey (USGS) were computed, and the IDWR record was adjusted so that median discharge values equaled those of the USGS record. The 10th and 90th percentiles of the percent difference between discharge records were applied to the IDWR dataset to create lower and upper bounds on daily discharge estimates and to show the uncertainty around the median adjusted IDWR discharge values. The result is a harmonized discharge record for 14 lower Boise River tributaries.