Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Civil and Environmental Engineering

Committee Chair(s)

Belize A. Lane


Belize A. Lane


Bethany T. Neilson


Charles P. Hawkins


In the western US, flow diversions for irrigation reduce the amount of water in rivers. Additionally, changes to the nearby landscape can reduce the amount of groundwater flow into rivers. These combined factors deplete rivers and can even completely dry up the stream channel. Depleted streams typically have warmer temperatures in the summer, which can be harmful for fish and other aquatic species. However, in these depleted streams, small amounts of colder water can buffer these impacts. These colder water inputs, or lateral inflows, can come from local springs, seepage from nearby canals, or irrigation fields. Some rivers now depend on these lateral inflows to maintain water instream when they are depleted. To better understand these lateral inflows, and specifically the role of seepage from nearby canals, on streamflow and temperature, we monitored the Blacksmith Fork River in northern Utah below multiple diversions for three summers. We found that lateral inflows were critical for moderating stream temperatures during hot days with high diversions and prevented temperature from reaching stressful or lethal conditions. This study provides information for local and regional water management about the impacts of summer water diversions on streamflow and stream temperature and potential consequences of changes in land and water management.