TEMPERATURE SURGE CHARACTERISTICS IN A DYNAMIC AND URBANIZED HEADWATER STREAM
The primary focus of our study is to determine the quickflow temperature required to create the temperature surges that we measured in the stream. We used the local minimum hydrograph separation method to determine the baseflow component of total stream discharge. After the baseflow component was separated we were able to subtract the baseflow from the stream flow to obtain the quickflow component. We used a similar technique to separate baseflow temperature during temperature surge events. We then used a simple energy balance equation to determine the quickflow temperatures for each surge event based on known stream and baseflow temperatures and calculated components of flow. The analysis indicates the temperatures needed to produce the temperature surges of the individual storm events. The maximum quickflow temperature calculated with the energy-balance model is 44.32 °C. Stream temperatures rose above 20 °C, a critical temperature threshold for cold-water species such as trout, in 17 surge events that had a mean maximum stream temperature of 22.17 °C and a mean maximum quickflow temperature of 30.13 °C. Our study suggests the need for mitigation of quickflow during temperature surge events in order to limit rapid temperature increases above the temperature threshold of cold-water species.