Stream confluences, the joining of two streams, represent both unique habitat patches and critical movement corridors within a riverscape. Although the hydraulic and thermal nature of a particular confluence influences the ability or likelihood of biota to travel through it, confluences generally have been ignored in restoration efforts because they are hydraulically and geomorphologically complex and dynamic systems. The doctoral dissertation research project will seek to advance basic understanding of the thermal, geomorphological, and hydraulic conditions present at stream confluences with the intention of informing conservation, management and restoration of these uniquely important river features. The doctoral student will explore answers to the question: How do tributary confluence dynamics influence thermal habitat patterns in the main channel? The student will employ cutting-edge distributed temperature sensing fiber optic arrays coupled with acoustic Doppler current profilers in a paired confluence sampling design.
This project will contribute to basic understanding of the processes through which channel morphology influences hydraulic and thermal habitat variability at confluences under different hydrologic conditions. It will integrate hydraulic, geomorphic, and thermal observations at stream confluences to form a holistic understanding of the complex interactions the influence thermal habitat dynamics in confluences. The knowledge generated will transform basic understanding of stream confluences by: investigating small confluences (small tributaries joining a large river), confluences on a Great Plains sand-bedded river, and thermal mixing patterns and associated thermal refuge habitat dynamics within both small and large confluences. The project will provide policy makers and public stakeholders with the greater knowledge that will facilitate scientifically based, cooperative decisions regarding confluence restoration. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
