- Brian Bledsoe, Ph.D., Department of Civil Engineering, Colorado State University
PROJECT SUMMARY
Headwater streams comprise the vast majority of stream reach length in most watersheds and could be important for regulating water quality in large basins. However, the relative influence of various physical, chemical, and biological stream attributes on solute retention remains ambiguous. This research focuses on the nexus of the current lack of a scientific basis for stream restoration, how geomorphic complexity is related to nutrient retention in impacted and restored headwater streams, and the need for an ecological underpinning for stream restoration techniques in water resources engineering curricula. The integrated research and education plan involves: (1) experimentally evaluating the nitrogen retention of impacted and restored streams in urban and agricultural settings as affected by different restoration interventions, (2) translating scientific understanding of linkages between geomorphic complexity, transient storage, and nutrient retention into process-based stream restoration strategies, and (3) establishing an Ecological Engineering concentration at Colorado State University (CSU) that builds on the foundations of the proposed research to provide experiential and collaborative learning opportunities for undergraduate and graduate students.
Specifically, we plan to couple intensive geomorphic characterization with field 15N-tracer experiments based on the Lotic Intersite Nitrogen eXperiment II (LINX II) protocols to determine the rates and factors controlling nitrate uptake and retention in streams of varying geomorphic complexity and context. These experiments and observations will allow us to test a variety of hypotheses dealing with the impacts of human disturbances and restoration activities on stream geomorphic complexity and nutrient retention to result in an extension of the LINX II database to include restored streams. We will perform experiments to trace the fate of nitrate in three streams spanning 8 geomorphic contexts near the CSU campus and in the Southern Rockies of Colorado: (1) urban channelized vs. urban natural recovery vs. urban restored (using an intensive structural approach), (2) grazed vs. natural recovery, and (3) grazed vs. restored (again using an intensive structural approach). This research should enhance our understanding of the ecological effectiveness of stream restoration and allow us to scale nutrient retention processes to river basins.
The educational component will include: (1) creating undergraduate and graduate concentrations in Ecological Engineering emphasizing interdisciplinary, multi-scale, and process-based approaches to aquatic ecosystem restoration, and (2) collaborating with the Women and Minorities in Engineering Program, Colorado Alliance for Minority Participation, City of Fort Collins, and other stakeholders to create outdoor laboratories proximate to the CSU campus. The sites examined (including a new treatment wetland on the CSU campus) will serve as outdoor classroom models for research, environmental education methods development, and short courses. The Ecological Engineering curriculum initiative will enhance recruitment and retention of students from underrepresented groups.
Headwater streams comprise the vast majority of stream reach length in most watersheds and could be important for regulating water quality in large basins. However, the relative influence of various physical, chemical, and biological stream attributes on processing of nutrient pollution remains ambiguous. This research focused on the nexus of the current lack of a scientific basis for stream restoration, how geomorphic complexity is related to nutrient retention in impacted and restored headwater streams, and the need for an ecological underpinning for stream restoration techniques in water resources engineering curricula. We experimentally evaluated the nitrogen retention of impacted and restored streams in urban and agricultural settings as affected by different restoration interventions. Specifcally, we examined linkages between geomorphic complexity, transient storage, and nutrient retention. Our studies revealed significant relationships between stream characteristics such as variability in channel form, hydraulic characteristics, and nutrient processing. Such understanding provides a basis for stream restoration activities aimed at reducing downstream delivery of nitrogen pollution. We also established an Ecological Engineering concentration for at Colorado State University (CSU) that builds on this research to provide experiential and collaborative learning opportunities for undergraduate and graduate students. This program is attracting a high proportion of female engineering students.
