Ecohydrology

The need for having better information regarding water quantity and water quality issues in riparian systems in the state of Oregon has been discussed by different stakeholders including producers, state and federal agency personnel, and researchers. Particular interest has been expressed for research studies that address concerns regarding stream temperature and sediment levels in riparian corridors. Proper understanding of surface water and groundwater interactions in riparian systems and how they can be impacted through land management practices becomes critical to properly address these water quantity and quality concerns. In a semiarid watershed in north-central Oregon, we are conducting a 3-yr pilot study that will enhance base knowledge regarding the relationships between stream temperature, sediment load, and riparian vegetation composition and distribution. Objectives of this study are: 1) To better understand how stream water temperature is affected by the interactions between surface water and shallow groundwater, and 2) To determine the overall effects that different land and vegetation management practices have in stream water temperature and runoff/sediment generation processes. A systems approach is being taken to better understand the complexities of multiple human and natural interactions in this and similar riparian systems. We are conducting intensive monitoring of selected ecologic and hydrologic parameters to determine surface water and groundwater relationships and their effects on stream water temperature and other water quality parameters. Also, we are conducting extensive field work to characterize, map, and assess water uptake by riparian vegetation along two-paired riparian corridors. In addition, runoff plots are being instrumented to evaluate sediment load in response to different natural and human disturbances (e.g., livestock and wildlife grazing) along the riparian areas. This pilot study contributes to our longer-term, broader, research effort in understanding resilience of riparian systems in the Western US.