Title

Modeling stream temperature to assess methods of managing the impacts of climate change and land use

Presentation Type

Presentation

Abstract

Warming due to climate change is expected to alter temperature in aquatic habitats but the degree, rate of change, and ecological effects are likely to be system specific. In addition, mitigation of these effects through water and land use management is also likely to be system specific. I analyzed factors controlling temperature in small streams (< 100 cfs) using SSTEMP, a USGS stream temperature model. I gathered field data on Gold Creek, a tributary of the upper-Clark Fork, for three study reaches and used the measurements to calibrate/validate the model. I used the model’s built in sensitivity analysis to identify the most temperature sensitive parameters. I then constructed a hypothetical baseline stream and manipulated the most sensitive parameters to assess their affects on the baseline temperature. I found that the model is adequate for short term studies along short reaches for a stream like Gold Creek. Hence, the model could be useful for assessing the implications of proposed management strategies for regulating stream temperature, but, not for complex, long term temperature studies. I found that there are various feedbacks, according to the model, between air temperature and other parameters. Discharge and stream shade are the most effective parameters for regulating mean daily water temperature. Stream shade and associated insulating effects are more efficient at regulating daily maximum and minimum temperatures. Depending on the stream, other parameters may be more important for regulating temperature. Management strategies should consider streams independently based on their environmental characteristics, biological communities, and existing impairments. These results suggest that less impacted streams may naturally resist climate change effects better than impaired streams. However, less impacted streams will have less ability to respond to mitigation strategies.

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Apr 12th, 10:20 AM Apr 12th, 10:40 AM

Modeling stream temperature to assess methods of managing the impacts of climate change and land use

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Warming due to climate change is expected to alter temperature in aquatic habitats but the degree, rate of change, and ecological effects are likely to be system specific. In addition, mitigation of these effects through water and land use management is also likely to be system specific. I analyzed factors controlling temperature in small streams (< 100 cfs) using SSTEMP, a USGS stream temperature model. I gathered field data on Gold Creek, a tributary of the upper-Clark Fork, for three study reaches and used the measurements to calibrate/validate the model. I used the model’s built in sensitivity analysis to identify the most temperature sensitive parameters. I then constructed a hypothetical baseline stream and manipulated the most sensitive parameters to assess their affects on the baseline temperature. I found that the model is adequate for short term studies along short reaches for a stream like Gold Creek. Hence, the model could be useful for assessing the implications of proposed management strategies for regulating stream temperature, but, not for complex, long term temperature studies. I found that there are various feedbacks, according to the model, between air temperature and other parameters. Discharge and stream shade are the most effective parameters for regulating mean daily water temperature. Stream shade and associated insulating effects are more efficient at regulating daily maximum and minimum temperatures. Depending on the stream, other parameters may be more important for regulating temperature. Management strategies should consider streams independently based on their environmental characteristics, biological communities, and existing impairments. These results suggest that less impacted streams may naturally resist climate change effects better than impaired streams. However, less impacted streams will have less ability to respond to mitigation strategies.