Stream Temperature Response to Three Riparian Vegetation Scenarios by Use of a Distributed Temperature Validated Model

Elevated in-stream temperature has led to a surge in the
occurrence of parasitic intrusion proliferative kidney disease
and has resulted in fish kills throughout Switzerland’s waterways.
Data from distributed temperature sensing (DTS) in-stream
measurements for three cloud-free days in August 2007 over
a 1260 m stretch of the Boiron de Morges River in southwest
Switzerland were used to calibrate and validate a physically
based one-dimensional stream temperature model. Stream
temperature response to three distinct riparian conditions were
then modeled: open, in-stream reeds, and forest cover.
Simulation predicted a mean peak stream temperature increase
of 0.7 °C if current vegetation was removed, an increase of
0.1 °C if dense reeds covered the entire stream reach, and a
decrease of 1.2 °C if a mature riparian forest covered the entire
reach. Understanding that full vegetation canopy cover is the
optimal riparian management option for limiting stream
temperature, in-stream reeds, which require no riparian setasideandgrowvery
quickly, appear to provide substantial thermal
control, potentially useful for land-use management.