channel widths in channel_properties.rvp file are too wide in 2nd order streams causing large surface area and warm water temperatures

[AreliaTW]

I have been using this version of Basin Maker to generate the HRUs and Raven Input files for most of the Province of BC.
([https://github.com/dustming/basinmaker/archive/fix_head_water_riv_segment.zip]

I am running Raven with the thermal components required to generate stream temperatures. In my test basin, I consistently found that water temperatures hit the maximum of 40oC in summer in the southern half of the basin. After a lot of testing, including exploring and changing the the channel properties, what I've discovered is if I reduce the channel width by a factor of 10, I can reduce the water temperature.

For example, in this particular watershed, the width of the channel was 179 m, which is not realistic for this region, therefore the surface area is too great and water temperatures are too warm (see the orange, yellow and purple lines in the plot below):
##############new channel ##############################
:ChannelProfile Chn_2000361
:Bedslope 0.0062252939
:SurveyPoints
0 1642.0922
16.0000 1638.0922
74.9945 1638.0922
76.9945 1637.0922
102.4918 1637.0922
104.4918 1638.0922
163.4864 1638.0922
179.4864 1642.0922
:EndSurveyPoints
:RoughnessZones
0 0.11653812
74.99454543 0.05855145
104.49181815 0.11653812
:EndRoughnessZones
:EndChannelProfile

Once I reduced the total width to 17 m, water temperatures became close to observations (see the green line in the plot below):
##############new channel ##############################
:ChannelProfile Chn_2000361
:Bedslope 0.0062252939
:SurveyPoints
0 1642.0922
1.60000 1638.0922
7.49945 1638.0922
7.69945 1637.0922
10.24918 1637.0922
10.44918 1638.0922
16.34864 1638.0922
17.94864 1642.0922
:EndSurveyPoints
:RoughnessZones
0 0.11653812
7.499454543 0.05855145
10.449181815 0.11653812
:EndRoughnessZones
:EndChannelProfile

If you could please check how the channel widths are generated and see if a limit can be placed to reduce these wide widths. This issue might be unique to the high elevation subbasins commonly found in the mountainous BC terrain.

Thank you.