NetMap's Technical Help Guide

Confluence Zone Refugia

Confluence Thermal Refugia (not scaled and scaled by tributary to mainstem drainage area)
 
Tool Description: This tool uses the downstream aggregated Current Shade-Thermal Energy parameter (SolMean) and compares the aggregate values at tributary confluences to the aggregate values in mainstem channels (e.g., mainstem value - tributary value) to identify potential tributary sources of cooler water (and also potential sources of warmer tributary water). To provide an index of cool water potential to a mainstem, the result is then multiplied by the ratio of tributary drainage area to mainstem drainage area to provide an index of the relative magnitude of the cooler or warmer water conditions in the mainstem channel.
 
NOTE, prior to running this tool, you will need to access and process Vegetation Data, such as LEMMA (see Tool).
 
Data Type: Line (stream layer)
 
Field Name: TrbThrm; Common Name: Tributary - Current shade thermal energy  MINUS Tributary - Current shade thermal energy; positive values means that tributaries are potentiall providing cooler water while negative values means that tributaries may be contributing warmer water.
Field Name: TrbThrmSc; Common Name: Tributary - Current shade thermal energy  MINUS Tributary - Current shade thermal energy, and then multiplied by the ratio of mainstem drainage area to tributary drainage area; this provides an index that combines TrbThrm with the relative magnitude of tributary flow, this providing information on the relative magnitude of the cooler or water waters.
 
Units:  Watt-hours/m2 and watt-hours/m2 multiplied by tributary drainage area/mainstem drainage area
 
NetMap Module/Tool: Vegetation/Fire/Climate - Vegetation - Shade/Stream - Thermal Refugia - Confluence Zone Refugia
 
Model Description: The model predicts thermal energy to stream channels using a combination of bare earth radiation and the effects of current shade conditions on bare earth radiation (See Current Shade-Thermal Energy tool). NetMap aggregates those values downstream (called Along Channel Refugia-Tributary Scale) creating an area weighted, running average based on inherent topographic controls on thermal energy to streams (topographic shading, stream orientation, stream width and solar angle) and the current shade conditions that reduce thermal energy to streams.  Then, at each tributary confluence, the downstream aggregated Tributary - Current shade thermal energy  is subtracted from  the downstream aggregated mainstem Current shade thermal energy. Results with positive values means that the tributary inflow has potentially cooler water temperatures (compared to the mainstem, and thus provides a confluence related thermal refugia) while results with negative values means that the tributary may be contributing warmer water (conditions) compared to the mainstem.
 
Figure 1 (left panel) shows the differences between the downstream aggregated values of Shade-Thermal Energy between tributaries and mainstems (e.g., mainstem value - tributary value); positive values means that a tributary has, in aggregate, more inherent landscape and shade cool water conditions compared to a mainstem while negative values means that a tributary has, in aggregate, more intrinsic landscape and shade warmer water conditions compared to a mainstem.
 
 
 
Figure 2.  Shows the same values as Figure 1 except they are multiplied (at confluences) by the ratio of the tributary drainage area to mainstem drainage area, to provide a proxy index that indicates the potential flow magnitude of either the cooler or warmer water conditions.
 
 

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