Add term: flow process

[pbuttigieg]

Linked to #7
As a unifying transportation concept, @brandonnodnarb, puts forward "flow"

This can be used to describe the flow of meltwater, glaciers themselves.

We're looking at ENVO's material transport process as a correlate.

[Garybc]

We are talking about a type of continuous process called flow where ice/snow transports downslope under its own weight from accumulation zone to ablation zone.
Glaciers flow through the processes of deformation and sliding.
Glacier flow, velocity and motion is controlled several factors (Jiskoot et al., 2011), including those listed below:

Ice geometry (thickness, steepness),
Ice properties (temperature, density),
Valley geometry,
Bedrock conditions (hard, soft, frozen or thawed bed),
Subglacial hydrology,
Terminal environment (land, sea, ice shelf, sea ice), and
Mass balance (rate of accumulation and ablation).

How much of these flow model factors do we take into account??
https://user-images.githubusercontent.com/9488418/39721049-32c68f84-520c-11e8-952c-083f0ff497d2.png