Summary of "Routing Processes" in the MOSART model:

Routing Processes in MOSART
- MOSART divides each spatial unit (e.g., grid cell, watershed) into three categories of hydrologic units: hillslopes, tributaries, and the main channel.
- MOSART represents three routing processes:
  1. Hillslope routing: Surface runoff is routed as overland flow into the sub-network channel, while subsurface runoff directly enters the sub-network channel.
  2. Sub-network channel routing: The sub-network channel receives water from the hillslopes, routes it through the channel, and discharges it into the main channel.
  3. Main channel routing: The main channel receives water from the sub-network channel and/or inflow from upstream spatial units, and discharges the water to the downstream spatial unit or the ocean.

Routing Equations
- MOSART uses Manning's equation to estimate the travel velocities across hillslopes, sub-network, and main channels.
- For hillslopes and sub-network channels, the hydraulic radius is approximated by the water depth.
- For the main channel, the hydraulic radius is calculated as the ratio of the wetted area to the wetted perimeter.
- A common continuity equation is used to describe the change in storage (dS/dt) for each routing process, with the inflow (Qin), outflow (Qout), and source/sink terms (R).

Key Assumptions
- MOSART only routes positive runoff, while negative runoff is mapped directly to the coupler.
- MOSART does not exchange water with the atmosphere or return water to the land model, but strictly transports water from runoff generation to the basin outlets.