LNWB Ch09 Artificial Drainage - Procedures

Correspondence between David Tarboton and Becky Peterson on drainage procedures, and two memos describing PhaseIII Task4 work.

Within the Rainfall-Runoff Transformation of Topnet-WM there are five subcomponents: canopy interception store, vadose zone soil store, groundwater saturated zone, channel flow, and artificial drainage. Surface water input to the canopy interception store comprises rainfall and snow as well as sprinkler irrigation. Throughfall is computed based upon the canopy interception capacity, surface water input, and water in canopy storage and is taken as input to the vadose zone soil store. Potential evapotranspiration not satisfied from the interception store becomes potential evapotranspiration from the vadose zone soil store. Drip irrigation is also an input to the vadose zone soil store. Based on the input and storage in the vadose zone soil storage, recharge to groundwater and surface runoff is calculated. The vadose zone soil storage is depleted for areas with artificial drainage, representing ditch and tile drains that remove water directly from the vadose zone soil storage to stream channels. The vadose zone soil store calculation also accounts for potential upwelling from groundwater where the water table is shallow. The groundwater saturated zone calculations account for recharge, upwelling and groundwater pumping and produce baseflow as an output. Baseflow and surface runoff from the vadose zone soil store are combined to calculate channel flow.

This resource is a subset of the LNWB Ch09 Artificial Drainage Collection Resource.