Species


Species
Conditions:	if the Include Advection Dispersion (AD) Water Quality option selected in the Simulation Specification dialogue ET Uptake Factor appears when ET water quality is included. Solubility in Surface Water appears when overland flow water quality is included.

In this dialogue, you add species by clicking on the Insert icon. You delete species by selecting the species from the table and clicking on the Delete icon.

The table includes the list of species for the WQ simulation and the physical properties of the chemical species.

· Include - Turning off the include checkbox allows you to exclude a species from the simulation without having to remove it and all of its accompanying sources, etc.

· Name - This is the displayed identifier in all subsequent dialogues and in the data tree.

MIKE ECO Lab note: The Name must be exactly the same as the State Variable Name used in the MIKE ECO Lab Template (except in the case of dual domain mass transfer, which uses the reserved suffix “_2”).

· Type - There are four species types. Species can be either:

– Dissolved - Dissolved species are mobile in the water. They are active in the subsurface and surface water. Disolved species have a default concentration of [mg/m³].

– Sorbed - Sorbed species are only available in the subsurface. They are fixed to the soil matrix and do not move with the water. Sorbed species have a default concentration of [g/g].

– Suspended - Suspended species are only available in ponded water. They do not infiltrate to the UZ or SZ, and they cannot become Sorbed species. If the ponded water infiltrates, the species is left behind. Suspended species have a default concentration of [mg/m³].

– Fixed - A fixed species is neither disolved or nor sorbed. It is used as an immobile state variable by MIKE ECO Lab. This allows MIKE ECO Lab to read and write arbitrary values to MIKE SHE during the simulation. Fixed species have an undefined unit.

· ET uptake transpiration factor - This is the factor that determines the rate at which plants will remove the mobile solute from the water.

· Solubility in Surface Water - Surface water (overland flow) sources are specified as a mass. Thus, the source will be active until all of the solute has been dissolved. This is important because the life of the source depends on the amount of surface water flow.

Since evaporation can cause the overland concentration to increase, solubility needs to be specified to avoid unrealistic high concentrations. The species precipitates if the concentration exceeds the solubility. The precipitate dissolves again if the concentration falls below the solubility.

The solubility is a uniform concentration value per species with the dimension [M L-3], that is, [mu-g/m³], [g/m³], [mg/l], etc, depending on the chosen user unit for Concentration. This means that, for example, a solubility of 100 [g/m³] implies that 100g of mass will dissolve per m² of cell area per m depth of ponded water.