ProcessesΒΆ

PITLAKQ accounts for the important processes in pit lakes. The figure shows the processes that are explained in the table below.

Please click on the picture to enlarge.

Processes of the model PITLAKQ

Process

Description

Implementation

hydrodynamics

Solution of the Navier-Stokes-Equation in two dimensions with density-dependent flow. Calculations of velocities, water temperature distribution and hence stratification.

CE-QUAL-W2

transport

Transport of dissolved substance in the lake. Added about 20 species.

CE-QUAL-W2, PITLAKQ

heat exchange

Budgeting of heat terms at water surface.

CE-QUAL-W2

wind impact

Wind energy effects water velocity of upper most lake layer.

CE-QUAL-W2

ice cover

Formation and melting of ice layer. Prevents atmospheric exchange during ice-covered periods.

CE-QUAL-W2

tributary inflow

Inflow from an unlimited number of sources (flow, concentrations, and temperature).

CE-QUAL-W2

atmospheric exchange (O2)

Oxygen can enter and leave at water surface layer.

CE-QUAL-W2

atmospheric exchange (CO2)

Carbon dioxide can enter and leave at water surface layer. Solubility depends on temperature and pH.

PITLAKQ

precipitation

Precipitation enters surface layer with amount, temperature and concentrations.

CE-QUAL-W2

evaporation

Water evaporates from surface layer.

CE-QUAL-W2

groundwater exchange

Groundwater characterized by flow, temperature and concentrations can enter and leave lake at any given cell.

PITLAKQ

groundwater flow and transport

The groundwater inflows and outflows can be given as inputs (off-line coupling) or can be supplied by a coupled groundwater model (on-line coupling) to model feedback.

Groundwater model, PITLAKQ

erosion (mass input)

Precipitation and wind waves move material into the lake.

PITLAKQ

erosion (water quality impact)

Eroded material effects lake water quality by adding dissolved substances and cation exchanger loadings that release substances.

PHREEQC, PITLAKQ

algae and nutrients

Algae grow depending on temperature, available light and nutrients. C has been added as limiting nutrient.

CE-QUAL-W2, PITLAKQ

chemical lake reactions

Equilibrium and kinetic reactions in all model cells. Organic matter from biological process is used as electron donators (linking chemical and biological reactions).

PHREEQC, PITLAKQ

mineral precipitation

Forming minerals can be allowed to precipitate.

PHREEQC, PITLAKQ

sediment release

Sediment at lake bottom can release substances. Release rates can be given as function of time or can depend on current lake water composition.

PITLAKQ

treatment

Substances can be added to the lake at any defined location with a time-variable scheme.

PITLAKQ

alkalinity of sinks and sources

In a post-processing step the alkalinity contributions of sinks and sources can be determined with a monthly time step.

PITLAKQ

coupling of all processes

All processes can use information generated by other processes. For example, lake water temperature is used in chemical reactions.

PITLAKQ

process additions / modifications

The model implementation is modular and allows for addition or modification of processes according to site specific needs.

PITLAKQ

Please contact us for more information.

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