1 LISEM 2.50 Baseflow Baseflow setup In LISEM 2.50 baseflow can be added to the channel flow. Baseflow is mutually exclusive with channel infiltration. If water enters the channel through groundwater, it is assumed there is no infiltration at the same time. Baseflow can be selected in the main window: Baseflow is calculated with 3 maps: 1. chanbaseflux.map: flux into the channel from wet perimeter in m 3 /s 2. chanvini.map: Initial channel volume in m 3 : a map with the volume of water that is in the channel for the event 3. chanincrease.map: factor (0-1) of increase in chanbaseflux.map from the start of the event to the end of the run. The increase in baseflux is triggered by the fcat of channel inflow from overland flow to t he chnnel. If this happens in any channel cell, the baseflux is increased gradually with this factor. For instance if the baseflux into the channel s 0.1 m 3 /s and chanincrease has a value of 0.01, the influx in LISEM is calculated as: channel volume = chan volume + ba seflux * (1+increase) Baseflow simulation: step 1 Because of the channel network length, dimensions, gradient and Manning's n, it cannot be calculated before hand what the baseflow in m 3 /s at the outlet will be fr om a given "chanbaseflux". In each cell this amount of water is added and starts to flow with the kinematic wave until an equilibrium is reached between inflow along the network and outflow at the outlet. The 3 variables above are therefore totally empirical. As an example we take the Ganspoel catchment and assume a baseflow of 200 l/s is measured at an outlet. On top of that a peak flow is measured. The two are separated through some peakflow separation procedure. First we have to simulate a baseflow of 200 l/s. LISEM. To do that we have to run he model without rain, but with a "baseinflux". To run the model without rain, an rainfall input file is made with zero rainfall for 1000 minutes: RUU CSF TIMESERIE INTENSITY NORMAL 1 station_1 0 0 100 0 1000 0