baseflow_sep: Baseflow separation
In RHydro: Classes and methods for hydrological modelling and analysis

Description Usage Arguments Details Value Author(s) References See Also Examples

Various baseflow separation methods

1	baseflow_sep(runoff, method="DFM", parms=c(c=0.925, c_slope=diff(range(runoff))/length(runoff)/2, window_size=10, f_lowess=0.1))

`runoff`	vector of runoff heights (equidistant temporal resolution) [L/T]
`method`	base-flow separation method, see details.
`parms`	method-specific paramters, see details. The effect of the parameter will be dependent on the temporal resolution of the runoff series.

method="DFM" (default) selects baseflow separation using a single-pass digital filter method (e.g. Sawicz et al, 2011). It uses the parameter c, varying between 0 (baseflow close to runoff) to 1 (constant baseflow). \ q_direct[i] = max(0, cc*qd[i-1]+(1+cc)/2*(runoff[i]-runoff[i-1]), na.rm=TRUE)

method="constant_slope" separates base flow by drawing a line with constant slope from the minima of the hydrograph to the next intersection with it. Dingman (2002) recommends for the parameter c_slope a value depending on catchment area A (A < 20 mi<b2>): c_slope = 0.05 ft<b3>/s * A /h. You do the math, imperial units suck.

method="RLSWM" re-scaled LOWESS-smoothed window minima. Determines the minima in a moving window of window_size timesteps and smoothes them using lowess with parameter f_lowess. If at any timestep baseflow is larger than the runoff, the entire baseflow-series is shrunk linearly.

vector holding base flow time series

Till Francke

Sawicz, K., Wagener, T., Sivapalan, M., Troch, P. A., & Carrillo, G. (2011). Catchment classification: empirical analysis of hydrologic similarity based on catchment function in the eastern USA. Hydrology and Earth System Sciences, 15(9), 2895<96>2911. http://dx.doi.org/10.5194/hess-15-2895-2011

Dingman, S. L. (2002). Physical hydrology. Upper Saddle River, NJ: Prentice Hall.

bfi

runoff = fuse.DATA[,"Q"]

bf = baseflow_sep(runoff, method="RLSWM", parms=c(window_size=50, f_lowess=0.2))
plot(runoff, type="l")
lines(bf, col="red")