hydrobm.benchmarks.bm_eckhardt_baseflow

hydrobm.benchmarks.bm_eckhardt_baseflow(data, cal_mask, precipitation='precipitation', streamflow='streamflow', precip_window_days=3, precip_threshold=0.1)

Baseflow separation using Eckhardt filter to create a mean annual baseflow signal.

Estimates both k (recession coefficient) and BFI_max (maximum baseflow index) from the data. The benchmark represents the average daily baseflow for the calibration period.

The Eckhardt method was selected because it was found to be the best of 9 evaluated baseflow separation methods in Xie et al. (2020). Parameters are estimated using: (1) recession analysis for k, and (2) backward filter method (Collischonn & Fan 2013) for BFI_max.

Parameters:

datapandas DataFrame

Input data containing precipitation and streamflow columns.

cal_maskpandas Series

Boolean mask for the calibration period.

precipitationstr, optional

Name of the precipitation column. Default is ‘precipitation’.

streamflowstr, optional

Name of the streamflow column. Default is ‘streamflow’.

precip_windowint, optional

Number of timesteps to check for precipitation when identifying recessions. Default is 3. Adjust for sub-daily data (e.g., 72 for 3 days of hourly data).

precip_thresholdfloat, optional

Precipitation threshold in same units as precip data. Default is 0.1.

Returns:

bm_valsdict

Dictionary containing: - ‘k’: Recession coefficient (estimated from recessions) - ‘BFI_max’: Maximum baseflow index (estimated from backward filter) - ‘baseflow_climatology’: Mean baseflow for each day of year

qbmpandas DataFrame

Benchmark baseflow time series representing the mean annual baseflow cycle.

References

Eckhardt, K. (2005). How to construct recursive digital filters for baseflow separation. Hydrological Processes, 19(2), 507-515.

Collischonn, W., & Fan, F. M. (2013). Defining parameters for Eckhardt’s digital baseflow filter. Hydrological Processes, 27(18), 2614-2622. https://doi.org/10.1002/hyp.9391

Xie, J., Liu, X., Wang, K., Yang, T., Liang, K., & Liu, C. (2020). Evaluation of typical methods for baseflow separation in the contiguous United States. Journal of Hydrology, 583, 124628. https://doi.org/10.1016/j.jhydrol.2020.124628