def get_actual_water_levels(station_id):
        # Fetch water levels and tide predictions for given station
        date_time, water_level, tide = fetch_noaa_tide_data(station_id,
                begin_date, end_date)

        # Calculate times relative to landfall
        seconds_rel_landfall = (date_time - landfall_time) / numpy.timedelta64(1, 's')
        # Subtract tide predictions from measured water levels
        water_level -= tide

        return seconds_rel_landfall, water_level