It flows southward , emerging from the hills near Sonoma Valley Hospital .
Arroyo Seco Creek springs near the Napa County line about 4 mi ( 6 km ) northeast of Sonoma , California .
Arroyo Seco Creek flows southward , emerging from the hills near Sonoma Valley Hospital .
Arroyo Seco Creek springs near the Napa County line about 4 mi ( 6 km ) northeast of Sonoma , California .