merge rivers based on gnis_id or else HUC8
merge rivers based on gnis_id or else HUC8

r-barnes/waterviz,r-barnes/waterviz,r-barnes/waterviz,r-barnes/waterviz,NelsonMinar/vector-river-map,HydroLogic/waterviz,NelsonMinar/vector-river-map,NelsonMinar/vector-river-map,HydroLogic/waterviz,NelsonMinar/vector-river-map,HydroLogic/waterviz,HydroLogic/waterviz