bank current England english flow Great Britain green landscape nature North Yorkshire peaceful quiet river River Ure tranquil trees water Yorkshire Dales National Park Aratiatia rapids blue danger forest natural new zealand pool rock Taupo tree Waikato River water resources watercourse Arrowtown branch leaf leaves Natural landscape plant River Arrow Salix shallow spring stream willow brown drainage flood overflow path residential riverbank saturation Surrey leafs summer wood woods canada cloud colour Fraser ripple shore silhouette sky sunset land meander mount mountain scape landscapes national parks parks u.s.a. yellowstone