The Sava Dolinka — the uppermost stretch of the Sava River — drops 180 vertical meters over ten kilometers between Kranjska Gora and Jesenice, carving a corridor through the Julian Alps that remains ice-fed even in August. Its rapids peak at Class III in spring melt, taper to Class II by midsummer, and thread a limestone gorge so narrow that sunlight reaches the water only between ten and three. The riverbed itself is younger than the surrounding peaks; tectonic uplift during the Quaternary reshaped the drainage pattern, and the Sava now cuts through bedrock laid down when this valley floor was still submerged beneath the Paratethys Sea. Sava river white water rafting became a commercial operation in 1989, two years before Slovenia's independence, when a collective of Bled-based mountaineers repurposed Soviet-era oar frames and began running half-day descents for Yugoslav adventure clubs. By 2026 the industry is formalized: certified guides, neoprene wet suits rated to twelve degrees Celsius, and shuttle vans that meet groups at the Dolinka put-in near the village of Mojstrana. The sector now moves roughly fourteen thousand paddlers per season, most of them first-timers drawn by proximity to Bled and the absence of portages. The gorge remains roadless — no bridge spans it for seven kilometers — so the experience retains a backcountry quality despite its accessibility. The geology is what makes the run distinctive. Triglav limestone fractures into clean, angular blocks, and the river has carved these into undercut ledges and pourover drops rather than the boulder gardens typical of volcanic drainages. Hydraulics form and collapse with seasonal precision: the keeper wave below Peričnik tributary appears in April, holds through June, then flattens by July as snowmelt recedes. Water temperature holds between eight and fourteen degrees year-round, fed by springs emerging from karst aquifers beneath Triglav's north face. The coldest reaches are the first three kilometers, where the Martuljek stream enters from the left and drops the aggregate temperature by two degrees in under a hundred meters. The rafting corridor lies entirely within Triglav National Park, Slovenia's only national park and a UNESCO biosphere reserve since 2003. Land use here is governed by a 2016 management plan that caps daily raft launches at forty boats and prohibits commercial activity after 18:00 to protect nesting dippers and grey wagtails. The park's northern boundary follows the ridgeline visible from the river — Škrlatica, Razor, and Prisojnik — all above 2,500 meters and part of the same Triassic thrust sheet that forms the Martuljek Wall. The juxtaposition of alpine scale and intimate river corridor is what anchors the experience: you are paddling at 550 meters above sea level, yet vertical relief rises 2,200 meters within three kilometers of the banks.