( CNN ) -- Canadian explorer Adam Shoalts knew he was heading into uncharted territory when he set out on a solo expedition to explore northeastern Canada 's remote Again River . What the 27-year-old from Fenwick , Ontario , did n't expect was to find himself hurtling over a 20-foot waterfall that had never been documented -- and then go on to discover six more waterfalls after fixing his canoe . The nearly 100-kilometer long Again River is a tributary of Quebec 's Harricanaw River , part of Canada 's Hudson Bay Lowlands . It 's one of the largest roadless areas on earth outside Antarctica , says Shoalts , containing rivers so remote that even today there are a few that have escaped accurate mapping -- including the Again . `` The expedition was five years in the making , '' he says . `` Extensive research went into it , looking through explorers ' records , Geological Survey notes , speaking directly with aboriginal elders . '' But his research did n't offer any hints as to the dangers that lay ahead . Even Google Earth 's low-resolution satellite imagery , all that 's available for this remote part of Canada , is deficient for detecting waterfalls . `` The plan was to explore the river , record information about flora and fauna , rapids and the geography in general , '' he says . `` I knew there would be lots of whitewater rapids , but no one knew that waterfalls existed on the river . '' 'Yikes , this is going to be bad ! ' With the support of the Royal Canadian Geographical Society , Shoalts conducted two reconnaissance expeditions to the area ( one in 2008 and another in 2009 ) , exploring the wilderness around the Again River . But he was n't able to canoe the Again , as just getting to the river 's isolated headwaters is a challenge that involves a few days of bushwhacking and creek-hopping . `` In August 2012 , I went back , this time alone , determined to canoe the river no matter what , '' he says . `` The seven waterfalls were so unexpected and special . '' The first waterfall Shoalts found -- before it was too late to go around it -- was 20-feet high . Of the six he went on to discover , the highest was 40-feet high . `` My first thought when I realized I was being swept over a waterfall was , 'Wow ! What an amazing discovery ! The Geographical Society will be thrilled ! '' he recalls . `` The second thought was , 'Yikes ! This is going to be bad ! ' I realized I could n't escape from the current so I just braced myself for the drop . '' Shoalts says he was sucked underwater beneath the fall `` for longer than was comfortable . '' He resurfaced , out of breath , and spotted his canoe upside down in an eddy near the riverbank . `` I swam to shore , recovered most of my gear -- except my hat , fishing rod and some moccasins -- and then set about repairing my canoe . `` Once I got my breath , that is . It took about an hour and a half to get the canoe back in shape and ready to continue downriver . '' Return to the scene of discovery . This week , Shoalts is heading back to the Again River to continue his work for the Royal Canadian Geographical Society ( RCGS ) . He 'll retrace his route and photograph , measure and document the precise location of each waterfall so that they can be added to topographical maps , pending verification from Spot satellite imagery . `` This expedition is geographical exploration in the truest sense : Shoalts 's work will change the map of Canada -- a rarity in 21st century exploration , '' says the RCGS . Technology is helping explorers make discoveries in an era when significant finds are incredibly rare . Most recently , in June of this year , archaeologists announced they 'd found a huge medieval city buried beneath impenetrable jungle on a remote mountain in Siem Reap , Cambodia . It would n't have been discovered but for the help of a remote sensing laser instrument . Though Shoalts says gadgets are useful in the field , it 's important not to rely on them completely . `` Modern electronic gear and other gadgetry is no substitute for traditional skills and knowledge , '' he says . `` In the beginning , I never used a GPS , only map and compass , sun and stars . Now I have a GPS , but I do n't rely on it . `` A satellite phone allows me to communicate from the wilderness , but it does n't work in the forest or in the rain , so it has limitations and I try not to rely on it . `` I use a modified theodolite , designed by my engineer father , to measure waterfall heights . '' He also relies on aerial photographs and satellite imagery when planning expeditions , `` but ultimately , they are no substitute for old-fashioned 'boots-on-the-ground ' exploration . '' For those with their own Magellan dreams , it 's not too late to get into the game , says Shoalts . `` The age of exploration will never be truly over -- the oceans , caves , Antarctica , so much of northern Canada -- it will take a long time to explore , '' he says . `` New species are still discovered , and then there will always be archeology , paleontology , science -- imagination is the only limit really . ''
Explorer Adam Shoalts , 27 , finds seven uncharted waterfalls on remote Canadian river . Royal Canadian Geographical Society says discovery will change the map of Canada . Shoalts recounts being swept over 20-foot-high waterfall in his canoe .