This past weekend I planned a trip (which is the norm, I don't like to stray from water sources) along a river based on current maps and knowledge from about 4 years ago. To my surpise, the whole river (waterfalls, ravines) was turned to swamp and small patches of barely flowing stagnant, skeeter infested "patches" of river. The cause was natures littl engineers (aka beavers). After a few hours I decided to call the trip, as I'm insistant on planning the hike and hiking the plan. Opened my eyes to the fact that I need to come up with a contingency plan as far as water supply goes in case I find myself in an area with water that I don't feel comfortable trusting my katadyn hiker pro to filter. Staging is not an option on most of my trips unfortunately, as I almost always hike rough trailless backcountry. Live and learn though! A good example to any new backpacker reading this to always have a plan B or know when to call a trip when there is unfortunatly no other option.