Mike Haasl wrote:
The run of piping from the far gutter has to be watertight to a point at least as high as the highest point of the IBC. Ideally a foot or two higher. So if there's water in the IBC, it will be at the same level in the pipe at the bottom of the downspout. So in your second picture, there will be water pressure to the top of the blue mark in your downspout. So you'd need to transition from downspout hardware to something more waterproof (like PVC) about 6' off the ground. Water seeks its own level so when the far side roof is adding a gallon of water to the downspout it raises the level in the downspout and the water will then be pushed towards the IBC tote until the level in the downspout and the IBC tote are the same. When that first heavy rain hits, that downspout may be higher than the IBC until the water starts moving so that's why you want it watertight for a few feet above the height of the IBC.
Daniel Benjamins wrote:@Mike: The winters here are long and cold (as I've been told). Curious how you know this, just by looking at this sunny picture?