If Caused By Flood Drainage Why is the Grand Canyon Where It IS?

If I remember correctly, the Colorado River displays many examples of stream capture. Maybe that's something to include in this discussion as well. Or is that what you meant by "barbed connection?"Here's a quick resource to help things along from Geology of National Parks, Volume 2:

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Hows does a River System Evolve?

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The Colorado River is a major through-flowing stream with a total length of 2450 miles from the Rocky Mountains to the Gulf of California. Like other streams, the Colorado developed in response to environmental variables over time; in the Colorado's case, its history has been more complicated. For over a hundred years, geologists have argued about possible courses and directions of flow of tributaries and ancestral streams that may have had some part in the Colorado's evolution. So far, no hypothesis has met with overall acceptance. The details of the problem are fairly technical, but some general principles that apply to stream development are outlined below.

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Base level. The limiting surface to which a stream can cut down is called the base level. Sea level is the ultimate base level for through-flowing streams like the Colorado, but sometimes local base level, such as a lake, a reservoir, or an interior basin without an outlet, controls a stream's downcutting ability. The Colorado's base level has been affected by uplift and also by sea level fluctuations, especially during the Pleistocene Ice Ages. Moreover, segments of the river, probably before it became through-flowing, may have emptied into inland lakes that functioned as temporary base levels.

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Gradient. A stream whose gradient (rate of descent, or slope) is low does not have much erosive power. But if an area is uplifted, the gradient steepens, increasing the velocity of stream flow. When this happens, a stream downcuts rapidly, especially if its volume of water also increases. Sometimes, during uplift, a stream is able to maintain its original course and cut a narrow trench down through bedrock.

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Headward erosion and stream capture. While a trunk <<no idea what 'trunk' means>> stream is downcutting or entrenching itself, its tributaries lengthen themselves by headward erosion, which means that they cut back into a plateau or upland at the head of each valley. A drainage system that is favorably situated, perhaps flowing on weaker rock, for example, is able to erode headward faster and eventually intersect and capture the headwaters of a neighboring stream or drainage system. Geologists are sure that stream capture occurred numerous times while the Colorado was evolving into a major stream; but the details of how, when, and where these events happened is not clear.

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The Key factors in the Colorado River's evolution are probably these:

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1. The river's source area in the Rocky Mountains, in addition to the Colorado Plateau, has undergone a long series of relatively rapid uplifts since the end of Mesozoic time (65 million years ago). Overall, the Colorado Plateaus rose 5,000 to 10,000 feet. Stream gradients became steeper, increasing stream velocity and erosion capability.

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2. More rain and snow fell in the Rocky Mountains as the elevation increased. In the colder Pleistocene climates, glaciers formed and grew. As more meltwater and runoff became available, streams gained volume. The streams that drained the Rocky Mountains were powerful forces in erosion as they poured out on the plateaus.

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3. The climate of the plateaus was (and is) drier than the mountain climate. Therefore, the high-volume, swift rivers cut narrow, deep canyons. Because rainfall is low on the uplifted plateaus, runoff is not ample enough to widen the valley side slopes.

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4. When the Gulf of California opened more than 6 million years ago, this lowered the base level for the Grand Canyon region and caused rapid headward erosion. The modern course of the through-flowing Colorado River was probably established after this time. Previous to the opening of this arm of the sea, the Colorado -- or ancestral stream that drained the Rockies -- flowed into the ocean at a different location.

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5. The east-west Grand Canyon segment of the Colorado's course across the Kaibab Plateau is asymmetrical; that is, the river flows closer to the south side due to slight tilting that occurred during uplift. The fact that the North Rim receives more moisture and sheds more sediment also tends to push the river to the south side of the canyon. The rate of erosion on the Kaibab Plateau is greater because all of the precipitation falling on the north side of the river, drains to the south and into the Grand Canyon. On the South Rim, rain and meltwater also drain to the south; since the runoff goes away from the canyon, it has less erosional effect.

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<snipped the rest as irrelevent>

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Oh yes, duh! Like the 'trunk' of a tree. That makes perfect sense. I'm not a hydrologist/hydrogeologist so some of the terminology is unknown to me.Well I don't think anything other than Creationist literature is going to help them in any discussion involving geology. But I thought perhaps understanding a few of the main controlling factors in stream development was handy: base level, gradient, and stream capture. When I first learned the concept of stream capture (or piracy), I thought it was absolutely fascinating. But that was pretty much the only thing I enjoyed about hydro.Thanks for the help. Edited by roxrkool, : No reason given.