如果曲线只在“出口”被切断，而在“入口”被切断怎么办?是吗?这可能是因为人为干预，也可能是沉积物没有足够的时间来关闭“入口”。这部分可能是湖泊，因为它几乎没有水流，但仍然与河流相连。

这仍然被认为是一个牛轭湖，或者有一个更好的术语?< / p >

<强>当土壤钙含量高时:当土壤风化了大量的碳酸钙基岩时，土壤钙的含量可能会很高。在农业环境中，化肥会导致钙含量过高。在某些粘土中发现相对较高的含量也并不罕见，因为它们的CEC较高。< / p >

• For example, this source (and others) suggest that calcium levels would be expected to be higher in clay vs sand (with some impact from pH):

  Calcium in soil is generally correlated with the amount of sand versus clay in soil as well as soil pH. Sandy soils tend to have calcium levels at or below 1000 lbs/acre, whereas high clay soils often have levels above 2,500 lbs/acre, Soils with a good pH level also tend to have plenty of soil Ca.

My situation: I've found relatively high levels (1200-2000 ppm) of soil calcium (measured by Mehlich III extraction; Mehlich 1984) from fairly non-acidic (pH = 5.5-6.5) alluvial sandy soils.

• the soil type: "Cartecay and Chewacla soils, 0 to 2 percent slopes, frequently flooded" (with perhaps mix of "White Store sandy loam, 10 to 25 percent slopes")

• the site is in a forested urban patch in central North Carolina (USA) and is neighbored by a small 1st order stream that occasionally floods the site after elevated post-storm drainage

For reference, nearby high-clay (more acidic) soils in higher topographic positions tended to have lower calcium levels between 200-1000 ppm.

My question: what would be the source/cause of high calcium in sandy alluvial soils?

• What role does the nearing-neutral pH have?

• Are there likely "natural" (e.g., geologic) sources of heightened calcium in this case, or is this likely a phenomenon due to high calcium effluent from upstream non-point pollution sources (e.g., golf course, hospital, parking lots)?

Update:

I've also now noticed that the soil has many traits (e.g., high pH, Mg, Cu, Fe, Mn, and Zn) that could associate it as being a result of an ultramafic intrusion (known to occur in this general region). However, I know that qualitatively speaking, ultramafic intrusions would have a high Mg/Ca ratio. My soil's ratios (for both A and B horizons):

• ppm_A: 350 ppm Mg / 1800 ppm Ca = 0.19

• ppm_B: 315 ppm Mg / 1150 ppm Ca = 0.27

• percent saturation A: 17% Mg / 50% Ca = 0.34

• percent saturation B: 19% Mg / 38% Ca = 0.5

I'm not sure what constitutes "high" as I'm unsure of a baseline (i.e., is high much greater than a ratio of 1 or simply greater than a ratio of 0?).

Is it possible that this hypothesis holds any weight??

• other issues: do ultramafic intrusions result in sandy alluvial soils?, here suggests there'd be high Na, of which my soil has very low amounts (1/50th of which the linked source suggests).

A man that lived on a river in the rugged part of the northern Washington Cascades told me an interesting story. He actually lived on the upper reaches of the Cascade River, a tributary, which eventually flows into the Skagit River.

The river is a high energy, steep gradient river full of rocks. Fast moving and cascading.

The man told me during a big flood flow, at night, he could hear the rocks and boulders bouncing around and bumping into each other. The most amazing thing is he said in the pitch black of night, he saw muted, periodic, random quick light flashes under water - creating an unusual effect. He and I speculated the flashes were produced by rocks colliding with each other. The rocks in the area were mostly granitic, perhaps with some gneiss.

I did not see it. Is this possible? I know you can get sparks from some rocks and minerals - but granite boulders - underwater!!? Any comments?

Larry

当查看"最小流量"科罗拉多河流域的24个月预测，我注意到米德湖图表的一些奇怪之处:2023年6月，预计侧流的流入为负。

日期峡谷释放侧流入Evap损失2023年6月577 -13 44 

水去哪了?它没有蒸发——这已经在其他地方得到了解释。据我所知，科罗拉多河在格伦峡谷大坝和米德湖之间没有分流河道，也没有重要的用户。在春季径流之后，地面应该很好地饱和了。那么，13000英亩英尺(16000立方米)的水发生了什么?< / p >

根据维基百科，北咸海正在部分恢复，通过恢复部分Syr达里亚河的流量(这条河被苏联改道用于灌溉)，并通过建造堤Kokaral将水保持在北咸海而不是流向南方。通过谷歌上的图片，你可以看到科卡拉尔大坝至少偶尔还能让水通过，这让我想知道，由于锡尔河的流量改善，南咸海是否还能像大坝建前那样接收那么多的水。

• 大坝的年流量是多少?
• 在灌溉工程修复和改善之前，Sy Darya河的年流量是多少?

• Gander:大约在4月和5月(大约从第101天到第141天，如果第1天= 1月1日)
• Humber稍微在Gander
• Terra Nova有一个峰值放电在3月左右，在其他之前

对于最小

• Terra Nova:大约在一年的201天
• Gander:大约211天(六月/七月)
• Humber:一月和二月，然后在甘德之后。<李> / < / ul >

  So clearly climate, both the precipitation of rain and snow affects this discharge but what is the cause behind the different times in max and min discharge of these three rivers?

我刚刚读到刚果河是>200米(650英尺)深 -我不知道这甚至是遥远的可能!Q1:是什么过程导致河流变得这么深?< / p >

Q2: By which method is the depth of rivers in this range measured?

The Professor had, among others, identified a location on the Zambezi River where the Zambezi and Chobe rivers meet +-40km upriver from the Victoria Falls, I assume close to the newly built Kazungula Bridge?

In essence the suggestion was that by the construction a 14 meter high, controllable weir, in times of flooding the river would be able to flow along the ancient route, filling Lake Liambezi, and pushing back to Maun and back via the Boteti river ultimately filling the Makgadikgadi pans. This would also mitigate he flooding downstream in Mozambique.

Building a 14m high Weir 1km wide using human and animal labour was an immense challenge 120 years ago. With modern earthmoving equipment such a task would be like building a "big farm dam" today!

My question and thinking - this would refill the MASSIVE "evaporation pans" as they were centuries ago, which would in turn raise the rainfall in especially the winter months in much of the Northern Cape, and especially Botswana moving over to Limpopo province, and ultimately raise the Average Rainfall throughout the entire Southern Africa. The thinking is that Lake Malawi and some of the lakes further north have large cloud formations late afternoons?

I assume in the 1900's many studies were done on energy rather than Water supply, with a considerably lower world populations at that time and sufficient water per capita. Thus the building of the Cahora Basa dam and Lake Kariba for Hydro Electricity

Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.

By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme? In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.

A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!

Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)

My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?

Any ideas?

When Lake Powell water level subsequently dropped, the river carved new meanders through the resulting silt beds, but within the much larger meanders that form the canyon. (Satellite Imagery from Google Maps)

The San Juan doesn't flash flood anymore due to the flow regulation of the upstream Navajo Dam, so it hasn't been able to wash out the silt.

Apparently "meanders in meanders" is not a unique phenomenon as Anders Sandberg has also captured it here, but I don't know where he took this picture.

Question: Can "meanders in meanders" also form naturally? How does this happen? Also, if there is a more scientific name for this phenomenon, it would be helpful.

"在喜马拉雅地区，这些河流的流向是非常曲折的，但在平原上，它们表现出强烈的蜿蜒倾向，并频繁改变其流向。

这是我在课本上看到的关于喜马拉雅河流的情况。我确实理解为什么他们在平原(印度北部平原)蜿蜒而行，但我不明白平原上的蜿蜒与在更高的山区“曲折”有什么不同。在这种情况下，“tortuous”和“mewandering”到底有什么区别?< / p >

在西班牙的马略卡岛，有一条河叫做Torrent Son Bauló。从照片中可以看到，它的尽头就在海边，似乎被海滩挡住了。这是什么原因呢?< / p >

My guess is that the water is absorbed by the sand and flows into the sea through it, or that it doesn't have enough discharge and simply soaks into the ground and/or evaporates.

Also, are there any other rivers that behave similarly?

我一直想知道，瀑布下面的水有多深?我怀疑随着时间的推移，侵蚀甚至会侵蚀岩石。有没有一些视觉线索来估计水深?还是唯一安全的手动测试深度的方法?我一直在想，跳崖者或卡雅克人是如何确定自己的“安全”的。

浏览谷歌地图，我在爱尔兰西南海岸发现了这个

它看起来非常符合河流及其支流可能形成的形状，但它让我困惑，因为它都在水下!主要的，最“像河流”的是在图片的中左，但在底部有更多(看起来更像峡湾)。

是什么导致这个特征?< / p >

我13岁的孩子正在研究水循环，他向我提出了一些我没有答案的问题，关于海洋的盐度水平是如何保持恒定的(在很长一段时间内)

Q1:海洋中的盐度是如何保持恒定的?他的推理如下:

(1)当水蒸发时盐留在海洋中(2)淡水从岩石中运输盐

如果(2)添加更多的盐，并且(1)不去除盐，盐度不应该随着时间的推移而增加吗?(即使是很长一段时间)

Q2:是不是有一段(很长)时间没有盐可以“带走”了?从岩石和地面?< / p >

How is that supply renewed over time?

Is there some sort of a salts cycle that somehow takes away salts from the oceans and adds them back into the ground/rocks?

I was thinking aquatic organisms take salts into their body, we eat them, we die, our body goes back into the ground... But, to mean, that does sound really convincing. Also living things decomposition maybe?

已知流序是高度规则的:

Horton通过简单的几何关系表明，流序与流的数量、通道长度和排水面积有关;也就是说，流顺序在半对数纸上以直线的形式对这些变量进行绘制。< / p > < p >[…在美国的许多盆地样本中，分岔比率接近等于3.5。当然，这是有变化的。在Horton (1945, p. 290)引用的盆地实例中，分岔比的值范围为2到4。< / p >

Fluvial Geomorphology, p.137

The stream bifurcation ratio is so regular in any given drainage basin that it's actually remarkable to look at a graph - as in these Indian continent sub-basins.

The process Fluvial Geomorphology describes for the evolution of these basins involves the random weathering of locally-level surfaces by rain, melt, or less commonly other liquid weathering. Small rivulets form via random depressions in the surface of the earth, which then merge into larger streams of higher order. But this got me thinking...

If the emergence of initial rivulets is a random process, shouldn't that random process be biased towards wherever the drainage basin happens to be the most erodible? I'd only expect this kind of macro-level structure to necessarily emerge if the earth were homogeneous in the drainage basin, but in practice this doesn't seem to need to be required in order for a drainage basin following a regular bifurcation ratio to emerge.

My questions are related:

1. Are there any known criteria for which drainage basins do not evolve in a way that produces regular stream orders? (When) has this happened?
2. Is my assumption that this macro-level order should only emerge for homogeneous substrate incorrect?

This indeed seems to be the case with closer-up images from the Perseverance rover taken from the edge of the delta.

Intuitively, I would guess that a river flowing would dig a kind of trench in the ground where it flows, so the ancient river bed would be lower than its surroundings. So how did the delta end up higher than its surroundings?

My hypothesis is that sediments were deposited, and erosion wore off the rocks around the delta, but somehow, the sediments from the delta were harder and didn't wear off as fast. Is this indeed the case, or is some other mechanism at play?

我正在寻找一个列表，其中包含欧洲河流的河口或河口的大小。哪里有这样的名单吗?我已经找了一段时间，但只找到了涵盖河流长度或流量的列表

我正试图找出这些河流之间是否有某种地质上的联系，例如A、B和C是同一流域的一部分。或者可能是同样的“河谷”、“水系”;或者别的什么，但这些词似乎不符合我的搜索。“河谷”一词;似乎很接近，但我找不到人们在同一个语境中使用这个词，而且河流有100-200英里长，似乎一个山谷不可能那么大。这些河流流入“低洼”。很容易就有100英里宽。< / p >

Is there any common term and way a geologist will find a connection between several rivers sharing a specific area?

溪流是否需要一定的宽度或体积才能被归类为河流?如果是，它是什么?< / p >

海洋学的新学生在这里!

谢谢!< / p >

这个列表还在继续。由此并使用Thornthwaite方程，我计算了I和Ep(其中Ep =月潜在蒸发量(mm)， N =相对日长，T =月平均气温(摄氏度)，我=月炎热指数)(3一般。)< / p > < div class = " s-table-container " > <表类=“年代桌子”> < thead > < tr > < th >月< / th > < th >我< / th > < th > Ep < / th > < / tr > < / thead > < tbody > < tr > < td > 1 < / td > < td > 0.106 < / td > < td > 114.941 < / td > < / tr > < tr > < td > 2 < / td > < td > 0.148 < / td > < td > 123.972 < / td > < / tr > < tr > < td > 3 < / td > < td > 0.474 < / td > < td > 100.546 < / td > < / tr > < tr > < td > 4 < / td > < td > 0.932 < / td > < td > 94.192 < / td > < / tr > < / tbody > < /表> < / div > < p >的例子不胜枚举。由此，我需要计算河流流量/溪流流量，给出每月降雨- Ep。因此:(3一般。)< / p > < div class = " s-table-container " > <表类=“年代桌子”> < thead > < tr > < th >月< / th > < th > Riverflow < / th > < / tr > < / thead > < tbody > < tr > < td > 1 < / td > < td > 276.159 < / td > < / tr > < tr > < td > 2 < / td > < td > 39.128 < / td > < / tr > < tr > < td > 3 < / td > < td > 195.954 < / td > < / tr > < tr > < td > 4 < / td > < td > 63.508 < / td > < / tr > < / tbody > < /表> < / div > < p >的例子不胜枚举。然而，我被问到2个原因，为什么我预测的流量是不准确的。换句话说，为了更准确地预测河流流量，我还需要哪些额外的数据?< / p >

The same entry mentions about Val de Travers which it warns that despite of its name is a longitudinal valley. But I don't know why does it make this claim.

Because none of the articles do properly explain this with some sort of picture other than a photo I can't exactly tell at which difference is being talked about. Thus an arrow or some sort of marker or indicator over the photo or a diagram would be of much help for better identification.