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So my friend's elderly mom, early 90s. . .
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Posted 3/29/2021 14:38 (#8923149 - in reply to #8916844)
Subject: RE: So my friend's elderly mom, early 90s. . .

Saginaw Bay Area - Michigan
sand85 - 3/26/2021 10:24
If you have some specific knowledge from a technical field, we could discuss it.  For example, we have way more rainfall gage data with much starker trend differences than we do temp data.  Millions of data points.  In general, it rains 20% more and 20% more intensely in Illinois than it did 50 years ago.  There are statistical atlases (atlai?).  This is due to some sort of shift. Reasonably accurate and backtested models (unlike a bunch of the IPCC wildest case scenarios) project that this will continue. Efforts to explain the shift include discussion of CO2 concentration, greenhouse gas effect, and global warning and larger climate change trends.  

Interesting points on your regional data. How accurate/detailed do you feel the data available for your area is for >50 years? Is there enough to describe a trend? If the trend was the other direction (20% less rain?) would you advise for less drainage tile in the "100+ year investment"? In my area, the notion of "less tile" is absurd; it's always been as much as the technology and pocket book could afford and to throw more at it later in life if feasible and reasonable.

One of my fields is very near a great lake. The field was initially tiled in the early 60s (and expanded upon a couple times). Two of those outlets from the original tile have been significantly below the water line (level of the great lake) for about 5 years. That height peaked 2 years ago though too soon to declare a trend, so maybe "peaked" is a bit optimistic.

Aerial photos of the shoreline show the lake was down (water was much further off shore) in the 50s & 60s and then up/down through the years for the photos we have. More of a cycle. So we know the water level was substantially lower 60 years ago from visuals and from actions (tile placement). 30 years ago the water was high, we could launch our boat at the tree line; 40 it was low as we had to carry our boat fifty feet from the tree line to launch. Just personal anecdotes that correspond to the scientific data.

We have, as far as I understand, a relatively good data set on lake height back to ~1918 here:
Which corresponds to what we've witnessed. There are periods of time (2-3 decades) with higher and lower water levels.

Other studies show that our lake level is on ~100 year cycles with 20-30 year "mini-cycles". Which also corresponds except I don't know where on the 100 year cycle we are.

Based on that, we should be into a ~20 year higher water line period that the graph indicates we started about 5 years ago. We opted to spend $ on a lift pump based on our experience and the data on hand.

None of that is what I would consider anthropogenic climate change, since there are demonstrable fluctuations/cycles prior to human industrial scale. If we are talking climate change over the course of a 20-30 year span, then yes, there is a variance or change that happens regarding longer term (~30 year) weather patterns since those weather patterns drive our lake levels here and are documented.

Focusing back on your 20% statements. Those things would have me spend more effort into surface management, specifically surface water flow and erosion mitigation. In no way am I suggesting your increased sub-surface drainage is wrong (I've never seen "too much" subsurface drainage, though I'm sure there is such a thing). I'm curious on your take.

PS - my apologies to the OP for getting so far off topic.
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