March 2024 Lake Levels and Flow

 I was not going to do these monthly summaries any longer, but with March's rare "double-dip" draw down low, I thought it was worth showing. The second, low at the end of the month was only 2.28 inches above the lowest level set on March 5th. 653.92 and 654.11 respectively, with April starting even lower by about an inch.

The Decade That Was (2010-2019) - Enter Climate Change

A new decade is upon us so it's time to take a look a the decade that was in terms of data. Getting right to it, below is the candlestick summary chart for lake levels and flow for the period of 2010-2019. If you're not familiar with this style of chart you can click here for a full explanation.

Lake Levels and Flow Rates for 2010-2019

The graph (click to enlarge) is a construct of 10 years of hourly data consisting of 87,600 data points. While I wouldn't dignify that much data as Big Data, it is a significant enough number that certain trends might be statistically significant.

So what can 87,600 data points tell us about the Lake of the Ozarks? Obviously it can show what has happened over the past ten years, but more interesting is that it may also indicate what will happen in the future. I'm not talking about predicting daily lake levels, or flow rates, but rather trends. One trend that stands out, almost visually, is the gradual increase in total flow over the years. If you compare the actual data for total yearly flow from 2010-2014 to the period of 2015-2019, you'll see that 10.652 trillion gallons passed through Bagnell Dam in the first half of the decade and 16.107 trillion gallons in the second half. That's an increase of 66% which is rather significant. You can easily see this trend by the graph alone comparing the left half orange bar heights to the right half. The latter half of the decade also contains the highest monthly flow rates and two record flooding events in July and December of 2015.

If that's not obvious from the first graph, let's look at a comparison of the first five years of the decade and the last from an average daily flow point of view. Below is a two-line graph, the green representing 2010-14, and the red 2015-19. From this graph it's even easier to see the difference in the latter half of the decade. With the exception of early spring, which in of itself may be statistically relevant, the period from 2015-2019 consistently shows a higher average flow rate. Even more interesting is that flow rates remain high throughout the summer months, rather than tapering off after spring. This means, more water, flowing all the time.



Climate change is not just about a hotter earth but the impact it has on the water cycle which has far reaching effects. The Lake of the Ozarks is very much a part of that water cycle and Bagnell Dam's ability to manage the changes in the water cycle is critical to the future of the Lake of the Ozarks. We'll be exploring this subject in greater detail in coming posts.

2019 Full Year Lake Level and Flow Rates Review

The amount of water that has flowed through Bagnell Dam this year is truly astonishing. Here's the big picture.



Nearly 3 times the "normal" flow for one year due to flooding. While the Lake of the Ozarks suffered no direct effects of the surrounding waters, over 37% of operational time was spent in maximum turbine flow conditions. How much of that interpolated into power generation, only Ameren knows, but it was there for the taking.

Here's how December itself looked on the daily candlestick graph.



And the hourly detail.


And finally we can now see the daily candlestick graph for the entire year. (click any image to enlarge)



And the monthly summary version

January 2019 Lake Levels and Flow Rates

Lake levels, lake levels. Is that all this blog is about?

What can I say, I have a life. Rest assured, there's plenty more to talk about and we'll be getting to it this year. But for now...

January is the official start to the lake draw down. When Ameren allows lake levels to fall below "normal" in order to accommodate shoreline work, and prepare for the coming spring rains. Spring is coming. My black tail hawks are working on their nest, and the groundhogs have started sniffing around for a place to start a new tunnel under my house, so I know it's coming.

The lake has already started it's inexorable fall to the March low. Below is the hourly detail with the grey line being the new moving five year average.

And below the daily candlestick

All in all, nothing remarkable and a nice steady incremental start to the draw down.

2018 Annual Lake Levels and Flow Review

Another year has come and gone, and with the annual draw down to prepare the lake for 2019 only days away, let's take a look at what happened in 2018.

Here's a quick summary graph that I made to try and put things in perspective. The lake is still just a flooded river and water flows in and out constantly. Putting up raw numbers like nearly one and a half trillion gallons of water passing through Bagnell Dam sounds impressive but what can we do to give it real meaning?  I've provided some conversions to help get a grasp of just how much water that is. Also, the circle in the middle with percentages indicates Bagnell Dam's operational statistics, how much of the time electricity actually was being generated. The answer is only about 25% of the time.

Operations in flood conditions were negligible, and I doubt the gates were actually open at all, I simply calculate that the maximum flow through the turbines is anything over 37,500cfs (cubic feet per second), but improvements to the turbines may have increased that number. I'll have to revisit that.  The more telling number is the 75.8% operational time below 5000cfs, an indication no commercial electrical power is being generated beyond the "house" generators used to power the Osage Energy Plant itself. This is a very low amount of power generation, and may be due to the extensive work being done this year on Bagnell. In short, Bagnell Dam was probably operating at a loss this year.

As far a lake levels themselves are concerned, this year is probably the most unremarkable we've had since 2012. Levels were right along the guide curve with no surprises.  Below is the candlestick summary for each month of the year.

Below is the daily candlestick for the entire year.

And finally, a candlestick summary of every month from 2010 to 2018.

8 Year Monthly Lake Level Summary

Here's a fun chart. This is a candlestick chart of each month for 8 years (2010-2017).

Click on image to enlarge
or click here for a full size downloadable image

A couple of interesting statistics. The eight year high level and low level occurred only three months apart of each other and the difference was nearly 11 feet! That's quite dramatic for a body of water that most people's experience is less than a foot difference during the summer months.  December 28, 2015's high of 663.83 was followed on March 9th, 2016 with a low of 652.92.

As for how much water passed through the gates of Bagnell Dam in those 8 years? About 19,725 BILLION gallons, or technically 19.725 Trillion gallons. That sounds like a lot of water, and it is, but comparatively speaking it's not as much as you might think. By the numbers, it took eight years for enough water to pass through Bagnell Dam to cover an area the size of Missouri to a depth of only about one and half feet (1.36 to be precise), but it was enough that it could raise the level of Lake Michigan four feet. To really put it in perspective? Water flowing over the Canadian Horseshoe falls of Niagara could pass that same amount of water in one year and fifteen days. But it's a tremendous amount of water no matter how you look at it.

New Lake Level Graphing

Data visualization is a hot topic in my industry, and one I personally enjoy despite not being very good at it.  One of the things I've been wanting to do for sometime is to add what are called "candlestick" graphs to the monthly lake level reports. I've done this type of charting before, in February 2014, when Ameren basically sent a small tsunami down the Osage river from a rapid discharge from the lake. I liked the chart, but it was bit labor intensive. I think I've figured out an easy way to produce it on a monthly basis now. For those familiar with stock market analysis, candlestick charts are the preferred graph for looking at stock prices over time. They tend to weed out the "noise" of daily trade prices and focus on the more important trends.

Using candlestick charts on lake levels will allow us to focus more on starting and ending levels and diminish the relevancy of the day to day highs and lows, while visually emphasizing large swings. For those who are not familiar with candlestick charts, or how to read them, they are quite simple but I've written a guide here, as it relates to tracking lake levels.

So here's the first, going back to July's data. (I even dolled it up with a nice background!)

As you can see, there's only 31 data points now, one for each day, rather than 746, one for each hour of the month, while basically providing the same information detail.

I'll try to add other elements to the graph such as the 5 year moving average and flow rate as time allows, but for now, I think this will be a great addition to the monthly lake level post. Hope you like it!

June 2018 Lake Levels and Flow Rates

Late on the post for June levels, but it's summer after all. Lake levels are where they should be and behaving predictably. Nothing notable to see and that's a good thing. Keep in mind the narrow range of data makes for an exaggerated graph scale. In reality, the difference all month long in lake levels is little more than 1 foot.

May 2018 Lake Levels and Flow Rates

It's summertime so there's rarely anything interesting for the charts. A minor exception this year is that we started the month well below the expected average but managed to get levels normalized by Memorial weekend to kick things off.

Lake Levels Stay Near Year Lows Despite the Rains

As I look out on the lake every morning I'm still a little surprised as to how low the level remains for for this time of year.  By my record keeping, the five year moving average lake level for this date (indicated in orange in the chart), March 28th is 655.36 feet, more than a foot higher than it is today.  So what gives?

Obviously the threat of flooding is on Ameren's mind and from the chart below, which is an incomplete graph for this month, they are adjusting flow (in green) through the dam in direct response to rising lake levels. It's a clear attempt to keep lake levels where they are in what appears to be a purely reactionary response to the rains as they come. Ongoing repairs to the dam may be the prime mover here since there's really no other reason to keep levels this low now.

Lake Draw Down 2018 - Are We There Yet? Final Update

March 15th -. I could easily be jumping the gun here, but I'm going  to go out on a limb and say we hit the draw down peak yesterday around 9am with a low of 654.30.  With discharge flow dropping below 4,000cfs it appears Ameren is content to let whatever rain occurs in the next 72 hours to accumulate and mild temperatures means there's no real demand for power generation. With all that in mind, and given we are nearly two weeks past the average peak low date, I'm pretty confident lake levels will begin the slow and steady rise toward spring numbers.

Below is the 9 year chart of lake levels for the period January-April. Yes, I know It's only March 15th and things could change, but I was kind of anxious to get this post done. No, that's no glitch in the data on the far right. The lake rose over four feet in about 36 hours last year.

Update = I've got a jump on the chart for March here

The chart, with nine years of data it's getting difficult to keep neat. Here's how to read it. The current levels for this year are in red, while the nine year average is in bold green.  The previous years are in various shades of grey starting with black for last year fading with each successive year further back in time.

March 22nd update below - yep, I called it. Lake levels are rising from the low of 654.3 on 3/14.

March 27th update below - Nope. I didn't call it.  Lake levels have dropped since the last update to it's lowest level of the year, 653.91 at 8am this morning. It's come up slightly since then but I won't venture to think we've hit the low.  I swear, sometimes I think Ameren reads this blog and adjusts levels just to prove me wrong.  ;-) As you can see, we're just about to match the latest date for reaching low level in the past 9 years which happened March 31st, 2011.

Final Update: Given the low levels late in the year for 2018 I decided just to wait until May 1st before a final update. The maximum drawdown level for 2018 came on March 27th at 653.91. A very typical peak low level.  Nine year data average for date and level is now March 11th, at an average level of 654.82.

Below is a simple graph of just 9 year hourly levels average. (= Green graph above)

February 2018 Lake Levels and Flow Rates

Ameren announced in early February that the low level draw down would probably occur on February 19th.  Looking at the chart above would seem to confirm they hit their target at just under 655', but I wouldn't count on the draw down being over  just yet. As you can see the recent rains elevated the lake by nearly a foot and half and power generation (green spikes) has already begun bringing levels back down. Typically early March (see the orange 5 year average line) is when the lowest levels are reached and the spring rains haven't begun in earnest so it is possible they will draw the lake back down toward the 655' mark.

September 2017 Lake Levels and Discharge Flow

A somewhat atypical September, as indicated by deviation from the five year average, but nothing too radical.  Generation was moderate.

July 2017 Lake Levels and Flow Rates

A very typical July chart with start and ending levels almost exactly at the 5 year average with power generation coinciding nicely with temperature demands for energy.  I'm sure this helped keep levels at full pool despite the modest lack of rain. Boring, but I like boring when it comes to this data. It means things are predictable and orderly.

One more month of peak summer to go.  Enjoy!

Memorial Weekend 2017 Finds the Lake Still in Cleanup Mode

Since the Summer of 2017 begins in earnest this weekend, I thought we might take a look at lake conditions beforehand and get a little early jump on this month's chart.

Believe it or not, lake level and flow rates are still under the influence of the torrential rains at the end of April.  Let's take a look at Truman Lake first to see why we are still where we are with flow rates.

Ten Year Graph of Truman Lake Levels

Truman Lake is controlled by the Corps of Engineers while Lake of the Ozarks is not, but there is a Memorandum of Agreement which says Ameren must coordinate operations with the CoE, especially during flood events.  As we can see above Truman Lake reached its highest level in the last 10 years at the end of April, while Lake of the Ozarks barely exceeded 661ft, and only briefly at that. Between the two lakes, Truman did its job protecting the Lake of the Ozarks from a *major* flood event that would have surpassed 2015s (both of them). But with the rains subsiding this month, Ameren has kept flow rates through Bagnell Dam well above average in an attempt to lower Truman Lake.  It's a very slow process and will likely continue through the first holiday weekend.  With that in mind, let's take a look at May's levels and flow rates.

May of course started with the lake at it highest levels for the year, and likely the highest for the entire year.  Discharge from Bagnell Dam remains above full turbine flow which means flood gates are still partially open sustaining nearly 50,000cfs.  For Memorial weekend, lake levels are just slightly below the 5 year average, but doable for those of us in shallow waters. As for all that water that's passed through Bagnell Dam? We'll examine just how much water in the regular end of the month report when the final data comes in.

For now just be advised that the lake is (relatively) murky and full of debris coming down from Truman.  Running your boat will be a little more risky this weekend as debris is everywhere.  As for night running, I will definitely be adopting a cocktail cruise speed.  On plane even at legal speed will be very risky to your outdrives.

Be safe. Have fun.

April 2017 Lake Levels and Flow Rates - over 4ft in 24 hours!

I try not to be critical of Ameren when it comes to their stewardship of the lake or how they treat lake home owners, after all they are an energy company whose only real interest in the Lake of the Ozarks is how much power they can generate and sell while fulfilling their regulatory compliance requirement for having a percentage of that energy produced by "renewable" energy sources.

But when Ameren manages the lake without any apparent consideration for ecology or property? It pisses me off.

Is that a harsh criticism? Does a lake level one foot above full pool really cause issues?  In a word, no. A lake level of 661 is not a "flooding" event at the Lake.  What is an event is rapid change. Take a look at the level and flow chart for April.  See anything striking? It's not the 661 lake level itself, but how fast it got there that is the problem.

The forecast for potential flooding rains was anticipated early in the last week of April and Ameren, as to be expected, began ramping up turbine flow on Wednesday April 26th, with full flow by Friday the 28th. But as the rains fell Ameren surely watched as lake levels began to rise at an alarming rate. This rate of change continued for nearly a day with full turbine flow (35Kcfs) having little impact on lake levels. At it's most dramatic, the lake rose one foot in just four hours on Saturday.

Ameren saw this rapid rise but did nothing until Sunday, April 30th at 6:00am. With the lake at 660.51 the flood gates were finally opened. Let's be clear here. It wasn't until the lake's level punched through 660ft (full pool) that flood gates were opened Sunday morning. This means that in just under 24 hours the Lake of the Ozarks was allowed to rise over 4 feet!

Note: My statement above, that flood gates were not opened until the lake reached 660.51 feet, is (indirectly) disputed by Warren Witt, the Director of Hydro Operations at Bagnell Dam who was quoted as saying they were opened when the lake reached 659.5 feet in a later interview with  Lake Expo. But I'm going off Ameren's own data so you be the judge (zoom in on the above chart). From the above chart the flow rate was still about 35,000cfs when the lake was at 659.5. But Witt should know of course when the gates were opened, and it is certainly reasonable that there is a delay from the time flood gates open until the change in flow rates registers with Ameren's own sensors. Flow rates measured independently by USGS seem to back up his statement that the gates were opened at 6am, so I'll have to give the benefit of the doubt here.

I'd have to check my own records, but I'm pretty sure the floods of 2015, both of them, didn't rise so quickly.  This rate of change is highly disruptive to the ecosystem and damaging to the very shoreline that Ameren makes us lake home owners all bend over backwards to protect.

I would not argue that there was anything that could have been done to prevent reaching the 661ft level given the pressures from Truman Lake and the Osage River, but I believe an earlier opening of the flood gates would have made the rate of change a little more bearable.  Management Grade? D

March 2017 Lake Levels and Flow Rates

Lake levels began rising on March 9th towards full pool by Memorial Weekend. March levels started low and remain about a half a foot under the five year moving average (in orange). Very modest power generation and days of rain should help bring the lake to normal conditions without difficulty. Summer is coming!

February 2017 Lake Levels and Flow Rates

A model February operational chart (see how closely it follows the 5 year moving average - in orange).  There's no guarantee lake levels won't dip lower over the next few weeks, but it appears we reached a winter drawdown low of 653.92ft on February 26th, about 10 days sooner than the average but just a couple of days sooner than my February 28th prediction. Not bad!

Flow rates were quite average as well and the lake should start rising slowly from current levels to about 656 by the end of March. If you're going to get any work done on the shoreline, time's awasting.

January 2017 Lake Levels and Flow Rates

At the beginning of the year it looked as if Ameren was going to get a jump start on the annual drawdown of the lake, but little precipitation and low energy production allowed lake levels to creep back up toward the moving average. It's interesting that energy production, as indicated by flow over 3,750cfs, ramped up just as lake levels reached the moving average of about 657.5ft.

Expect lake levels to continue to drop in February as the drawdown continues. Data indicates the low lake level for the year will be 654ft on February 28th. Let's see how close I get!

2016 Bagnell Dam Operations Summary