A shrinking river.
Putting together a slide deck for a talk next week, borrowing Brad Udall’s trick of a horizontal line for visualizing the mean during different time periods.
The Colorado River Problem, In Brief
Putting together a slide deck for a talk next week, borrowing Brad Udall’s trick of a horizontal line for visualizing the mean during different time periods.
1950 through 1970 loo like it might even be lower. Just proves the vicissitudes of flow. Just pick your proof of any position you want to justify.
Funny that you show this ‘trick’ at this time. I’ve seen the same method used in the immigration statistics for different political administrations to show cause and effect of policy.
In the case of the river’s flows, this method could be considered as cherry picking to prove one’s point. There’s bias in this. Just my two cents here…
1950 – 1970 was 13.1 maf.
To be more informative you should do another version with 20 year means in the 30-40’s and 50’s-60’s so you see the droughts then. Also do 1900-1920ish and 80’s-90’s which were very wet decades that pulled up the 20th century mean.
Your graph is oversimplifying a complex system
Dave – No ‘trick’. Just data.
Here’s the point of this graph. We built a legal structure presuming we had 17-18 maf. (The graph will probably get a 1906-1928 – Boulder Canyon Project Act line before I’m done.) We built infrastructure, and communities depending on it, based on a 15maf river. We finished building out that infrastructure in the late 1990s. That’s the basis for the time period selection.
For the last quarter century, we’ve had a 12.5maf river, and we emptied the reservoirs. We ignored E.C. LaRue’s warning about the dry periods in the 19th century, had no plan for a long sustained dry period, and now we’re in a bit of a mess. That’s what Ima talk about next week.
Okay John…I get your point. I’d like to add some points as well to the argument if that’s okay with you?
Data Collection: My general statement here is that there are no absolutes in figuring out exactly how much water flowed during any given year. Why do I say this? The key word is ‘absolute’. We can only make close assumptions of what flowed based on the instruments and the number of readings over time. In the case of the USGS station at Lee’s Ferry, I’d get the history of the instruments used over the timeframe and the number of times per day that the measurements were made. Prior to 1920 there were very few strip chart recorders used. Some sites were read twice a day and the results were written down. I recall that this was done at Yuma at the Union Pacific Railway bridge and was done by the railway agent. The accounting on this amounts to less than 800 measurements per year. That data figured into the big picture. Like I said, it would be interesting to see the history of how Lee’s Ferry was operated over time. I would also look at the discharge at Glen Canyon Dam for comparison after the 1990 timeframe. That’s the type of data that you need to see a more accurate accounting.
Something else about Data Collection. The standing rule is that it is being done with the best equipment obtainable at the time and done using the best techniques known at the time. Case in point, the data of yesteryear is not as accurate as what is being collected by today’s technology. There is more precision, better accuracy in the product but it still isn’t perfect or absolute.
One other factor for the drop in the average flows from the river might be attributed to better methods and the instrumentation over the last few decades. I got introduced into Data Collection on the Colorado River in 1992 as a side project (not my main tasking). I can tell you firsthand about the strides that we made in the product due to the integrity of the equipment we used. The same is true about knowing about the amount of water that entering the system. The point I want to get across is I honestly think the numbers went down because we became better at recording a better picture of the situation.
Another point that you brushed on was ‘we could have managed the reservoirs’ better. I wholeheartedly agree. The trade off here is that when the bottom line goal is to regulate the flows for optimal capacity in the reservoirs, keeping in mind that nobody can predict the weather no more than ten days in advance. Remember 1983? We almost lost the Glen Canyon Dam due to the levels in Lake Powell. Now put yourself in the shoes the Water Operations Manager for Powell or Mead. You tend to be conservative rather than taking a chance. You have to consider that in the overall equation.
I have to agree with some aspects of mismanagement in regard to releasing more water from the system. I remember one year of non stellar flows in the river yet there was a ‘surplus’ declared. I attribute that to politics and wanting to please the stakeholders.
My last point about mismanagement is about distribution. Once that precious water is released to the States, Tribes or Mexico in distribution, the usage is determined by the stakeholders. I often look at the disconnect between the States and their local municipalities on land development and water usage. It’s an ugly situation as the demand is greater than a reliable supply.
Anyway, the decisions made was far above my pay grade. If anything is to blame, it’s politics and money.