What Happens When a Reservoir Goes Dry?

A severe drought seems like a good time to do extensive maintenance on exposed sections of the dam.

one point i think maybe this video could have hit a little harder was that reservoirs are sized based on the demand predicted by planners when the reservoir was built. However, the meteoric growth of a lot of areas of the southwest in the last 40-50 years was, to an extent, unforeseen. So not only do you have less water coming in than normal, you have more water going out than expected, exacerbating the problem.

Back in the day, plenty of people predicted this would eventually happen. It wasn't rocket science... moving millions to the desert was bound to be a disaster.

I did a motorcycle trip through the S/W in June '22. I saw reservoirs 40% down immediately after the spring melt. Farmers were irrigating during the heat of the day, because that is when they were scheduled to draw, using high volume, high position sprinklers that have much more evaporation rate than the more expensive low volume, low elevation sprinklers. Grass lawns were irrigated everywhere in a climate that is naturally semi-arid scrub land. There was new house construction near dry-as-a-bone Sacramento when the water supply is obviously failing. Much could be done in a very short time.

This is why the massive exodus to the deserts of the Southwest can't continue indefinitely. The Sinagua and Hohokam people abandoned many settlements throughout the Southwest long before Europans arrived, and I think unsustainable droughts were a major factor in what happened. They left a lot of canals that we still use today, so it's clear they were dealing with a water scarcity of their own. It seems we're still making the same mistakes today.

A couple of years ago Cape Town faced “Day Zero” when all the water supplying dams would run dry. It was a close run thing where emergency measures were enacted to allow citizens to fetch water from designated municipal/government sites. An extended period of water saving measures avoided having our taps run dry. It’s easier to survive without electricity (also a problem in SA) than without water! Fortunately rains since then have been good (enough).

In South Africa, due to poor city planning, our family has installed 4x5kl (20kl) tanks and now use rainwater exclusively. It’s impressive how much water can be collected in that way.

I appreciate your positive outlook on low reservoir levels, and that it isn’t always a bad thing. I was in a meeting with USBR back in June and learned that the concern they were looking at, at the time, was the water being below the intakes for the pumps to actually use the water. I don’t remember exactly but I think it was below the pump intakes the time, would have to look it up to be sure. They’re exact words were “we’re looking into it but don’t worry we’re not at the point of considering blasting the dam yet.” Hearing this conversation really brought the severity of Lake Mead’s level to prospective for me.

Gosh who’d have ever guessed tens of millions of thirsty humans moving into a desert could have had such problems🤦🏼

So the question of the video title was never quite answered--only many of the factors of a reservoir going dry were mentioned. But what does actually happen with the turbines and turbine-related generation systems? What happens to water distribution networks downstream? Do they tend to silt over as flow rates drop well below normal? Do the metal parts and pipes tend to oxidize at a greater rate when no longer submerged? What are the alternatives when the reservoir is massive with high levels of dependency in many communities and in agricultural production? And do we have any example of it happening anywhere near the scale of the subject reservoirs here?

I am a retired Science teacher. Your video sets an example for others here on YouTube to learn from... no lies, no exaggerations, no use of 'attention getting' techniques (read: 'BS'). Instead, you present good quality Science in a friendly, easy to follow and straightforward way. Wonderful!! 👍👍

Will you do another regarding the consequences of the reservoirs going dry? Best and thank you as always. These are great videos.

Surface reservoirs being depleted are only the start of the reservoir issues we are about to have to deal with. Underground reservoirs that make up 95% of liquid fresh water and the bulk of the water we use are being emptied at an unsustainable rate. They take a long time to recharge and once they empty can become permanently closed due to the soil compressing over them.

Can we just talk about how nice Grady is? Despite nearly every episode being sponsored, he keeps the mention to the minimum and pushes it to the back of the video, focusing on the content before all.

Thank you Destin! We love watching this channel Smarter Every Day! Thanks again!

This did help expand my understanding of reservoirs and drought. Here in L A. we are only allowed to water outdoors one day a week and it is quite a challenging shift in lifestyle and priorities

I wonder if this lack of water pressure pushing against the dam will cause structural problems? Just asking...

8:39 "you are unlikely to turn the tap and not have flowing water" All Latin America falls off the chair laughing

Not what I came to YouTube for...but your voice and the way you convey knowledge...you earned a sub off the first video of yours I found. That's happened maybe 3 times...can't wait to dive into this channel

It's always amazing to watch your videos. Every one of them are informative, beautiful, and somehow relaxing :D