Endorheic, but not "terminal" lakes
And their important flies they support.
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Terminal lakes dot the Great Basin and arid landscapes around the world.
They are called terminal because the rivers that flow into them end — or terminate — at the lakes. That is, they do not drain to the sea. Scientists describe these watersheds as “endorheic basins,” hydrologically landlocked areas where water flows within (endo).
Over the past century, many endorheic lakes have shrunk as a result of diversions for cities and farms, in addition to a changing climate. Places like Owens Lake. Walker Lake. Mono Lake. The Great Salt Lake. Not only in the Western U.S., but globally.
These lakes are accurately described as terminal in that they form the hydrological endpoint for the rivers that flow toward them. But they should not be thought of as terminal in its other definition of the word. As they have shrunk — and some have effectively dried up in recent decades — it might feel accurate to think of them as “terminal” in another way. That they are incurable or dying lakes. But they are not.
These landscapes, it turns out, can be resilient. What it requires is a little water.
Earlier this year, I reported out a story for Vox about brine flies, which published last month for subscribers (and should go in front of the paywall soon). These flies in the Ephydridae family are evolved to live at inland salt lakes, and they form an ecological backbone for bird migrations, which depend in part on their presence and abundance.
They are small and mighty. But when lakes have dried up, they have disappeared.
This was the case in Lake Abert, which has dried up several times in recent years. It was the case at Owens Lake, where inflows were infamously diverted to quench the thirst of a growing L.A. at the start of the 20th Century. Yet even dried up, the lakes are neither terminal nor dead. When water returns, flies and birds can return too.
When I was reporting the Vox story, I interviewed David Herbst, a researcher who has studied the interactions of brine flies for several decades. When lakes are dry, the flies can survive in groundwater-fed seeps and springs nearby. If and when water returns to dry lakes, the flies often come back too. And with the flies, migratory birds return.
It has even happened at Owens Lake (often viewed as a “dead lake”), as Herbst wrote in a paper for the magazine of the North American Lake Management Society. When I interviewed him, such resilience was one of his main points: “These places can really recover — and recover quickly,” he said. “So we really should not be writing them off.”
In other words, they might be terminal and endorheic, but they are not terminal.
Recovery takes water, and it takes looking at these lakes in a different light. They form critical habitats and are sources of water in otherwise arid areas. Still, people have not always viewed their inhabitants with the recognition they deserve — which has come at a cost to wildlife, the environment and the communities that depend on these lakes.
In the 1970s, Utah recreation officials sprayed the shores of the Great Salt Lake with chemicals — a mixture of malathion and diesel oil — to get rid of brine flies. This was an anecdote I first heard from Herbst, and later confirmed with newspaper archives.
Here’s a clip from the Ogden Standard-Examiner on August 16, 1970 below:
Those days appear to be over. And what was once considered to be an invasion of brine flies is actually the sign of a healthy lake. More on all this in the Vox story.
Here’s what else I’m reading and watching this week:
California’s farming heartland goes solar (E&E News)
Lahontan cutthroat trout spawning in Lake Tahoe tributary (Nevada Independent)
‘Immediate threat’: Mussel invades California’s Delta (CalMatters)
California and the Biden administration preparing new water plans (L.A. Times)
California has its own ‘hurricanes’ and is vulnerable to flooding (PPIC)
A completely useless dam in Malibu is finally coming down (SFGATE)
That’s all for now. Except for one thing…
Exercise your democratic right, and make a plan to vote!
Until next time,
Daniel