11 December 2024

While writing about Lake Erie last month I found this amazing fact.

The Great Lakes hold nearly 20% of the world’s fresh surface water. And, more astonishingly, the lakes hold more than 90% of North America’s fresh surface water.

But this water supply is not unlimited. The Great Lakes are a one-time gift from the glaciers that melted in our region thousands of years ago. Less than 1 percent of the lakes’ water is renewed annually through rainfall and snowmelt. That means the Great Lakes can be depleted if we don’t keep Great Lakes water in the Great Lakes Basin.

— Alliance For The Great Lakes: The Great Lakes Compact

The Great Lakes watershed map shows how little of the surrounding land drains into lakes. This is especially true of northern Pennsylvania and Chautauqua County, NY.

As climate change puts enormous strains on fresh water resources, multinational companies look longingly at bottling our rivers and lakes. Fortunately the Great Lakes basin had an early wake up call.

In 1998, an obscure Canadian consulting company, the Nova Group, announced its intention to ship 158 million gallons of Lake Superior water to Asia. Though that specific plan seemed unlikely to materialize, it raised alarms about the vulnerability of the Great Lakes in an increasingly hot and thirsty world.

— Alliance For The Great Lakes: The Great Lakes Compact

And so the Great Lakes Compact was born. Signed into law in 2008, it prohibits diversion of water outside the Great Lakes basin with very limited exceptions.

This one-time gift of the Ice Age glaciers won’t be frittered away.

p.s. Prior to 1945 humans diverted Great Lakes water in four locations but these have barely made a dent in the total watershed.

• Ogoki pulls water from Hudson Bay watershed into Lake Superior. 1943.
• Long Lac pulls water from Hudson Bay watershed into Lake Superior. 1939.
• The Chicago River is diverted away from Lake Michigan and into the Mississippi watershed. Beginning in the 1800s.
• Welland Canal is a navigation channel from Lake Erie to Lake Ontario that bypasses Niagara Falls. Beginning in 1824.

The combined effects of the Long Lac, Ogoki and Chicago diversions and the Welland Canal have been to permanently raise Lake Superior by an average of 2.1 centimeters (0.8 inches), lower Lakes Michigan-Huron by 0.6 cm (0.2 in), lower Lake Erie by 10 cm (4 in) and raise Lake Ontario by 2.4 cm (1 in), according to the IJC’s 1985 Great Lakes Diversions and Consumptive Uses report. 

— international Joint Commission: An Overview of Great Lakes Diversions

2nd p.s. The Colorado River Basin is an extreme example of what happens when water is diverted. See Disappearing Into This Air.

11 November 2024

In late October all of Pennsylvania went into a Drought Watch. We are not alone.

Every US state except Alaska and Kentucky is facing drought, an unprecedented number.

More than 150 million people and 318 million acres of crops are affected by drought after a summer of record heat.

— Guardian: Nearly all of US states are facing droughts, an unprecedented number

As of 5 November the drought is Severe to Extreme in Southeastern Ohio, West Virginia, western Maryland and the southwestern corner of Pennsylvania.

The amazing thing is that it took only four months to get that way.

In April the Monongahela River flooded the Duck Hollow parking lot — twice — when we had two downpour days of more than 2.6 inches each.

Then it stopped raining in June and the weather turned exceptionally hot. A drought began in July that became Severe that month in West Virginia and western Maryland.

By late August the boating season was over at Youghiogheny River Lake due to low water. On 1 November when Judy Stark took these pictures, the lake had dropped so far that an old bridge and the foundations of a submerged town were revealed above low water.

In just four months the Monongahela River switched from flood to drought. Since it flows from West Virginia to Pittsburgh, it’s useful to look at precipitation in Morgantown, WV to understand these extremes.

The graph below shows Morgantown’s 2024 monthly precipitation through yesterday, 10 November. Normal precipitation is in green, Actual is in blue. Notice it was at or above normal until July and severely below normal in September and October. (“Normal” precipitation in August came in two downpours that ran off rather than soaking in.)

Yesterday it rained in the Monongahela watershed for the first time in weeks, a long soaking rain that lasted all day. In Morgantown it accumulated just over an inch (1.02″) and was enough to match their month-to-date “normal” for November.

We’re so thankful for yesterday’s soaking rain but we’ll need more than one day to end the drought.

Fingers crossed. Thursday looks good for rain.

p.s. Yes, Sunday’s rain was not enough. This evening KDKA TV News showed footage of brush fires over the weekend, including one that was burning while it was raining.

The NWS meteorologist in this video, Colton Milcharek, says that it will take a rainy day like yesterday every week for 5 weeks for us to get out of this long term drought without mishaps.