(CNN) -- Well before Hurricane Isaac hit Louisiana and brought localized heavy flooding, the weather story of the summer was not about an abundance of water -- it was the lack thereof.
And it still is.
Farmers and residents in 40 states know this all too well, as this summer's blend of low rainfall and extreme heat has created a crisis for many. Over a recent six-week stretch, the U.S. Department of Agriculture designated 1,692 counties as disaster areas due to the drought. The department notes about 80% of agricultural land in the country is affected, making this year's drought more far-reaching than any since the 1950s.
The impact has been felt by farmers and ranchers nationwide, but they're hardly alone. Outdoor activities, commercial transportation and wildlife have been impacted by the drought, in myriad ways.
Central Illinois: Dozens of dead deer found along rivers and at watering holes
In a three-mile stretch of the Kaskaskia River -- a tributary of the Mississippi River about 80 miles southeast of Springfield, Illinois -- a group of people found 26 dead deer, according to local resident Karen Forcum, who reported these findings to the Community Collaborative Rain, Hail and Snow Network.
Many of the deer were tested by animal control officers and found to have a hemorrhagic fever -- likely brought on by disease-carrying gnats that thrive in drought conditions, Forcum said. They ended up dying at water sources, she added, in their attempts to cool their fevers, albeit to no avail. Similar deer deaths have been reported in Nebraska near the Lower Platte River, around a lake in Delaware, and elsewhere.
Other animals have also been affected by drought in the rural area known for its forests and farmland, with many fish kills, turtles and other animals reported dead. One of the few species to thrive are turkey vultures, feasting on the carcasses that suddenly abound.
"I think it's all in the hands of nature," said Forcum.
Lower Platte River in Nebraska: Riverbed now looks like a 'sand volleyball court'
It's not uncommon for the Lower Platte River to dip during the summer, as the hot weather expedites evaporation and irrigation waters flow to nearby farms. Even so, summer is supposed to be fun time in this swath of Nebraska, as people take to canoes and kayaks to enjoy the refreshing waters and great outdoors.
Not this year.
Parts of the Lower Platte look more like a sand volleyball court than a river, according to Meghan Sittler, the Lincoln-based coordinator of the Lower Platte River Corridor Alliance. That's due to a combination of intense heat and a dire shortage of rain.
The water was moving in other parts of the river, but just barely -- at a rate of about 250 cubic feet per second, compared to the norm of 600 cubic feet per second, in late August. Sittler said it's not unusual for water temperatures to be in the 92-to-97-degree range.
All these factors have contributed to the deaths of "a huge number of fish," among them endangered pallid surgeon, said Sittler.
"This is very, very rare occurrence," Sittler said of conditions over the 103-mile swath of river her organization oversees.
Oklahoma and beyond: Produce running out months early at farmer's markets
More and more farmers markets have been popping up all over the United States in recent years, a testament to people's desire to buy fresh, locally produced food. That's been true in Oklahoma, where Nathan Kirby of the state's Department of Agriculture says there are over 70 farmer's markets, many of them proudly touting the fact that items for sale are "100% Oklahoma grown."
However, the last few years have been a struggle for vendors at these markets -- not because customers haven't been interested and showing up, but because Mother Nature has.
Last summer, the combination of high heat and lack of precipitation led many Oklahoma farmers markets to shut down mid-summer because of a lack of vendors. It's not quite as bad this year, though Kirby (who coordinates with the markets from his state-funded position) says many of them had hardly any produce left to sell by August.
In a normal year, the markets should be stocked with produce through October. But 2011 and 2012 have been anything but normal for many Oklahoma farmers.
"They are running out right now," Kirby said. "The heat has definitely taken a toll."
Western Indiana: Hundreds of dead fish and an alarming absence of birds
White pelicans, herons, egrets and even a number of bald eagles had been frequent summer visitors to lakes, rivers and wetlands in western Indiana.
"But you don't see any of those birds there now," said Michael Gerringer of Terre Haute.
The reasons are obvious: Waters are creeping down to alarming levels, with some lakes and ponds drying up altogether according to Gerringer, a CNN iReporter, nature buff and graduate student in wildlife biology at Indiana State University.
By the end of July, 70% of Indiana was experiencing "extreme to exceptional drought conditions," according to the National Weather Service. A relatively wet August (Indianapolis' airport, for instance, got its most rain in 23 years this month after getting the least ever measured between April 1 to July 31) has helped some, though temperatures have been scorching throughout the state all summer. And even with recent rains, much of western Indiana especially remains very much in dire straits.
That much has been especially evident in the Wabashiki Fish and Wildlife Area, near the Wabash River just west of Terre Haute. Besides the absent birds, Gerringer said hundreds of dead fish amassed earlier this summer at what once was a lake bottom -- some of them invasive Asian carp and also others from species that have been native to the area for centuries.
Along the Lower Mississippi River: ''The mighty Mississippi has been a weakling lately'
Last summer, the headlines about the Mississippi River related to floods and attempts to mitigate the impact of the potent, iconic river as it carried dangerously excessive amounts of water.
But this summer -- at least until Hurricane Isaac hit -- the big problem with the Mississippi was too little water, not too much of it.
A swath of the river near Greenville, Mississippi, began closing "intermittently" after August 12 when a vessel ran aground, said New Orleans-based Coast Guard spokesman Ryan Tippets. The Army Corps of Engineers has been dredging in the area to deepen the channel and help navigation.
Typically, 50 vessels run past this point on a given day. But that traffic came to a halt around August 20, when the Coast Guard shut down an 11-mile stretch between Mississippi and southeastern Arkansas to most vessel traffic because of low water levels, idling nearly a hundred boats and barges.
These low levels made history, and affected it as well. The American Queen Steamboat Company, for example, couldn't take its cruise of Civil War battlefields to Vicksburg, Mississippi, and instead set off from Memphis, Tennessee. Passengers were taken off the boat and bused to the site where then-Gen. Ulysses S. Grant laid siege to Vicksburg, arriving not by water as they'd intended, because of concerns that their steamboat might get "bottled up someplace behind a stranded barge."
"The mighty Mississippi has been a weakling lately," said Greg Brown, America Queen Steamboat's executive vice president of marine operations, on the company's blog.
Isaac provided some rainfall and relief, though flooding was confined largely to Louisiana and was due more to storm surge than anything else. Mark Svoboda, a climatologist with the National Drought Mitigation Center, noted Isaac's overall impact on the river was muted elsewhere because "we were so dry that the soil soaks it up like a dry sponge."
Southern Missouri, near The Ozarks: Hard times for dairy farmers
Longtime dairy farmers like Mark Argall have had to sell many of their cows after the drought combined with high prices for feed and low prices for milk forced them into debt. Another man, Stacey McCallister, said six of his cows got sick -- two of them fatally -- after eating a certain kind of grass that was so dry it became toxic. And the small town of Mountain Grove's hardware store is going out of business because the region's farmers are struggling so much, said 76-year-old Joe Robertson, who has worked there for over two decades.
While larger farms owned by corporations can more easily ride out a drought, it's harder for small farmers. Many say they have consistently lost money this year, to the point they can hardly afford to feed the cows they have -- thus prompting them to sell many of them off.
And it's not just happening in Missouri. Cattle ranchers in Oklahoma "liquidated" -- meaning sold off or slaughtered, without replacing them -- roughly 14% of their livestock last year because they couldn't keep up with the drought, said Derrell Peel, an Oklahoma State University faculty member who works extensively with ranchers and affiliated companies around that state.
Cows must be fed year round, and when it gets hot they face more stress and need more water. So when pastureland dries up or feed gets prohibitively expensive, many feel like they have no choice. Peel described
"If you run out of all those resources, you have no alternative but to sell those animals," Peel said.
From Washington: The military aims to get its meat now, while it's (relatively) cheap
In mid-August, the U.S. Defense Department announced President Barack Obama had directed the agency to look into buying more beef, pork and lamb, and sooner rather than later. The rationale? Such mass purchases of meat could "provide some relief" to those who raise and sell livestock during a devastating drought, and at the same time it would be more cost-effective for the government to buy meat now before prices likely spiral even higher.
While the drought's full effect on food prices, especially for packaged and processed items, won't be felt for 10 to 12 months, the U.S. Department of Agriculture estimates beef, pork, poultry and dairy prices should rise "within two months." The increase for these items should extend through the end of this year and into 2013, even if "herd culling" increases the meat supply and leads to lower prices in the short term.
The Defense Department is no ordinary shopper when it comes to meat or most anything else. It buys massive quantities of food for troops, staffers and civilian employees. Each year, in fact, the military purchases about 94 million pounds of beef, 64 million pounds of pork and 500,000 pounds of lamb.
Given its buying power, stepping up what it buys now could provide a short-term boost for this sector of the agriculture industry, no doubt. But a few months from now -- when times could be tougher, even as prices are higher -- ranchers and others could be looking for more help, given that one of their biggest buyers would already be well-stocked.
Plaquemines Parish, Louisiana: Residents get a taste of salty tap water, compliments of the drought
When people tasted their tap water in Plaquemines Parish in early August, they got a salty surprise -- compliments of the Mississippi River.
With river levels low due to the drought, the southern tip of the Mississippi has been awash in saline from the Gulf of Mexico. And that crept into the tap water in the parish south of New Orleans.
Guy Laigast, director of the parish's Office of Homeland Security and Emergency Preparedness, insisted in mid-August, "The water's perfectly safe to drink. It's just got the elevated salt."
But for those on low-salt diets, drinking the water could cause big health problems -- hence a warning.
After the mighty Mississippi fell to near its all-time low, the salty water crept in as a wedge, Laigast said. Because salty water is denser than fresh, it tends to collect at lower depths, he added. And pipes that pull drinking water from the river tend to draw from those same depths.
Sodium levels in the parish's drinking water ranged from 60 mg/L to 200 mg/L, far exceeding the EPA recommendation of no more than 20 mg/L for people on very low sodium diets.
What happened a few weeks later, though, shows that conditions can change, and fast, in southern Louisiana. Plaquemines Parish was among the areas hardest hit by Hurricane Isaac, with scores of homes flooded by a powerful, expansive storm surge.
Nationwide and up above: American Farm Bureau asks people to turn to God to end drought
Farming practices have come a long way over the past several decades, especially since much of Texas, Oklahoma and Nebraska was devastated by a decade-long drought in the 1930s' Dust Bowl era. Soil preservation, irrigation and other developments make people who work the land better able to adapt and grow what Americans' eat.
But one thing hasn't changed, in the opinions of many: A higher authority is still in charge of the weather.
Desperate for rain and a respite from extreme heat, the American Farm Bureau called on people nationwide to join them August 23 in a day of prayer. The request pointed to the need to support all those affected by the drought whether their crops withered away, their livestock were in desperate need of clean water, or their home regions were struck by prairie fires.
Everyone involved in agriculture has been affected, the bureau said in a blog post, as has every consumer.
"Let's pray for abundant rain to start nationwide and for those people (who) are dealing with such hardship," the bureau said. "It is a great way to support everyone being challenged by this ongoing drought."
CNN's John Sutter and Tom Watkins contributed to this report.