Module 4: Articles on Water

In the U.S., for instance, municipal water falls under the purview of the Environmental Protection Agency, and is regularly inspected for bacteria and toxic chemicals.

In the U.S., for instance, municipal water falls under the purview of the Environmental Protection Agency, and is regularly inspected for bacteria and toxic chemicals.

While public safety groups correctly point out that many municipal water systems are aging and there remain hundreds of chemical contaminants for which no standards have been established, there’s very little empirical evidence that suggests bottled water is any cleaner or better for you than its tap equivalent.

Today, global demands for food, energy, and shelter are putting unprecedented pressure on the resources of the planet.

The water sources they depend upon—rivers, lakes, and aquifers—have for decades been heavily used for irrigated agriculture.

Since 1950, the consumption of water globally for irrigation has tripled in volume, a trend that played a large role in enabling food production to more than double over the same period.

Promising opportunities exist to free up the water presently used in agriculture through techniques such as reducing unproductive water consumption (e.g., stopping canal leakage, reducing soil and reservoir evaporation), changing crop types, introducing rotational fallowing, temporary fallowing during droughts, or the elimination of low-value farming.

Thankfully, there are a variety of promising techniques and technologies—such as drip irrigation—that could both conserve and increase the productive use of water in our agricultural sector while rendering Iowa’s farms more resilient to the future uncertainty of our climate.

Three hundred million people now get their water from the sea or from brackish groundwater that is too salty to drink.

“Desalination is not a cheap way to get water, but sometimes it’s the only way there is.”

The first desalination method—and still the most common, especially in oil-rich countries along the Persian Gulf—was brute-force distillation: Heat seawater until it turns to steam, leaving its salt behind, then condense it.

The current state of the art, used, for example, at plants that opened recently in Tampa Bay, Florida, and Perth, Australia, is reverse osmosis, in which water is forced through a membrane that catches the salt.

The closest to commercialization, called forward osmosis, draws water through the porous membrane into a solution that contains even more salt than seawater, but a kind of salt that is easily evaporated.

Brine discharges are especially tricky to dispose of at inland desalination plants, and they’re also raising the salinity in parts of the shallow Persian Gulf.

“I asked the engineers, ‘What if you are in a tiny village of 3,000, and the water is a hundred feet underground and laden with salt, and there is no electricity?’”