The world has only a small amount of usable water, and Utahns must be careful with the little allotment they have, said a Brigham Young University professor Wednesday night.

Biology professor Mark Belk spoke at the monthly Utah Valley Sierra Forum meeting about the importance of handling water with care.

The UVSF is associated with the Sierra Club, which focuses on enjoying and protecting the planet, said the group's chairman, Jim Westwater. The forum focuses on a healthier and sustainable Utah Valley and Earth, and preserving water goes hand-in-hand with that principle.

"Water is a very, very important issue here in Utah, the West and around the world," he said.

Belk said the Earth is known as the blue planet, and images from space often focus on big, blue oceans. Although the Earth has abundant water, Belk said its inhabitants have an incorrect view of how much is available.

"We get the impression that there's lots of water around, and there is," he said. "But not for us."

Belk held up a 20-ounce bottle of water representing all the water on the planet. He poured a small amount into a 1-inch tall cup, saying this was the only usable water on Earth, as 95 percent of the earth's water is unusable saline.

The fresh water on the Earth is important to humans, Belk said, but it is also important to the biodiversity all around. In order to find a high diversity of plants or animals, one must go to a source of fresh water.

"Fresh water is disproportionately important to this biodiversity we have," he said.

The importance of fresh water can be seen in recent events with a drought in the southeast area of the country, Belk said, or in the desire to pump western aquifers to supply Las Vegas with water.

As important as energy conservation is in politics today, Belk said fresh water will be an even bigger issue in the next 20 years. There are ways to use non-fossil fuels, he said, but fresh water is vital.

"Water either takes energy to convert it from saline to fresh or you have to use what you have," he said.

Belk said fresh water in Utah has been harmed the same way other resources have in the past. The Western United States was once an area of exploitation, he said, and no amount of exploitation was too much.

Species of fish in Utah Lake were eaten to extinction, with only two of the original 14 species still remaining. The Provo River was dyked and diverted to straighten it out in the 1930s by the Army Corps of Engineers, Belk said.

These types of exploitation exemplify the attitude that resources should be used to the benefit of people.

"The natural thing that happens with that sort of attitude is you divide the world into good species, species that are useful to you, and bad species," Belk said.

Other examples of this attitude are the terms "non-forage vegetation" and "trash fish." These terms put plants and fish into categories based on their usefulness to humans.

There has been a recent shift in the way people think, Belk said, and now more people are concerned about how to reverse the damage done to the environment.

It is difficult to divert a river back to its original path, he said, and Utah Lake has become polluted from waste that was deposited there for years.

Belk said it is impossible to not influence the environmental systems, but it is important to be a good steward over the resources available. decisions, he said, should not be made based on one's personal interests, but based on what is best for the future.

"We have to develop this stewardship," he said. "There are good ways of interacting with and being part of the environment."

Tony Tsosie, a member of the forum, said it is important for people to return to the natural, basic way of living that requires fewer resources. It is everyone's world, he said, and everyone is affected by what happens to the Earth.

"I think [reversing the harm on the environment] is on the individual level," he said. "It has to be."