Shannon Babb, an 18-year-old from Highland who is a senior at American Fork High School, has won the Intel Science Talent Search, contest officials announced Tuesday.

The announcement came at an awards banquet in the Ronald Reagan Building in Washington, D.C., attended by about 700 contestants, their families, scientists and other dignitaries.

First place in what is often termed the "Junior Nobel Prize" competition carries enormous prestige and a $100,000 scholarship. That is in addition to Babb's earlier Intel winnings for herself and her school, garnered when she advanced to the semifinalist and finalist stages. Utah's last previous Intel finalist reached that level in 1994.

Speaking by telephone with the Deseret Morning News shortly after the announcement, Babb said that when she learned she had won, she felt "absolute shock."

"At first they announced 'American Fork High School,' and I was the only person (competing) who was from American Fork High School, so all of a sudden, it was like, 'Whoa, did I just hear that, American Fork?' Then they followed with my name, so yes, I did.

"So I kind of stumbled to the front. Apparently, I looked very shocked."

During a six-month study, Babb sampled water quality and checked the health of the ecosystem of the Spanish Fork River, waking at 4 a.m. each day for the project. Her entry was judged best among those of 1,558 students who competed, representing 486 high schools in 44 states, the District of Columbia, Puerto Rico, the U.S. Virgin Islands and an overseas school, according to Intel.

Officials said six previous winners went on to become Nobel laureates, three received the National Medal of Science, and 10 are fellows of the MacArthur Foundation.

Intel saluted Babb's "rare ability to combine research and remediation in environmental science." Contest officials noted Babb began researching water quality at age 13, and analyzed the chemical and physical properties along the river drainage system.

"She concluded that humans, through urban and agricultural factors, have a negative effect on the water quality of the river," according to an Intel press release. "She believes the water quality problem can be resolved with a combination of restructuring and educating the public that household chemicals should not be poured down storm drains."

Altogether, Intel awarded prizes totaling $530,000 to competitors, including a $75,000 scholarship for second-place winner Yi Sun of The Harker School in San Jose, Calif., cited for discovering new geometric properties of random walks, and a $50,000 scholarship to Yuan "Chelsea" Zhang of Montgomery Blair High School in Rockville, Md., for her third-place entry researching the molecular genetic mechanisms behind heart disease.