The city has completed a program of covering open-air reservoirs with floating "shade balls" to protect water quality.
為了保護(hù)水質(zhì)，洛杉磯市向露天水庫投放了9600萬個“遮陽球”，這些球浮在水面上，水庫表面已被遮蓋。目前該項(xiàng)目已全部完成。

City officials this week dumped the last 20,000 of 96 million black balls into the Los Angeles Reservoir in Sylmar, 25 miles northwest of downtown. The 4-inch-diameter plastic balls block sunlight from penetrating the 175-acre surface of the reservoir.
本周，洛杉磯市官員將最后2萬個黑色塑料球投放到洛杉磯水庫，該水庫位于西爾馬，距離洛杉磯市中心西北部25英里。這些塑料球直徑為4英寸，覆蓋了水庫175英畝（約71公頃）的水面，使其避免太陽光照射。

That prevents chemical reactions that can cause algae blooms and other problems, allowing the Department of Water and Power (DWP) to meet U.S. Environmental Protection Agency water-quality requirements.
這也可以避免發(fā)生化學(xué)反應(yīng)，而化學(xué)反應(yīng)可能導(dǎo)致水藻滋生等其它問題。此舉使得洛杉磯水電局達(dá)到美國國家環(huán)境保護(hù)局的水質(zhì)標(biāo)準(zhǔn)。

They have the added perk of aiding with the ravages of the drought, and are expected to keep about 300 million gallons annually from evaporating.
此舉已經(jīng)緩解了干旱所帶來的破壞，預(yù)計(jì)每年可以減少3億加侖的蒸發(fā)量。

"In the midst of California's historic drought, it takes bold ingenuity to maximize my goals for water conservation," Mayor Eric Garcetti said in a statement, noting that the effort is "emblematic of the kind of the creative thinking we need to meet those challenges."
洛杉磯市長埃里克?賈西提在一次聲明中說道：“面對加州史上少有的干旱，我們需要有相當(dāng)大膽的創(chuàng)造力來幫助我們最大化地實(shí)現(xiàn)節(jié)水，”市長還強(qiáng)調(diào)，此舉“體現(xiàn)出我們迎接挑戰(zhàn)所需要的創(chuàng)造性思維”。

The 36-cent balls also will help prevent evaporation of 300 million gallons of water annually from the 3.3 billion-gallon reservoir, the DWP said.
水電局工作人員稱，洛杉磯水庫的儲水量為33億加侖，每個遮陽球的成本為36美分，每年可幫助該水庫減少3億加侖的蒸發(fā)量。

The city began using shade balls in 2008.
洛杉磯市自2008年開始使用遮陽球。

Vocabulary
algae: 水藻
perk: 額外津貼
evaporate: 蒸發(fā)
emblematic: 象征

英文來源：美聯(lián)社
譯者：實(shí)習(xí)生馮佳佳
審校&編輯：許晶晶