1. It might be there for a long period of time, a little reservoir of contamination.

2. The evacuation order came after water levels in the reservoir rose sharply last week.

3. The fall in the water level has exposed dozens of old cars dumped into the reservoir over the years.

4. Inside the chip is a reservoir array which contains and protects the hormone.

5. The reservoir provides water to 2.6 million people in the San Francisco Bay area.