((PKG)) DROUGHT AND WATER TECHNOLOGY
((Banner: Not Enough))
((Reporter: Crystal Dilworth))
((VOA Persian))
((Adapted by: Martin Secrest))
((Map: Pasadena, California))
((NATS))
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
To put it simply, drought is when weather on the supply side, and society on the demand side, don’t see eye to eye. So, it’s when you don’t have enough water to fulfill a specific need. You know, about 96, 97% of the water on the planet is in the oceans, and that’s salty water. Only about, maybe, three percent of the water on the planet is fresh water, and most of that is locked up in the ice sheets. So, you got about 0.4% of all the water on the planet that’s actually fresh liquid water on land for us to access to drink.
((NATS))
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
We are earth scientists who study water. We study the movement of the water around the planet, which includes everything from precipitation to snow to soil moisture and groundwater, and we understand how those things change in time, and then how it affects society.
((NATS))
((Banner: Data about global water is provided by the US-German GRACE Satellite Mission))
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
These are two satellites that orbit the earth in tandem. They’re in an orbit of about 450 kilometers and they have a spacing of about 250 kilometers between them. These two satellites were put in orbit together to watch each other. So, they measure changes in each other’s orbits as they progress around the planet, and those changes in the distance between the satellites tell us something about the gravity signal underneath those satellites. Grace is really one of the only missions that doesn’t ‘shoot something’ down to the earth or take pictures of the earth. It just sits there in orbit. There’s GPS trackers on the top of the satellite, just like the ones in our phones, and they tell us where the satellites are as they make these range measurements.
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
So, then we create these big maps as scientists of where these gravity anomalies are, and the biggest and heaviest thing that actually moves around the planet pretty quickly tends to be water. And so, we know most of these signals are due to water movement.
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
What we’re expecting to happen with climate change is something called the ‘rich get richer mechanism,’ which is that places that are already wet are probably going to get more water in the future, and places that are already pretty dry are probably going to get drier in the future with changing climate. So, for dry places with large populations, that’s something we really have to think about and so far, what we’ve been seeing on the planet is consistent with that prediction, that these dry places will get drier.
((J.T. Reager, Hydrologist, Jet Propulsion Laboratory))
As population grows and people want to move to sunny and lovely places, like California, for instance, you’re near the ocean, then we have to consider, is there enough water in these places to support a growing population? One of the exciting things about water is that we have several technological solutions, which probably are viable into the future. So, one of them is water retreatment. So, the recycling of water through intensive chemical or other treatment activities that can create fresh water essentially from toilet water. So, toilet-to-tap is one of those exciting technologies that tends to, kind of, creep people out a little bit, but it’s actually really safe.
((NATS))
