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第一段
1 .Listen to part of a lecture in an environmental science class.
听一段环境科学课程的演讲
第二段
1 .I'd like to continue with the topic of managing water resources, but I want to focus on a particular case.
我想继续讲水资源管理的这个话题，我想要专注地讲一个特例，
2 .Uh, um, an example of water management that's made us reconsider the methods we use when we make these decisions.
一个让我们思考做水资源管理方面决定时所用的方法的例子。
3 .So let's look at what's happening in the Colorado River basin.
那么，我们来看看正发生在科罗拉多河谷流域的事吧。
第三段
1 .The Colorado River basin is a region in the Southwest United States.
科罗拉多河谷盆地是位于美国西南部的一个区域。
2 .Seven states rely on the Colorado's water.
你们能想到，好几个州都依赖科罗拉多的水源，
3 .And as you can imagine, as the populations of these states began to grow, it became clear that a system to distribute, uh, to make sure each state got its fair share of water... some kind of system had to be created.
随着这些州人口的增长，便有了建立某种系统的必要，好来合理分配每个州水源供给、分配。
4 .And in 1922, a water-sharing agreement was made.
1922年，水源共享的协议被签订了
5 .Elizabeth, you have a question?
。伊丽莎白，你有问题吗？
第四段
1 .Well, how exactly do you figure out how to share a river?
到底能如何想出共享一个河流的方法呢？、
2 .I mean, you can't... like cut it up into pieces.
我是说，肯定不能把河流分成一块一块的吧？
第五段
1 .Well, let's start with the first step.
好，先说第一步吧。
2 .And that's trying to figure out how much water on average flows through the river each year.
首先要知道每年流经河谷的平均水量。
3 .Now, researchers had started gathering data on water flow back in the late 1890s using instruments they placed in the river.
。现在，研究者们通过在河中放置器械来开始搜集从1890年开始该流域的水流量数据。
4 .When the 1922 water-sharing agreement was made, there were about twenty years of data on water flow available.
1922年时，水源共享的协议签订后，人们手上有20年的水流量数据来参考。
5 .The average annual flow was calculated.
人们算出了年平均水流量，
6 .And, well, the agreement was based on that calculation.
协议也是以这个平均的水流量为基础来计算的。
7 .The same basic agreement is in effect today.
这份协议一直沿用至今。
第六段
1 .Wait! That was all the data they had?
等等！他们手里只有那些数据，
2 .And they based their decision on that?
他们就仅仅根据这些数据来确定协议了？
第七段
1 .Yes. And we'll see why that was a bad decision in the moment.
对，我们稍后就会讲为什么这么做不妥。
2 .OK. As decades passed, it became clear that measuring river flow was much more complicated than we had thought.
。好，几十年过去了，测量河谷的水流量比我们想象得更复杂这一事实越来越明了。
3 .See... a river has periods of low flow and periods of high flow.
因为，一条河既有起潮期又有高潮期，
4 .And this wasn't taken into consideration when the 1922 agreement was made.
1922年签订协议的时候却没有考虑到这一点。
5 .In the 1970s, the population of the area was rising while the amount of water flowing through the river seemed to be falling.
到了20世纪70年代，该区域的人口增长了，同时，该流域的水流量却下降了。
6 .By this time, we had... what?
但到了这个时候，我们有什么？
7 .A hundred years of recorded data to look at?
我们手里已经掌握了100年的数据。
8 .That's still a pretty short time for an ancient river.
但对于一条古老的河流来讲，一百年也是很短的时间
第八段
1 .To get more data, we looked at a different source - a source that was able to tell us about hundreds of years of the river's history - tree rings.
我们获取的数据越多，我们便会参照不同的数据来源，这个来源能够让我们知道该条河流过去几百年的历史，这个来源就是树的年轮。
2 .OK. Let me explain.
好，让我来解释。
第九段
1 .You probably know that we can determine a tree's age by counting the rings on a cross section of its trunk.
你们大概知道要决定一个树的年龄，我们可以去数树横截面上的年轮。
2 .Each ring represents one year of the tree's life.
每一个年轮都代表了一年树龄。
3 .So if you know the year the tree was cut, you can count inwards and date each ring all the way back to the center.
以如果一棵树被砍了，我们就可以从外往里数年轮，来决定树的年龄。
4 .You can also tell how much moisture the tree got during each of those years by looking at the width of the rings.
我们还可以从年轮的宽窄来判断当年树所吸收到的水分。
5 .A wide ring means plenty of water while a narrow one indicates less.
一个宽的年轮意味着水分多，窄的年轮意味着水分少。
第十段
1 .Fortunately for us, certain areas of the Colorado River basin are home to some very old trees, some 800 years old and older.
幸运的是，科罗拉多河谷生长有许多古老的树木，有的800年之久，有的则更老
2 .Researchers can drill core samples, uh, basically get a cross section of a tree without having to kill it, look at the rings and get a picture of what the climate was like in the basin for each of the tree's years.
研究者们可以从树木获取核心样本，基本上就是在不杀死树木的前提下获取它的横截面，通过样本可以观察树的年轮，大概可以知道过去每年中当地的气候是什么样的。
第十一段
1 .Well, the results tell us something we wouldn't have known without this data, that over the past 500 years or so, the Colorado River basin has experienced severe droughts, some worse than any we've ever recorded.
这样做获得了我们无法从其他数据得来的信息：在过去的500年左右间，科罗拉多河谷经历了一些严重的干旱，其中一些要比人们记载的严重。
2 .They also showed that the early to mid-1900s, when most of the data that led to the water-sharing agreement was collected... well, this was the wettest period in the past 400 years.
年轮的数据还表明，从20世纪的早期到中期，尽管这段时间的大部分数据都被用来起草水源共享协议了，但事实上这段时期是过去几百年间该地区气候最潮湿的阶段。
3 .Well, obviously, had water management officials known then what we know now, the 1922 agreement would have been handled differently.
那么显然，如果当年的人们知道我们现在所知道的，1922年的那份协议就会以不同的方式来处理水源问题了。
第十二段
1 .But today we can use the past to help prepare us for the future.
但是，今天，我们还可以利用过去为未来做准备
2 .With the demand for water in the basin states increasing and with the real likelihood of lower flows in the river, if history is our teacher, we can develop innovative methods of water conservation and reevaluate how water is distributed.
随着科罗拉多河流域水资源需求的日益增高，也随着水流量会下降的可能性，如果历史是我们的老师，我们可以开发出水源保护的创新方法并且重新评估水资源该如何分配。