In the Book of Revelation, passage 16:3-4 reads: "The second angel poured out his bowl on the sea, and it turned into blood like that of a dead man, and every living thing in the sea died. The third angel poured out his bowl on the rivers and springs of water, and they became blood."
Now, in West Texas, a reservoir has turned red as blood. Preacher Paul Begley, whose youtube video is linked below, claims that this is a sign of the End of the World, as foretold in Revelation:
(Video after the fold)
Except that this is hardly the first time that a body of water has turned red. It turns out that there's been a drought in Texas, depleting the oxygen concentration in the water. In turn, this caused a bloom of Chromatiaceae bacteria thereby reddening the water.
A quick survey of the scientific literature (aka a search on google scholar) turned up this paper from FEMS Microbiology Letters. Apparently, in Prevost Lagoon, France, the water has periodically turned red for quite some time, having been subject to scientific study since 1977.
There are other species of mico-organisms that cause the appearance of red water as well. There's a particularly deadly dinoflagellate called Pfiesteria which has, at times, poisoned the waters in North Carolina and the tributaries of Chesapeake Bay. Under certain conditions, they begin to rapidly reproduce (which, in North Carolina, has been partly linked to pesticide run off from farms). In a phenomenon known as red tides, those periods of rapid reproduction will turn the water red "as blood". More information on red tides is available here.
Given that both of these phenomena have been occurring for some time, and that the world has yet to end, we have very little to fear from the water turning red in Texas.
I also highly doubt that Begley has a real understanding of the text of Revelation 16:3-4, or any of the text that comes immediately before it. As an atheist, I do not believe that any of the prophecies in the Book of Revelation will come to pass (or even that they are relevant to today's world.) Nonetheless, we can ask whether, in the context of Begley's own theological tradition, this interpretation even makes any sense.
Since Begley is intent on interpreting the Book of Revelation literally and as relevant to today's world, and not as something that refers to political happenings near the end of the first century CE (or as allegory related to the first plague in Exodus), there are other things we would expect to see. Namely, the happenings in Revelation 16:2. In 16:2, another angel drops another bowl of God's wrath upon the Earth, this time on those who had "the mark of the beast and who worshipped its image". This bowl is supposed to leave painful sores on these supposed heathens. It's also supposed to happen before the seas turn to blood.
Since we do not see publicised reports of massive throngs of heathenous people with sores on their bodies, even the most devout Christians should not expect this happening in Texas to be a sign of the End Times.