Repetitious redundancy

The holiday week is taking its toll. Since this is Friday for Nevadans in state employ it didn't dawn on me until this evening that the news about the CIA leak probe expected Friday would actually come tomorrow. While searching the day's stories on the topic I came across this sentence on, "..when Bush's approval ratings already are at a low ebb."

How does a low ebb compare to a high ebb? Since ebbs are declines or times when things go down what is a low decline? Is it like a peak summit? Or, perhaps, does it mean that it's not a major ebb but just a small ebb? (Though there is a factual problem with this argument since the president's approval ratings haven't been lower.) I'm sure I'll make many similar mistakes before my time here is done, but it is always a sad commentary to see major news organizations make such mistakes that anybody who reads at a 7th grade level would catch.