SAN DIEGO — Seven years ago, when baseball's All Star Game at Petco Park prompted officials to clear nearby encampments, a local environmental group noticed an apparent spike in the number of homeless people by the San Diego River. The same thing happened around 2017, when a hepatitis outbreak killed more than a dozen. But the San Diego River Park Foundation didn't have enough data to show a definite connection. As a result, nonprofit staffers increased how often they counted people living by waterways, and the numbers paint a clear picture: Riverbed encampments have risen repeatedly for years...