Northern California’s major rivers swelled and then began receding during a pause between rainstorms Monday, leaving a trail of toppled trees and damaged roadways but no major urban flooding in Sacramento or elsewhere. The weekend’s big rainfall, the most Sacramento has seen in a two-day stretch since 2000, put another dent in the drought and left precipitation totals for the season at twice the average for this time of year. With a second storm expected to hit late Monday or early Tuesday, emergency officials remained watchful.