December 1861 and January 1862 brought about devastating floods that placed the future of the city in doubt. In order to resolve the situation, the city residents agreed that additional levee construction was necessary. However, the city was divided between camps that supported a relatively small grading of a few feet to raise the city just above the rivers' cresting levels and those that supported a substantial grading to accommodate basements in city businesses. In the upcoming election of 1863, the level at which the city should be raised became a primary factor; a candidate that supported high-level grading won, and high-level grading renovation proceeded. Earth was removed from a dangerous bend nearby the confluence of the two rivers and used to raise city blocks in 1868; the city's sidewalks, until construction was finally finished, were uneven because neighbors of raised city blocks often remained at the pre-construction level. After the filled regions beneath buildings had settled, new streets had to be paved. While planking had been used in the past, newly raised streets chose either the smooth (though indurable) Nicolson pavement or the easily dirtied (though durable) cobblestone pavement. Grading and paving processes were fully completed by 1873, leaving the first floors of many buildings at the time as basements and leaving second floors as new main floors. Today, this system of 19th-century basements is known as the Sacramento Underground.