decades of overgrazing and flash flooding had rendered the Rio Puerco country virtually uninhabitable and it was abandoned. Sediment and erosion As it carries high levels of sediment, the Rio Puerco is a major source of suspended particulate matter. Overgrazing has made the Rio Puerco Basin of central New Mexico one of the most eroded river basins of the western United States and has increased the high sediment content of the river. The USGS collects suspended-sediment samples at its stream gage three miles (5 km) above the river's mouth. A maximum daily mean of sediment concentration of 417,000 mg/L was recorded on July 25, 2008. The maximum recorded daily sediment load was 2,240,000 tons, recorded on August 7, 1957. See also List of rivers of New Mexico List of tributaries of the Rio Grande Silvester Mirabal References Tributaries of the Rio Grande Rivers of New Mexico Rivers of Socorro County, New Mexico Rivers of Valencia County, New Mexico Rivers of Bernalillo County, New Mexico Rivers of Sandoval County, New Mexico Rivers of Rio Arriba County, New Mexico