Precipitation in the San Juan Mountains of Colorado is usually higher than in the Rio Chama Watershed.
The San Pedro Mountains south of the Rios Gallina and Chama Watersheds, and the more easterly groupings of mountains have higher than average precipitation.
Compared with precipitation downstream along the Rio Grande, north central New Mexico, including the Rios Gallina, Chama, and Grande Watersheds clearly supply much of the water for central New Mexico and beyond.