CIBOLA COUNTY, N.M. – Cibola County closed August with another round of monsoon storms in the forecast and a mixed picture for local water conditions. The Rio San Jose ended the month higher than it began, while Bluewater Lake continued its steady decline despite summer rainfall. With September beginning, forecasts show additional precipitation possible across the county, giving the monsoon another opportunity to add moisture before the summer rainy season begins to wind down.
Bluewater Lake
According to provisional U.S. Geological Survey data, Bluewater Lake measured 7,364.44 feet on Sept. 1, down from 7,364.52 feet on Aug. 25.
That represents a weekly decline of 0.08 feet, or just under one inch.
Looking across August provides a clearer picture of the lake's trajectory. Bluewater measured 7,365.00 feet on Aug. 2, meaning the lake lost approximately 0.56 feet, or 6.7 inches, during the month.
August included multiple periods of monsoon rainfall across Cibola County. Those storms brought moisture to soils, vegetation, arroyos and streams – and at times caused flooding – they did not produce a sustained rise in the lake's measured elevation.
The longer-term decline is even more pronounced. Bluewater Lake stood at 7,368.77 feet on Jan. 1, putting the Sept. 1 reading approximately 4.33 feet below its level at the beginning of 2026.
Rainfall does not translate directly into reservoir gains. Where rain falls, how quickly it falls, soil conditions, runoff into the watershed, evaporation and water losses all affect whether precipitation ultimately reaches and remains in the lake.
Rio San Jose
The Rio San Jose at Acoma Pueblo measured 1.99 feet on Sept. 1, according to provisional USGS data, unchanged from the Aug. 25 reading.
Unlike Bluewater Lake, however, the river ended August higher than it began.
The Rio San Jose measured 1.95 feet on Aug. 2, compared with 1.99 feet on Sept. 1, an increase of 0.04 feet during the month.
A USGS field measurement taken Aug. 11 recorded the Rio San Jose at 1.98 feet, providing another point of comparison during the month.
Precipitation Across Cibola
This year is proof summer precipitation can affect Cibola County's water resources differently. The Rio San Jose responded to periods of monsoon moisture during July and August and has generally remained near the higher levels reached later in the summer. Bluewater Lake, meanwhile, continued losing elevation.
The final days of August brought renewed monsoon activity and repeated concern for heavy rainfall, even though precipitation remained highly uneven across Cibola County.
Drought.gov's sevenday precipitation map, valid Aug. 28, shows generally light accumulated rainfall across much of the county, with broad areas receiving roughly 0.01 to 0.5 inches and isolated pockets receiving more. The map reinforces a pattern seen repeatedly this summer: countywide precipitation can appear modest even when individual thunderstorms are capable of producing much heavier rainfall over a small area.
The National Weather Service Weather Prediction Center's seven-day forecast for Aug. 31 through Sept. 7 shows substantially more precipitation possible across portions of Cibola County than was recorded during the previous seven days.
Much of central Cibola County, including areas west and southwest of Grants and around El Malpais, is forecast to receive approximately 0.5 to 1 inch of precipitation, with some pockets approaching or exceeding 1 inch. Lower totals are forecast in portions of eastern and western Cibola County.
As always with monsoon precipitation, actual totals will depend heavily on where thunderstorms develop.
The monsoon remains active, and the coming weeks will help determine how much of this summer's rainfall translates into longer-lasting improvements to local water conditions.
Water data courtesy of the United States Geological Survey. Temperature, precipitation and drought information courtesy of Drought.gov, the National Weather Service, the U.S. Drought Monitor, the Climate Prediction Center and the New Mexico Environment Department.