The week of September 27–October 4 on AAA’s reservoir charts: Carraízo up 11 cm, La Plata down 60 cm. The numbers first, then what they add up to.
Week 9: where the reservoirs stand
Week 9 of the metro rotation — where the 19 reservoirs stand as of Oct 4: each column is that reservoir's own ladder of AAA bands, the bar its level in metres, the dashed tick where it stood on August 8, day one of the rotation, the triangle this week's direction. Source: AAA's 5 AM readings; bands as AAA's monitoring chart defines them.
16 of 19 reservoirs sit in safe (seguridad) or above, 2 in watch (observación); La Plata is in adjustments (ajustes). Since August 8, Carraízo (adjustments → safe), Cidra (adjustments → watch), Río Blanco (watch → safe), Matrullas (watch → safe), Guayabal (watch → safe) have moved up a band; La Plata (watch → adjustments), Guineo (spilling → safe) have slipped down. This week’s biggest move is Guineo, down 1.39 m to 901.00 m.
At a glance
Carraízo
Sep 27 → Oct 4
40.63 → 40.74 mseguridad band today
Net change
+11 cm1.6 cm a day on average
Best morning
+14 cmOct 4
Worst morning
−5 cmSep 28
Rain nearby, last 7 days
2.31 inmost on Oct 1 (1.45 in)
Above the observación line
1.04 mrising — desborde line ≈ 8 days up
La Plata
Sep 27 → Oct 4
44.39 → 43.79 majustes band today
Net change
−60 cm8.6 cm a day on average
Worst morning
−17 cmOct 4
Rain nearby, last 7 days
0.76 inmost on Sep 30 (0.5 in)
Above the control line
3.29 m≈ 38 days at this week's pace
Cidra
Sep 27 → Oct 4
400.52 → 400.53 mobservación band today
Net change
+1 cm0.1 cm a day on average
Best morning
+2 cmSep 30
Worst morning
−1 cmSep 29
Rain nearby, last 7 days
2.5 inmost on Oct 1 (0.89 in)
Above the ajustes line
0.30 mholding
Carraízo, this week
Carraízo, morning by morning — tap a day for that chart check
Teal = up from the previous reading, coral = down; a bold border marks a move of 20 cm or more.
Three reservoirs, one scale
Change since Sep 27, in centimeters — three reservoirs on one scale. Hover or tap a point for the day's reading. Data: AAA Monitoreo Diario.
What it adds up to
The week’s big change came at Carraízo. After 1.45 in of rain on October 1, it gained 13 cm the next morning, then 14 cm on October 4, and now sits in the seguridad band, moving toward the desborde line at 40.95 m. That is a rise from rain, not a settled recovery: the rain that fell the day before (0.53 in) was followed by a 4 cm drop.
The rain did little for the other two. La Plata took 0.50 in on September 30 and fell 9 cm the next morning; it has dropped 11 mornings running and is still losing ground faster each week, sliding through the ajustes band toward control. Cidra barely moved. Its rain produced 2 cm, 1 cm and 0 cm, and it sits in observación, 0.30 m above the ajustes line. The 38-day projection for La Plata is arithmetic at its latest weekly pace, not a forecast.
Each reservoir against its own next band lineCarraízo since Sep 27, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.La Plata since Sep 27, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.Cidra since Sep 27, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.All 5 daily chart checks this week
Numbers from AAA’s Monitoreo Diario charts, read each morning for our reservoir board; rain from USGS gauges within 12 km of each reservoir (a proximity proxy, not a basin measurement). Rates and pace dates are arithmetic over the stored readings, not forecasts. The narrative is drafted by Claude from the computed figures and checked number-by-number against them before publishing.
Cite this
Source: 787daily, “Water Week in Review: Carraízo Up 11 cm, September 27–October 4”, Oct. 4, 2026 — https://787daily.com/news/2026-10-04-water-week-in-review-carraizo-up-11-cm-september-27-october-/