Water Week in Review: Carraízo Down 18 cm, Sep 20–27
Published Sep 27, 2026, 6:04 AM AST787daily · Original analysis
At a glance
Carraízo: 40.81 → 40.63 m (−18 cm) over 7 days — Safe band, 0.05 in of rain nearby in the final week
La Plata: 44.66 → 44.39 m (−27 cm) over 7 days — Adjustments band, 0.26 in of rain nearby in the final week
Cidra: 400.54 → 400.52 m (−2 cm) over 7 days — Watch band, 0.6 in of rain nearby in the final week
Week of September 20–27; 6 daily chart checks this week, all archived on our reservoir board
Why this matters: What the week changed is the distance to the next band line — 0.93 m for Carraízo, 3.89 m for La Plata — and the pace at which it is closing or opening.
The week of September 20–27 on AAA’s reservoir charts: Carraízo down 18 cm, La Plata down 27 cm. The numbers first, then what they add up to.
Week 8: where the reservoirs stand
Week 8 of the metro rotation · Where the 19 reservoirs stand as of Sep 27: each column is that reservoir's own ladder of AAA bands, the bar its level in meters, 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.
14 of 19 reservoirs sit in seguridad or above, 4 in observación; La Plata is in ajustes. Since August 8, Carraízo (ajustes → seguridad), Cidra (ajustes → observación), Matrullas (observación → seguridad), Dos Bocas (seguridad → desborde) have moved up a band; La Plata (observación → ajustes) has slipped down. This week’s biggest move is Dos Bocas, up 0.57 m to 90.03 m.
At a glance
Carraízo
Sep 20 → Sep 27
40.81 → 40.63 mSafe band today
Net change
−18 cm2.6 cm a day on average
Worst morning
−5 cmSep 23
Rain nearby, last 7 days
0.05 inmost on Sep 23 (0.04 in)
Above the observación line
0.93 m≈ 34 days at this week's pace
La Plata
Sep 20 → Sep 27
44.66 → 44.39 mAdjustments band today
Net change
−27 cm3.9 cm a day on average
Best morning
+4 cmSep 21
Worst morning
−9 cmSep 26
Rain nearby, last 7 days
0.26 inmost on Sep 26 (0.2 in)
Above the control line
3.89 m≈ 75 days at this week's pace
Cidra
Sep 20 → Sep 27
400.54 → 400.52 mWatch band today
Net change
−2 cm0.3 cm a day on average
Worst morning
−1 cmSep 25
Rain nearby, last 7 days
0.6 inmost on Sep 23 (0.3 in)
Above the ajustes line
0.29 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 20, 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
Carraízo and La Plata both reversed course this week, falling steadily after a prior week of gains, while the rain that fell — 0.05 in at Carraízo, 0.26 in at La Plata — was too light to slow either decline. Carraízo dropped to 40.63 m, still in seguridad and 0.93 m above the observación line, but at the current 7-day pace it would reach that line around November 1 — arithmetic, not a forecast. La Plata slid to 44.39 m in ajustes, 3.89 m above the control line, with the same caveat putting that line around December 11 if the pace holds.
Cidra barely moved, easing to 400.52 m in observación despite catching the most rain of the three, 0.6 in, which kept its drift to just 2 cm since the week began. It remains 0.29 m above the ajustes line, essentially flat rather than trending toward it.
Each reservoir against its own next band lineCarraízo since Sep 20, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.La Plata since Sep 20, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.Cidra since Sep 20, meters above sea level, shaded by AAA alert band. Data: AAA Monitoreo Diario.All 6 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.