- Before
- Starts at 07:00 with yesterday's lab results and the analyser trends. “I find out the far end was low when the sample fails. By then I'm writing to the regulator.”
- Now
- Sees Saltmarsh Lane fall below 0.2 a day before it happens, with the reason, three options and their by-product effect — and approves the booster dose before 07:30.
One Tuesday morning, from a forecast to a booster dose and a signed notification
Lumina Utilities supplies its network from the Coralstone Desalination Plant (seawater reverse osmosis, 260 ML/d) and the Ashvale Water Treatment Works (groundwater, 85 ML/d) through four supply zones — Harbour, Central, Tern Point and Kestrel Bay. It is Tuesday 13 October 2026, 07:10. Here is what happens next, screen by screen, in the working solution.
- 0107:10
The day opens on the network, every point against its limits
Hana Rahimi · Water quality managerHana owns every exceedance on the network. Her first screen is the map: 26 sampling points with results in the last 24 hours and 38 analysers reporting every 5 minutes, each point's latest results drawn as bars against its limits. Points near a limit pulse, and pipes are shaded by water age from 0 to 7 days. The watch list on the right already holds a low chlorine forecast at Saltmarsh Lane and a coliform result at Harbour Quay.
“October so far: 642 of 642 samples taken on time · 617 of 618 results inside every limit”
- 02+36 h
She slides the forecast to tomorrow evening
Hana Rahimi · Water quality managerThe time scrubber runs Now, +12 h, +24 h, +36 h and +48 h, and redraws the chlorine bars from the forecast. At Wednesday 19:10 the bar at SP-388 Saltmarsh Lane — the dead end of the Gannet Hill spur in Kestrel Bay — drops under its line. The analyser there reads 0.24 mg/L now; the forecast is below the limit from Wednesday 07:00, lowest 0.18 mg/L at 19:00.
On the map: “Forecast 0.18 mg/L · below the 0.2 limit” — and the next routine sample is Thu 08:30.
- 03Why
Older water, and the decay rate on that spur
Residual forecasterRidgeback Reservoir has been held at 92 % since Friday for the Mill Cross pump overhaul (WO-58817), and demand is down 11 % in the cooler weather. Water age at Saltmarsh Lane rises from 6.0 days now to 7.2 days by Wednesday evening, from the 06:00 hydraulic run. On this spur chlorine decays at 0.225 per day, fitted from 41 grab samples and six weeks of analyser KB-CL2 (R² 0.91), and Monday's grab sample already read 0.26 mg/L.
“The next routine sample here is Thu 08:30: without an action it would be the first anyone knew.”
- 04Every far end
Fourteen far-end points, ranked by their lowest forecast
Residual forecasterThe forecast covers every far-end point for the next 48 hours, with water age, decay per day and confidence. Saltmarsh Lane is the one below 0.2. Dune End (0.20) and the Gannet Hill booster outlet (0.21) sit on the same spur; Marina Gate, Bayview Terrace and the rest need nothing. Harbour Quay's chlorine is normal at 0.46 — its problem is bacteria, EX-1041.
“Alerts need a confidence of R² 0.80 or more” — below it, the forecaster asks for a sample instead.
- 055 steps · 6.6 s
A booster dose, a flush or doing nothing, side by side
Action plannerThe planner finds what can act on the spur — the Gannet Hill booster on standby, hydrant H-2291, the routine sample — and models each option. Booster dose: +0.25 mg/L from 08:00, reaching the end at about 01:00 Wednesday, low 0.39 mg/L, TTHM 55 µg/L (+3, limit 80), no water to waste, about 9 kg of hypochlorite a day. Flushing H-2291: 140 m³ to waste and a crew for 3 hours, and the residual is still below 0.2 from 07:00 to about 09:00 on Wednesday, before the crew's fresh water reaches the end. Doing nothing: below 0.2 for about two days.
Do nothing: “The Thursday sample would likely read below 0.2 mg/L: a licence breach, a notification to the regulator within 24 hours, repeat sampling and, if it persisted, advice to customers on the spur.”
- 06Approve
Hana approves the booster dose, with a note to the control room
Hana Rahimi · Water quality managerShe approves +0.25 mg/L at the Gannet Hill booster from 08:00 today, until Ridgeback Reservoir is back to its normal level. The setpoint request goes to Tomasz Wren in the control room, who applies it. Her note travels with it, and the approval is recorded on the audit trail with the forecast it answers.
“Gannet Hill to +0.25 mg/L from 08:00. Hold until WO-58817 is closed and Ridgeback is back below 80%. Call me if the outlet reads above 0.6.”
- 0707:31
The control room confirms, and the forecast re-runs
Tomasz Wren · Network control room operatorTomasz confirms the setpoint. The residual forecaster re-runs the forecast with the booster dose in it: the lowest residual at Saltmarsh Lane is now 0.39 mg/L on Wednesday at 19:00, Dune End 0.44 and the Gannet Hill outlet 0.45. The sampling scheduler puts an extra grab sample on Sam Ofori's Route 4 for Wednesday 10:00 to prove it.
Approvals: Hana Rahimi “Approved 07:21” · Tomasz Wren “Confirmed 07:31” · Sam Ofori “On the route”
- 08Tomorrow, redrawn
Saltmarsh Lane is back above its line
Hana Rahimi · Water quality managerBack on the map at +36 h, the Saltmarsh Lane bar reads 0.39 mg/L and the watch list marks the spur as fixed: “booster dose running”. The strip at the bottom now reads “0 breach forecast”. No sample failed, so there is nothing to notify.
“Booster dose at Gannet Hill running from 08:00. Lowest forecast tomorrow now 0.39 mg/L (was 0.18).”
- 0905:52 → 05:55
A coliform result, caught a minute after the lab released it
Limit checker and Sampling schedulerEarlier that morning, Lumina Central Laboratory released certificate LC-2610-4471 for SP-134 Harbour Quay: 2 coliform bacteria per 100 mL, E. coli not detected, free chlorine 0.46 mg/L. At 05:53 the limit checker opened EX-1041 and started the 24-hour repeat clock. At 05:54 the sampling scheduler put three repeats — the site, SP-130 upstream and SP-136 downstream — first on Owen Marsh's Route 2, leaving 09:30. At 05:55 Hana was texted as on-call manager.
Suggested cause: the sample tap in the Harbour Quay kiosk was last disinfected on 14 Aug — “disinfect the tap before the repeat”.
- 10Signed
Leila signs the notification with 22 hours to spare
Leila Haddad · Compliance officerThe report writer drafted the notification at 06:30 from the exceedance record: what was found, where and when, the certificate, the three repeats and the tap disinfection. Leila reads it beside the minute-by-minute timeline and signs and sends it through the regulator portal, with the receipt saved to the record.
“You are sending the EX-1041 notification to the regulator as Leila Haddad, compliance officer.”