PSD.5:5.1 - Flood-pump models that answer different questions
In this illustrative continuation of the flood-pump inquiry, the board needs a pre-season decision-support return about permanent pumps, mobile capacity, maintenance, staffing, and access. The current formulations distinguish capacity shortage, deployment reliability, unequal service, and transferred downstream consequences. The scope includes the next flood season and preserves relocation rights and long-term watershed change as material exclusions.
The inquiry team constructs the following bounded account. The values are illustrative case premises, not engineering advice.
| Question and model | Account slice | Consequence for inquiry |
|---|---|---|
| Can nominal capacity meet the assumed inflow? A capacity calculation. | Permanent and mobile branches meet the assumed requirement only with the stated operating units available; no deployment delay is represented. | Nominal capacity alone cannot discriminate reliability or access. |
| Can mobile units reach and serve the district? An access-and-deployment scenario model. | With the main road unavailable, the mobile branch has no supported arrival-time claim. A second route is a hypothesis requiring an operations result. | Keep the mobile branch conditional; arrival time remains unsupported. A route/deployment request is selected only if its obtainable contribution warrants acquisition for this decision. |
| What counts as adequate service, and for whom? An attributed concern map. | The residents’ association emphasizes property protection. A separately heard group of mobility-constrained residents requires reachable assistance. Neither statement represents all residents. | Preserve the two service meanings; the hydraulic output does not settle their relation or priority. |
The account returns: “Nominal capacity is not presently the discriminating uncertainty. The mobile branch depends on an unqualified access premise. The service comparison must retain both property protection and reachable assistance.” It does not rank the branches.
If verified access evidence closes the transport gap, only the affected model claim and its dependent uses reopen. If no feasible pump branch supports the service concern, the problem boundary reopens. Repeated use of the same inflow dataset by both technical models supplies one evidence dependency, not two confirmations.
Suppose the board additionally asks whether securing an alternative road would get mobile pumps operating sooner during a main-road closure. Two mechanisms remain plausible: road access delays an otherwise ready crew and pump, or the flood also disables power at the staging site, preventing pump preparation even with another road. Use the causal-construction branch in :4.2 to compare road availability, pump-and-crew readiness and time to operation under the same assumed flood conditions. In the first account a usable alternative road removes the named access delay; in the second, preparation remains a limiting condition. These are conditional consequences of the proposed mechanisms. The scenario provides no evidence to choose between them or assert an arrival time.
Return the narrowed answer: another road could remove the access delay, while pump preparation remains a premise that can change its practical benefit. An operations result about readiness and the alternative route could resolve that distinction; :4.4 governs whether obtaining it is worthwhile. The residents’ two service meanings remain as stated in the concern map.