---
title: "Flood hazard maps: two notices nine days apart, two opposite effective-date rules"
description: "Two notices from the same river basin authority, five municipalities, nine days apart: the same flood hazard change takes effect on the day of publication in one case, seven months earlier in the other."
url: https://csidia.com/en/notes/pericolosita-idraulica-due-regole-di-efficacia-opposte/
lang: en
date: 2026-08-31
label: "Regulation"
publisher: CSIDIA S.r.l. (https://csidia.com/)
italiano: https://csidia.com/note-operative/pericolosita-idraulica-due-regole-di-efficacia-opposte/
---

# Flood hazard maps: two notices nine days apart, two opposite effective-date rules

On 20 August 2026 the Official Gazette, General Series no. 192, publishes a notice from the Eastern Alps river basin district authority *(Autorità di bacino distrettuale delle Alpi Orientali)*: under decree no. 98 of the Secretary General, dated 21 July 2026, the flood hazard classification was changed for four municipalities in the province of Udine — Basiliano, Lestizza, Talmassons, Bertiolo. Nine days later, on 29 August, Gazette no. 200 publishes a second notice from the same authority: same subject, a fifth Udine municipality, Forni di Sopra, its flood hazard classification changed by secretarial decree no. 111 of 12 August 2026. Same authority, same subject, nine days apart — and two opposite rules on when the change actually takes effect.

## Two paragraphs, two legal bases

The first notice invokes Article 6(2) of the technical implementing rules *(norme tecniche di attuazione)* of the Flood Risk Management Plan; the second invokes Article 6(4) of the same rules. We have not read those technical implementing rules, so we make no claim about what substantively separates the two paragraphs. We record a textual fact: the two notices cite different legal bases, and — set side by side — those different bases carry two opposite effective-date rules.

## In force from the day you can read it, or from seven months earlier

Decree no. 98 is dated 21 July 2026; the Gazette announces it thirty days later (our calculation), on 20 August. For Basiliano, Lestizza, Talmassons and Bertiolo the notice is explicit about which date counts: «L’aggiornamento ha efficacia dalla data di pubblicazione del presente avviso nella Gazzetta Ufficiale della Repubblica italiana» *(the update takes effect from the date this notice is published in the Official Gazette of the Italian Republic)*. Not the decree's date: the notice's date. In force from 20 August 2026, the day anyone can read it.

Decree no. 111 is dated 12 August 2026; the Gazette announces it seventeen days later (our calculation), on 29 August. Here the mechanism runs the other way. The secretarial decree took note of the opinion of the Operational Conference *(Conferenza operativa)* no. 53 of 27 November 2025, and of the outcome of the district-wide mapping update ordered by resolution no. 12 of the Permanent Institutional Conference *(Conferenza istituzionale permanente)* of 18 December 2025 — twenty-one days after the opinion, our calculation — «vigenti dalla data del 22 gennaio 2026» *(in force as of 22 January 2026)*: thirty-five days after the resolution, again our calculation. The 29 August Gazette notice does not create that effective date: it records it. The mapping incorporated by decree no. 111 had already been in force for 218 days — a little over seven months, our calculation — by the time the notice appeared in the Gazette.

Neither notice says what actually changed — whether the hazard class went up or down, for which parts of each municipality's territory, relative to which earlier map. Both say only that the classification was modified, and point the rest to a secretarial decree the Gazette does not reproduce, saying only that it is «consultabile sul sito www.distrettoalpiorientali.it» *(available on the website www.distrettoalpiorientali.it)*.

## The timeline no single system holds in full

Flood risk, and how much of it climate change already accounts for, is something we have covered [elsewhere](https://csidia.com/en/notes/piena-autunno-cambiamento-climatico): the question here is narrower, and different — not how much risk a territory carries, but since when its official map legally says so.

For anyone who has to establish which hazard class a site was in on a given date — a building permit to check, a [catastrophe policy](https://csidia.com/en/notes/polizza-catastrofale-premio-proporzionale-al-rischio) to renew, due diligence on a warehouse, an investment appraisal — the difference between the two rules changes the answer. In the first case the date that matters is 20 August 2026. In the second it is 22 January 2026, seven months before the news reached the Gazette: anyone who stopped at 29 August to ask *since when* would have read the wrong date.

Reconstructing it for a single site means cross-checking six elements, and no archive holds them together: the management-plan mapping, with its version and validity date; the secretarial decree, which neither notice attaches; the Gazette notice, which in one case sets the effective date and in the other merely records it; the municipality's own planning instrument, which incorporates the classification on its own schedule; the building permit or the sale deed, with their own dates; the catastrophe policy, with its own coverage period. The Gazette publishes notices, not maps. The district authority's website publishes maps, not a register of effective dates per parcel. The municipality incorporates when it incorporates. None of the three holds the full sequence: it gets rebuilt by hand, one piece at a time, only when someone actually goes looking for it.

## Two notices out of nine issues

We checked how often this happens across the nine General Series issues published between 20 and 29 August 2026 — numbers 192 through 200; 23 August, a Sunday, has no ordinary issue. Across all nine, the word «pericolosità» *(hazard)* appears exactly twice, in the two notices examined here, both from the same authority: no other river basin district authority published a notice of this kind in the same window.

## What you need to keep, to answer three years from now

Three years from now, whoever has to establish which flood hazard class applied to a property in Bertiolo, or a plot in Forni di Sopra, on a specific date will need six things held together, not six separate archives: the version of the mapping in force on that date; the number and date of the secretarial decree that introduced it; the text of the Gazette notice, with its drafting code, because that — not the decree — is where the effective-date rule is stated; the matching extract of the municipal planning instrument; the building permit or notarial deed; the policy's coverage period. Today none of these six elements knows the other five exist.

## What we have not verified

We have not read the technical implementing rules of the Flood Risk Management Plan, so we do not know what substantively separates paragraph 2 from paragraph 4 of Article 6. We have not obtained the text of secretarial decrees no. 98/2026 and no. 111/2026: we know their numbers and dates, not their cartographic content. We do not know whether the new classification is more or less severe than the previous one, for any of the five municipalities: the notices do not say. We have not extended the recurrence count beyond the 20–29 August 2026 window, nor to other river basin district authorities in other periods. The website www.distrettoalpiorientali.it, named in both notices, was reachable at the time of our check (31 August 2026, 06:48 CEST); within the time available we did not, however, locate the specific page for the two secretarial decrees — which is not proof they are absent from the site. One verified technical detail, though: that server presents only its own certificate, without the chain’s intermediate one, so stricter clients refuse the connection while browsers fetch the missing piece themselves.

## Sources

- [Notice, Official Gazette General Series no. 192 of 20-08-2026, code 26A04258](https://www.gazzettaufficiale.it/eli/id/2026/08/20/26A04258/sg)
- [Notice, Official Gazette General Series no. 200 of 29-08-2026, code 26A04299](https://www.gazzettaufficiale.it/eli/id/2026/08/29/26A04299/sg)
- [Autorità di bacino distrettuale delle Alpi Orientali — institutional website](https://distrettoalpiorientali.it/)

Note by CSIDIA S.r.l. (Vignola, MO, Italy): https://csidia.com/en/notes/pericolosita-idraulica-due-regole-di-efficacia-opposte/ · Who we are and what we do: https://csidia.com/en/at-a-glance/ · engagement@csidia.com