---
title: who already works the montreal overflow
canonical_url: https://ensurance.app/guide/who-already-works-the-montreal-overflow
markdown_url: https://ensurance.app/guide/who-already-works-the-montreal-overflow.md
subtitle: the city holds the tanks. there is no watershed fund on this island.
category: ecosystem-services
---

# who already works the montreal overflow

*the city holds the tanks. there is no watershed fund on this island.*

The City of Montréal already works the overflow. It builds tanks so wastewater waits, and it is building ozone disinfection at the plant that discharges to the St. Lawrence. There is no watershed fund beside that work. This series will not invent one, and it will not send you a bill for the plant the city is already constructing.

That is an unusual last page. The island depends on the river and on the interceptors. The river, the port's channel, and the boroughs depend on the island. The person who already shows up for the sewer half of that dependence is the city's water department. The specific next step is to use their pages, and, if you want the reach itself named, to co-create a line under the agent that already exists. It is not a pitch to a pension fund.

:::johnson
**the city holds the tanks. nobody has priced the river.**

The overflow program is the hero. A fund that does not exist is not a hero, and this page will not pretend otherwise.
:::

## what the city already operates

Retention structures are the overflow program in hardware. The city says the network can capture nearly **49 million litres**, then send that volume to **Jean-R.-Marcotte** when the plant can take it. **Rockfield**, in LaSalle, holds up to **45,000 cubic metres** once it is the largest of the set. **Lavigne** is described as **20,000 square metres**, an area, not a volume. Those are the city's figures. They are not added here, and they are not a certificate.

The plant is the other half of the same public works. On 16 March 2022 the executive committee's deck put a revised disinfection budget at **$696.2 million**, design flow at **40 cubic metres per second**, and the commissioning aim at mid-2025. On 27 March 2026 the city's own project page said phases 4 through 6 run to the **end of 2028**. The end date moved. The budget figure did not get a new public revision in these notes. Treat the deck as the money document and the 2026 page as the schedule document. Do not blend them into a single "almost done."

The English project page is plain about the remaining discharges. Overflows are expected when it rains hard or when snow melts, including while treatment capacity is reduced for the works. The tanks and the ozone unit are the city's answer to that. Ozonation treats wastewater. It does not restore a rapid, and it is not a shore. The notes on this island put any later funding on the retention landscapes and on the receiving river, not on a second disinfection technology. Read that as a boundary around the city's project. Read it as respect for work already in construction. Do not read it as a product.

The English city page's claim that the plant treats **45%** of Québec's wastewater sits next to a daily-volume sentence these notes do not use. If you cite the 45%, cite the caveat with it.

## what is not a fund

A watershed fund, in the sense of a standing pool that already pays for the living reach, is not in the record. The city is spending public money on gray works. That is an operator. It is not a FONAG, and it is not a ratepayer endowment with a name you can join.

The port is also already moving. Shore power in 2024 was **12** connections, **717,064 kWh**, and **570.4 tonnes** of greenhouse gas avoided. The authority is in a process with Environment and Climate Change Canada toward a National Wildlife Area at Îles-de-Boucherville, and it has mentioned reforestation at Contrecœur. That is real work on emissions equipment and on a shoreline file. It is not a fund that pays for spring stage on Rivière des Prairies. Operating revenue of **$143 million** in 2024 is the size of the port's business. The notes say the recommended nature investment was not sized. This page refuses to turn the revenue into a budget.

Hydro-Québec should be on a flood map. The 2017 report said the vulnerability of utility networks was incompletely understood. No utility flood dollar is available, so none is printed. Ice and canopy stay on [what financing urban heat island mitigation actually is](/guide/what-financing-urban-heat-island-mitigation-actually-is?from=guide).

Ivanhoé Cambridge, operating as La Caisse real estate since June 2025, has its headquarters on the island. The Montréal buildings that might take flood or heat were not listed. Until they are, there is no exposure to price and no buyer to invoice. Insurers paid a two-province bill in 2017. Their Montreal book was not opened. They are not a row on this page.

Nothing in the sources is an annual nature budget for this outcome. A reader who needs a dollar before they can act does not get one from us. They get a sentence that says the dollar was not published.

## the reach, named, without a sale

The fluvial St. Lawrence around the island exists whether or not anyone buys a certificate. **Ensurance** is a way that reach could be funded. It is not the reach, and this series is not selling a unit of it.

What does exist is a parent. [Rivers and lakes](/rivers-lakes.ensurance?from=guide) is live. [Flood resilience](/flood-resilience.syndicate?from=guide) is live. A line called **fluvial st lawrence** is in ideation under the rivers-and-lakes agent. The name means the island reach: Rivière des Prairies, Lac Saint-Louis, the Lachine Rapids, the harbour channel. It does not mean the whole river to the gulf.

Co-create it with us. A person reviews what you submit. The parent agent receives it. Use [this suggest door](/specific/create?mode=suggest&agent=rivers-lakes.ensurance&name=fluvial%20st%20lawrence&from=guide). That is a name for a living edge, with a human in the loop. It is not a checkout, and it is not a claim that a certificate is already on a shelf.

Do not route this through the old Montreal situs, and do not route it through the legacy city basin. Those objects exist onchain and they are the wrong door. A deprecated place marker is not the river.

## what you can do on monday

If you live on one of the shores the 2017 report named, the useful objects are the city's report and the city's tank page, not a new pledge. Read [the 2017 flood report](https://ville.montreal.qc.ca/pls/portal/docs/PAGE/COMMISSIONS_PERM_V2_FR/MEDIA/DOCUMENTS/DOCCONSULT_ANG_20171212.PDF) and the page on [retention structures](https://montreal.ca/en/articles/retention-structures-limiting-wastewater-discharge-14459). Then you know which mechanism reached your street, the spring or the surcharge.

If you work the plant or the port, keep the river distinct from the tank, and correct the public profile that still marks river flood as unknown while your own report counts the homes. The GCoM field is on [the Montréal profile](https://www.globalcovenantofmayors.org/cities/canada/canada/montreal/).

If you want the dependence from the other side, start back at [montreal stands in the river](/guide/what-montreal-stands-in?from=guide). The port's channel is [who depends on the river at montreal](/guide/who-depends-on-the-river-at-montreal?from=guide). The drop that is not a pipe is [the lachine rapids](/guide/the-lachine-rapids-are-not-a-pipe?from=guide). The homes are [the spring that reached montreal](/guide/the-spring-that-reached-montreal?from=guide).

The living thing is the river around the island. The person who already cares, in public works rather than in a slogan, is the city's overflow program. One next step: open the retention page and see the volume they are already holding out of that river. If the reach itself should have a name other people can find, co-create the line. Bring a number if you have one. This page did not invent one for you.

## frequently asked questions

### who pays for montreal's sewer overflows today?

Ville de Montréal. The retention network and the Jean-R.-Marcotte ozone project are public works. The 2022 deck's revised disinfection budget was $696.2 million. The 2026 city page runs the remaining phases to the end of 2028. That is the city's project, not a watershed fund.

### is there a montreal watershed fund?

No fund of that kind is in the notes. The port publishes climate-risk work, shore power, and a wildlife-area process. Those are not a standing fund for spring flood. This series does not invent a substitute.

### is there a price for the port or for property on this island?

No price is in these notes. The port's nature investment was not sized. Property capital's Montréal slice was not sized. Insurers were not assessed as a Montreal book. A line under rivers and lakes can be co-created. It is not an invoice.

### where does the wastewater go?

To the St. Lawrence, from Jean-R.-Marcotte, after the plant treats what it can. What the interceptors cannot take in a hard rain or a melt can still discharge before that. The tanks exist to cut that discharge. The river is the receiving water either way.

## sources

[City of Montréal, retention structures](https://montreal.ca/en/articles/retention-structures-limiting-wastewater-discharge-14459) — what the overflow program holds.

[Executive committee deck, 16 March 2022](https://ville.montreal.qc.ca/documents/Adi_Public/CE/CE_DA_ORDI_2022-03-16_09h00_Presentation_Desinfection_station_epuration_-_Jean-R._Marcotte.pdf) — $696.2 million revised, design flow, mid-2025 aim.

[City page, 27 March 2026](https://montreal.ca/articles/travaux-la-station-depuration-jean-r-marcotte-actualites-et-impacts-35019) — works through December 2028.

[Ozone project, English page](https://montreal.ca/en/articles/ozone-disinfection-construction-jean-r-marcotte-water-treatment-station-27451) — overflows still expected.

[Montreal Port Authority, benefits and traffic 2024](https://www.port-montreal.com/en/benefits-and-traffic-2024) — shore power and the Boucherville process.

[GCoM, Montréal](https://www.globalcovenantofmayors.org/cities/canada/canada/montreal/) — river flood still marked not known.

## the series

- [montreal stands in the river](/guide/what-montreal-stands-in?from=guide)
- [who depends on the river at montreal](/guide/who-depends-on-the-river-at-montreal?from=guide)
- [the lachine rapids are not a pipe](/guide/the-lachine-rapids-are-not-a-pipe?from=guide)
- [the spring that reached montreal](/guide/the-spring-that-reached-montreal?from=guide)
- [who already works the montreal overflow](/guide/who-already-works-the-montreal-overflow?from=guide)