1001 Smart Cities

Permanent project revision

TARP: Chicago's Deep Tunnel & Reservoir System

Revision 2026-10-05-baseline · effective 2026-10-05

Current revision. This is the snapshot used by the live entity page.

unreviewed

Created the first structured Evidence Passport with 18 claims and 8 source dossiers.

sha256:f73abad17a695d8ea7600f0271c7bf5694141c6f4b80e8f020e39bdb81a4415e
All revisions → Current entity page →

Change set

  • add /evidencePassport — Added claim-level evidence mapping and source dossiers.
  • add /revisionHistory — Established a permanent, hash-addressed baseline revision.
18
of 18 claims mapped
8
source dossiers
3
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-35e3497fcff2d510 descriptive
a county agency, not the city
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD describes itself as a special purpose government agency responsible for wastewater treatment and stormwater management in Cook County, and publishes a page on the differences between itself and the Chicago Department of Water Management.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 2 clm-b9f41ba0708fc4e7 quantitative
has built TARP since 1975
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'TARP tunnel construction began in 1975.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 4 clm-408dfb0463afc209 quantitative
150 to 300 feet down
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: tunnels '8 to 33 feet in diameter and 150 to 300 feet underground'.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 5 clm-e0443c6cbfbf3f93 quantitative
feeding reservoirs that now hold over 11 billion gallons
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'The system currently has a capacity of more than 11 billion gallons for combined sewage and stormwater.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 6 clm-22590ba1b87e22c8 descriptive
MWRD publishes reservoir fill levels on a public live map
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD's TARP Reservoir Levels page shows a map of fill levels at Thornton, McCook and Majewski, with a full-screen view and a link to a live view of McCook.
Caveat
The page states no update interval.

Sources carrying this claim

  1. MWRD — TARP Reservoir Levels (authority, the data layer)
Claim 7 clm-aabe815e3d8110a4 quantitative
Overflow days fell from about 100 a year to 50
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'Since the tunnels were completed in 2006, CSOs have been reduced from an average of 100 days per year to 50.'
Caveat
The district's own figure.

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 8 clm-e76203669ab1a602 quantitative
McCook Stage 2 has slipped to 2032
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD (Aug 2025): consent decree required operation by 31 December 2029; 'the current estimate for McCook Stage 2 going online is now Dec. 31, 2032.' The June 2026 status report repeats 2032.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — issues update on the Tunnel and Reservoir Plan, 15 August 2025 (authority)
  2. MWRD — TARP Status Report, second quarter of 2026 (August 2026)
Claim 9 clm-c7d492567020dc23 quantitative
MWRD reports combined sewer overflows fell from an average of 100 days a year to 50 once the tunnels came online
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'Since the tunnels were completed in 2006, CSOs have been reduced from an average of 100 days per year to 50.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 10 clm-defd61cb87509e8c quantitative
overflows in the Thornton Composite Reservoir's service area have been eliminated since 2020
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'Thornton Reservoir has completely eliminated CSOs within its service area since 2020.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 11 clm-3f6df8c1e62feada quantitative
TARP has captured over 1 trillion gallons of combined sewage since 1981
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: 'Since the first portions of the system were put in operation in 1981, TARP has captured over 1 trillion gallons of combined sewage.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
Claim 12 clm-7a4d30b183b648d8 quantitative
about 140 billion of it by McCook Stage 1 alone by June 2026
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Status report as of 30 June 2026: 'Since becoming operational, Stage 1 of the McCook Reservoir has captured approximately 140 billion gallons of combined sewage.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — TARP Status Report, second quarter of 2026 (August 2026)
Claim 13 clm-d2e4d532034512d6 quantitative
the tunnel system captures about 85% of the combined-sewer-overflow pollution from its service area
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Status report: Phase I projects 'capture and enable treatment of about 85% of the combined sewer overflow (CSO) pollution from TARP’s service area.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — TARP Status Report, second quarter of 2026 (August 2026)
Claim 14 clm-f0f94e0a0b868a48 descriptive
All figures are the district's own; no independent evaluation was found
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The only independent technical source on file, a University of Illinois modelling programme, describes model development, not an evaluation of outcomes.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Ven Te Chow Hydrosystems Laboratory, University of Illinois — Tunnel and Reservoir Plan (academic, boundary source)
Claim 15 clm-4435ec2225107b69 quantitative
Fifty years and more than $3 billion halved overflow days
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Construction began 1975 (MWRD); Wikipedia gives 'over $3 billion' across 30 years of construction and the 2026 status report totals $3.861 billion in contract-award dollars; MWRD reports overflow days cut from 100 to 50.
Caveat
Costs are contract-award amounts, not adjusted for inflation.

Sources carrying this claim

  1. MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator)
  2. Wikipedia — Tunnel and Reservoir Plan (reference)
  3. MWRD — TARP Status Report, second quarter of 2026 (August 2026)
Claim 16 clm-f39f38a0ed70d7b8 quantitative
in July 2026 McCook sat between 96% and 100% full
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
WBEZ: 'The McCook reservoir in southwest suburban Bedford Park fluctuated between 96% and 100% full.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. WBEZ Chicago — Deep Tunnel nearly full after days of heavy rain, 6 July 2026 (press)
Claim 17 clm-5bee81a65b0d4f79 quantitative
311 logged almost 400 complaints of water in basements
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
WBEZ: 'The city’s 311 system received almost 400 complaints about water in basements and nearly 600 reports about flooded streets between Thursday and Monday afternoon.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. WBEZ Chicago — Deep Tunnel nearly full after days of heavy rain, 6 July 2026 (press)
Claim 18 clm-f20a91e569a4825d quantitative
the neighbourhood sewers, which handle about 2 inches of rain before flooding is likely, not the tunnels, are the bottleneck
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
MWRD: basement backups can occur 'even when there is plenty of room in TARP' if small neighbourhood sewers lack capacity; Smart Cities Dive, citing the Chicago Sun-Times: 'the city’s sewers can handle just 2 inches of rain before flooding is likely'.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MWRD — TARP Reservoir Levels (authority, the data layer)
  2. Smart Cities Dive — with extreme rainfall overwhelming Chicago's sewers, the city tries a new approach, July 2026 (trade)

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-10-05-baseline effective 2026-10-05 · created 2026-10-05

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:f73abad17a695d8ea7600f0271c7bf5694141c6f4b80e8f020e39bdb81a4415e
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
18
of 18 claims mapped
8
source dossiers
3
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Metropolitan Water Reclamation District of Greater Chicago (MWRD), a county-wide agency separate from the City of Chicago
Actor types
utility
Funding model
public
Funding description
MWRD, with federal cost-sharing through the US Army Corps of Engineers
Cost
$3.861bn total programme cost (MWRD status report, 30 June 2026)
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

8 source dossiers

MWRD — Tunnel and Reservoir Plan (TARP) (authority, operator) mwrd.org · 10 linked claims

Open original source ↗

Stable source ID
src-80e956e9e0d826da
Publisher
Name not classified · mwrd.org
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Operator page. Carries the scale and the outcome figures sentence-level: 'four tunnel systems totaling 110 miles of tunnels, 8 to 33 feet in diameter and 150 to 300 feet underground'; 'The system currently has a capacity of more than 11 billion gallons for combined sewage and stormwater'; 'since the first portions of the system were put in operation in 1981, TARP has captured over 1 trillion gallons of combined sewage'; 'CSOs have been reduced from an average of 100 days per year to 50'; Thornton eliminating CSOs in its service area since 2020. Reservoir dates: Majewski 1998, Thornton 2015, McCook Stage 1 2017.

Descriptive only — not page/paragraph exact
Claims linked
MWRD — TARP Reservoir Levels (authority, the data layer) mwrd.org · 2 linked claims

Open original source ↗

Stable source ID
src-8f31e8b33b7e0558
Publisher
Name not classified · mwrd.org
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

This is the measurement layer the entry rests on: a public interactive map of live reservoir fill levels, with a full-screen view and a live camera on McCook. The page states no update interval or units, so the entry claims only that fill levels are published live, not any accuracy or frequency.

Descriptive only — not page/paragraph exact
Claims linked
MWRD — issues update on the Tunnel and Reservoir Plan, 15 August 2025 (authority) mwrd.org · 1 linked claim

Open original source ↗

Stable source ID
src-db5fbe1ffae9ee27
Publisher
Name not classified · mwrd.org
Type / language
web-page · language not classified
Published
2025-08-15
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Currency source, and the correction that matters: 'The current estimate for McCook Stage 2 going online is now Dec. 31, 2032.' Consent decree entered 6 January 2014 originally required mining complete by 31 December 2028 and operation by 31 December 2029; the delay is attributed to a slowdown in Chicago-area stone demand. Also: McCook Stage 1 'has already captured approximately 130 billion gallons'; Stage 2 brings McCook to 10 billion gallons; the system serves 3.1 million people across Chicago and 36 suburban municipalities.

Descriptive only — not page/paragraph exact
Claims linked
WBEZ Chicago — Deep Tunnel nearly full after days of heavy rain, 6 July 2026 (press) wbez.org · 2 linked claims

Open original source ↗

Stable source ID
src-5fa5fe5b043f01a9
Publisher
Name not classified · wbez.org
Type / language
web-page · language not classified
Published
2026-07-06
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Counterweight and 2026 currency, sentence-level: 'The McCook reservoir in southwest suburban Bedford Park fluctuated between 96% and 100% full' after 'more than 8 inches of rain over the past 30 days'; 'The city's 311 system received almost 400 complaints about water in basements and nearly 600 reports about flooded streets between Thursday and Monday afternoon.' Also carries the independent view: 'Experts say that Deep Tunnel isn't enough to prevent flooding.'

Descriptive only — not page/paragraph exact
Claims linked
Ven Te Chow Hydrosystems Laboratory, University of Illinois — Tunnel and Reservoir Plan (academic, boundary source) vtchl.illinois.edu · 1 linked claim

Open original source ↗

Stable source ID
src-5b22692946ae6eed
Publisher
Name not classified · vtchl.illinois.edu
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Boundary source, and the reason this entry claims no automation: 'The MWRDGC now desires to develop a new, updated and enhanced computer model for each TARP system, to allow real-time control of the TARP systems.' Real-time control is a stated goal of a modelling research programme, not a documented operating system. Earlier models 'were based on design, rather than as-built specifications for the system and are now outdated.'

Descriptive only — not page/paragraph exact
Claims linked
Wikipedia — Tunnel and Reservoir Plan (reference) en.wikipedia.org · 1 linked claim

Open original source ↗

Stable source ID
src-09b747e9e81d2eb5
Publisher
Name not classified · en.wikipedia.org
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Reference work, used only for dates and cost where MWRD does not state them: 'adopted in 1972, commenced in 1975, and completed and operational by 2006'; '109.4 miles of drainage tunnels ranging from 9 to 33 feet in diameter, up to 350 feet underground'; 'Across 30 years of construction, over $3 billion has been spent on the project.' Its reservoir capacities (Majewski 350 million, Thornton 7.9 billion, McCook Stage 1 3.5 billion gallons) and 2032 Stage 2 date agree with MWRD.

Descriptive only — not page/paragraph exact
Claims linked
Smart Cities Dive — with extreme rainfall overwhelming Chicago's sewers, the city tries a new approach, July 2026 (trade) smartcitiesdive.com · 1 linked claim

Open original source ↗

Stable source ID
src-7bf429bb042b71fc
Publisher
Name not classified · smartcitiesdive.com
Type / language
web-page · language not classified
Published
2026-07-13
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The city's local answer to TARP's limits, and the source of the agency split: the $12 million Wing Storage pilot is 'a partnership between the Chicago Department of Water Management and the Metropolitan Water Reclamation District of Greater Chicago' — two vaults under West Side streets holding nearly 1.7 million gallons for more than 2,900 buildings, announced 8 July 2026. No sensors, monitoring or control layer is described; water is released back into the sewer as capacity frees up.

Descriptive only — not page/paragraph exact
Claims linked
MWRD — TARP Status Report, second quarter of 2026 (August 2026) mwrd.org · 5 linked claims

Open original source ↗

Stable source ID
src-905f5de4a1f1d5ee
Publisher
Name not classified · mwrd.org
Type / language
pdf · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-05
Dossier created
2026-10-05
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Phase I's 110 miles of tunnel capture about 85% of CSO pollution from the service area; McCook Stage 1 has captured about 140 billion gallons; Stage 2 about 75% excavated and expected operational in 2032; total TARP cost $3.861 billion in contract-award dollars.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this file
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.