Northeastern Connecticut Planning RegionConnecticut
Thompson, Connecticut
1 high-hazard dam is rated in poor or unsatisfactory condition. 5 of its 33 inventoried bridges are rated poor (15%, against 5% statewide).
- Live · as of Sep 11, 2026
- 9 public sources · method
- ← All towns
Bridges rated poor
5
of 33 inventoried
Poor high-hazard dams
1
National Inventory of Dams
01 · Dams & disasters
1 high-hazard dam needs work
| Dam | Condition | Built |
|---|---|---|
| North Grosvenordale DamFrench River | Poor | 1900 |
High hazard potential means failure would probably cost lives — it rates the consequences, not the dam’s condition.
02 · Bridges
5 of 33 bridges are rated poor — above the Connecticut rate of 5%
Every highway bridge and large culvert in the 2025 National Bridge Inventory that stands inside Thompson. Median age 61 years; 3 posted for weight.
9% good, 15% poor
FHWA good / fair / poor rating — the lowest of deck, superstructure, substructure or culvert.
- Good3 · 9%
- Fair25 · 76%
- Poor5 · 15%
Structures by decade built
n = 33 structuresSource: FHWA National Bridge Inventory 2025
▸ Show the numbers▾ Hide the numbers
| Built | Structures |
|---|---|
| 1920s | 1 |
| 1930s | 6 |
| 1940s | 3 |
| 1950s | 3 |
| 1960s | 14 |
| 1970s | 2 |
| 1980s | 2 |
| 1990s | 1 |
| 2000s | 1 |
The poor-rated bridges
| Carries | Over | Built | Daily traffic |
|---|---|---|---|
| BUCKLEY HILL ROAD | FRENCH RIVER | 1937 | 2,300 |
| BUCKLEY HILL ROADposted | FRENCH RIVER CANAL | 1976 | 2,300 |
| WILSONVILLE ROAD | FRENCH RIVER | 1936 | 1,300 |
| SPICER ROAD | FIVE MILE RIVER | 1972 | 275 |
| BAKER ROADposted | QUADDICK LAKE | 1940 | 246 |
03 · Next door
Thompson and the 6 towns that border it
A dash means no data for that layer, not zero.
| Town | Poor bridges | Rock depth |
|---|---|---|
| Thompson, CT | 5 / 33 | — |
| Putnam, CT | 2 / 27 | — |
| Burrillville, RI | 6 / 22 | — |
| Dudley, MA | 2 / 10 | 18 ft |
| Woodstock, CT | 2 / 9 | — |
| Webster, MA | 0 / 9 | 28 ft |
| Douglas, MA | 0 / 8 | 19 ft |
Where these numbers come from
Method, sources & caveats
Thompson is the Census county subdivision 0915075870 (Northeastern Connecticut Planning Region). Every record is placed here by its coordinates, not by the place name the source uses.
- Towns are Census county subdivisions: cities, towns, plantations, and Maine/New Hampshire unorganized territories and townships. Every record is placed in a town by its coordinates (point-in-polygon), not by the source's own place label — so a bridge in Roxbury counts for Boston and a well in 'North Waltham' counts for Waltham.
- Bridges: FHWA NBI 2025, highway structures ≥ 20 ft including large culverts. 'Poor' is FHWA's good/fair/poor rating (lowest of deck, superstructure, substructure or culvert ≤ 4). Percent-poor is shown only for towns with at least 5 structures.
- Depth to bedrock is the median of driller- and boring-reported depths in the town, shown only where at least 10 logs exist. Water-well logs over-sample rural lots and hilltops; one town median never describes a particular site.
- Bedrock depths use the same state databases and filters as the Bedrock & soils module (bedrock wells and borings that reached rock, 0 < depth ≤ 400 ft, exact re-filings dropped), but every log is placed in a town by its coordinates rather than the driller's town field, so town counts can differ slightly between the two pages. Connecticut and Rhode Island have no statewide public well-log database with depths.
- Dams: only high-hazard-potential dams whose latest condition assessment is Poor or Unsatisfactory are counted (live NID). Connecticut and Rhode Island assessments may lag.
- FEMA Public Assistance dollars are federal share obligated for disasters declared since 2010, reported by county — they are county context, not a town figure.
- Grant awards are Massachusetts only (EEA Dam & Seawall program, MVP Action grants, CZM Coastal Resilience). Other states' programs are not yet included.
- Ground-related permit counts cover only the municipal portals the pipeline reads (Boston, Cambridge, Somerville, Worcester, Framingham, Providence, Portsmouth, Hartford and a few others) — an absent count means 'not covered', not zero.
- Data as of
- Sep 11, 2026
- Generated
- Sep 11, 2026
- Records
- 367,748
- Refresh
- Live pull · weekly
- U.S. Census Bureau cartographic boundary files — county subdivisions (2024, 1:500k)Public domain
- FHWA National Bridge Inventory (2025 delimited files)Public domain
- USACE National Inventory of DamsPublic domainHigh-hazard dams rated Poor or Unsatisfactory (live NID).
- USGS U.S. Landslide InventoryPublic domain
- MassGIS / Massachusetts Geological Survey — Bedrock Data PointsPublic recordBorings and well logs that reached rock (MassDEP well drillers, USGS, MWRA, MassDOT…); seismic/HVSR and map-derived shallow-bedrock/outcrop points excluded.
- NH DES Water Well Inventory, Maine Geological Survey Wells Database, Vermont DEC well recordsPublic recordBedrock wells only; driller-reported depth to bedrock / overburden thickness.
- OpenFEMA Public Assistance Funded Projects Details (v2)Public domain
- MA EEA / CZM grant awards — Dam & Seawall, MVP Action, CZM Coastal ResiliencePublic record
- Municipal open-data permit portals (Boston, Cambridge, Somerville, Providence, Portsmouth, others)Public recordOnly permits flagged as ground-related (retaining walls, excavation, foundations) are counted.
Published by Earth Support Corp as a public resource. Regional statistics for planning and curiosity. They are not an engineering report, a bid recommendation or a statement about any particular site, firm or project. Spot an error? Tell us and we will correct it. Full method: methodology.