From Arcanum Illyria
The Gravel Pit is a sovereign structure, enabled by scaffolding, which accelerates stone production.
Each level of gravel pit on any city's sovereign squares increases the stone gathering rate by about 1% (0.2% per stone plot). To build or upgrade a gravel pit on a tile, the owning city must have a sovereignty claim of matching level on the tile, and have achieved all the research prerequisites.
Economics
Building and upkeep costs
Level
| Build Cost
|
Wood Natural resource
| Clay Natural resource
| Iron Natural resource
| Stone Natural resource
| Measured span of time either expressed as components ([Ad] [Bh] [Cm] [Ds]) or one to three ordinals ([[hhh:]mm:]ss). Times are always exact to the second.
|
1
| 20 | 20 | 30 | 10 | 3:00
|
2
| 196 | 196 | 294 | 98 | 26:00
|
3
| 2,624 | 2,624 | 3,936 | 1,312 | 3:34:00
|
4
| 25,820 | 25,820 | 38,730 | 12,910 | 18:10:00
|
5
| 183,176 | 183,176 | 274,768 | 91,592 | 2d 13h 20m 61:20:00
|
Sovereign structures for natural resources have no
upkeep.