Brief description

A man-made channel constructed to convey water from a distant source to a point of use, such as a city, farm, or industrial site.

Use / Function

Primary use: Supplying fresh water for drinking, irrigation, and baths.
Secondary uses: Driving watermills, mining (hushing), and removing waste (sewers).
Scale: Massive civil engineering projects spanning kilometers.

Gravity Flow: The entire system relies on a continuous, very gradual downward slope (gradient) to keep water moving.
Bridges and Siphons: Arched bridges carry the channel across valleys, while inverted siphons (pressurized pipes) can cross deeper depressions.

Surveying: Use tools like a level (chorobates) to find a source higher than the destination and map a route with a constant slope.
Tunnelling: Dig tunnels through hills to maintain a direct path and protect the water.
Construction: Build the channel (specus) from stone or concrete lined with waterproof mortar.
Bridging: Construct arched bridges to cross valleys or rivers.
Distribution: At the destination, use a castellum (water tower) to settle sediment and distribute water via pipes.

Essential: Stone, Brick, Concrete (Roman).
Waterproofing: Hydraulic mortar (mixed with crushed pottery or pozzolana), Lead (for pipes).
Tools: Pickaxes, shovels, levels, cranes.

Open Channel: Simple ditch for irrigation (high evaporation).
Covered Channel: Stone or concrete tunnel to prevent evaporation and contamination.
Pressurized Pipeline: Modern aqueducts often use pumps and pressure, allowing them to go uphill.

Gradient: Too steep, and water damages the structure; too shallow, and it stagnates.
Maintenance: Mineral buildup (sinter) must be cleaned regularly.
Cost: Extremely expensive and labor-intensive to build.
Vulnerability: Strategic target in war (cutting water supply).