Placing Channel Drains
A channel drain is a surface-level linear drain with a grate that intercepts sheet flow across paved surfaces. Use it along driveways, patio edges, pool surrounds, and at building thresholds.
Channel DrainsA channel drain (also called a trench drain) is a linear, surface-level grated drain that collects water flowing across a paved area along its full length. You draw it as a multi-point path on the canvas — like a pipe — and set its channel width in the Inspector to match the product you intend to install. Use it anywhere a single point inlet would miss most of the flow: across a driveway apron, at the foot of a sloped patio, or along the edge of a pool deck. The Channel object lives in the Water tab under Surface Collection.
Draw the channel drain path
In Drainage mode, select the Channel Drain drawing tool. Click on the canvas to place the starting point of the channel, then click to add waypoints along the intended line of the drain. Double-click or press Enter to finish the channel. The channel renders as a thick surface-level line with a grate texture on the 2D plan.
Configure grate width and depth
Select the drawn channel drain to open the Inspector. Set the grate width in millimeters — typical residential channel drains are 100 mm to 200 mm wide. Set the channel depth in millimeters to reflect the internal depth of the drainage body. These values affect the visual scale on the plan and the flow capacity displayed in the Inspector.
Connect to the underground drainage network
Switch to the Draw Pipe tool and draw a drain pipe from the end of the channel drain (or from an outlet sump along its length) to a catch basin or outlet. The channel drain collects water along its full length and routes it to this connection point. Set the pipe diameter to match or exceed the channel's outflow capacity.
Set the channel width
Select the channel and open its Channel section in the Inspector. Drag the Channel Width slider to a value between 0.05 m and 0.5 m to match the grate product you plan to specify. The width is stored in meters internally and displays in your project's unit system.
Name the channel (optional)
In the General section, type a descriptive label in the Name field such as 'Driveway apron drain' or 'Pool deck perimeter'. Clear names make it easy to cross-reference the channel in cost takeoffs.
Connect to the drainage network
Place a Drain Pipe from the Conveyance & Discharge section to carry collected water from the channel to a catch basin or outlet point. The channel and pipe appear connected in your drainage plan.
Orient the channel perpendicular to the direction of slope. A channel running across the flow path intercepts the full sheet width; one running parallel collects far less water and may allow ponding at the low end.
Channel drains appear on the layer you draw them on. If you cannot see an existing channel, check that its layer is visible in the Layers tab.
Frequently Asked Questions
When should I use a channel drain instead of a drain inlet?
Use a channel drain when water sheets across a wide paved surface and a single point inlet would miss most of the flow. Use a drain inlet (point drain) when water converges to a single low spot.
How wide should I make the channel?
Set the Channel Width to match the grate product you intend to specify. The Inspector accepts widths from 0.05 m to 0.5 m. The width appears in cost takeoffs and any exported schedule.
Can a channel drain have bends or change direction?
Yes. Click additional intermediate points while drawing to create an L-shaped or stepped path. Each segment is straight; tight corners in real installations typically require a junction box or catch basin, which you can add with the Catch Basin object at the corner.
How does the channel drain appear in cost reports?
The channel is listed with its total run length and width. The run length is calculated from the path you drew, so drawing at true scale keeps the quantity right. Open the Cost view to see the line item and assign a rate.