Designing the Network

With your background map or CAD layout imported, you are ready to construct the physical drainage network. The platform features an intuitive, node-link based drawing interface.

Drawing Pipes and Nodes

1. Activate the Pipe Tool: On the top Toolbar, click the "Pipe" icon.
2. Start Drawing: Click anywhere on the canvas to place your first manhole (Node).
3. Continue Routing: Click a second location to place the next node. A pipe will automatically be drawn connecting them. Continue clicking to route the mainline.
4. Branching: To create a branch line, press Escape to drop the current pipe, hover over an existing node until it highlights, click to start the new line from that node, and route as required.
5. Moving Nodes: Switch back to the "Select" tool (arrow icon). You can now click and drag any node. The connected pipes will rubber-band and maintain their connections.

Defining Catchment Areas

To assign runoff to specific nodes, you must define the impermeable areas draining to them.

1. Activate the Catchment Tool: Click the polygon icon on the Toolbar.
2. Draw the Boundary: Click around the perimeter of a roof or car park on your background map to draw a polygon. Double-click to close the shape.
3. Assign to Node: Click and drag the circular centre-handle of the new catchment polygon and drop it onto the target manhole. A dashed line will confirm the connection. The physical area of the polygon (in hectares) will automatically populate the "Catchment Area" property of that node.

Configuring Hydraulic Properties

With the layout complete, you must define the engineering parameters.

1. Select a Node or Pipe using the Select tool.
2. Open the Properties tab on the Right Sidebar.

Critical Node Properties

• Cover Level: The ground elevation. If you imported LandXML, this may already be populated. Otherwise, type it in manually.
• Invert Level: The elevation of the pipe invert at the bottom of the chamber.
• Storage: If the node represents an attenuation tank, change "Storage System" to Crate or Pond, and define the area and depth.
• Flow Control: If this node restricts flow, select a control type (e.g., Hydro-Brake or Orifice) and define the design flow ($L/s$) and design head ($m$).
• Outfall Type: The final node in your network must be configured as an Outfall. Select "Free" for standard discharge, or "Fixed Depth" / "Variable Stage" to model submerged outfalls (e.g., discharging into a river or tidal estuary).

Critical Pipe Properties

• Diameter: Define the internal pipe diameter in $mm$.
• Roughness ($k_s$): The Colebrook-White friction factor (e.g., $0.6$ for concrete).
• Slopes: The platform automatically calculates pipe gradients based on the Invert Levels of the connected nodes.

Tip: Use the Long Section chart at the bottom of the screen to visually verify that your pipes have positive gradients and are set at appropriate depths below the cover level.

Automated Pipe Sizing

Instead of manually setting every pipe diameter, you can use the Automated Pipe Sizing Algorithm to calculate them for you.

1. Once your network topology and catchments are defined, click the Auto Size Pipes (magic wand icon) button on the Toolbar.
2. The platform will dynamically calculate the Time of Concentration ($T_c$) for each pipe by tracing upstream flows.
3. It determines the exact rainfall intensity using your project's specified FSR/FEH parameters.
4. Using the Rational Method and Colebrook-White equation, it finds the required pipe capacity and selects the appropriate commercial diameter (e.g. 150mm, 225mm, 300mm).
5. Surcharge Handling: Pipes situated between an attenuation storage structure and a flow control device are expected to surcharge. The algorithm detects these zones and enforces a minimum diameter (150mm) rather than unnecessarily upsizing them.
6. Soffit Alignment: When the algorithm upsizes a pipe, it automatically adjusts the downstream pipe and node invert levels to keep the soffits (tops of pipes) aligned, while maintaining the existing gradients.

Version Control and Rollbacks

Drainage design is an iterative process. The built-in version control system lets you experiment safely.

1. Commit a Version: On the Top Bar, click the Commit button. The platform will automatically calculate a summary of what changed since your last commit (e.g., "Added 2 nodes, changed 3 pipe diameters"). You can accept this or write your own commit message.
2. View History: Click the History button to open the Version History panel. Here you can see a timeline of all saved checkpoints and their change summaries.
3. Rollback: If an experiment didn't work out, select a previous checkpoint from the history and click Rollback to instantly restore your network to that exact state.