Video recap: ‘Transforming Drainage Design with AECOM’ using InfoDrainage + Civil 3D

As climate volatility and urban growth intensify, drainage systems are becoming a frontline resilience challenge. Across the UK and globally, heavier storms and expanding impermeable surfaces are overwhelming legacy sewer networks and increasing flood risk.

These are a few reasons why regulation has been shifting toward more sustainable outcomes – and that’s why SuDS (Sustainable Drainage Systems) have become so important. In the UK, in particular, the advancement of Schedule 3 of the Flood and Water Management Act has made SuDS mandatory for new developments.

We talked about this in a recent webinar “Transforming Drainage Design with AECOM”, which highlighted how AECOM are advancing this shift using Autodesk InfoDrainage and Civil 3D, creating more integrated, validated, and scalable drainage delivery.

Hosted by Smart Water Magazine and moderated by Editor-in-Chief Olivia Tempest, the webinar brought AECOM Senior Engineer Robin Chambers and our own InfoDrainage Product Manager Javier Soto to explore how integrated digital workflows are reshaping drainage design to better support SuDS outcomes.

You can watch the webinar right here on the One Water Blog, or you can read the summary we’ve put together below. 👇

AECOM’s workflow: start where the geometry lives, then iterate

One of the most practical parts of the webinar session was a question we at Autodesk like to ask of our customers who use both Civil 3D and InfoDrainage: Do you start in InfoDrainage, or do you start in Civil 3D?

Like most big design organisations, the answer was “it depends”:

• If you already have a road network and surfaces defined, starting in Civil 3D is efficient, especially since the location, grading, and slope of the site play a crucial role in shaping the initial drainage design approach.
• If you’re early-stage and working from architect layouts (or partial information), starting directly in InfoDrainage can be faster.

What matters is that the workflow supports iteration. As Javier put it, the integration between these two apps is already strong and improving continuously, so engineers can really work in whichever environment they’re most comfortable in, and still keep the data moving.

What did the audience say? In the webinar poll, a majority of attendees reported starting in Civil 3D and then importing into InfoDrainage. Either answer is correct, of course, but most people appear to start in Civil 3D.

Demo takeaway #1: Upgrading a foul network – and avoiding rework

The session contained multiple live demonstrations showing how existing drainage designs can be taken from legacy models to modern design. Rob demonstrated importing an existing foul network, then:

• Locking elements before using sizing tools (so the wizard doesn’t overwrite critical intent)
• Cleaning up inflows when needed (e.g., removing zero-area warnings), and inspecting pipes for blockages or damage that may require repair
• Reintroducing pump behaviour appropriately (rather than letting legacy constraints drive the outcome)
• Updating outfall levels, checking profiles, and maintaining a gravity-to-pumped system, emphasizing the importance of ongoing maintenance to ensure system performance

The point wasn’t just “you can import old files.” The point was: you can upgrade a design without starting over, then expand it with new phases and surfaces while preserving control.

Demo takeaway #2: Upgrading surface water UK SuDS features properly

The second demo is where SuDS really stood out. When converting from older workflows, SuDS features (ponds, permeable paving, etc.) may import as simplified shapes because the legacy approach often stored volume relationships without true spatial geometry. That’s not “wrong,” but it is incomplete for modern SuDS design.

Rob’s refinement steps were exactly what SuDS approval teams expect:

• Redraw SuDS features as freeform geometry that matches the intended footprint
• Move pipe connections to the true edge of a pond or feature (so lengths, gradients, and headloss are realistic). It is also essential to provide proper inlet and outlet protection at these entry and exit points to prevent erosion and sediment buildup, ensuring long-term performance of the drainage structures.
• Ensure the feature behaves as a flow-through system, not just a storage box, by providing sufficient capacity for water flowing through the system and incorporating debris control and sediment management to prevent blockages and maintain hydraulic efficiency.
• Culvert design, stream crossings, and open channels must also account for energy dissipation, debris, and sediment transport to prevent erosion and maintain the structural integrity of the system.
• The use of appropriate materials, such as concrete, for structures like culverts, bridges, and outlet structures is important to ensure durability and resistance to excess water and storm events.
• Proper foundation and grading are critical for drainage structures to ensure stability and optimal performance.
• Contractors and the right equipment play a key role in implementing and maintaining drainage features, including ditches, drains, and other structures.

When refining SuDS features, the most important aspect of drainage design is to ensure effective discharge and prevent the negative effects of excess water, erosion, and sediment transport, which can affect the longevity and safety of the infrastructure.

The message: This is the practical difference between “a model that runs” and “a model that represents the design.”

Sidenote: Why ‘validation-first’ is a big quality leap

Before analysis, InfoDrainage requires validation and this demo showed how useful InfoDrainage can be for validation. In Rob’s demo for validation, the software flagged:

• Unused inlets (after pipe edits)
• Missing conductivity values for permeable paving

This validation step is a hidden productivity win for UK SuDS teams because it catches the small issues that otherwise become late-stage review comments, resubmissions, or design assurance headaches.

Demo takeaway #3: turning analysis into deliverables via Civil 3D

Once the model was validated and running, Rob brought the design into Civil 3D. That workflow enables:

• Parts mapping to UK standards (eg, DCG-style components)
• Creating plan labels quickly
• Generating long sections using Civil 3D presentation tools
• Bringing SuDS geometry in as surfaces (useful for earthworks, coordination, and visual checks)
• Integrating drainage design with roadway layouts to ensure drainage structures accommodate traffic loads and support overall highway stability

For UK SuDS delivery, this matters because approvals and construction don’t happen inside the analysis tool alone, they happen through drawings, schedules, and coordinated models.

Q&A: common UK SuDS modelling questions

A few Q&A points from the webinar are worth capturing here because they come up on nearly every project:

• Permeable paving with underdrains: You can define underdrains within permeable paving (and similar features), including diameter and invert/release settings. This is critical for matching expected hydraulic performance.
• Sloped-bottom long ponds: Where ponds don’t support sloped bottoms directly, model the intent using multiple linked features (often swales or segmented elements) to reflect changing depths and gradients.
• Exceedance flows: Static checks are useful, but dynamic 2D analysis provides clearer evidence of where water goes, how deep it gets, and whether flooding is “acceptable” or critical. During extreme events, surface runoff is managed through drainage channels and stormwater systems to convey excess rainwater and prevent flooding, ensuring the drainage design performs as intended.

Of course, you must also audit drainage designs against local regulatory requirements and sometimes scale it from site-level design to city or catchment-scale modelling. The discussion reinforced that different tools serve different scales, but connected workflows enable better system-wide decisions.

What this means for UK SuDS teams

The strongest lesson from AECOM + Autodesk wasn’t a single feature – it was a workflow mindset: Design UK SuDS as an integrated system. Validate early. Iterate often. Output clearly.

If you do that, you get tangible benefits:

• Faster model build and updates
• Fewer “late surprises” in validation and review
• Better SuDS geometry fidelity (ponds, permeable paving, trains)
• Smoother handoff into Civil 3D deliverables and coordination

Finally, a comprehensive drainage report is essential for documenting runoff volume calculations and design decisions, ensuring regulatory approval and providing a clear record for agencies and stakeholders.

AECOM’s repeatable UK SuDS design workflow

At the end of the webinar, Rob laid out a practical step-by-step process to set based on how he advises AECOM’s drainage designers to do it:

1. Start your geometry in Civil 3D or InfoDrainage (whichever owns the truth first)
2. Bring in surfaces early
3. Model UK SuDS features as geometry, not placeholders
4. Analyze the course of water, watershed characteristics, and groundwater flow to ensure accurate hydrological modeling and effective drainage design
5. Use validation as a design gate, not an afterthought
6. Export to Civil 3D for drawings, schedules, and stakeholder communication

If you’re moving from legacy drainage tools or trying to standardise delivery across teams, this process is perhaps the best way to accommodate both Civil 3D and InfoDrainage users and ensure everyone is working together in lock step.

The high-level takeaway from the webinar

The webinar demonstrates how integrated digital drainage workflows support SuDS principles by improving coordination, validation, and design quality. By linking detailed site-scale modelling with broader system thinking, engineers can deliver drainage solutions that are more resilient, sustainable, and fit for future conditions.

Using InfoDrainage in your SuDS work

• We are big fans of SuDs and have articles about all of the SuDS features inside InfoDrainage detailing how they work, including rain gardens, bioretention systems, swales, infiltration trenches, cellular storage, porous pavement, soakaways, and wet ponds and infiltration basins.
• Grab a copy of Our essential guide to the CIRIA 753 SuDS manual for water management.
• Want to try InfoDrainage yourself? Download a free trial for 30 days (no credit card required). Are you a student or educator? You can use our water software for free.