Onn Point Civil Engineering

When drainage is considered early, it rarely feels like a problem.

✅ The layout works.

✅ The levels make sense.

✅ The SuDS features have space.

✅ The discharge route is clear.

It is when drainage is pushed to the end that it starts forcing compromises. ❌

At Onn-Point, we help developers, architects and planning consultants build drainage into the site strategy from the outset - so the design is practical, compliant and ready for scrutiny before it becomes a planning issue.

📞 01902 585206 | ✉️ [email protected]

At Onn-Point, we support developers, architects, planning consultants and contractors with drainage and civil engineering design that is practical, compliant and built around the realities of the site. 🏡💧

Our services include:

- SuDS strategies and stormwater attenuation

- Private drainage design

- Adoptable S104 drainage networks

- Highway and road design support

- Section 38, S184 and swept path design

- Flood Risk Assessments and drainage reports

- Percolation testing and hydraulic calculations

From early feasibility through to planning support and detailed design, we help identify constraints, reduce approval risk and create buildable solutions that move projects forward.

📞 01902 585206 | ✉️ [email protected]

No two sites behave the same. So no two drainage strategies should look the same either.

📍 Some need infiltration-led design.

📍 Some need attenuation and control.

📍 Some need a smarter route through difficult constraints.

Our job is to work out what fits, and design it properly.

That's the difference between a drainage strategy that fills a page, and one that helps move a project forward.

Get in touch with our team to discuss a project:

📞 01902 585206 | ✉️ [email protected]

Onn-Point was recently appointed to design an attenuation pond for a 5x building development with a total impermeable area of 970m² in Coleford, Gloucestershire. 📍

With the main site infrastructure already in place, the scheme required a dedicated attenuation feature to control surface water flows before discharge to the existing watercourse south of the site.

Key elements of the design included:

✔️ A new attenuation pond separating proposed flows from existing drainage features

✔️ Discharge restricted to 1 l/s in line with the agreed LLFA rate

✔️ 1 in 3 pond side slopes with minimum 300mm freeboard

✔️ Hydraulic modelling for the 100-year storm event plus 40% climate change allowance

✔️ Hydro-Brake flow control integrated within the outlet structure

A site-specific attenuation solution designed to manage runoff effectively, protect the wider site, and support long-term drainage performance.

📞 01902 585206 | ✉️ [email protected]

A site can look straightforward on paper - until the drainage is properly tested. 🌊 ❌

Ground conditions, levels, discharge routes and planning expectations all influence what can realistically be delivered, and what absolutely cannot.

At Onn-Point, we help developers, architects and planning consultants understand the site properly from the outset, so the drainage strategy is based on real constraints, accurate data and a buildable route forward. 🏡 ✅

The earlier that picture is understood, the stronger the decisions that follow.

📞 01902 585206 | ✉️ [email protected]

Following the national standards published in 2025 - meant to improve consistency, resilience and long-term performance in surface water design across England - a growing industry trend is that more councils are beginning to apply the new SuDS standards more directly at planning stage. 📍

What that means in practice:

✔ Closer review of drainage submissions

✔ More emphasis on how each standard has been addressed

✔ Stronger focus on maintenance and long-term performance

✔ Less tolerance for vague or generic SuDS statements

The direction is clear: drainage strategies now need to be sharper, better evidenced and more clearly aligned with the standards from the outset.

📞 01902 585206 | ✉️ [email protected]

Percolation testing is a simple process, but it has a major impact on the drainage strategy that follows.

At Onn-Point, the process typically looks like this:

1️⃣ Test the ground - A trial pit is prepared and water is introduced to assess how the soil drains.

2️⃣ Review the results - The infiltration rate is measured to understand whether soakaways are viable.

3️⃣ Shape the drainage route - Those results then inform whether an infiltration-led solution is realistic.

4️⃣ Support the next stage - The data is carried into the wider drainage design and planning submission.

Done properly, percolation testing removes assumptions early and gives the rest of the project a clearer route forward.

📞 01902 585206 | ✉️ [email protected]

Onn-Point was recently appointed to deliver a drainage strategy for a farm developments in Cirencester, supporting a scheme comprising a barn and multiple associated outbuildings. 📍

Following positive BRE365 infiltration test results, the strategy was designed around a straightforward SuDS-led approach that allowed surface water to discharge naturally via soakaways.

Key elements of the design included:

✔ Soakaway systems sized to suit the site and runoff volumes

✔ Permeable paving across hardstanding areas

✔ Filter drain directing flows to the proposed soakaway

✔ Catchpit manholes integrated into the layout

✔ A system designed for the 100-year storm event plus climate change allowance

A practical drainage solution designed to support planning while delivering reliable long-term surface water management across a working rural site.

📞 01902 585206 | ✉️ [email protected]

Onn-Point provides practical drainage support from the first site questions through to planning-ready design. 🤝

Our service offering includes:

1️⃣ Percolation testing and infiltration-led design

2️⃣ SuDS strategies and drainage statements

3️⃣ Soakaway and attenuation design

4️⃣ Hydraulic modelling and supporting calculations

5️⃣ Drainage layouts, details and maintenance strategies

Everything is built around one objective - giving clients a drainage solution that is clear, compliant and ready to move the project forward.

📞 01902 585206 | ✉️ [email protected]

In England, the new national SuDS standards published in 2025 are intended to promote consistency and improve long-term performance and resilience. They now apply to new development and can also inform retrofit schemes.

What that means in practice:

💧 More scrutiny on surface water strategies

🛠️ Greater focus on long-term maintenance

📍 Stronger expectation for site-specific design

❌ Less room for generic drainage submissions

The direction is clear: drainage design needs to be more robust, better evidenced, and built for long-term performance.

📞 01902 585206 | ✉️ [email protected]