82 A personal history of urban drainage modelling 1984 to 2044 – Part 1

Background

Last week saw the annual UK conference of the Urban Drainage Group of the Chartered Institution of Water and Environmental Management.? It was a great conference with presentations and workshops on DWMPs (of course) but also sessions on reducing the environmental impact of overflow spill and urban runoff and on the use of blue-green infrastructure to both improve drainage and improve our living spaces.

It was a particularly great conference for me as I was unexpectedly awarded the WaPUG prize for significant contributions to the development of urban drainage practice.? I was honoured and gobsmacked in equal parts.? It is the second time that UDG has honoured my work.? In 2014 I was asked to present the keynote address at their thirtieth anniversary conference - on the history of urban drainage modelling from 1984 to 2014.? I expanded the scope to look forward to 2044.?

I thought that it was time to revisit that presentation as a blog.? I have had to make a few edits so that it is understandable as a blog in 2023 rather than as a presentation in 2014, but I have not otherwise updated it.?

For each five years I take a person or event that influenced or inspired me.? So this episode is longer and more personal than usual.

This blog is the first half of it to 2014.? The second half is to follow.

Previous

Back before 1984, when I was first starting my career as a graduate civil engineer, it was still not only permissible, but even laudable to aspire to Treadgold’s definition of a civil engineer – “to direct the sources of power in nature for the use and convenience of man”.

Since then we have discovered that there are some forces of nature that we cannot direct; the climate, the world economy, corporate greed.? So we perhaps need a different approach.? At the FutureFest conference in 2013, one of the speakers suggested that we should turn this on its head and direct the sources of power in man for the use of nature.? He had in mind genetic engineering and prosthetics but I think that we can do a lot with modifying our behaviours and the way that we think about solving problems.? What will you do?

1984

In 1984 I was working at WRc on the pilot studies of the Sewerage Rehabilitation Manual and the Wallingford Procedure.? The team was led by this man, David Fiddes, shown here in 2014 enjoying his retirement in the west of Scotland.? One of the principles that he helped to establish in the Sewerage Rehab Manual was that the biggest cost of sewer collapse is the increase in repair cost and the cost of traffic and business disruption.? The flooding and pollution impacts were much less.

Admittedly things have changed since; construction techniques have improved and we put a higher value on flooding and pollution, but traffic has got worse.? So I think that in general it is still repair and disruption that are the biggest impacts.

And yet the methodologies that many water companies use to prioritise and assess collapse risk; ignore those disruption costs because they are costs to society; instead they only consider the flooding impacts that count towards customer SIM.

The result is that we do not prevent collapse of disruptive sewers.? I had thought of illustrating this point with photographs of all of the traffic jams caused by sewer collapses that I have been stuck in during the last couple of years but there were too many.

So the big lesson is that we need to keep adapting our methodologies to cope with the current day; but not forget the principles and the learning that underpins those existing techniques.

1989

Moving forward 5 years and the new focus was water quality modelling and the Urban Pollution Management manual.? This is Judy Payne who worked with me at HR Wallingford on developing those techniques.? But I wasn’t going to talk about her influence on that.? She then moved to the Construction Industry Research Association, CIRIA, and headed up their work on Sustainable Drainage Systems; but I wasn’t going to talk about that either.? She now works as a specialist in knowledge management techniques, advising companies on how to encourage a culture of sharing know-how.? One of her themes is that there is no longer such a thing as an individual expert – a team can always know more.

At the first WaPUG events in London we had a Modellers Question Time.? A panel of four supposed experts, who were expected to be able to answer any urban drainage modelling questions that the audience wanted to ask.? WaPUG and the industry have moved on since then.? No four people would now be expected to know everything and we have moved from a panel of experts towards a learning community where knowledge flows freely between members.? Except it tends to flow freely only three times a year at the conferences and the training day.? We tend to be dormant in between.

So a challenge to UDG and all of us who are part of the community.? How do we keep the sharing of knowledge going throughout the year; particularly through the use of on-line communication and social networking?

So 1989 was, I think, the first year that Judy and I both gave papers at the WaPUG autumn conference.? We did so again in 1991 and at the end of that conference was a public announcement of our engagement.? We were married the following year and yes, we are still together.

1994

This is Professor Ben Chie Yen who pretty much invented the idea of urban drainage simulation modelling.? Ben had a catchphrase that always stuck with me “all models are wrong; but some of them are useful”.? I have since discovered that he stole it from a famous statistician.

I understand it to mean that when we compare the results of a model to reality we will always find a discrepancy.? But what is important is what the model can tell us about other conditions that we cannot actually measure

I think that we have lost sight of Ben’s legacy.? We focus so much on “verifying” a model to exactly match inaccurately measured flows caused by uncertain rainfall on a catchment of unknown condition; that we lose sight of the impact of the changes on predictions of performance in design storms.

We need to focus much more on historical verification, where we are close to the conditions that we are actually interested in.? But we still consider historical verification to be an afterthought when we have done the “real” verification against flow monitors.

I want to see changes to the way that we report on verification.?? We need to report historical, dry weather and storm verification together; not in separate chapters and there should also be a discussion of the impact of the changes that we have made to the accuracy of the predictions in a design event.? Let’s start now.

1999

Not someone who directly worked on urban drainage but he wrote a lot about problem solving and thinking outside the box.? It is Douglas Adams the author of the Hitch Hikers Guide to the Galaxy.

I used to have a quote from the Hitch Hikers Guide pinned above my desk.? It originally referred to the drinks machines made by the Sirius Cybernetics Corporation; but I thought that it was a good description of urban drainage models.

“Their fundamental design flaws are completely hidden by their superficial design flaws”

The point that I want to make here is that there is so much information that goes into building an urban drainage model that it is almost impossible to check it once it is completed. ?Yes we can audit models, we can even use automated confidence scoring tools; but we might still find that the fundamental flaws are completely hidden by the superficial flaws.

I think that we need to replace the audit specifications that we have been using for the last 20 years and adopt a new approach where we audit the process of producing the model, as well as the resulting model.? So the approach would be much more like ISO9000 audits that look at how the work is being done not just the outputs.? We are now adopting this at Mouchel with Technical Reviews from outside of the project team as the work is being done.? How about something more formal with modelling teams audited for good practice and perhaps even issued with a certificate.? What role for UDG in establishing that?

2004

In 2004 the Public Accounts Committee issued a report on sewer flooding.? They didn’t pull their punches – "Sewer flooding is among the worst service failures that a householder can suffer."

The change in our complacency about flooding was influenced by this lady, Mary Long-Dhonau who got fed up with being repeatedly flooded and decided to do something about it; so she started the National Flood Forum.? The first time that I saw her present at a conference it brought home to me that flooded households are not just numbers on the DG5 registers but also lives blighted and damaged.

So yes, things have improved, but not enough.? We have reduced the number of properties at risk of flooding due to hydraulic overload but we don’t give enough priority to properties flooded by blockage and collapse.? These failures now account for as much as 80% of flooding incidents.

Some companies have done a lot on proactively dealing with blockages but not all.

But maybe the next five years will be different.? We now have to consider outcomes – the numbers of properties flooded; and we need to consider how to reduce that using capex, opex, totex.? I foresee a point about half way through AMP6 when Mary’s message finally hits home and companies want to do something about other causes flooding.? Mouchel has been working on it for 10 years; we may be able to help.

2009

The floods in the UK in 2007 were a real wake up call, at least in the short term, and the Pitt review of 2008 and the Flood and Water Management Act of 2010 finally gave some official recognition to the concept of sustainable drainage.

Here is a quote from one of the early advocates of sustainable drainage.?

“A tarred road, she shoots every drop o' water into a valley same as a slate roof.? 'Tisn't as 'twas in the old days, when the waters soaked in and soaked out in the way o' nature”

It was written a hundred years ago in a short story “The Friendly Brook” by this man, Rudyard Kipling.

Kipling wrote a lot about engineers and engineering and was commissioned by the Canadian Society of Civil Engineers to write their “Obligations of an Engineer” – effectively their code of conduct.

But back to sustainable drainage and making space for water.? Four years on, the surface water drainage parts of the Flood and Water Management Act have still not been implemented and possibly never will be.? There is now a move for water companies to take responsibility for sustainable drainage; but how well would that work out?? There is already one UK water company that has taken on this role; but their idea of a sustainable drainage pond has a paved access road all the way round and a 2m security fence.? They haven’t got it!? I suggest everyone should read the CIRIA guide on Planning for SUDS to get some inspiration for how it should really be done.

2014

2014 was not a good year for me.? Amongst other things, my close colleague and friend Adam Dean took his own life.?

Adam was passionate about skill development and training and this is something where I think UDG has a role.

Urban drainage is one of the most challenging areas of civil engineering; it is multi-disciplinary; hydrology, hydraulics, water quality, civils, M&E and it has to deal with a lot of uncertainty; rainfall, sediment, blockages, boundary conditions.? We do have a lot of experienced modellers but we need to be developing and inspiring the next generation.? Just look round the room at the number of people here who over the next 10 years will be reaching retiring age or becoming too expensive to do hands on modelling.? How do we fill that gap?

UDG has the Wastewater Planners competency framework that defines what team members need to know, but do we make enough use of it?? I know of only a couple of water companies who asks for evidence of the competency status of their supply chain.

Several years ago, largely driven by Adam, we set up an in-house training course for our staff.? That has now developed into MUDA the Mouchel Urban Drainage Academy.? This is a structured one day a month training programme lasting 2 years.? About 4 years ago we invited our clients to send staff on it as well and this year we actually have more client staff than Mouchel staff.? I am proud of that.? We haven’t yet invited our competitors to send their staff but that will come.? Also this year we are starting to include some assessment of learning achievements – although well short of requiring written coursework.

Our ambition is to get MUDA to have some formal status as a recognised qualification and we would like to achieve that by this time next year.? It won’t be easy.? It already costs us a lot to run MUDA but we see it as an investment in our staff and in the industry in general but at some point we need others to contribute.? And we enjoy running MUDA and we don’t really want to lose control; but at some point we will have to give up some control for the good of the industry.

So what is the future and how do we work together to take it forward?

To be continued.