News & Views
by Venu Kandiah, PhD, P.E.
The effort required to develop water resources engineering models can be significant. But once developed, in many instances the models are only evaluated for a limited, or a single set of conditions. The results and predictions obtained from these evaluations are the ones used in design, presented in reports and conveyed to decision makers and the public. This approach might serve the immediate needs of a project; however, for most modeling efforts a limited amount of additional effort can provide more knowledge and understanding at a low marginal cost to that required to develop the model itself.
Advances in the hydrological sciences and in the areas of climate change, which are providing new insight into the foundational data used in the models, and advances in computational modeling and computational resources that increase overall reliability and capacity of modeling methods provide additional reasons to get more out of models. In many instances, for decision makers and the general public, a single outcome is often all that is associated with the overall modeling effort. Modelers should aim to deliver more, and in the process can increase the value and insight that modeling brings to the decision making processes and engineering project, and increase the profile of the modeling practice in general.
The traditional approach of reporting model outcomes based on a limited set of runs need to be reconsidered for a number of reasons. For example, flood extents might be evaluated using a “design storm”, or stormwater facilities sized using a continuous simulation covering a long term period for which rainfall records and other records needed for model development and calibration are available. Reported results are often assumed to be accurate, and fail to properly convey the uncertainties associated with them. Beyond the limitations of the model itself, there is inherent uncertainty in the parameters and boundary conditions used: inaccuracies exist in model data inputs.
Hydrological models used in the engineering community are underpinned by the idea of stationarity, the concept that hydrological systems operate within a window that can be established from past records. Research indicates that hydrological trends are changing. Climate change, and changes associated with development, are impacting rainfall, evapotranspiration and stream flows. Means and other statistical measures for these parameters, obtained from historical records, and assumed to be good descriptors for these parameters might no longer be valid in light of observed increased variability and extremes in hydrological events.
To ensure that users of model results are fully aware of the limitations in model results, modelers should attempt to better convey the variability and possible wide range of outcomes given uncertainties. This can be achieved by running a large number of model evaluations, and conducting more rigorous sensitivity analysis exercises. In the past limitations in computational power and computing acted as a constraint and provided a justification to limit model runs. Advances in computing (better numerical methods and algorithms), desktop computer technology (increased processing power and speeds, the advent of multi-core machines and graphical processing units) and computational models allow a greater number and more accurate models to be run in shorter amounts of time by modelers . Multiple evaluations can be done, ranging from a few scenarios using scenario-builder tools, to running an ensemble of models to numerous evaluations for parameter estimation.
Mauger G.S., et al., “State of Knowledge: Climate Change in Puget Sound”, Report prepared for the Puget Sound Partnership and the National Oceanic and Atmospheric Administration, Climate Impacts Group, University of Washington (2015).
Milly P.C.D., et al., “Stationarity Is Dead: Whither Water Management?”, Science, Vol 319 (2008).
Peel M.C., and Bloschl, G., “Hydrological modeling in a changing world.”, Progress in Physical Geography, Vol 35(2), 2011.
by Anthony Kuch, MSc
On a recent flight to instruct at one of our xpswmm/xpstorm training workshops that we hold around the country, I had the opportunity to connect on the airline's Wi-Fi. As we crossed the country I could see that we would hit certain landmarks or points, make adjustments to our route, and then proceed on an arc of the shortest path until we were close to the destination. From the point of near arrival there were several turns as we dovetailed with other aircraft, made the final decent into headwinds, arrived at the correct runway and then proceeded to the gate.
This had me thinking about the importance of professional training and the many positive experiences I have had both as the instructor and as an occasional attendee. I can see a correlation between the adjustments on that flight path and those that happen to the students of a professional workshop. Students' experience levels vary, with some of them being further along on their journey to being an expert modeler than others. Each of them have their own perspective and takeaways of understanding to becoming more productive modelers.
They learn some fundamental principles which clarify the "why" of model choices. Being self-taught without significant reading in reference manuals leads software users to rely on observations and make assumptions on those observations. Many years ago in our technical support department I remember speaking with someone who had a model with 15% model continuity error. He mentioned that he thought it was a reasonable amount due to the amount of infiltration in the Runoff mode. He falsely assumed this numerical loss was akin to the infiltration loss. At that time I explained what the error actually was and that it is after an accounting of infiltration. However, if the person had been to a training course they would have learned the true definition, actions to reduce the error and acceptable range of error.
While that would have been a major course correction early on the journey, I have many experiences about minor corrections even from the most experienced modelers.
I recently taught at an FMA-sponsored training in southern California. The group (see photo) were very specialized in the regional approach to modeling Hydrology and Hydraulics, while my modeling background includes influence from Australia, Canada and the diverse USA. It was important for me as an instructor to listen and cater to the needs of the class since the regional focus and the experience of the class members was primarily with software specifically related to Southern California. The feedback from the class was very positive especially about two main things:
I recently attended training as a student and welcomed the opportunity to gain insight to other hydraulic tools, to network with other attendees and also learn about software features. I was able to ask questions that I thought were unique to me and my focus but found them to have a common interest with the other attendees.
I look forward to applying my new skills and understanding. In my professional flight path, I have made a course correction and am now heading in the right direction. I will leverage my learning time and gain building better models faster so that I can pass this on to other growing experts.
The way that we choose to navigate our modeling decisions is important, and we at XP are dedicated to making sure that our users have all of the navigation tools possible so that they make corrections early and arrive at the most accurate and appropriate destinations.
Read more about XP Solutions Public Training Workshops.
by Greg Kowalsky
I recently joined XP Solutions as Vice President Americas. I’m excited to lead a team dedicated to water resources and advancing the industry with leading software tools. There is a strong desire at XP to make a real difference in the world with the work we do. We recognize that we can only have a positive impact on water resources if we improve the efficiency or capability of our engineering customers. This requires a strong partnership with our users. One of my goals at XP Solutions is to advance an already strong partnership and further develop the two-way dialogue to speed the enhancement of our products.
Previous to XP Solutions, I spent a decade focused on stormwater and developing progressive solutions to meet evolving regulations. During this time the progression of LID advanced and is now common practice. One area that hasn’t kept pace with this evolution is design tools for Civil Engineers working at the site level. Many of our customers still use basic programs, CAD modules, or local calculators based on Excel to aid the design process. While engineers have several options for modeling flood and stormwater for larger watersheds, these tools aren’t focused on site design and meeting stormwater regulations associated with land development.
XP Solutions has been providing design tools for civil engineers in the United Kingdom for years. We are also experts at stormwater and 2D urban flood modeling. We are very excited to match these two capabilities with xpdrainage, our automated stormwater design tool to aid civil engineers doing site design on land development projects. We want to transform the industry and provide a powerful, flexible tool that shortens the design cycle, integrates with CAD and GIS, and provides the right data to meet regulatory requirements that continue to evolve.
xpdrainage 2016.2 will be released this summer and we have several new features that will allow engineers to design faster, more accurately, and to quickly adapt to project changes. But we're not done. In fact, we’ll never be done. This is where the partnership with our customers comes in. We want our customers to participate in the future of xpdrainage and help transform the site design process along the way. We are forming an xpdrainage Customer Advisory Team to provide key input and help steer future capabilities. Here is what we are looking for:
You’ll be part of a team that has direct input to the xpdrainage Product Manager for future feature enhancements, gets a first look at new releases ... and we can probably provide some XP swag from time to time!
If you want to join this team, or work with someone who you think would be a good fit, please email email@example.com.
We look forward to hearing from the engineers that want to help shape the future of stormwater site design!
by Zach Sample, P.E.
Conversation at the 2016 SESWA Stormwater BMPs, LID and Green Infrastructure Seminar in Atlanta GA that I attended recently touched upon the idea of computers taking our jobs and ‘Engineering Bots’. This has of course happened in other industries, but I didn’t anticipate it happening in the stormwater planning, design and management world.
During a session break I chatted with a few colleagues who saw information on the ‘one click’ Runoff Reduction optimizing feature we implemented as part of the xpdrainage 2016 release. There was a lot of interest in what it can do and eventually someone made the joke that one might ‘optimize’ their way out of a job, which led to a discussion about what IBM’s supercomputer ‘Deep Blue’ would look like as a civil designer. Considering that my profession centers on the development of software tools to help engineers do their job faster and more efficiently, I got stuck on the idea that (even in jest) - would automated stormwater design harm the people we hope to help? Could we actually ‘optimize’ someone’s job away?
The answer: absolutely not.
In fact, I see the creation of these tools as only creating less flawed, more elegant solutions to infrastructure problems that we often address rather clumsily. These tools are created with the idea of a human being making the creative and educated choices while the software conforms the design to those choices.
Here’s what I mean: with our latest release of xpdrainage, the focus is on clarity, automation and optimization. Rather than having separate tools for different teams (spreadsheet, AutoCAD, hand calcs, maybe a hydrology software program) in order to design a treatment train or multiple-BMP site, we’ve created a solution that brings it all together so that the entire design is transparent and easy to understand. Input for treatment and conveyance systems are locked into the plan view so that all stormwater controls are represented on plan, to scale and in the proposed location. This frees the designer from risk of inappropriately placed or sized BMPs in the final deliverable.
Runoff Reduction reporting and sizing automation take another big step toward automated optimization. Select the facilities on the site that are targeted to retain the site’s water quality volume and click a button to match the facility dimensions to meet the connected Inflow Area runoff.
While this is a foolproof (and fast) sizing tool, the design isn’t done! The Runoff Reduction event is only the start of the stormwater design process. The larger Protection Events need to be accounted for and safely, responsibly managed. In addition to Runoff Reduction and Protection Event sizing, xpdrainage provides a single place for streamlined high flow bypass conveyance, outlet configurations and treatment train configurations.
xpdrainage reduces the potential for mistakes and makes parts of the workflow faster so that you, the engineer, can spend your time making creative and educated decisions.
In summary, the 2016 release of xpdrainage will let you…
Save some time?
Improve your reputation and help you feel more confident in your stormwater design?
Lose a project bid to an Artificial Intelligence Super Computer?
by Netsanet Mebrate, PhD
The updated SuDS Manual has now been out for a while, with a complete rewrite of the last manual that was created around 2007. The new manual answers most of the technically challenging questions regarding SuDS (also called Low Impact Development or Water Sensitive Urban Design).
The famous SuDS triangle has now become the SuDS square, encompassing water quantity, water quality, amenity and biodiversity. These four components are all presented with specific design criteria to be attained and identifies the detail needed. This accomplishment is one positive step forward in the long journey towards making SuDS acceptable as a norm for providing drainage on new or redeveloped sites.
Although a significant part of the drainage industry positively recognises SuDS as an opportunity to deliver multiple benefits, the battle to convince some parts of the drainage industry is yet to be won. Most of the resistance originates from groundless myths such as:
Though most of the data we see debunks these myths, a considerable amount of work is still required to convince the entire drainage community. The onus is on all SuDS advocates to preach to the unconverted in order to bring about a paradigm shift on the viability of SuDS as a real and sustainable alternative to traditional drainage.
The beauty of SuDS is not only the accomplishment of a sustainable drainage scheme but in that it will also force drainage to be considered at the forefront of a development. Studies show that considering drainage earlier in the development process can actually increase savings when using sustainable drainage measures. Drainage should not be considered as a problem simply to be mitigated, but rather as a resource that will help to deliver multiple benefits. This is accomplished by the collaborative efforts of engineers, landscape architects and urban designers working in cooperation, drawing upon the skills and experience that each discipline provides to deliver a win-win solution for all stakeholders.
One of the ways to convince the sceptics is the development of cutting edge technological solutions. Being able to create and model a design to deliver a range of SuDS schemes for urban environments as efficiently, robustly, credibly and as quickly as traditional drainage, will remove one of the barriers to achieving universal acceptance of SuDS. Moreover, the development of technology that is acceptable to both designers and approving authorities will be an added advantage.
To that end, MicroDrainage has been able to leverage on the great wealth of knowledge and experience acquired over the last 35 years dealing with traditional drainage design to come up with a technological solution for designing SuDS schemes within the United Kingdom and similar markets. The ability to holistically simulate fully integrated SuDS networks in a similar fashion to designing traditional networks has now been made possible.
Further, newer xpdrainage can help users automatically design sustainable drainage networks in a treatment train approach that makes SuDS/LID/WSUD design much faster and accurate than most traditional methods of design.
Do you fully participate in sustainable drainage design? If not, what are the hurdles that you face in implementing sustainable practices?
XP Solutions is excited to announce our business partnership with Hydroingenieria in Colombia. Located in Floridablanca, Santander, Colombia, Hydroingenieria is a company of multi-disciplinary engineering services for civil engineering and environmental consulting. They are a small business that works with a network of experts in niche areas of geology, hydrology, hydrogeology, geophysics, flood management and engineering. Welcome to the XP Solutions family!
Visit the Hydroingenieria website here.
by John Howell
Living near water requires that we plan for situations when we have too much of it. Throughout history we have dealt with flooding when weather events exceed “normal” parameters. Over time we have found different ways to mitigate the risk of flooding, up to a point. Levees, dams, drainage systems, building codes, urban planning; all have a place in reducing risk from flooding. Some of our mitigation strategies have been codified into law. However, rules and regulation, building codes and laws are not enough. Engineers and water professionals need to apply creativity and critical thinking when designing and implementing infrastructure to mitigate flood risk. A recent event in my hometown illustrates this need.
Huntsville, Alabama rests on the eastern edge of the Tennessee Valley. The traditional eastern boundary of the city is the western edge of the Appalachian Mountains. Here the mountains are separated by flat valleys, typically bisected by a stream, creek or river. Huntsville has experienced explosive growth since the 1950’s growing from a small city of 20,000 to a metro area of 500,000 people. The demand for housing dictated that the once peaceful valleys of the foothills are now suburbs.
One suburb in particular very recently experienced a situation that highlights the importance of comprehensive planning. Hampton Cove is a planned community of 1,200 homes just east of Huntsville in a valley between Mount Monte Sano and Keel Mountain. Before the construction of Hampton Cove the valley existed almost entirely within the 100 year floodplain of the Flint River, a tributary to the Tennessee River. Hampton Cove was carefully planned to mitigate flood risk. All of the land was graded so that lots were 10 feet above the 100 year floodplain. The community was designed around a man-made lake that is basically a large detention pond. The pond has an overflow spillway that drains to the Flint River.
In the 72 hours between December 24th and 27th the Huntsville area received over 8 inches of rainfall (Click Here for Gauge Data). The 3 inches received on December 24th was followed by 5 inches on the 26th. A 5 inch rain event normally wouldn’t overtax the flood control structures already in place. A 5 inch event occurring so closely after a 3 inch event, with the ground already saturated and downstream capacity limited proved to be problematic.
The stormwater infrastructure designed for Hampton cove worked as planned. The lake did reach maximum storage capacity and the spillway received flow for about 3 hours on December 26th. None of the homes in the subdivision experienced flooding.
However, the subdivision is served by two roads; one road entering the valley from the north and the second entering from the south. Both roads have stretches that are barely above the 100 year flood line. On the night of December 26th the Flint River topped its banks, and water rose to 7 feet above flood stage. While the homes in the subdivision were high and dry, both roads entering the area were under several feet of water in some areas. The homeowners of Hampton Cove had no way to leave the area for the better part of a day. Residents returning home from Christmas festivities couldn’t travel the last mile home.
Residents of the area are asking questions as to why road elevations weren’t considered when the plans were being drawn up for the subdivision. The basic answer was that the law didn’t require it.
The roads that flooded have been in existence for over a hundred and fifty years, and they travel through two municipalities and one unincorporated area of Madison County. The building codes and regulations relative to new housing don’t consider the traffic infrastructure outside the scope of the housing development. Their concern was mitigation of flood waters directly at the site which did indeed work as intended.
This is not an isolated incident. Traditional methods of flood management do not always take into account what is happening directly outside the boundaries of a specific project. But the fact remains that upstream and downstream conditions affect and are affected by flooding situations, and those are not always completely handled by municipal or federal regulations.
The resolution that can prevent future flooding in situations like this is for governing bodies that are stakeholders to cooperate in developing an integrated flood management plan for the valley. Coordinating future road and housing development with an overarching flood management plan can help resolve issues that can occur when we simply “go by the book”.
by Adam Rose
You may have heard about the tragedy in Flint, Michigan (https://www.wikiwand.com/en/Flint_water_crisis) - but to keep everyone on the same page the water in that system has turned toxic. So toxic that it has tripled the levels of elevated lead in children of the city, potentially started an outbreak of Legionnaires disease, and triggered a large number of lawsuits, and done what may be irreparable harm to many in the community. The story has a lot of political twists and turns that reach all the way to the governor of the state: but I want to focus on the physical aspects of the system.
What caused this? Some major industrial disaster? Some act of vandalism or terrorism? No, rather something that happens throughout the US and world very often -- a change in the water supply to the system. That's right - moving to a more corrosive water (the Flint River) from the typical water (supplied by Detroit) caused lead to leach from the old pipes in the system. Changing the water source for basic economic reasons caused what you read above to happen. And even more eye-opening is that the Flint River (the bad guy in this story) was always the backup supply for emergencies.
Obviously this case is more severe than average, but you may be surprised to know that many systems rely on similar diverse supply strategies. They may have water from two sources with different properties (perhaps groundwater and surface water) or water from different areas of the same source (perhaps different groundwater aquifers). To make this even more complex, these strategies change over the seasons (you generally need more water in the summer) and over time (people move in or out of areas). We haven’t even discussed the other actor in this play: the changing properties of the pipes themselves.
(Click on the image Left to enlarge.)
That can be some scary stuff to think about. But this isn’t meant to scare you – only to make you appreciate the work that goes in to managing these systems. Most systems produce water above and beyond the US Federal requirements. Most systems are also required to give you laboratory information (check your water bill) about the quality of the water. Did you also know that many also compete for the best tasting water? http://www.awwa.org/resources-tools/public-affairs/public-affairs-events/taste-test.aspx
So what can we learn? Where do we go from here? What can we do? In some ways, nothing. After all, you turn on the tap and only one kind of water comes out – and most of us cannot drill a well or live on bottled water or expensive filtration systems. Probably not what you were expecting, right?
But in some ways we have a lot of power. We, as water system professionals, have plenty of tools to model, project or review quantity and quality data. We, as project managers, have discretion on where our projects/contracts focus their time. We, as owners, have plenty of say on what our professionals do to prioritize risks versus economics. We, as citizens, have a lot of power to demand that we receive the highest practical quality water. We, all, must work harder to keep our buried system alive by feeding it funding and attention.
Where do we go from here? What can we learn?
by Gavin Fields
I have just had the pleasure of taking a much needed holiday through China – but unfortunately the engineer in me still could not turn off.
Everywhere I went I was constantly thinking to myself ‘why did they build that there’ or ‘why that way’. The effect of simple construction techniques in the historical areas however can be incredible at times.
There is a small city near Yellow Mountain (they filmed Crouching Tiger Hidden Dragon there) which is in the order of 800 years old and has a very complicated, while relatively small sized, drainage network that brings water to every property for drinking, washing and drainage purposes linked between multiple lakes. This infrastructure was supplemented with weirs every 30 odd meters to control flow rates and water elevations to ensure sediment is controlled and supply is maintained in dry periods. I had no questions when my tour guide advised that this area was famous for its scholars during its history.
In another area I visited the tomb of a regional King that was excavated into a mountain with again another interesting drainage solution to ensure that the chambers remained dry. I felt awkward walking around with friends who were amazed at the contents of the site while I was staring at tunnel techniques and side drains cut into solid rock almost 2000 years ago…
In Beijing I was able to visit the ‘Summer Palace’ and see the mountain areas not far from the Great Wall of China. This area was ‘manicured’ using manual labour to create large open drainage systems and a manually excavated lake system. Having been involved in lake excavation using large modern machinery I would love to find out more on how they were able to dewater the excavation during construction.
Moving back to the more modern areas of China, such as Shanghai, drainage infrastructure became more familiar – with gully inlets, headwalls, pipes, road crossing culverts and detention structures. The way with which they are often ‘crammed’ into the corner or appear to be an afterthought or imposition made me appreciate the true craftsmanship that the historical areas actually have. Drainage infrastructure is something that humankind will continue to need, as it always has, in order to live the security and comfort we desire to avoid being flooded and move around freely on foot or in vehicles.
I am sure that I am not alone thinking how fortunate practicing engineers are these days have computers and technology at our fingertips to assess and confirm our assumptions for construction. Next time I will have to take my laptop with and I will try to see if I can prove the drainage systems work as efficiently in xpswmm. But it prompted another curious question: have any other engineers out there been inspired by ancient or historic drainage techniques to innovate their drainage designs? I’d love to hear your ideas.
Portland, Oregon, U.S.A.; Brisbane, Australia; Newbury, United Kingdom – 3 December 2015 – XP Solutions proudly announces the release of xpdrainage 2015.3. This Sustainable Drainage Design software package streamlines the planning and design process and provides an easy way to verify the quality of these designs.
“Version 2015.3 is a major leap in the maturity of xpdrainage,” notes Product Owner, Jessica Jefferys. “The ability to combine green and grey infrastructure with more automation and visualization really does give our users an advantage in their work. One software program can provide faster planning and design and makes it vastly easier to review and check designs of LID/SuDS/WSUD. This is a turning point in sustainable drainage.”
Features new to version 2015.3 include (and are not limited to):
These are just a few of the improvements being made in xpdrainage 2015.3.
For more information on the new version, click here.
To request a trial version or request more information, please click here.
XP Solutions is a world leading provider of software solutions aimed at improving the physical and social environment. Our reliable software technology and professional solutions are used every day around the world by engineering organizations, environmental management organizations, and governmental agencies to plan, design, simulate and manage the impact of human interaction with the natural world.