March 2018 Print

President's Report

This last month I attended the APWA/ASCE spring conference in St. George, Utah.  It was a great conference this year’s theme was “Make the Grade”.  This conference had some really good sessions that included topics from Water/Wastewater, Transportation, and even a session on Washington County Economic status.  It was a very informative conference this year.  I have served on the conference planning committee for the last few years and have enjoyed being part of the process to put on a successful conference.

At this year’s conference the keynote speaker was Kristina Swallow the current ASCE President.  Her topic was “Engineering the Future” and covered some of the initiatives of the ASCE.  One point that she discussed that really intrigued me was the raise the bar initiative.  When I first heard about this initiative a few years ago I was skeptical because it is an initiative that involves more education for professional engineers prior to licensure.  I thought this would ultimately discourage students from graduating in the field of engineering because of the time required to achieve this degree and then the time required to get licensed.  As it turns out the Universities have been pressured to reduce the number of credit hours to graduate with a bachelor’s degree.  Due to high tuition cost and other bachelor degree requirements it seems they are trying to make the Engineering degree more competitive with other degrees as far as required credits to graduate.  As a result this is reducing the number of engineering courses that a student needs to take to graduate.  So a person receiving a bachelor’s of science degree in civil engineering today most likely has taken less engineering courses than somebody that graduated 15 years ago.  I remember when I chose to do civil engineering the counselor told me to plan on 5 years of college, but today they are trying get it down to 4 years.  So the initiative at its current state could be renamed “maintain the bar” it seems.  I think the education required to be a civil engineering is very important although you learn a lot as a practicing engineer having the theoretical background it important in being successful.  I also feel the engineers of today are faced with a dynamic field that is constantly changing, so continued training and getting education is a crucial part of our profession.  As I think back on my experience in college I can’t think of any courses that I could have done without, but there are many courses I wish I had taken.  I am excited to be part of an organization that takes the initiative to maintain and try to raise the standard in our profession.

This last month I also attended the Utah Engineer Councils (UEC) awards banquet.  This was the first UEC banquet I have attended and was very impressed with the venue.  Although we ultimately did not have any of our nominees win any of the awards all the nominees were recognized and given a plaque.  I would like to congratulate our nominees:

            Matthew Roblez           Engineer of the Year

            Laurie McNeill             Educator of the Year

            Imanuel Aswandi         Fresh New Face of the Year

The UEC awards is a very prestigious award because the nominees come from multiple disciplines of engineering.  I appreciate the opportunity to have nominees form our organization represented at this event.

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Technical Article

Weir Nappe Vibration: What is it and how can it be mitigated?

Weirs are common hydraulic structures used throughout the State of Utah to control water flow releases or diversions from reservoirs or canals. The gravity-driven free-falling jet of water on the downstream side of a weir, referred as the nappe, typically follows a stable parabolic trajectory.  Weir nappes can, under certain conditions, experience instabilities that affect their shape and trajectory, resulting in a “wavy” pattern in the longitudinal direction of the weir nappe (see figure 1). This unstable weir nappe exhibits a vibrating behavior that creates a large amount of energy and noise. Standing within proximity of a vibrating nappe is impressive. The energy generated by this phenomenon has to observed to rattle the windows of building up to a mile away from the flowing weir structure!

Figure 1 – Visible waves in vibrating weir nappe

            The topic of nappe vibration has been studied academically for over a century, and while the exact cause of nappe vibration has not been fully identified, a number of theories have been put forward. 19th century studies by Hermann von Helmholtz (1) have established the common theory behind the nappe instability mechanism known as the “Helmholtz Instability”, which is created by shear forces occurring at the interface between two fluids traveling at different velocities (e.g. the curtain of water falling through an air medium). Other theories (2) pertaining to nappe vibration include the concept that the vibrations are caused by the enclosed air volume behind the nappe (in the case of a suppressed, non-vented weir). However, laboratory results have shown that a weir can and will vibrate even if the air behind the nappe is fully vented to atmospheric pressure. Another theory (3) suggests that the source of nappe instability is related to a pressure discontinuity that occurs as water flows over the weir and enters its free-falling state.

To better understand this phenomenon and to evaluate different countermeasures to nappe vibration, a study was conducted at the Utah Water Research Laboratory at Utah State University. The study included two physical weir models; one small scale model (4’ tall weir with a 6’ wide spillway crest) and a large, prototype scale weir (12’ tall weir with a 16’ wide spillway crests). These models were used to first replicate the nappe vibration phenomenon and were then modified in an effort to mitigate the behavior.

Previous research (4,5) suggests that nappe vibration can be mitigated by:

  • Placing nappe splitters on the weir crest that break of the larger nappe into a series of smaller nappes. This application has its limitations, especially in rivers or reservoirs with a large amount of debris (such as floating logs) that can break or damage the nappe splitters.
  • Changing the geometry of the weir crest to modify the trajectory of the nappe. This method also has its limitations, and it usually not feasible for existing facilities.
  • Roughening the weir crest by a variety of means, such as gluing small stones on the weir crest.

Of these three techniques, adding roughness to the crest is likely the most practical because it is relatively simple, can be applied to an existing weir structure, and has minimal impact on the operation of the weir itself. The research conducted at the UWRL focused on examining a number of weir roughness modifications to identify the most efficient application of this technique.

3 of the modifications tested in this study were:

  • A: Applying ¾” stones to the quarter round weir crest (R=6”) on the upstream side of the weir up to the elevation of the top of the weir crest. This application has the benefit of providing roughness to the crest without raising the effective elevation of the weir crest (Figure 2)
  • B: Applying the stones of the entirety of the weir crest (Figure 3)
  • C: Applying a single row of stones to just the downstream edge of the weir (Figure 4).

To quantify the effectiveness of each modification, an accelerometer was secured to the structure to measure the intensity and frequency of the vibrations.  Figure 5 displays a sample accelerometer reading while the nappe is vibrating, and Figure 6 displays the reading for a non-vibrating condition. As shown, the vibrating nappe readings show a repeatable, distinct pattern, while the non-vibrating nappe shows a sporadic, non-uniform pattern.

            The results of this study showed that while Modification A was somewhat effective at eliminating nappe vibration, Modifications B and C eliminated the vibration to a point where it was no longer detectable. These results support the theory that nappe instability is initiated at the weir crest (because it was disrupted by adding roughness to the weir crest). These findings can be used in real world applications to help mitigate a weir or spillway structure that exhibits this behavior. It should be noted that adding roughness to the crest does have an influence on the discharge coefficient of the weir (i.e. the head-discharge characteristics of the weir will change).           


Figure 2 – Weir Modification A


Figure 3 – Weir Modification B


Figure 4 – Weir Modification C


Figure 5 – Accelerometer readings for a vibrating nappe


Figure 6 – Accelerometer readings for a non-vibrating nappe

You may be asking yourself – why are we discussing information that I don’t use and will likely never use? I present this information for the following reasons:

  • While you may have not run into this issue to date, it doesn’t mean you never will. Having a general idea of the concept may be what sets you apart when a client or employer comes to you with the question.
  • At times, in the world of engineering standards that we live in, we fall into the mindset that everything in our profession are already been discovered. The truth is that there are still amazing things to be studied and discovered in the world of civil engineering. Innovation is what keeps us moving as a civilization.
  • A vibrating weir nappe is just plain cool!



1. Helmholtz, H.V.,(1868). "Über discontinuierliche Flüssigkeits-Bewegungen [On the discontinuous movements of fluids]". Monatsberichte der Königlichen Preussische Akademie der Wissenschaften zu Berlin [Monthly Reports of the Royal Prussian Academy of Philosophy in Berlin] 23: 215–228.

2. Naudascher, E. and Rockwell, D., (1994).  “Flow-Induced Vibrations: An Engineering Guide.” 142-146.

3. Chanson, H., (1996). “Some hydraulic aspects during overflow above inflatable flexible membrane dam”. The University of Queensland Department of Civil Engineering. Report CH47/96.

4. Metropolitan Water, Sewage and Drainage Board, (1980).  “Investigation into Spillway Discharge Noise at Avon Dam.  ANCOLD Bulletin No. 57, 31-36.

5. United States Bureau of Reclamation, (1964).“Experiences of the Bureau of Reclamation with Flow-Induced Vibrations.”

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Wasatch Front Branch Update

I had a fantastic time at Parkview Elementary School with our Engineer’s week activity.  We also visited Escalante Elementary School.  Seeing the young faces eager to learn about engineering and the world around them was a great experience.  We made structures out of cards and tape, then saw how much weight they would hold.  We made hovercraft out of balloons and CD’s and saw how far we can get them to hover.  Finally, we made water screws out of tubing and water bottles, which we used for teams to race each other to see how much water they can move.  Interacting with these kids was the highlight of my month!  Thanks to everyone who participated.

In February we heard from Mr. Michael Smith with the American Council of Engineering Companies, (ACEC), will be talking about what is currently going on up at the State Legislative Session.   I felt much more informed about the issues that affect me as an engineer.

Currently ASCE's movie "Dream Big" is continues to be played at the Clark Planetarium. Follow this link for ticket information:

The March luncheon will be held Friday March 16th from 11:30 to 1:00 at WesTech Engineering Offices, (3665 South West Temple).  Brian Bolinder of Richards, Brant, Miller, & Nelson will be speaking to us about issues in contract negotiations.  We have filled all of the luncheon speaker slots before the summer, but are always looking for additional speakers to help us fill our remaining luncheons through the rest of this year and into the next. If you or anyone you know are interested in helping us out by presenting, please contact us at

We are currently looking for volunteers to serve in the Wasatch Front Branch Leadership.  It is a 4 year commitment.  Nominations are due by the end of the month.  Please contact us for forms.


J. Darren Burton, President, ASCE Wasatch Front Branch

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Northern Utah Branch Update

ASCE offers a multitude of opportunities to advance your career and serve the public both locally and on other levels. Visit the ASCE website ( for an opportunity that fits your interests.

If you are interested in something on a local level, the branch is seeking nominees for the upcoming branch and section elections. This is a great opportunity to meet new folks and to increase knowledge of what ASCE truly represents. Be on the lookout soon for an invitation to run for a leadership position. Don’t miss your opportunity to help guide the future of your local chapter.

Thursday March 15 at noon, Michael Smith from the American Council of Engineering Companies will be presenting a legislation update to the Northern Utah Branch. The one hour presentation will be held at the Bluebird Restaurant at 19 North Main Street in Logan. We have plenty of room for visitors. Lunch is on your own.

The Northern Utah Branch (NUB) and the USU Student branch are planning a joint event in April. The event will focus on transition/retention students graduating in May.

The NUB service project to be held in May. The board will meet on Tuesday to finalize a project and date. The Northern Utah Branch is considering a joint meeting/training with the local chapter of APWA. A successful event with APWA could help strengthen relationships and respect between engineers and those that inspect our work.

The board is planning a date and details for this year’s closing social to be held in May. Last year members, nonmembers, and their families attending an outing in Wellsville. Even with the poor weather, over 40 people gathered for fishing, games, kayaking, scholarship awards, and the opportunity to celebrate the prior year’s successes.

The board continues to work on providing diverse monthly training topics and is trying to find ways to expand reach to extended areas within the branch. Our next board meeting is scheduled for March 12th where we will finalize our season closing events and discuss upcoming branch and section elections.

-Tom D.

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Younger Member Forum

ASCE Utah YMF is here for you. One of the goal is to bring young engineers together throughout the state of Utah. The only way we can do this is if you come out and join us! Bring your co-workers, family, and friends along as well. We are focused on offering opportunities to network with peers, learn more about the profession, participate and facilitate the transition from students to young professionals. We offer young engineers an opportunity to get out of the office and meet others in their professional community. While ASCE on a national and global scale is about promoting and regulating our profession, YMF is more about getting out and having fun. Here are some upcoming activities in the YMF.

Join us in a Community Project while mingling with your peers for the students from elementary to high school. We are judging in the University of Utah Science and Engineering Fair in March 20-21 from 7-9 PM at the Rice Eccles Stadium at the University of Utah. Please contact Imanuel Aswandi if you would like to join us judging the fair at

ASCE YMF is also organizing a fundraising event of Corn Hole Tournament in May. Tentative date is May 12th or May 19th. Details to come!

We are going to start a social night once a month every last Thursday of the month. The next one will be held on March 29th. Visit our website ( or join our Facebook to keep up-to-date with our social night.

We definitely want YOU in ASCE Utah YMF! We are currently looking to fill the officers roll: President-Elect, Secretary, and Treasurer. If you (or know somebody) are interested, email us at Also, don’t forget to sign up on our email list (

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Central Utah Branch Update

Our February meeting was held at BYU in conjunction with Engineers Week.  Blaine Leonard of UDOT, and past national President of ASCE spoke to us about the future of self-driving vehicles.   He spoke out the 5 levels of automation for vehicles, 0 for no automation to 5, fully autonomous.  We cannot get level 5 vehicles yet but should be seeing level 3 to 4 vehicles in the very near future.  He also spoke about a study they are doing on Redwood Road where they have fitted traffic lights and UTA busses with sensors such that if the bus is running behind schedule it will change the lights to allow the bus to pass.

This month we are looking forward to hearing from Bishnu H. Adhikari of Meet the Mormons movie fame. He will be sharing his thoughts, experiences, and some expert observations on construction practices in Nepal and other developing countries.   Our meeting will be at the Eleve’ Events Center in Pleasant Grove on Tuesday, March 13 at noon.  This is a different day than our usual so make note on your schedules!

Please plan to join us, and bring a colleague!  We would love feedback on speaker ideas from our members so let us know if you have a suggestion or are willing to speak on a project you are working on.  If you are not receiving our emails with meeting date and time information please contact our Secretary, Steven Lord to make sure we have a correct email address for you.

The time to elect new Branch Officers for the upcoming 2018-2019 year is fast approaching.  Elections will be held in May with new officers sworn in in June at the annual ASCE Utah Section meeting.  If any of you are willing to serve please contact our secretary, Steven Lord.

Finally, we received from ASCE National a list of several members in our Branch who have yet to pay their annual ASCE Membership dues.  Please double check that you have paid for your 2018 ASCE membership.  You wouldn’t want to miss out on all the benefits ASCE makes available to its members!  Thanks.

Jeff Egbert, 2017-2018 President, Central Utah Branch

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Southern Utah Branch Update

Last month we had our annual APWA/ASCE conference in St. George.  We had a good conference, with National President Kristina Swallow giving our keynote address on Engineering the Future.  Thanks to all who came to the conference.  

This month for our luncheon we will have Michael Smith, ACEC, give the legislative update on Thursday, March 22, at noon at the DXATC Emergency Training Response Center, 610 South Airport Road, Room 1E.  Hope to see you there! 

We are also seeking nominations for Secretary-Treasurer. If you or someone you know would like to volunteer, let us know.   Please consider this opportunity to provide service to our community and profession. If you are wondering what the position entails or have any other questions, please contact one of the officers. 

Southern Utah Branch

Kirt McDaniel, P.E.

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Structural Engineering Institute Chapter

Early registration for Structures Congress has passed, but it’s not too late to register.  Spring construction season is starting, so if you don’t get plans made now, your workload will make them for you….  Here are a few reasons to go:

  • Over 100 technical sessions - hear from the experts that developed ASCE 7-16, ASCE 41-17, and other standards, along with what changes are proposed in the future.
  • Earn up to 14 PDHs
  • Enjoy social events like the Friday Special Evening Reception Celebrating the Future of SE, hosted by CSI.
  • Networking with more than 1,200 colleagues from the U.S. and abroad.
  • Keynote speakers each day

The conference hotel is filling fast, and looks like a seriously nice place to stay. Get those rooms now while the ASCE discount rate is available. 

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Utah Geo-Institute Chapter

The Utah Geo-Institute provided a presentation on understanding and interpreting Geotechnical Reports this past month at the Annual SEAU conference.  The event was well attended with great questions.  We are looking forward in 2018 – please let us know of any activities, presentations, or events on the horizon.

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