How to Have both Depth and Elevation for the Node Rim Elevation in InfoSWMM

Subject:  How to Have both Depth and Elevation for the Node Rim Elevation in InfoSWMM

How to Have both Depth and Elevation for the Node Rim Elevation in InfoSWMM by dickinsonre Subject:  How to Have both Depth and Elevation for the Node Rim Elevation in InfoSWMM If you turn on  store Absolute Junction Rim option  then the Rim Elevation = Invert Elevation + Maximum Node Depth will be shown in the DB Table Junction Hydraulic Modeling Data and the Attribute Browser of InfoSWMM and H2OMAP SWMM Figure 1.  Store Absolute Junction Rim Elevation Option Now the Rim Elevation can be copied from the DB Table Figure 2.  The DB for Junction Modeling Data And Pasted to the Elevation Table in Junction Information Figure 3.  The DB for the Junction Information Data Then you can go back and turn off the Preferences flag and you will have the Rim Elevation in in the Information Table and the Maximum Depth in the Junction Hydraulic Modeling Data DB Table,  I do this all of the time as it helps to see both the depth and the Elevation. via Blogger http://www.swmm5.net/2013/08/how-to-have-both-depth-and-elevation.html

InfoMaster Overview

Overview

InfoMaster is an Esri-based business analytics, optimization, and management system for sewer networks. It leverages existing GIS and IT investments to give utilities a cost effective business intelligence and a data collection platform for informed decision making. With versions designed for the desktop, Web, and iOS mobile devices, InfoMaster provides for day-to-day operational management and long-term network planning for users throughout the organization.

Applications

• Water and sewer network business intelligence
• Risk-based rehabilitation planning
• Proactive operational planning
• Condition assessment management
• Infrastructure data validation
• CCTV data management

Business Intelligence for Water and Sewer Systems

The data available in water and sewer networks continues to grow exponentially, whether CCTV video of sewer lines or hundreds of thousands of smart meter readings. InfoMaster is designed to help utilities review, organize and analyze all this information within their existing Esri architecture. Using sophisticated built-in tools, SQL query sets, or custom scripting, users can manage their infrastructure data in ways not previously achievable.

Out-of-the-Box Data Hub

Unlike many traditional business intelligence applications, InfoMaster comes preconfigured to understand water and sewer networks. InfoMaster knows that sewer pipes have upstream and downstream manholes, a hydrant is connected to the distribution system with a lateral, scoring of CCTV defects, and dozens of other items functionality specific to water networks. The database leverages the existing Esri water and wastewater data models to include the ability to store information about incidents and tasks related to the network. Central to InfoMaster is its ability to exchange with other enterprise CMMS or ERP databases enabling a true 360 degree view of the infrastructure.

Proactive Capital and Operational Planning

InfoMaster gives utilities a new perspective on their capital and operational planning. Armed with a clear view of their infrastructure condition, capital and recurring costs, likelihood of failure, consequence of failure, historical incidents and maintenance, planners and managers can revamp capital and operational plans. Utilities can shift operational budget away from reactive and into proactive management.

Rich Results Presentation and Reporting

InfoMaster utilizes the rich Esri results and presentation environment, letting users create thematic maps with flexible symbology and rich detail. Its built-in report generator comes with dozens of standard reports and also allows users to quickly build custom reports and graphs against any piece of data stored in the system. In addition, management dashboards make it possible to effectively track level of service metrics and other key operational data, allowing ata- glance assessments of the past, present and future state of strategic assets.

InfoMaster Mobile

InfoMaster Mobile enables infrastructure data to be created, used, consumed, and verified by staff in the field on a variety of devices. Using the Esri ArcGIS Server, InfoMaster Mobile leverages the geodatabase for use outside the office. It can run on both Web browsers and iOS (iPad, and iPhone) devices.

• Update task/work order status online
• Complete task dependent records
• Create and upload add-on notes, pictures, video and documents

You Don't Work as Hard as You Think You Do

You Don't Work as Hard as You Think You Do

—By Kevin Drum

| Fri Oct. 19, 2012 8:14 AM PDT

Via Matt Yglesias, here's an interesting BLS study from David Yanofsky about how many hours people say they work vs. how many hours they actually work. This is actually sort of a pet topic of mine. My experience is solely with white-collar offices, but for years I noticed that my colleagues routinely overestimated how many hours they worked. As it happened, I frequently worked a little late and a little on weekends, so I had a good sense of just how many people were in the building after 6 pm or on Saturdays. Answer: virtually no one. You could fire a cannon through the place and not risk hitting anyone. And yet, people routinely thought they worked something like 50 hours a week.

But guess what? 50 hours a week is actually a lot. It means working until 7 pm every night. Or it means working until 6 pm every night and then working a solid chunk of hours on Saturday. And there just weren't many people who did that. (Nor was much work being done at home. You'll just have to trust me on that.) The numbers are even worse for 60 hours a week. You'd have to work 10-hour days routinely and a good chunk of hours on both weekend days. There are people who do this, but honestly, not all that many.

Anyway, the chart below demonstrates this graphically. It shows the gap between hours reported and hours actually worked:

As you can see, people who report working 50 hours a week typically overestimate by about 5 hours. My take on this has always been simple. If you stay late a couple of days a week, itfeels like a strain. You feel like you've really put in the hours. And since, in the modern work environment, 50 hours sounds only moderately hardworking (60 hours is the lower bound for real workaholics), that's what you convince yourself you worked that week. But the truth is that two or three late nights actually adds up to maybe 45 hours or so.

At the high end it gets even worse: 75 hours is 10-11 hours every day, or 12-13 hours six days a week. Not many people really do that. But if you work 60 hours a week, the truth is that you're working a helluva lot of hours. That's 10-hour days six days a week. But since 60 hours is just your basic workaholic level, and you feel like you're doing more than basic workaholic hours, you figure you must really be working 70 or 80 hours a week.

There are some people who really do work these kinds of hours, of course. And there are people who work multiple jobs and put in lots of hours. But among your typical hardworking office types, bragging on your hours comes with the territory. As with other kinds of bragging, however, you should take it with a grain of salt.

Nobel economics prize goes to two Americans: Lloyd Shapley, Alvin Roth

By Neil Irwin, Updated: Monday, October 15, 8:46 AM

Two researchers whose work has made for better matchups among students and the schools they wish to attend, and between kidney donors and recipients, were awarded the Nobel Prize in economicsMonday.

Lloyd Shapley and Alvin E. Roth will share the $1.2 million prize for work that broke new theoretical ground (in the case of Shapley) and resulted in concrete uses for that theory (developed by Roth). It is an award that is not terribly relevant to the great macroeconomic crises of the day but that honors work that provided a deeper understanding of how markets work and put that knowledge to use for the practical benefit of humanity.

“The combination of Shapley’s basic theory and Roth’s empirical investigations, experiments and practical design has generated a flourishing field of research and improved the performance of many markets,”the Nobel committee said in its announcement awarding what is formally known as the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel.

Shapley, a professor emeritus at UCLA, developed a theory of “matching methods,” for how to best to match people up in large groups of, for example, men and women considering marriage. The goal is to ensure that the system is “stable,” that both partners feel that they have gotten the most attractive possible match; otherwise, they might separate in search of something better.

Shapley and colleague David Gale developed a process for ensuring that those matches are as stable as possible. In the process, known as the “Gale-Shapley algorithm,” there are a series of rounds in which men and women rank potential mates, and matches are made until everyone finds a spouse and the system is stable.

That work was purely theoretical — no marriages were arranged through the algorithm. But years later, Roth, now at Stanford University, developed ways to apply Shapley’s work to practical uses. The earliest and most widespread was in the system used to match new medical residents with hospitals that wish to employ them.

Roth first recognized that the National Resident Matching Program, which attempts to ensure that new doctors and the hospitals looking to hire them can get as good a match as possible, closely matched the Gale-Shapley algorithm. After all, an employer and employee trying to find the best match are in many ways similar to a hypothetical husband and wife looking to match up.

Roth then helped the resident matching program adapt its process to deal with couples who wished to ensure that they be hired by hospitals in the same city and to make the system less prone to manipulation by participants trying to game the system.

New York City schools faced similar problems in their old system for matching students with schools; students listed their preferred schools, but the system was prone to manipulation when less-qualified students could improve their odds of getting into a school by ranking it higher than they really viewed it.

Roth helped the schools revamp the system, using the lessons from the resident matching program and the theoretical work by Shapley. The result, according to materials from the Nobel committee, was a 90 percent drop in the number of students who were assigned to a school for which they had expressed no preference.

The field of “matching” has life-and-death consequences as well. Research is underway on applying the Gale-Shapley algorithm to the challenge of matching up kidney donors and those who need a transplant. This is a field with particular complications, as many willing to give a kidney to a loved one are not a match, so multi-direction trades can be useful — but that requires a complexity far beyond the original Shapley work in the 1960s or Roth’s efforts to put it to work in the 1980s.

“Some say economics has all kinds of good tools and techniques, but it has an absence of interesting problems,” Roth, 58, told Forbes magazine in 2010. “I look around the world, and I see all kinds of interesting, important problems we ought to solve with the tools we have.”

Link Washington Post

How to Use the Arc Map Editor in InfoSWMM

Note:  How to Use the Arc Map Editor in InfoSWMM

How to Use the Arc Map Editor in InfoSWMM by dickinsonre Note:  How to Use the Arc Map Editor in InfoSWMM Step 1 is to use the Edit Feature for example the Subcatchment layer to bring up the Arc Map Editor Tool. Step 2 is to use the Reshape Feature tool or Vertex tools to bring together mis matched Subcatchment Boundaries Step 3 is to use save the edits and then Update the DB from the Map to recalculate the area of the Subcatchments Sh. via Blogger http://www.swmm5.net/2013/08/how-to-use-arc-map-editor-in-infoswmm.html

SWMM 5 Control Rules for Pumps

Subject:  SWMM 5 Control Rules for Pumps

If you want to define the setting for a pump between the Pump On and Pump Off depths then an IF statement based on the Pump flow will work better as in this example, which changes the setting for the pump between a depth of 18 and 20 meters.   The IF statement based on flow will ensure the rule only applies when the Pump Control depth is moving from the Pump On depth to the Pump Off depth and NOT between the Pump Off and Pump On depth.  Figure 1 shows how the Pump Flow is related to the Pump Setting.

RULE CONTROL_Rule2

IF PUMP PUMP1 FLOW > 0.000000

AND NODE WELL HEAD > 18.000000

AND NODE WELL HEAD < 20.000000

THEN PUMP PUMP1 SETTING = 0.700000

PRIORITY 2.000000

Figure 1   Pump Flow is related to the Pump Setting

Hydrology and Floodplain Analysis (5th Edition)

Hydrology and Floodplain Analysis (5th Edition) [Hardcover]

Philip B. Bedient (Author), Wayne C. Huber (Author), Baxter E. Vieux (Author)

This text offers a clear and up-to-date presentation of fundamental concepts and design methods required to understand hydrology and floodplain analysis. It addresses the computational emphasis of modern hydrology and provides a balanced approach to important applications in watershed analysis, floodplain computation, flood control, urban hydrology, stormwater design, and computer modeling. This text is perfect for engineers and hydrologists.   The book does have large sections on SWMM 5 and HEC-RAS along with Radar Rainfall and 2D flow modeling.

From Amazon 

Lambda Calculus and Link Variables in the InfoSWMM, H2OMAP SWMM and SWMM 5 Dynamic Wave Solution

Subject:  Lambda Calculus and Link Variables in the InfoSWMM, H2OMAP SWMM and SWMM 5 Dynamic Wave Solution

Successive under-relaxation for the SWMM 5 Dynamic Wave Solution by dickinsonre Subject:  Successive under-relaxation for the SWMM 5 Dynamic Wave Solution SWMM 5 uses the method of Successive under-relaxation to solve the Node Continuity Equation and the Link Momentum/Continuity Equation for a time step.  The dynamic wave solution in dynwave.c will use up to 8 iterations to reach convergence before moving onto the next time step.  The differences between the link flows and node depths are typically small (in a non pumping system) and normally converge within a few iterations unless you are using too large a time step.  The number of iterations is a minimum of two with the 1st iteration NOT using the under-relaxation parameter omega. The solution method can be term successive approximation, fixed iteration or Picard Iteration, fixed-point combinatory, iterated function and Lambda Calculus. In computer science, iterated functions occur as a special case of recursive functions, which in turn anchor the study of such broad topics as lambda calculus, or narrower ones, such as the denotational semantics  of computer programs (http://en.wikipedia.org/wiki/Iterated_function).  In the SWMM 5 application of this various named iteration process there are three main concepts for starting, iterating and stopping the iteration process during one time step: ·         The 1st guess of the new node depth or link flow is the current link flow (Figure 3) and the new estimated node depths and link flows are used at each iteration to estimate the new time step depth or flow.  For example, in the node depth (H) equation dH/dt = dQ/A the value of dQ or the change in flow and the value of A or Area is updated at each iteration based on the last iteration's value of all node depths and link flows.  ·         A bound or a bracket on each node depth or link flow iteration value is used by averaging the last iteration value with the new iteration value.  This places a boundary on how fast a node depth or link flow can change per iteration – it is always ½ of the change during the iteration (Figure 1).   ·         The Stopping Tolerance (Figure 2) determines how many iterations it takes to reach convergence and move out of the iteration process for this time step to the next time step. Figure 1.  Under relaxation with an omega value of ½ is done on iterations 2 through a possible 8 in SWMM 5. This is not done for iteration 1. Figure 2.  if the change in the Node Depth is less than the stopping tolerance in SWMM 5 the node is considered converged.  The stopping tolerance has a default value of 0.005 feet in SWMM 5.0.022.  Figure 3.  The differences between the link flows and node depths are typically small (in a non pumping system) and normally converge within a few iterations unless you are using too large a time step.  The number of iterations is a minimum of two with the 1stiteration NOT using the under-relaxation parameter omega. via Blogger http://www.swmm5.net/2013/08/successive-under-relaxation-for-swmm-5.html

St. Venant equation – this is the link attribute data used when the St. Venant Equation is used inSWMM 5, H2OMAP SWMM and InfoSWMM.  Simulated Parameters from the upstream, midpoint and downstream sections of the link are used.

Normal Flow Equation – this is the link attribute data used when the Normal Flow Equation is used in H2OMAP SWMM. Only simulated parameters from the upstream end of the link are used if the normal flow equation is used for the time step.  The normal flow equation is used if the flow is supercritical or the water surface slope is less than the bed slope of the link.

Non Linear Term in the Saint Venant Equation of SWMM 5

The flow equation has six components that have to be in balance at each time step:

1. The unsteady flow term or dQ/dt

2. The friction loss term (normally based on Manning's equation except for full force mains),

3. The bed slope term or dz/dx

4. The water surface slope term or dy/dx,

5. The non linear term or d(Q^2/A)/dx and

6. The entrance, exit and other loss terms.

All of these terms have to add up to zero at each time step. If the water surface slope becomes zero or negative then the only way the equation can be balanced is for the flow to decrease. If the spike is due to a change in the downstream head versus the upstream head then typically you will a dip in the flow graph as the water surface slope term becomes flat or negative, followed by a rise in the flow as the upstream head increases versus the downstream head.

You get more than the normal flow based on the head difference because in addition to the head difference you also get a push from the non linear terms or dq3 and dq4 in this graph.

Innovyze President Dr. Paul F. Boulos Named Chair of the Lebanese American UniversityBoard of Trustees

Innovyze President Dr. Paul F. Boulos Named Chair of the Lebanese American UniversityBoard of Trustees
Broomfield, Colorado USA, October 2, 2012 — Innovyze, a leading global innovator of wet infrastructure modeling and simulation software and technologies, today announced that its president and chief operating officer, Dr. Paul F. Boulos, has been named chairman of the Board of Trustees of the Lebanese American University (LAU) in Beirut, Lebanon. Dr. Boulos succeeds Dr. Charles Elachi, director of NASA’s Jet Propulsion Laboratory (JPL) and Vice President of the California Institute of Technology, who has served as chair since 2009. Dr. Boulos has held key leadership roles as a member of the LAU Board of Trustees since 2009, including serving on the Executive, Audit, and Nominating committees, and chairing the Advancement committee. He also served as chair of the LAU Board of International Advisors from 2006 to 2009. A renowned international authority on water resources and navigation engineering, Dr. Boulos has co-authored nine authoritative books and more than 200 technical articles on issues critical to the water and wastewater industry. He is the recipient of numerous honors from national and international scientific and engineering societies, governments, universities, and NGOs. Among these acknowledgements are notable technical awards for excellence in scholarship from the American Society of Civil Engineers, the American Water Works Association and the U.S. Environmental Protection Agency. Dr. Boulos also received the U.S. Ellis Island Medal of Honor, one of America’s highest accolades; the Pride of Heritage Award from the Lebanese American Foundation; the Alumni of the Year Award by LAU; and was inducted into the University of Kentucky College of Engineering Hall of Distinction, the highest honor the university bestows on its alumni. He was also recognized with Honorary Diplomate status by the American Academy of Water Resources Engineers as well as Distinguished Diplomate status in Navigation Engineering by the Academy of Coastal, Ocean, Port & Navigation Engineers, both academies’ top honors. He is a Fellow of the American Society of Civil Engineers and a Diplomate (by Eminence) of the American Academy of Environmental Engineers. Dr. Boulos serves on the Board of Trustees of the American Academy of Water Resources Engineering (Reston, VA); the Boards of Directors of Innovyze, MWH Global (Broomfield, CO) and America-Mideast Educational and Training Services, Inc./AMIDEAST (Washington, D.C.); and the Dean’s International Council of the Harris School of Public Policy Studies at the University of Chicago (Chicago, IL). He has been a member of advisory boards and councils for many organizations, including the Advisory Council of the Buck Institute for Research on Aging (Novato, CA), the Arab American National Museum (Dearborn, MI), the USEPA Science Advisory Board, the Urban Water Resources Research Council of the Environmental and Water Resources Institute, and the National Academy of Sciences/National Research Council. Dr. Boulos received his Doctorate, Master of Science, and Bachelor of Science degrees in Civil Engineering from the University of Kentucky as well as a Bachelor degree in General Science from the Lebanese American University. He has also completed Harvard Business School’s Advanced Management Program. The President of LAU, Dr. Joseph G. Jabbra, hailed as historic the appointment of Dr. Paul Boulos, as Chairman of the LAU Board of Trustees. “This is the first time in the history of LAU that the Chairman of the Board of Trustees is an alumnus of our beloved institution,” he said. “Dr. Boulos is passionately committed to the well-being of his Alma Mater and to its continued success. He also brings to this position a bundle of energy and a great deal of knowledge and experience. LAU is indeed honored to have Dr. Boulos as the Chairman of its Board of Trustees. Under his dynamic leadership, his Alma Mater will continue its meteoric rise.” One of the top academic institutions in the Middle East, LAU is a private American not-for-profit higher education institution, and is fully accredited by the Commission on Institutions of Higher Education (CIHE) of the New England Association of Schools and Colleges (NEASC), one of the most esteemed authorities on higher education in the world. It has over 8,200 students (representing seventy-five nationalities) enrolled in seven major schools: Arts and Sciences, Business, Architecture and Design, Engineering, Medicine, Nursing, and Pharmacy. The latter is the only Pharm. D. program accredited outside the United States. Over 1,800 students graduate from LAU each year, and its alumni are employed at leading companies around the world. The university has over 250 faculty members and two campuses, in Beirut and Byblos. It is building a third campus in New York. Founded by the Presbyterian Church, USA, in 1924, LAU is governed by a Board of Trustees which derives its authority from the Board of Regents of the University of the State of New York. The Board of Trustees consists of 25 members, most of them American, and is responsible for ensuring that the university furthers its mission organizationally, administratively, educationally, spiritually, socially, and financially. It also assures that LAU has adequate facilities and sets the policy framework for the university’s administration. “It is an honor to follow Dr. Charles Elachi, who has done a phenomenal job of supporting the forward movement of the University as Chair,” said Boulos. “I received an excellent education at LAU, one that I continue to draw on each and every day. I can leave no better legacy than to work diligently to ensure that the LAU we pass on to future generations is even better than the one that so profoundly affected our lives. LAU is an extraordinary place with an inspirational history, and it’s entering an exciting new phase of rapid growth. We are building one of the world’s finest universities, providing our students with the richest educational experience possible as we prepare the next generation of leaders, problem-solvers, and creative thinkers and doers for Lebanon, the MENA region, and the world. I look forward to working with the board, the president, and the vibrant LAU community in the coming years to realize that vision.” For more information on LAU, visit www.lau.edu.

How to Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE

Subject:   How to Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE

How to Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE by dickinsonre Subject:   How to Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE InfoSewer does not have table of node continuity errors only an overall continuity error balance.  If you have a continuity error then you can use the process of divide and conquer to find the continuity error.  Start at the Outlets and using the Trace Upstream command, Domain Manager and Facility Manager take out whole sections of the network until you isolate the section of the network with the continuity error.    Here are the steps you can take: Step 1.             Use Trace Upstream Network to find the and place in a Domain the Upstream Network (Figure 1). Step 2.                          Once the upstream domain is created use the Domain Manager to add in any extra links without nodes (Figure 2) Step 3.             Make the Domain Inactive using Facility Manger (Figure 3) Step 4.                        Run the network and check the overall continuity error (Figure 4) Step 5.                         Continue and repeat until you isolate the area that is the main source of the Continuity Error (CE). Figure 1.  Trace Upstream Network and Place it in a Domain Figure 2.  Use Domain Manager to take out links without nodes Figure 3.  Use Facility Manager to Make the Domain Inactive Figure 4.  Find and Isolate the Area with the CE.

InfoSWMM (d/D v. Surcharge d/D)

Subject:   InfoSWMM (d/D v. Surcharge d/D)

What is the difference between the output variables d/D and Surcharge d/D in InfoSWMM and H2OMap SWMM

The d/D is calculated as link capacity based on the midpoint depth of water in the link or Link depth/ Link Maximum Depth
            Since the depth in the link is restricted to the Maximum Depth the d/D value is always between 0 and 1
The Surcharged d/D is calculated from the end node depths at each end of the link
            The two node depths are averaged and the value of Surcharge d/D is the Average Node Depth / Link Maximum Depth,

The value of Surcharge d/D varies from 0 to a large number depending on the maximum depths of the nodes and the possible surcharge depth of the nodes

The value of d/D is based on the middle of the link and the value of Surcharge d/D is based on the average of the node depths at the end of the link.  They may be and often are different.   However, if you have a Surcharge d/D greater than 1 it will indicate at least one end of the link is surcharged.  A Surcharge d/D may be greater than 1 with a d/D less than 1 due to the ends of the node being surcharged and not surcharged.

·         A Surcharged d/D indicates that at least one end of the link is Full, but
·         A d/D value less than 1 does not preclude that one end may be Surcharged.

InfoSWMM (d/D v. Surcharge d/D) by dickinsonre Subject:   InfoSWMM (d/D v. Surcharge d/D) What is the difference between the output variables d/D and Surcharge d/D in InfoSWMM and H2OMap SWMM The d/D is calculated as link capacity based on the midpoint depth of water in the link or Link depth/ Link Maximum Depth             Since the depth in the link is restricted to the Maximum Depth the d/D value is always between 0 and 1 The Surcharged d/D is calculated from the end node depths at each end of the link             The two node depths are averaged and the value of Surcharge d/D is the Average Node Depth / Link Maximum Depth, The value of Surcharge d/D varies from 0 to a large number depending on the maximum depths of the nodes and the possible surcharge depth of the nodes The value of d/D is based on the middle of the link and the value of Surcharge d/D is based on the average of the node depths at the end of the link.  They may be and often are different.   However, if you have a Surcharge d/D greater than 1 it will indicate at least one end of the link is surcharged.  A Surcharge d/D may be greater than 1 with a d/Dless than 1 due to the ends of the node being surcharged and not surcharged. ·         A Surcharged d/D indicates that at least one end of the link is Full, but ·         A d/D value less than 1 does not preclude that one end may be Surcharged. Figure 1.  Plot of d/D and Surcharged d/D in InfoSWMM. via Blogger http://www.swmm5.net/2013/08/infoswmm-dd-v-surcharge-dd.html

Reasons A Pump H-Q Curve may be Different than the Design Curve

Subject:   Reasons A Pump H-Q Curve may be Different than the Design Curve

From Allan R. Budris and Water World

Actual system H-Q curve not known:

The actual current system H-Q curve may be different than the original system design. Once a plant is commissioned and the plant is put in service, the system head begins to change. In the short term, levels change in the tanks and wells, valves open and close, and filter screens become clogged. As maintenance occurs, pipe schedules are changed, equipment is changed and new equipment is added into the system. In the long term, equipment loses efficiency, scale forms on the internal pipe walls and the plant undergoes expansion and contraction. Even when new, the original calculated system curve may differ from the actual system performance due to the assumptions used in the calculation, such as 10 year old pipe. Any pump change should, therefore, start with the development (confirmation) of the true current pumping system “Head-Capacity” curve, as detailed in the writer’s January 2009 Column on: “Creating an Accurate Pumping System Head-Capacity Curve...“ A field test of the pump total developed head at one or more measured flow rates can help determine the actual (current) pump and system H-Q curves. By developing the true system head-capacity curve, an accurate determination of the current and new pump operating conditions can be established.

Additional references on aging pumps

Cooling Pumps and Towers

Two Steps to a Longer Pump Life

Pump System Hydraulic Design

From Pump System Hydraulic Design 10.2.4 Determination of Pump Operating Points—Single Pump

The system curve is superimposed over the pump curve; (Fig. 10.6). The pump operating points occur at the intersections of the system curves with the pump curves. It should be observed that the operating point will change with time. As the piping ages and becomes rougher, the system curve will become steeper, and the intersecting point with the pump curve will move to the left. Also, as the impeller wears, the pump curve moves downward. Thus, over a period of time, the output capacity of a pump can decrease significantly. See Fig. 10.7. for a visual depiction of these combined effects

.

Storage Nodes in InfoSWMM and H2OMAP SWMM

Subject:   Storage Nodes in InfoSWMM and H2OMAP SWMM

Figure 1 shows how to use the various constants, coefficients and exponents in the Storage or Wet Well data of H2OMAP SWMM.     If you have a Wet Well or Storage Diameter you should convert the Wet Well diameters into an Area with the units of either square feet or square meters.  The computed area will then be a constant or coefficient in the Attribute Browser.  You would only use the exponent or a table of depth and area if the Wet Well area varies with depth. 

Figure 1.  Options for Defining a Storage Node in H2OMAP SWMM or SWMM 5