SWMM5

How to Make a Smaller Model out of a Large Model in InfoSWMM

Fri, 17 Feb 2012 13:50:38 -0800

Subject: How to Make a Smaller Model out of a Large Model in InfoSWMM

InfoSWMM and H2OMAP SWMM will export only those ACTIVE elements to SWMM 5 as defined by the Facility Manager.

You can use the feature to make smaller SWMM 5 models and then reimport the exported smaller SWMM 5 model back into a H2OMAP SWMM or InfoSWMM scenario.

Permalink | Leave a comment »

Maximum Surcharge Height Over Crown Explanation

Wed, 08 Feb 2012 02:59:00 -0800

Note: Maximum Surcharge Height Over Crown Explanation

Here is an example of how the Maximum Surcharge Height over the Node Crown is calculated. Consider a manhole with an invert of 10 feet, one incoming pipe (Pipe A), one outgoing pipe (Pipe B), both pipes with a diameter of 2 feet, but the invert of Pipe A is 10 feet and the invert of Pipe B is 11 feet. What is the Maximum Surcharge height if the HGL at the node is 17 feet?

HGL at Node ---- 17 feet

Maximum Surcharge Height Over Crown is 4 feet

Node Crown --- 13 feet Pipe B Crown --- 13 feet

Pipe A Crown --- 12 feet

Pipe B Invert --- 11 feet

Pipe A Invert --- 1o feet MH Invert --- 10 feet

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Permalink | Leave a comment »

The Importance of Viewing Results at the Proper Time Scale

Sun, 05 Feb 2012 20:34:23 -0800

Subject: The Importance of Viewing Results at the Proper Time Scale

In SWMM 5 when you are simulating rapidly changing flow – such as pump flows – it is important to remember that you are only seeing the results of the simulation at your selected report time step. Here is an example model with the same number of pump starts for all three simulations (318), the same average time step during the simulation (10 seconds) but different report time steps. The conception of the pump starts is totally different visually depending on the selected report time steps. You should always compare the starts using the pump graphs and the pump summary table. The percent utilized and the number of pump start ups tells you the mean pump start length or in this case 153 seconds or 45.1 percent of 30 hours divided by 318 pump starts.

Permalink | Leave a comment »

An Example of the Importance of the Term DQ4 in the SWMM 5 St Venant Solution

Sun, 05 Feb 2012 19:06:00 -0800

Subject: An Example of the Importance of the Term DQ4 in the SWMM 5 St Venant Solution

The four terms are are used in the new flow for a time step of Qnew:

Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1)

when the force main or gravity main is full dq3 and dq4 are zero and Qnew = (Qold – dq2) / ( 1 + dq1)

The dq4 term in dynamic.c uses the area upstream (a1) and area downstream (a2), the midpoint velocity, the sigma factor (a function of the link Froude number), the link length and the time step or

dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma

where Sigma is a function of the Froude Number and the Keep, Dampen and Ignore Inertial Term Options. Keep sets Sigma to 1 always and Dampen set Sigma based on the Froude number, Ignore sets Sigma to 0 all of the time during the simulation.

The value of dq4 increases when there is a significant difference in the cross sectional area of the downstream end of the link and the upstream end of the link. In this example, the downstream storage node causes a backflow in the link (Figure 1). The flow may look unstable in the link flow time series but the change in flow is simply due to the water sloshing back and forth. There is no continuity error as the term dq4 keeps the water in the link in balance (Figure 2).

Figure 1. GIF of Water Surface Showing the effect of the term dq4

Figure 2. Time Series of Flow - the Link has Mass Balance due to the term dq4

See the full gallery on Posterous

Permalink | Leave a comment »

ArcToolBox GIF

Sun, 05 Feb 2012 18:14:19 -0800

Permalink | Leave a comment »

Use the SWMM 5 Scatter Graph to show the Pump Curve used during the Simulation

Sun, 05 Feb 2012 17:40:34 -0800

Subject: Use the SWMM 5 Scatter Graph to show the Pump Curve used during the Simulation

You can use a scatter graph to show the relationship between the pump during the simulation and the Storage Depth. If the pump is on the curve based on the pump summary table then the scatter graph should look like the pump curve. The pump summary table in the SWMM 5 RPT also shows you the time off the pump curve low and high.

See the full gallery on Posterous

pump_scatter.INP Download this file

Permalink | Leave a comment »

From SciAM - Why Plants are important to River Formation

Sun, 05 Feb 2012 08:13:43 -0800

Thanks to Plants, We Will Never Find a Planet Like Earth

Earth's flora is responsible for the glaciers and rivers that have created this planet's distinctive landscape

Perhaps even more surprisingly, vascular plants formed the kinds of rivers we see around us today, according to another article by Martin Gibling of Dalhousie University in Nova Scotia and Neil Davies of the University of Ghent in Belgium, who analyzed sediment deposition going back hundreds of millions of years. Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses. Only when enough vegetation grew to break down rock into minerals and mud, and then hold that mud in place, did river banks form and begin to channel the water. The channeling led to periodic flooding that deposited sediment over broad areas, building up rich soil. The soil allowed trees to take root. Their woody debris fell into the rivers, creating logjams that rapidly created new channels and caused even more flooding, setting up a feedback loop that eventually supported forests and fertile plains.

"Sedimentary rocks, before plants, contained almost no mud," explains Gibling, a professor of Earth science at Dalhousie. "But after plants developed, the mud content increased dramatically. Muddy landscapes expanded greatly. A new kind of eco-space was created that wasn't there before."

Permalink | Leave a comment »

How to Import the SWMM 5 Report File as a Layer in infoSWMM

Sat, 04 Feb 2012 17:27:00 -0800

Subject: How to Import the SWMM 5 Report File as a Layer in infoSWMM

The idea of this blog of note is to show how one may extract information from the SWMM 5 or InfoSWMM RPT file and import the Excel File as a feature in InfoSWMM. This blog has an example Excel file to illustrate the linkage. The steps are:

Step 1: Copy the whole row from Conduit Summary from the InfoSWMM Browser

Step 2: Add the two columns length and slope from the Link Summary Table and the InfoSWMM Browser

Step 3: You need a few calculations based on the table values from SWMM 5 to estimate the CFL time steps in the .

Step 4: Add the Excel Spreadsheet as a layer in InfoSWMM – the Named Range should be added to insure valid numbers and not Nulls after the join

Step 5: You can now plot the CFL Time Step for the Links using the Layer Properties command in Arc Map

Step 1: Copy the whole row from Conduit Summary

Step 2: Add the two columns length and slope from the Link Summary Table

Step 3: You need a few calculations based on the table values from SWMM 5 to estimate the CFL time steps.

The CFL Step = Length / (Full Velocity + (Gravity * Full Depth)^0.5)

Full Velocity = Full Flow / Full Area

You also need to create a Name A Range for you data so that the data does not show up as Nulls

Step 4: Add the Excel Spreadsheet as a layer in InfoSWMM – the Named Range should be added

Step 4: Join the Excel Table to the InfoSWMM Conduit Feature Layer

Step 5: You can now plot the CFL Time Step for the Links using the Layer Properties command in Arc Map

swmm5_summary_table.xlsx Download this file

How to Import the SWMM 5 Report File as a Layer in infoSWMM.docx Download this file

Permalink | Leave a comment »

How to Approximate a Timer in the RTC Rules of SWMM 5

Sat, 04 Feb 2012 08:19:00 -0800

Subject: How to Approximate a Timer in the RTC Rules of SWMM 5

SWMM 5 does not have a explicit timer in its Real Time Control (RTC) rules but you can approximate it by using a Control Curve as in the attached example model. The Control Curve will modify the setting of the Weir by the Inflow to the Storage node. You can have normal weir flow settings based on the invert elevation of the weir and the Surface node water surface elevation but in addition you can control the weir setting by:

1. Closing the weir when the inflow is low,

2. Closing the weir by staggered Storage node depth,

3. Opening the weir gradually when the inflow increases

4. Closing the weir by a combination of Node Depth IF statements and Control Curve rules

For example, you can have the Weir Setting controlled the Node Depth, Link Inflow and Node Inflow simultaneously approximately with the depth and the inflow parameters closing the weir by proxy instead of by time since the closing.

gate_timer.INP Download this file

How to Approximate a Timer in the RTC Rules of SWMM 5.docx Download this file

Permalink | Leave a comment »

North Carolina City Chooses InfoSewer

Tue, 31 Jan 2012 10:14:57 -0800

North Carolina City Chooses InfoSewer

ArcGIS Based Sewer Modeling Package Helps Hendersonville, NC Model and Manage Its Collection System

Broomfield, Colorado, USA, January 31, 2012

Innovyze, a leading global innovator of business analytics software and technologies for wet infrastructure, today announced the City of Hendersonville, North Carolina, has selected InfoSewer for ArcGIS (Esri, Redlands, CA) as its sewer modeling platform. InfoSewer has helped define the standard in the industry for GIS-centric sewer network analysis, planning and design since 2003.

The City of Hendersonville’s Water and Sewer Department is responsible for providing water service to more than 62,000 residents and businesses of Hendersonville and Henderson County and sewer service to more than 19,000 residents and businesses. The Department is also responsible for the operation and maintenance of over 580 miles of water mains, 57 water pumping stations, 24 water storage tanks (ranging in size from 100,000 gallons to 5 million gallons), over 185 miles of sewer mains and 37 sewer pumping stations. “InfoSewer gives us the blend of powerful, easy-to-use analysis capabilities we need to effectively plan and manage our sewer system,” said Brent Detwiler, City Engineer. “We have a significant investment in Esri ArcGIS technology, and InfoSewer lets us leverage our GIS data for fast and accurate modeling.”

Certified by the National Association of GIS-centric Software, InfoSewer is a powerful ArcGIS-based computer program for planning, designing, analyzing, and expanding sanitary, storm and combined sewer collection systems. It can be effectively used to model both dry-weather and wet-weather flows and determine the most cost-effective and reliable method of wastewater collection. Built atop ArcGIS, InfoSewer enables engineers and GIS professionals to work simultaneously on the same integrated platform, commanding powerful GIS analysis and hydraulic modeling in a single environment using a single dataset.

InfoSewer is used worldwide by municipal engineers and planners to create detailed, accurate models of their sewer infrastructure systems. These models enable them to evaluate the effect of new developments, zoning changes, and other additional loads on system flows; pinpoint current and future problem areas; predict overflows and backups; and determine how best to restore needed capacity lost to infiltration and inflow with the least rehabilitation.

Users also rely on these models to compute hydrogen sulfide generation and corrosion potential; analyze the rate of Biochemical Oxygen Demand (BOD) exertion; track sediment movement and deposition; trace pollutant contribution from source nodes; perform time of concentration calculations; calculate the amount of pollutant transported to the wastewater treatment plant; and assess pollutants’ impacts on receiving waters. Extensive scenario management functionality enables users to analyze existing or future sewage collection systems. The application also provides vital tools for meeting and exceeding environmental regulations and improving community relations via database queries and map displays.

InfoSewer also delivers advanced design functionality and exponential increases in efficiency while simplifying use. Users can quickly and reliably design new sewer collection systems that consider standard design criteria such as flow depth-to-pipe diameter ratios, velocity, slope, soil cover depth, and pipe crown drop. Using user-input manhole locations and rules, InfoSewer calculates the optimal pipe and slope, invert elevation of conduits and manholes, soil cover depths at both ends of each pipe section, and cost of excavation and reinstatement to meet target design criteria. Results can be reviewed using profile plots with advanced labeling of 30 node and link variables, color-coded sewer maps of these variables, or 20 comprehensive tabular reports. The profile plots can be automatically updated in the model database for steady state and extended period simulations of new and existing designs, greatly simplifying the model-building process.

Together, these capabilities help wastewater utilities worldwide dramatically raise productivity and efficiency by rapidly developing practical and optimal capital improvement strategies that minimize costs while improving system reliability, integrity and performance. By making engineering professionals more productive and their organizations more competitive, InfoSewer delivers benefits utilities can pass on to their customers through better designs and higher quality standards, achieved in a shorter turnaround time.

“InfoSewer continues to evolve to meet the growing needs of top utilities around the globe,” said Innovyze Americas Operations Director J. Erick Heath, P.E. “We are thrilled that progressive leading utilities like Hendersonville are using InfoSewer to design and manage the most efficient sewer collection systems possible.”

Permalink | Leave a comment »

Changing the rules in the middle of the game: Philadelphia's green infrastructure

Sun, 29 Jan 2012 11:29:00 -0800

Changing the rules in the middle of the game: Philadelphia's green infrastructure

Category: Water
Posted on: January 18, 2012 4:14 PM, by Liz Borkowski

Philadelphia and Green Infrastructure

Aging US water infrastructure has meant more leaks, flooded basements, and massive sinkholes in cities across the US. Fixing the water and sewer systems in need of repair will take billions of dollars, and it's hard to find that kind of money in the budget these days.

Saqib Rahim reports for ClimateWire on Philadelphia's decision to use "green infrastructure" rather than building a larger pipe system to handle the water that's dumped on the city during severe storms. The combination of more intense storms and more paved area is a problem: Impervious surfaces like roads, sidewalks, and parking lots can't absorb rainfall, so it ends up in the city's stormwater collection system -- which, in many older cities, is combined with the sewage system. When these combined systems are overwhelmed by heavy rainfall, the result is often that a rainfall-and-sewage mixture gets discharged into a local waterway. (Read more about this problem here.) Rahim explains Philadelphia's solution to this problem:

Instead of building an even larger pipe system to address the issue, [Water Department Commissioner Howard] Neukrug pitched the most aggressive "green infrastructure" plan in the country. Through increased vegetation, rain barrels, sponge-like roads and other measures, the city would try to absorb more water where it fell. The ground would filter out pollutants, reduce strain on the pipelines and make the city a more attractive place.

Neukrug tells Rahim that the green infrastructure solution will cost Philadelphia $2 billion, compared to $8 billion to $10 billion for larger underground tunnels. But the part of the city's plan that's currently causing a controversy is what water customers will pay. They'll now be charged not just for the water they use, but for their contributions to stormwater problems -- that is, sites with a lot of impervious surfaces will pay more.

The average household will see an average bill rise from approximately $60 to around $63.50, Rahim reports. For some large businesses, though, costs could rise significantly over the next few years -- and 100 of these businesses have hired a lobbyist and met with the Water Department to oppose implementation of the new billing practices.

I can understand why these businesses are upset. When they invest and plan for their businesses' futures, they assume the rules will stay the same. Their extensive impervious surfaces are causing problems for public health, but they might not have realized that their decisions about what to pave were raising costs for the city's residents (and everyone else affected when its sewage ended up in local waterways).

Changing the rules isn't ideal, but it's the best solution if the current rules create incentives for behavior that harms public health. If this country had never changed the rules to make businesses start bearing more of the cost for problems they cause the general public (externalities, in economic language), we'd still have rivers so polluted that they catch fire. Governments can ease the pain by providing grants or low-interest loans to help businesses and individuals invest in greener setups -- and, Rahim reports, Philadelphia is offering loans to businesses that want to green their facilities. Increases in bills will also be capped at 10% or $100 per month.

Such an approach could also be used to address other public health issues like CO2 emissions -- but so far, opposition to a carbon tax has been stronger than support. In the meantime, I'll be watching Philadelphia's effort and hoping it succeeds with a green solution to water infrastructure challenges.

Source: http://scienceblogs.com/thepumphandle/2012/01/changing_the_rules_in_the_midd.php#more

Permalink | Leave a comment »

Example SWMM 5 Model for Activated Sludge

Sat, 28 Jan 2012 15:20:00 -0800

Note: Example SWMM 5 Model for Activated Sludge

Here is one example of how to model an activated sludge tank. The image is Wikipedia (http://en.wikipedia.org/wiki/Activated_sludge) and is the watermark background in the SWMM 5 GUI. There is 100 lps inflow, 20 percent recycle and 10 percent sludge drawoff. You can adjust the amount of recycle and sludge altering the pump type 2 flows or if you want to increase the inflows – add more flow in the RawWater inflow node.

activated_sludge.inp Download this file

Permalink | Leave a comment »

Three Flow Divider Link Example in SWMM 5

Sat, 28 Jan 2012 08:58:00 -0800

Subject: Three Flow Divider Link Example in SWMM 5

You can have more than 2 downstream OUTLET Type links in the SWMM 5 dynamic wave solution. Each link, Under5, Over5 and ReturnFlow is an OUTLET Link with a rating curve depth/flow table. Depending on the depth in the storage node DIVIDER, the flow is computed from the table for links Under5, Over5 and ReturnFlow.

ReverseFlow.inp Download this file

Permalink | Leave a comment »

Output Statstics Manager to find negative flows in InfoSWMM

Sat, 28 Jan 2012 05:01:00 -0800

Subject: Output Statstics Manager to find negative flows in InfoSWMM

Output Statstics Manager to find negative flows with these parameters:

1. Pipe Features

2. Use a Domain with your force mains

3. Select Flow

4. Event Dependent

5. Total – NOT Mean or Peak to find the negative and positive flows

6. Large NEGATIVE Flow Threshold

7. Large NEGATIVE Volume Threshold

8. Zero for Interevent Time to pick up all values

9. You will get a table that shows you the minimun flows, and a histogram of the flows

Permalink | Leave a comment »

Flow Dividers in SWMM 5 Dynamic Routing

Sat, 28 Jan 2012 05:00:00 -0800

Note: Flow Dividers in SWMM 5 Dynamic Routing

You can have flow dividers in SWMM 5 dynamic routing by using Storage Nodes for the dividers, OUTLET links for the downstream links and minimizing downstream HGL effects. The needed components are:

1. A Storage Node for the divider node as a OUTLET Link does not have a Surface Area,

2. Two or More OUTLET Links as the downstream diversion and cutoff links,

3. Two or More Rating Curves to divide the flow up based on either depth or head,

4. Pumps, Outfalls or Steep Sloped Links Downstream of the diversion and cutoff links to minimize downstream HGL effects

dividers_in_dynamic_wave.inp Download this file

Permalink | Leave a comment »

Keep and Dampen options and their effect on the four main terms of the St Venant equation

Tue, 24 Jan 2012 05:09:00 -0800

Note: The Keep and Dampen options and their effect on the four main terms of the St Venant equation.

The four terms are are used in the new flow for a time step of Qnew:

Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1)

when the force main or gravity main is full dq3 and dq4 are zero and Qnew = (Qold – dq2) / ( 1 + dq1)

dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma

the dq3 term in dynamic.c uses the current midpoint area (a function of the midpoint depth), the sigma factor and the midpoint velocity.

dq3 = 2 * Velocity * ( Amid(current iteration) – Amid (last time step) * Sigma

dq1 = Time Step * RoughFactor / Rwtd^1.333 * |Velocity|

The weighted area (Awtd) is used in the dq2 term of the St. Venant equation:

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length or

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length

Normally, dq1 (Friction Loss / Maroon in the Graph) balances dq2 (Water Surface Slope Term or Green in the Graph) but often for links with a large difference between upstream and downstream depths dq4 (Red in the Graph) can have a significant value. If dq4 or dq3 are important then the depth of water to increases to pass the same flow using the Keep option over the Ignore. If you have a link with a Froude number near or over 1.0 (Supercritical) then using Keep or Dampen for the Options may result in depth differences. The effect of Keep is to increase the “loss” terms in the St Venant Equation. The effect of Dampen and Ignore is to decrease the sum of the “loss” terms in the St. Venant Solution and lower the simulated depth.

Permalink | Leave a comment »

Rooftop gardens could solve Singapore's flooding problem

Thu, 19 Jan 2012 16:29:00 -0800

Rooftop gardens could solve Singapore’s flooding problem

By Tyler Falk | January 18, 2012, 9:09 AM PST

From SmartPlanet

In the last two years, rapid urbanization and changing weather patterns have lead to major flash floods in Singapore.

“[It] can be safely presumed that the weather patterns in Singapore have changed,” said Singapore’s Minister for the Environment and Water Resources last year after a flash flood where in one day Singapore received 77 percent of the amount of rainfall that usually falls in June. “It is very likely that our drainage systems will have to be redesigned to cope with such intense flashes.”

Singapore convened a panel to come up with the best options for dealing with flash floods and stormwater runoff. Their suggestion? Not an overhaul of the drainage system, but rooftop gardens.

Big infrastructure projects are costly and take time to replace. And while the upgrading the drainage system is likely necessary, the panel suggests a quick fix to Singapore: require rooftop gardens on all new and retrofitted buildings. Rooftop gardens don’t just add beauty to the city, they can also play a big role in mitigating floods by reducing and slowing stormwater runoff and filtering pollutants.

But it’s not just rooftop gardens, Singapore’s Today reports:

These measures are to be complemented with diversion canals, storage tanks along “pathways” of drains, drain capacity improvements, and finally, flood barriers, raised platform levels - some of which is already being done, but “could be carried further”, noted Prof Balmforth.

The panel also suggested storage tanks, rain gardens, and porous pavement.

Photo: HenryLeongHimWoh

/Flickr

Urbanisation has led to increase in storm water run-off: Expert panel [Today]

Permalink | Leave a comment »

Innovyze Surge Line Brings Surge Events to Life With Cutting-Edge Pipe Profile Animations

Tue, 17 Jan 2012 10:15:17 -0800

Innovyze Surge Line Brings Surge Events to Life With Cutting-Edge Pipe Profile Animations

High Quality Animation Gives Engineers Inside View of Model Activities for the First Time

Broomfield, Colorado USA, January 17, 2011 — Innovyze, a leading global innovator of business analytics software and technologies for wet infrastructure, today announced the worldwide release of the SurgeAnimatemodule for its industry-leading surge product line. The breakthrough pipe profile animation module brings a new level of visualization and interpretation power to transient analysis, helping engineers quickly gain a thorough understanding of the complex phenomena occurring within their distribution systems.

Available for InfoSurge and InfoWorks TS, the module is ideal for assessing the strength and effectiveness of water supply and distribution systems under a wide range of hydraulic transient conditions, from routine operation to emergency states. It has unprecedented power to help users confidently determine the best combination of surge protection devices to minimize the impact of objectionable pressure transients. The enhanced product suite reflects Innovyze’s vanguard position in the water industry and its continuing commitment to delivering pioneering technology for improving the safety and reliability of the world’s water supply.

“This key new modeling functionality makes it easy to get a handle on how transient waves propagate over time in distribution systems, allowing water utilities worldwide to better see how transient events are mitigated by surge protection devices,” noted Christopher W. Baxter, Ph.D., President of HYDRANNT Consulting Inc., in Port Coquitlam, BC, Canada. “Innovyze continues to raise the standard in the industry.”

Anticipating and controlling transient response is critical to ensuring the protection, integrity, and effective/efficient operation of water distribution systems. Transient responses can introduce pressures of sufficient magnitude (upsurge) to burst pipes and damage equipment. The resulting repercussions can range from extended service outages to loss of property and life. Transient responses can also produce sub-atmospheric pressures (downsurge) that can force contaminated groundwater into the distribution system at a leaky joint, crack or break, leading to grave health consequences when carried out downstream in the pipe system. Sustained sub-atmospheric pressures may also lead to cavitation and water column separation, resulting in severe “water hammer” effects as the vapor cavity collapses.

The Innovyze transient flow simulation technology suite addresses every facet of pressure surge analysis and its role in utility infrastructure management and protection, delivering the highest rate of return in the industry. It provides the engineer-friendly simulation framework water utilities need to identify characteristics that can make their water supply and distribution systems more susceptible to transient pressure events. Users can quickly and efficiently assess the effects of power outages, pump shutdowns and startups, valve closures, rapid demand and pump speed changes, as well as the efficacy of any combination of surge protection devices. The product suite also accurately simulates cavitation and water column separation and evaluates their intensity. Its blazing simulation speed, unrivalled in the industry, makes transient analysis an easier and more enjoyable task.

The new SurgeAnimate module enables users to create live animations of pipe profiles simply by specifying the first and last nodes; the rest is done automatically. Tank and reservoir levels, pump speeds, water flow or velocity rates are all animated. Many surge devices (such as air valves and bladder tanks) are also animated in detail. Animation speed can be set and stopped or restarted interactively at any simulation time period, allowing the user to thoroughly view and analyze the model’s transient activities (including cavitation pressure). Animations can be saved as AVI files.

Armed with these mission-critical network modeling capabilities, water utilities can more accurately assess their susceptibility to low or negative pressures caused by transient surges, identify vulnerable areas and risks, evaluate and design sound control and mitigation measures, and determine improved operational plans and security upgrades.

“The ability to confidently assess distribution system vulnerability to pressure transients is becoming more critical every day,” said Innovyze President and Chief Operating Officer Paul F. Boulos, Ph.D., BCEEM, Hon.D.WRE, F. ASCE. “Our new SurgeAnimate module makes models come alive, allowing users to go inside the pipes and network elements for the first time. This unprecedented ability to see and experience model transient activities in real time is critical to designing reliable, enduring systems and protecting public health.”

Permalink | Leave a comment »

Surcharged Node and the Link Connection in SWMM 5

Mon, 16 Jan 2012 08:51:00 -0800

Subject: Surcharged Node and the Link Connection in SWMM 5

A surcharged node in SWMM 5 uses this point iteration equation (Figure 1):

dY/dt = dQ / The sum of the Connecting Link values of dQ/dH

where Y is the depth in the node, dt is the time step, H is the head across the link (downstream – upstream), dQ is the net inflow into the node and dQ/dH is the derivative with respect to H of the link St Venant equation. If you are trying to calibrate the surcharged node depth, the main calibration variables are the time step and the link roughness:

1. Mannings’s N

2. Hazen-Williams or

3. Darcy-Weisbach

The link roughness is part of the term dq1 in the St Venant solution and the other loss terms are included in the term dq5. You can adjust the roughness of the surcharged link to affect the node surcharge depth.

Figure 1. The Node Surcharge Equation is a function of the net inflow and the sum of the term dQ/dH in all connecting links. Generally, as you increase the roughness the value of dQ/dH increases and the denominator of the term dY/dt = dQ/dQdH increases.

Figure 2. The value of dQ/dH in a link as the roughness of the link increases.

Permalink | Leave a comment »

HOW MOSQUITOES FLY IN RAIN from 3Quarks

Sun, 15 Jan 2012 18:33:21 -0800

HOW MOSQUITOES FLY IN RAIN

Mariel Emrich in Talking Science:

Mosquitoes are as adept at flying in rainstorms as under clear skies. But how is that possible? Wouldn’t rain crush a mosquito to the ground since mosquitoes weigh 50 times less than raindrops?

David Hu, an assistant professor of mechanical engineering and biology at the Georgia Institute of Technology, and his graduate research assistantAndrew Dickerson have found that while mosquitoes do get hit by raindrops, they don’t get crushed by them.

Hu discussed their research in a talk at November's APS Division of Fluid Dynamics Meetingthat was entitled “How Mosquitoes Fly in the Rain”.

The researchers measured the impact forces of raindrops on both regular mosquitoes and custom-built mosquito mimics. The mimics were made from small Styrofoam spheres of mosquito-like size and mass. They used high-speed video to capture images of the mosquitoes getting hit with raindrops.

Since the bugs fly so slowly (a maximum of 1 meter per second) compared to the drops (which fall between 5 to 9 meters per second), the mosquitoes cannot react quickly enough for avoidance, and most likely cannot sense the imminent collision.

More here.

Posted by Abbas Raza at 03:42 PM | Permalink

Permalink | Leave a comment »