Saturday, June 30, 2012

How does the Infiltration Maximum Time to Drain the Upper Soil Zone Work in SWMM 5 Green Ampt?

Subject:  How does the Infiltration Maximum Time to Drain the Upper Soil Zone Work in SWMM 5 Green Ampt?

How does the Infiltration Maximum Time to Drain the Upper Soil Zone Work in SWMM 5 Green Ampt?

by dickinsonre
Subject:  How does the Infiltration Maximum Time to Drain the Upper Soil Zone Work in SWMM 5 Green Ampt?

You can use the monthly soil recovery factor (Figure 1) in SWMM 5 to change how the Infiltration Maximum Time to Drain the Upper Soil Zone (Figure 2) is computed each month during a continuous simulation. 

The  depth of the upper soil zone in the internal  SWMM 5 units of feet is calculated at the start of the simulation based on the Green Ampt Soil Saturated Hydraulic Conductivity

Upper Soil Zone Depth = 4  * (Soil Saturated Hydraulic Conductivity * 12 * 3600)^0.5 / 12

And the Upper Zone Moisture Depletion Factor  and Infiltration Maximum Time to Drain the Upper Soil Zone is calculated at each hydrology time step in SWMM 5.

Upper Zone Moisture Depletion Factor  = Upper Soil Zone Depth / 300 * 12 /3600 * Monthly Evaporation Recovery Factor

Infiltration Maximum Time to Drain the Upper Soil Zone = 6 / (100 * Upper Zone Moisture Depletion Factor  )

Figure 1.  Monthly Soil Recovery Factor


Figure 2.  Infiltration Maximum Time to Drain the Upper Soil Zone for a Subcatchment



Sunday, June 24, 2012

A Canopy of Man-Made Solar-Powered Supertrees Flourishes in Singapore

A Canopy of Man-Made Solar-Powered Supertrees Flourishes in Singapore


A national park filled with electrified, man-made trees sounds like a paradox. But Singapore’s latest landscaping project, a 250-acre site called Gardens by the Bay, mixes nature and mechanics with an "artificial forest" full of glowing trees, globally-sourced plants, heritage vegetation, and a conservatory built around a 35-meter mountain complete with the world's tallest indoor waterfall. The project is pushing the boundary of what an urban park can be.
On June 29, Singapore’s National Parks Board will open a section of this project, called Bay South Garden, to the public, welcoming visitors to 18 just-installed "Supertrees," climbing to 50 meters in height.
"Many countries now do tree-planting and call themselves garden cities," CEO of Gardens by the Bay, Dr. Kiat Tan explained in a 2011 speech. "To retain our edge and continue to improve our living environment, we have been transforming Singapore into a City in a Garden."
The man-made canopy, much like its natural counterparts, will serve as air venting ducts for nearby conservatories, collect rainwater, and provide shade to park tourists. Eleven of the Supertrees are adorned with photovoltaic cells that will harvest solar energy to light up the trees in the evening, providing energy and lighting, to conservatories throughout the park, and serving as air and temperature regulators.
The massive structures are also vertical gardens, dressed in a living bouquet of climbing flowers, ferns, and bromeliads from around the world. Come evening, these trees will regale the park with light and sound shows. Visitors can look on from a new "Skyway" bridge connecting two 25-meter trees.
The project was commissioned by the National Parks Board to redevelop Singapore’s south side Marina Bay area and designed by UK architectural firm Grant Associates. Once completed, the Gardens by the Bay hopes to become an eco-attraction that showcases not only a collection of plants from around the world, but also the innovative uses of green technology.
Photos from Gardens by the Bay

Saturday, June 23, 2012

What are the Equations for Weirs in SWMM 5, Part 2?

Subject:   What are the Equations for Weirs in SWMM 5, Part 2?

What are the Equations for Weirs in SWMM 5, Part 2?

by dickinsonre
Subject:   What are the Equations for Weirs in SWMM 5, Part 2?
 There are four types of Weirs in SWMM 5:  Transverse, Sideflow, V Notch and Trapezoidal.   The trapezoidal weir is a combination of the Sideflow and V Notch Weir and the Sideflow acts like a Transverse Weir when the flow is reversed (Figure 1).  The Weirs can have zero, one or two end contractions (Figure 2) and the Weir Length is a function of the Weir Setting and Horizontal Weir Length.  A V Notch weir works as Trapezoidal Weir when the Weir RTC Setting is less than 1.0 
 Figure 1.   Weir Equations in SWMM 5
 Figure 2.   Valid Number of End Contractions
 
Figure 3.  Weir Length Calculations
 

Water Quality Treatment Removal Variables in SWMM5

Subject:    Water Quality Treatment Removal Variables in SWMM5

Water Quality Treatment Removal Variables in SWMM5

by dickinsonre
Subject:    Water Quality Treatment Removal Variables in SWMM5

The treatment variables for Water Quality in a SWMM 5 storage unit (Figure 1) can be either: 
1.       A Process Variable
a.       HRT or Hydraulic Residence Time
b.      DT or Time Step
c.       FLOW or The Current Inflow
d.      DEPTH or the Mean Flow over the Time Step
e.      AREA or the Mean Area over the Time Step
2.       Pollutant Concentration
3.       Pollutant Removal based on the Removal of Other Pollutants 
With a Wide Range of Treatment Functions (Figure 2).

Figure 1.  SWMM 5 Treatment Variable Names in the Treatment Equation
Figure 2.   Treatment Functions in SWMM 5

What are the Equations for Weirs in SWMM 5?

Subject:   What are the Equations for Weirs in SWMM 5?

There are four types of Weirs in SWMM 5:  Transverse, Sideflow, V Notch and Trapezoidal.   The trapezoidal weir is a combination of the Sideflow and V Notch Weir and the Sideflow acts like a Transverse Weir when the flow is reversed (Figure 1).

Figure 1.   Weir Equations in SWMM 5
Weir Equations in SWMM 5



Friday, June 22, 2012

Toilets Save Lives

Toilets Save Lives

Erika Christakis advocates for better sanitation. She points out that the "impact of poor sanitation — and its economic consequences — is well-known": Source, The Dish
So why hasn’t this become an issue of global concern? Instead, between 1997 and 2008, the percentage of international aid that went to sanitation and water fell from 8% to 5%. Concerns over safe drinking water get much more attention, despite a recent World Bank study that found a more pronounced impact on health from building toilet infrastructure than from drinking-water improvements. Few people enjoy talking about bodily functions, and it’s hard for emerging economies to get excited about pit latrines and compost toilets when they’d rather showcase their shiny new buildings and high-speed trains. Feces and open sewers are a hard sell for donors too. There’s no pretty logo — no babbling brook or fresh water spring — for a toilet.

Thursday, June 21, 2012

Convolution of the RDII UH from R, T and K in SWMM 5

Subject:  Convolution of the RDII UH from R, T and K in SWMM 5

Convolution of the RDII UH from R, T and K in SWMM 5

by dickinsonre
Subject:  Convolution of the RDII UH from R, T and K in SWMM 5

The convolution uses the value of R and the Time Base to estimate the amount of Infiltration and Inflow in the Sewer Network.  The short, medium and long term UH's are estimated at each Wet Hydrology time step to make a smooth hydrograph out of the R, T and  K parameters of the Rainfall Dependent Infiltration and Infiltration Method (Figure 1).  The three UH's can be displaced as well if you use the RTK storage parameters (Figure 2)

Figure 1.  The short, medium and long UH's are convoluted in SWMM 5 from the Rainfall Time Series.
Figure 2.   The Initial Abstraction Depth can be used to shift the generated UH in time or reduce the peak flow and total volumes.

c.

Duluth Minnesota Flooding of June 20, 2012

Subject: Duluth Minnesota Flooding of June 20, 2012

T

Duluth Minnesota Flooding of June 20, 2012

by dickinsonre
Subject: Duluth Minnesota Flooding of June 20, 2012

The images come from this Duluth Link.    Radar Map

A series of "training" thunderstorms that all passed over the same region have dumped 4 - 5 inches of rain over a wide swath of Northern Minnesota overnight and early this morning. Nearly 8 inches of rain fell in the Denfeld area of western Duluth. This is more rain than fell in the city's previous worst flood on record, which occurred August 20, 1972. Major flooding is occurring, and only emergency travel is recommended in the city due to flooded roads. system and the saturated ground cannot take much more rain. According to wunderground's weather historian, Christopher C. Burt, the all-time 24 hour precipitation record for Duluth is 5.79" on 8/22 - 8/23 1978; 4.14" was recordedon Tuesday at the airport.


Water overflows from a storm sewer in Duluth, Minn. on June 20.
Duluth Mayor Don Ness said he would declare a state of emergency after the deluge of up to 9 inches of rain that he said caused extensive damage to the port city of about 86,000.
Bob King/The Duluth News-Tribune/AP


This car fell into a huge sinkhole on Skyline Parkway in Duluth.

Bob King  /  Duluth News Tribune
This damage Wednesday was on Duluth's Olney Street.
Major flooding in Duluth, Minnesota
A serious flood emergency is occurring in Duluth, Minnesota. A series of "training" thunderstorms that all passed over the same region have dumped 4 - 5 inches of rain over a wide swath of Northern Minnesota overnight and early this morning. Nearly 8 inches of rain fell in the Denfeld area of western Duluth. This is more rain than fell in the city's previous worst flood on record, which occurred August 20, 1972. Major flooding is occurring, and only emergency travel is recommended in the city due to flooded roads. system and the saturated ground cannot take much more rain.
According to wunderground's weather historian, Christopher C. Burt, the all-time 24 hour precipitation record for Duluth is 5.79" on 8/22 - 8/23 1978; 4.14" was recorded on Tuesday at the airport.

Figure 4. Radar-estimated rainfall from the Duluth, Minnesota radar.

Monday, June 11, 2012

Mass and Concentration Water Quality Loadings in SWMM 5

Subject:   Mass and Concentration Water Quality Loadings in SWMM 5

If you have a time series of flow and water quality at a node in SWMM 5 you have the option of using either a Mass loading or a concentration loading (Figure 1).     If you have a concentration then the load to the node internally in SWMM 5 is the flow times the concentration.  Alternatively, if you have Mass loading then the program will calculate the concentration from the flow and the load.  The table below shows some combinations of flow in cfs and load in pounds per day to yield various BOD 5 concentrations it the network nodes and  links (Figure 2).  For example, at a flow of 10 cfs you can get a BOD5 concentration of 100 mg/l with a loading of about 5400 pounds of BOD5 per day (Figure 3).

Figure 1.  If you use a time series load in SWMM 5 you need TWO time series, one for the flow and one for the mass load or concentration.


Figure 2.   The Mass loading needed to generate a concentration at a particular flow rate.

Flow (CFS)
BOD5 (mg/l)
BOD 5 Pounds Per Day
1
1
5.39
1
10
53.89
1
50
269.45
1
100
538.89
1
200
1077.79
10
1
53.89
10
10
538.89
10
50
2694.47
10
100
5388.93
10
200
10777.87
100
1
538.89
100
10
5388.93
100
50
26944.66
100
100
53889.33
100
200
107778.66

Figure 3.  The calculated BOD 5 concentration in the link from the Mass Loading.

Sunday, June 10, 2012

Virginia Lawmaker Says ‘Sea Level Rise’ Is A ‘Left Wing Term,’ Excises It From State Report On Coastal Flooding

Virginia Lawmaker Says ‘Sea Level Rise’ Is A ‘Left Wing Term,’ Excises It From State Report On Coastal Flooding

Virginia’s legislature commissioned a $50,000 study to determine the impacts of climate change on the state’s shores. To greenlight the project, they omitted words like “climate change” and “sea level rise” from the study’s description itself. According to the House of Delegates sponsor of the study, these are “liberal code words,” even though they are noncontroversial in the climate science community.
Instead of using climate change, sea level rise, and global warming, the study uses terms like “coastal resiliency” and “recurrent flooding.” Republican State Delegate Chris Stolle, who steered the legislation, cut “sea level rise” from the draft. Stolle has also said the “jury’s still out” on humans’ impact on global warming:
State Del. Chris Stolle, R-Virginia Beach, who insisted on changing the “sea level rise” study in the General Assembly to one on “recurrent flooding,” said he wants to get political speech out of the mix altogether.
He said “sea level rise” is a “left-wing term” that conjures up animosities on the right. So why bring it into the equation?
“What people care about is the floodwater coming through their door,” Stolle said. “Let’s focus on that. Let’s study that. So that’s what I wanted us to call it.”
There is a resistance to calling science what it is, even in the studies commissioned to investigate the impact of climate change. The reality is that coastal cities are spending millions to respond to rising sea levels, like Norfolk, Virginia. Norfolk spends $6 million a year to elevate roads, improve drainage, and help homeowners raise their houses, according to BBC. Already, 5 percent to 10 percent of the city’s lowest-lying neighborhoods have heavy flooding. The world’s largest naval base, based in Norfolk, is spending hundreds of millions to replace piers to withstand rising water. Yet they manage to make no mention of climate change or sea level rise in their response strategy.

Tuesday, June 5, 2012

Modeling H2S in InfoSWMM

Subject:   Modeling H2S in InfoSWMM

Modeling H2S in InfoSWMM, ICM and InfoSewer

by dickinsonre
Subject:   Modeling H2S in InfoSWMM, ICM and InfoSewer
You can model Sulfide in InfoSWMM/ICM and InfoSewer using the H2S water quality modeling option which uses BOD5 loading at nodes to estimate the  S concentration in the nodes and links of the network using constant network parameters for: 
1.       The Reaction Rate Coefficient,
2.       The Sulfide Loss Coefficient,
3.       Sulfide Flux Coefficient,
4.       Temperature in Degrees C,
5.       Soluble Sulfide Percentage,
6.       pH for the whole network, and
7.       The Ionization Constant.
Relationship between BOD5 and EBOD
Figue 1.  The concentation  of H2S and BOD5 can be graphed at each node and link.
Figure 2.   Dialogs for H2S and BOD5 in InfoSWMM

Mass Balance for Water Quality in SWMM 5

Subject:   Mass Balance for Water Quality in SWMM 5

Mass Balance for Water Quality in SWMM 5

by dickinsonre
Subject:   Mass Balance for Water Quality in SWMM 5

The rainfall concentration is listed in the wet deposition row of the Runoff Quality Continuity Table, the washoff such as EMC washoff is listed in the Surface Runoff row.  If you are simulating groundwater quality then it is listed as a separate value in a row of the Quality Routing Continuity table alongside RDII quality, DWF quality and WWF quality. 


Hidden features of the 1D St Venant solution for SWMM5, InfoSWMM, and ICM SWMM Networks

1/ There is also an ArcEngine version of InfoSWMM call InfoSWMM SA. I will SA to show some hidden features of the 1D St Venant solution f...