Drainage Wells or a Vertical Exfiltration Trench in InfoSWMM

Subject:  Drainage Wells or a Vertical Exfiltration Trench in InfoSWMM

Note, this is just one way to model an Exfiltration Trench.  The source for the image below is Rice Creek Watershed. 

You can make a storage node to simulate the trench with the following characteristics:

·         Functional or Shape Curve to describe the shape of the trench,

·         Infiltration parameters to simulate the infiltration flow out of the bottom or sides of the trench,

Step 1:  Define the shape and geometrical characteristics of the Infiltration Trench

Step 2: Define the soil infiltration characteristics of the trench

Step 3:  Run the simulation.  The Storage Volume Summary tells you the volume infiltrated and the average outflow.

Step 4:  Output Manager will also show the infiltration  outflow, the depth and the volume of the infiltration/storage node.

Step 4:    Infiltration losses out the side and bottom of the orifice.

The Time Base is T + T*K from the Time(T) and Storage (K) values for RDII in SWMM5

Note:  Each of the RDII UH's has a base time for the convolution of the RDII from each UH.  The Time Base is T + T*K from the Time(T) and Storage (K) values  used in the RTK data.  In this particular case:

·         The Fast UH has a time base of 22 hours,

·         The Medium UH has a time base of 430 hours, and

·         The Slow UH has a time base of 4212 hours.

If this is altered as in the  bottom image you can see the difference in the total  RDII I&I Flow

·         The Fast UH has a time base of 22 hours,

·         The Medium UH has a time base of 36 hours, and

·         The Slow UH has a time base of 52 hours.

SWMM5 Runoff and Depth Relationships

Note:  The surface runoff is a non linear function of the independent depth in both the pervious and impervious areas of the subcatchments.   No surface runoff occurs until the depth over either the impervious or pervious area is greater than the respective depression storage (Figure's 1, 2, 3 and 4).

Figure 1:  Surface Runoff, Depth and  Depression Storage Relationship.

Figure 2:  Subcatchment Runoff and Depth over time with a Subcatchment Width of 500 feet.

Figure 3:  Subcatchment Runoff and Depth in a Scatter Graph with a Subcatchment Width of 500 feet.

Figure 4:  Subcatchment Runoff and Depth in a Scatter Graph with a Subcatchment Width of 2000 feet.

SWMM 5 Subcatchment Runoff and Depth Relationship

Note:  The surface runoff is a non linear function of the independent depth in both the pervious and impervious areas of the subcatchments.   No surface runoff occurs until the depthover either the impervious or pervious area is greater than the respective depression storage (Figure's 1, 2, 3 and 4).

Figure 1:  Surface Runoff, Depth and  Depression Storage Relationship.

Figure 2:  Subcatchment Runoff and Depth over time with a Subcatchment Width of 500 feet.

Figure 3:  Subcatchment Runoff and Depth in a Scatter Graph with a Subcatchment Width of 500 feet.

Figure 4:  Subcatchment Runoff and Depth in a Scatter Graph with a Subcatchment Width of 2000 feet.

Three Types of Surfaces in each Subcatchment of SWMM 5

Note:  There are Three Types of Surfaces in each Subcatchment of SWMM 5.  The overall depth in a subcatchment is the weighted average of the impervious without depression storage area, the impervious with depression storage area and the pervious area depth.  The depths on each type of area are independent of each other. 

Figure 1:  The processes that occur on each type of Subcatchment Area.

Figure 2:  The three independent Depths on a Subcatchment.  The SWMM 5 reported Depth is the weighted average of the three depths.

Storage Nodes in InfoSWMM 2D

Storage Nodes in InfoSWMM 2Dyoutu.be/Jqk4YPMu3hY via @youtube

— RDickinson (@RDickinson) March 15, 2013

Singapore - Catching Every Drop of Rain

Singapore - Catching Every Drop of Rain

The source of the map of the rivers of Singapore is the Singapore PUB

As a small island that doesn't have natural aquifers and lakes and with little land to collect rainwater, Singapore needs to maximize whatever it can harvest.

Currently, Singapore uses two separate systems to collect rainwater and used water. Rainwater is collected through a comprehensive network of drains, canals, rivers and stormwater collection ponds before it is channelled to Singapore's 17 reservoirs for storage. This makes Singapore one of the few countries in the world to harvest urban stormwater on a large scale for its water supply.

The newest reservoirs are Punggol and Serangoon Reservoirs which are our 16th and 17th reservoirs. By 2011, the water catchment area has increased from half to two-thirds of Singapore’s land surface with the completion of the Marina, Punggol and Serangoon reservoirs.

With all the major estuaries already dammed to create reservoirs, PUB aims to harness water from the remaining streams and rivulets near the shoreline using technology that can treat water of varying salinity. This will boost Singapore’s water catchment area to 90% by 2060,

The goal is to capture every drop of rain (Figure 1)

Reservoirs

Pandan Reservoir	Kranji Reservoir
Jurong Lake Reservoir	MacRitchie Reservoir
Upper Peirce Reservoir	Lower Peirce Reservoir
Bedok Reservoir	Upper Seletar Reservoir
Lower Seletar Reservoir	Poyan Reservoir
Murai Reservoir	Tengeh Reservoir
Sarimbun Reservoir	Pulau Tekong Reservoir
Marina Reservoir	Serangoon Reservoir
Punggol Reservoir

Rivers

Singapore River	Sungei Kallang
Rochor River	Sungei Whampoa
Geylang River	Sungei Bedok
Sungei Ketapang	Sungei Changi
Sungei Selarang	Sungei Loyang
Sungei Tampines	Sungei Api Api
Sungei Blukar	Sungei Serangoon
Sungei Punggol	Sungei Tongkang
Sungei Pinang	Sungei Seletar
Sungei Khatib Bongsu	Sungei Seletar Simpang Kiri
Sungei Sembawang	Sungei Mandai
Sungei China	Sungei Mandai Kechil
Sungei Peng Siang	Sungei Tengah
Sungei Kangkar	Sungei Buloh Besar
Sungei Jurong	Sungei Lanchar
Sungei Pandan	Sungei Ulu Pandan

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM?

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM?

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM? by dickinsonre How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM? The time, volume and flooded rate shown in the InfoSWMM and H2OMAP SWMM Report File Node Flooding Summary (Figure 2) are calculated as follows (Figure 1): For All Nodes NOT Outfalls ( this includes Junctions, Storage Nodes, Dividers) If the New Volume is greater than the Full Volume of the or there is Overflow then at each time step the Time Flooded is increased If the New Volume is greater than the Full Volume of the or there is Overflow then at each time step the Volume Flooded is increased by the Overflow *Time Step If the New Volume is greater than the Full Volume of the or there is Overflow AND Surface Ponding is Used then the Ponded Volume is New Volume – Full Volume If the Node Depth Plus the Node Invert Elevation is above the Node Crown Elevation then at each time step the time surcharged is increased.   The InfoSWMM andH2OMAP SWMM Map Display variables should be FLOOD_VOLM for the No Surface Ponding option (Figure 3) and PONDED_VOL if you are using the Global Surface Ponding Option (Figure 4). Figure 1.  Levels of Surcharged and Flooding in SWMM 5. Figure 2.  SWMM 5 Node Flooding Summary or the InfoSWMM and H2OMAP SWMM HTML Report file. Figure 3.  The Map Display of the Node Flooding using the No Surface Ponding Option should use the Map Display Variable FLOOD_VOLM Figure 4.  The Map Display of the Node Flooding using the Surface Ponding Option should use the Map Display Variable PONDED_VOL which shows the Maximum Stored Pond Volume. via Blogger http://www.swmm5.net/2013/08/how-are-flooded-time-surcharged-time.html

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in SWMM 5?

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in SWMM 5?

How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM? by dickinsonre How are Flooded Time, Surcharged Time and Flooded Volume Calculated in InfoSWMM and H2OMAP SWMM? The time, volume and flooded rate shown in the InfoSWMM and H2OMAP SWMM Report File Node Flooding Summary (Figure 2) are calculated as follows (Figure 1): For All Nodes NOT Outfalls ( this includes Junctions, Storage Nodes, Dividers) If the New Volume is greater than the Full Volume of the or there is Overflow then at each time step the Time Flooded is increased If the New Volume is greater than the Full Volume of the or there is Overflow then at each time step the Volume Flooded is increased by the Overflow *Time Step If the New Volume is greater than the Full Volume of the or there is Overflow AND Surface Ponding is Used then the Ponded Volume is New Volume – Full Volume If the Node Depth Plus the Node Invert Elevation is above the Node Crown Elevation then at each time step the time surcharged is increased.   The InfoSWMM andH2OMAP SWMM Map Display variables should be FLOOD_VOLM for the No Surface Ponding option (Figure 3) and PONDED_VOL if you are using the Global Surface Ponding Option (Figure 4). Figure 1.  Levels of Surcharged and Flooding in SWMM 5. Figure 2.  SWMM 5 Node Flooding Summary or the InfoSWMM and H2OMAP SWMM HTML Report file. Figure 3.  The Map Display of the Node Flooding using the No Surface Ponding Option should use the Map Display Variable FLOOD_VOLM Figure 4.  The Map Display of the Node Flooding using the Surface Ponding Option should use the Map Display Variable PONDED_VOL which shows the Maximum Stored Pond Volume. via Blogger http://www.swmm5.net/2013/08/how-are-flooded-time-surcharged-time.html

InfoSewer to InfoSWMM Import Tips

Subject:   InfoSewer to InfoSWMM Import Tips

InfoSewer to InfoSWMM Import Tips by dickinsonre Subject:   InfoSewer to InfoSWMM Import Tips The direct import of InfoSewer to InfoSWMM (Figure 1) is both direct and robust but you need to be aware of Run Manager changes to optimize the InfoSWMMmodel: 1.       Make sure that the Flow Units in InfoSWMM Run Manager match the default flow units in InfoSewer so that the DWF values are comparable, 2.      Make sure that the Output Flow Units in InfoSWMM match the Output Flow Units in InfoSewer so direct comparisons are easier, 3.      Add a Pump On and Pump Off depth to the Pumps in  InfoSWMM so that the pumps work better in a fully dynamic solution, 4.      The Fixed Pump Curves of InfoSewer should be checked in the Pump Curve section of InfoSWMM to make sure they are comparable, 5.      The InfoSWMM conduit step lengthening option should be used to speed up the model if you have short links in InfoSewer, 6.      You can check the overall balance in the two modeling platforms by comparing the System Load Graph in InfoSewer to the Total Inflow Graph inInfoSWMM. Figure 1   Dialog for Importing InfoSewer to InfoSWMM via Blogger http://www.swmm5.net/2013/08/infosewer-to-infoswmm-import-tips.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

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

Rules for NRSCS Unit Hydrographs in InfoSWMM

Subject:  Rules for NRSCS Unit Hydrographs in InfoSWMM

Rules for NRSCS Unit Hydrographs in InfoSWMM and H2OMap SWMM by dickinsonre Subject:  Rules for NRSCS Unit Hydrographs in InfoSWMM and H2OMap SWMM Rules or Guidelines for NRSCS Unit Hydrographs if used as the Hydrology Option in InfoSWMM and H2OMAP SWMM: 1.       The Unit Hydrograph CN comes from the Subcatchment Table and the NRCS_CN Column 2.      Time of Concentration is from the TC column in the Subcatchment Table 3.      The Infiltration Model should be from the CN infiltration Model Column in the Subcatchment Database Table 4.      The CN in the Soil Database Table should be the same as the CN in the Subcatchment Database Table 5.      If the Depression Storage is zero in the Subcatchment Database Table then the Initial Abstraction in inches will be calculated as 0.2*(1000/CN-10) internally in the engine 6.      Initial Abstraction or IA in US Units =  0.2*(1000/CN-10) in American Units via Blogger http://www.swmm5.net/2013/08/rules-for-nrscs-unit-hydrographs-in.html

How is RDII Storage Simulated in SWMM 5?

Subject:  How is RDII Storage Simulated in SWMM 5?

How is RDII Storage Simulated in SWMM 5? by dickinsonre Subject:  How is RDII Storage Simulated in SWMM 5? If you are using the SWMM 5 Rainfall Dependent Infiltration and Inflow(RDII)  feature you can also use the RDII storage parameters to change the RDII runoff by simulating the storage in the Sewershed.   The code in RDII.C as implemented by Lew Rossman of the EPA keeps track of used and unused initial abstraction or IA (Figure 1) When there is rainfall the following actions are taken: ·         The raindepth available to be convoluted by the RDII unit hydrograph method is reduced by unused IA ·         The amount of IA used up is then updated   When there is no rainfall ·         A portion of the IA already used is recovered using the recovery rate parameter and the variable IAUsed  Figure 1.  The long term effect of the RDII storage on the generated RDII Unit Hydrographs.  IA1, IA2 and IA3 are the Storage values for the short, medium and long term UH's. via Blogger http://www.swmm5.net/2013/08/how-is-rdii-storage-simulated-in-swmm-5.html