From the Dish and Andrew Sullivan “The Cheerful World Of Japanese Manhole Covers”

The Cheerful World Of Japanese Manhole Covers

by Maisie Allison

Michelle Aldredge introduces us to a minor feat in public art:

One of my favorite book discoveries this summer is Drainspotting

 by Remo Camerota. The book celebrates an array of fascinating manhole cover designs from Japan. According to Camerota, nearly 95% of the 1,780 municipalities in Japan have their very own customized manhole covers. The country has elevated this humble, practical object to its own art form. The designs depict everything from local landmarks and folk tales to flora and fauna and images created by school children. Camerota explains the evolution of these custom covers in Drainspotting  http://www.gwarlingo.com/2011/drainspotting-61-amazing-manhole-covers-from-japan/

“In the 1980s as communities outside of Japan’s major cities were slated to receive new sewer systems these public works projects were met with resistance, until one dedicated bureaucrat solved the problem by devising a way to make these mostly invisible systems aesthetically appreciated aboveground: customized manhole covers.”

Subject - Smoother Switching Between Pumps in SWMM 5 - A better simulation of a VSP?

An oft requested feature in SWMM 5 is the ability to better simulate a variable speed pump.   The basic feature we are trying to model is multiple pumps between two nodes, one pump curve for all of the pumps and the ability to turn on and turn off the pumps based on either the head or depth at a Wet Well (Figure 1).  You can turn on or off the pumps Pump1, Pump2 and Pump3 based on the depth at the Wet Well but this feature is stepwise linear and usually uses three pump curves.  A better way to simulate this feature is to use the SWMM 5 Real Time Rules (RTC) to simulate the Pump setting based on a control curve.  

The Pump flow at any time step is the Pump Flow estimated from the Pump Curve (Figure 2) * The Pump Setting (Figure 3)

Each of the three pumps has a different Control Curve (Figure’s 4, 5 and 6, respectively) which turns on or turns off the Pump based on a range of Wet Well Depths.  The overall effect is that the total flow summing all three pumps together is smoother (Figure 7 and Figure 8) and the user can simulate different pump speeds based on the same pump curve depending on which pump is currently on.

Figure 1.   Example RTC Rules and VSP Pumps in a SWMM 5 model.

Figure 2.  The Pump Curve Used for all 3 Pumps

Figure 3.  The Pump Setting for all Three Pumps

Figure 4.   Pump Control Curve for Pump 1.  The Pump has a Setting of ¼ between 0.5 and 3 feet at the node Wet Well and zero otherwise.

Figure 5.   Pump Control Curve for Pump 2.  The Pump has a Setting of 1/2 between 3 and 5 feet at the node Wet Well and zero otherwise.

Figure 6.   Pump Control Curve for Pump 3.  The Pump has a Setting of 1 above 5 feet at the node Wet Well and zero otherwise.

Figure 7.  The Flow in all 3 Pumps.

Figure 8.  The total flow from all three Pumps to the downstream node.

Subject:   Map Display of LID Usage in SWMM 5 

 A new Map Display feature in SWMM 5.0.022 is the LID Usage parameter which shows you whether a Subcatchment has LID’s or not.   You use it by using Map Display and choosing LID Usage as the Map Display.

Subject:   Example VSP Pump in SWMM 5 - Version 1 

Here is one way to model multiple pumps between the same downstream and upstream nodes using the pump curves and the Real Time Control Rules (RTC) in SWMM 5.  Here are the steps:

1.   Enter the data for three pumps in the browser by using the Add Pump Icon

2.   Enter three Pump Head/Flow Curves so that the 2^nd and 3^rd Pump Curves are the sum of the flows in the 1^st and 2^nd Pumps together and the sum of the flows in the 1^st, 2^nd and 3^rd respectively for the 2^nd and 3^rd Pump Curves

3.   Enter a RTC Rule in the Control Editor so that when the 1^st Pump is turned on – the 2^nd and 3^rd Pump is turned off

4.   Enter a RTC Rule in the Control Editor so that when the 2^nd Pump is turned on – the 1^st and 3^rd Pump is turned off

5.   Enter a RTC Rule in the Control Editor so that when the 3^rd Pump is turned on – the 1^st and 2^nd Pump is turned off

 Using these rules you can see that for the 1^st Pump turns on when the Node WetWell has a depth below 2 feet, the 2^nd Pump turns on when the Node is between a depth of 2 to 5 feet and the 3^rd Pump turns on when the Node Depth is above 5 feet.

 RULE Pump1

IF Node WetWell Depth <= 2

THEN PUMP PUMP2 STATUS = OFF

AND PUMP PUMP3 STATUS = OFF

Priority 1

RULE Pump2

IF Node WetWell Depth > 2

AND Node WetWell Depth <= 5

THEN PUMP PUMP1 STATUS = OFF

AND PUMP PUMP3 STATUS = OFF

Priority 2

RULE Pump3

IF Node WetWell Depth > 5

THEN PUMP PUMP1 STATUS = OFF

AND PUMP PUMP2 STATUS = OFF

Priority 3