Tuesday, January 29, 2013

Ten years of cumulative precipitation

Ten years of cumulative precipitation

January 28, 2013 to Mapping by Nathan Yau
We've all seen rain maps for a sliver of time. Screw that. I want to see the total amount of rainfall over a ten-year period. Bill Wheaton did just that in the video above, showing cumulative rainfall between 1960 and 1970. The cool part is that you see mountains appear, but they're not actually mapped.  Source on FlowingData
The hillshaded terrain (the growing hills and mountains) is based on the rainfall data, not on actual physical topography. In other words, hills and mountains are formed by the rainfall distribution itself and grow as the accumulated precipitation grows. High mountains and sharp edges occur where the distribution of precipitation varies substantially across short distances. Wide, broad plains and low hills are formed when the distribution of rainfall is relatively even across the landscape.
See also Wheaton's video that shows four years of rain straight up.
Is there more recent data? It could be an interesting complement to the drought maps we saw a few months ago. [Thanks, Bill]

How To Run the SWMM 5 Console from the SWMM 5 GUI

How To Run the SWMM 5 Console from the SWMM 5 GUI

Use the SWMM 5 tools, define the program as the DOS engine or SWMM5.EXE (1), run the tool (2) and see the dos output in the command window of Windows 7 or Windows XP.  It should also be possible to call Matlab and have Matlab call the SWMM 5 program using the SWMM 5 interface.


Saturday, January 26, 2013

InfoSWMM Import and Export from SWMM

Outlets in SWMM 5 can have reverse flow

Outlets in SWMM 5 can have reverse flow

Outlets in SWMM 5 can have reverse flow (1) if the downstream head is greater than the upstream head (2), a flap gate (3) will prevent the flow reversal (4).  An outlet can have both positive and negative flow as long as you do not prevent it by having a flap gate.


Thursday, January 17, 2013

Stopping Tolerance in InfoSWMM, H2OMAP SWMM and SWMM5 Internal Units

Stopping Tolerance in InfoSWMM, H2OMAP SWMM and SWMM5 Internal Units

InfoSWMM, H2OMAP SWMM and SWMM 5 share the same underlying dynamic engine code but one small difference is that InfoSWMM and H2OMAP SWMM allows the user to select the node stopping tolerance instead of always using the default SWMM 5 stopping tolerance of 0.0005  feet.  SWMM 5 uses internal units of feet and shows the output in meters if you are using SI units, as does InfoSWMM and H2OMAP SWMM.  The following table shows how the stopping tolerance translates to inches and millimeters in the engine of a US and SI model.   The smaller the tolerance the larger the number of iterations used during the simulation but using a very small tolerance does not always mean a better simulation.  If possible, for example, with pumps it is better to use a small time step and a medium level tolerance – for example 1 millimeter is a good starting  value, but maybe 2 or 3 millimeters may help if you have a continuity error at a pump node. 
The nodes are considered converged if the depths between successive iterations is less than the stop tolerance of the program (the default stop tolerance is less than the stopping tolerance (Figure 1)

Stopping Tolerance
Inches
Millimeters
0.1000000
1.2000000
30.4800000
0.0500000
0.6000000
15.2400000
0.0100000
0.1200000
3.0480000
0.0050000
0.0600000
1.5240000
0.0001000
0.0012000
0.0304800
0.0005000
0.0060000
0.1524000
0.0000100
0.0001200
0.0030480
0.0000500
0.0006000
0.0152400
0.0000010
0.0000120
0.0003048
0.0000050
0.0000600
0.0015240
0.0000001
0.0000012
0.0000305

Figure 1  If the node depths between successive iterations are less than the stopping tolerance then the node is considered to be converged.

Importing a Link Shapefile into InfoSWMM via GIS Gateway

Importing a Link Shapefile into InfoSWMM via GIS Gateway

Here is how you map the shapefile pipe fields to the InfoSWMM data fields.  One note, you had two diameter fields (feet and inches) and the feet column was mostly zero so I used the inch column.  Here are the four steps and mapping you need to import all of the data from your shapefile.  You will have to use blockedit and convert the diameter from inches to feet in the DB link table (Step 5 – note there are still three missing pipe diameters).

Step 1.  Use the GIS Gateway command and set up the import of the file name, and ID field

Step 2. Set up the mapping between the Shapefile fields and InfoSWMM.  We used link offset and the pipe diameter in inches.

Step 3. Load the mapped shapefile

Step 4.  The imported data from your shapefile into the DB table of InfoSWMM

Step 5  Convert to feet from inches

Thursday, January 10, 2013

Climate-proofing cities

Here's just one example, from Singapore:
Singapore's Marina Barrage.RnD.de.PortraitsSingapore's Marina Barrage.
The Marina Barrage and Reservoir, which opened in 2008, is at the heart of Singapore's two-billion-dollar campaign to improve drainage infrastructure, reduce the size of flood-prone areas, and enhance the quality of city life. It has nine operable crest gates, a series of enormous pumps, and a ten-thousand-hectare catchment area that is roughly one-seventh the size of the country. The system not only protects low-lying urban neighborhoods from flooding during heavy rains; it also eliminates the tidal influence of the surrounding seawater, creating a rainfed supply of freshwater that currently meets ten percent of Singapore's demand. More over, by stabilizing water levels in the Marina basin the barriers have produced better conditions for water sports. The Marina's public areas, which include a sculpture garden, a water-play space, a green roof with dramatic skyline vistas, and the Sustainable Singapore Gallery, bolster the city's tourist economy as well.
That's a brilliant way to address two climate impacts -- large precipitation events and rising sea levels -- at once. Singapore has also elevated all access points to its underground subway a least a meter above high-water flood levels. It's also building desalination plants and systems to reuse waste water. It's also burying its power lines.
Engineers at the Dutch firm Arcadis recently proposed a large new sea barrier for north of New York City's Verrazano-Narrows Bridge. The price tag: $6.5 billion. And that's just one small piece of the puzzle. All this stuff is prudent, but it's expensive.

Tuesday, January 1, 2013

How to Compile SWMM 5 in Visual Studio 2010 Express

How to Compile SWMM 5 in Visual Studio 2010 Express

Download the newest SWMM 5 code(Figure 1) from http://www.epa.gov/nrmrl/wswrd/wq/models/swmm/#Downloads and then make a new directory on your computer. We will call it c:\newSWMM5Code with a subdirectory C:\newSWMMCode\VC2005_DLL  in which the attached vcxproj file is placed.  The source code from the EPA should be placed on C:\newSWMMCode.  You can then open up the file swmm5_ms.vcxproj and make a new SWMM 5 DLL model with your code modifications (if needed). 

swmm5_ms.vcxproj Download this file

InfoSWMM Version Numbers and the version of Arc Map they use and which EPA SWMM5 Engine is used for Each InfoSWMM Version

 InfoSWMM Version Numbers  InfoSWMM Version 14.7  Update 3 for Arc Map 10 to 10.8 and Windows 7/8/8.1/10 - EPA SWMM 5.1.014   4/12/2020   ...