# Design a storm sewer fixing speed

Submitted by Nicola Rainiero on 2012-07-23 (last updated on 2015-06-10)

In this tutorial I will show you how to use my program, storm_sewer.exe, in order to design a system, fixing the speed line by line. The sewer data are taken by a duplicated lecture note, so you will able to compare my results with these. Besides I prove how a complex system could be subdivided for a better compatibility with my software.

Here is the article with the software e for lazy people here is the zipped folder for download: Storm_sewer_0_9_2.zip
New releases are available here(2012/10/10) I begin the conversion of Storm Sewer into a web application, to see how it will work and the progress of this project, go here: Storm sewer webapp: concept.

## Input data

The system is taken by this PDF: Calcolo_condotte.pdf edited by prof. Salandin (University of Padua):

 Line Lenght Surface Φ - m ha - AC 50 0.29 0.4 BC 70 0.50 0.5 CD 85 0.65 0.6

1 ha = 104 m2

The IFD curve is the following:

h = 51,4 t0,375 (a is in mm hour -n)

The circular ducts are in fiber cement, with KS=75 m1/3/s and with this increase of commercial diameter: 300, 400, 500, 600 in mm.

I convert the network in this way, modifying the input_rete.dat file:

"|system data|"
"|on the left the values, on the right the description|"
75        "|KS - Gauckler-Strickler in m^(1/3)/s|"
51.40        "|a of IFD curve [mm hour^-n|"
0.375        "|n of IFD curve [-]|"
1        "|1 if n must multiplicated by 4/3 or 0|"
40        "|VO in m^3/ha|"
0.005        "|tolerance|"
3        "|number of lines to design|"
"|description of single line|"
"A"        "|label upstream|"
2900        "|surface in m^2|"
50        "|length in m|"
0.4        "|degree of permeability|"
0        "|if line is internal [1] otherwise [0]|"
"B"        "|label upstream|"
5000        "|surface in m^2|"
70        "|length in m|"
0.50        "|degree of permeability|"
0        "|if line is internal [1] otherwise [0]|"
"C"        "|label upstream|"
6500        "|surface in m^2|"
85        "|length in m|"
0.60        "|degree of permeability|"
1        "|if line is internal [1] otherwise [0]|"

## Output on the screen

I show you some meaningful screen with the more useful steps to use the program. I highlight the choice of the fixing parameter: the speed is 1 m/s and the attempts to determine the correct diameter.

Reading the final summary, the line_from_A_to_C.txt:

___________________________________________________________________________
SUMMARY

Line from   L           ST      D      y/D      v      Q       i      TAU
-       m          m^2      m       -      m/s    l/s      -     N/m^2
A     50.00     2900.00  0.300    0.45   1.000  30.62  0.00617  4.233
B     70.00     5000.00  0.400    0.57   1.000  74.15  0.00345  3.661
C     85.00    14400.00  0.600    0.69   1.000 208.26  0.00179  3.107



You can note the necessity to subdivide further the BC and CD lines, because they jump two diameters: 0,300 mm for BC and 0,500 mm for CD.

## Input data for subdivided system

New schematization with two new subdivisions: BC becomes BB1 e B1C and CD CC1 and C1D:

 Line Length Surface Φ - m ha - AC 50 0.29 0.4 BB1 25 0.20 0.5 B1C 45 0.30 0.5 CC1 25 0.20 0.6 C1D 60 0.45 0.6

1 ha = 104 m2

In my program this sewer can't be completely inserted, but it will be divided into two parts:

1. the line from B to C will be analyzed firstly and will produce the final design for this section of the system;
2. the network will be reassembled with the union of the first part results (considered as a single line), with the rest of the sewer data.

In this manner:

 I design the first external part, with two or more subdivisions I assemble the system, converting the first part in a single line (using the output data in the <> paragraph)

## input_system_from_B_to_B1.dat:

"|system data|"
"|on the left the values, on the right the description|"
75	"|KS - Gauckler-Strickler in m^(1/3)/s|"
51.40	"|a of IFD curve [mm hour^-n|"
0.375	"|n of IFD curve [-]|"
1	"|1 if n must multiplicated by 4/3 or 0|"
40	"|VO in m^3/ha|"
0.005	"|tolerance|"
2	"|number of lines to design|"
"|description of single line|"
"B"	"|label upstream|"
2000	"|surface in m^2|"
25	"|length in m|"
0.5	"|degree of permeability|"
0	"|if line is internal [1] otherwise [0]|"
"B1"	"|label upstream|"
3000	"|surface in m^2|"
45	"|length in m|"
0.50	"|degree of permeability|"
1	"|if line is internal [1] otherwise [0]|"


## input_system_from_A_to_C1.dat:

"|system data|"
"|on the left the values, on the right the description|"
75	"|KS - Gauckler-Strickler in m^(1/3)/s|"
51.40	"|a of IFD curve [mm hour^-n|"
0.375	"|n of IFD curve [-]|"
1	"|1 if n must multiplicated by 4/3 or 0|"
40	"|VO in m^3/ha|"
0.005	"|tolerance|"
4	"|number of lines to design|"
"|description of single line|"
"A"	"|label upstream|"
2900	"|surface in m^2|"
50	"|length in m|"
0.4	"|degree of permeability|"
0	"|if line is internal [1] otherwise [0]|"
"B_B1"	"|label upstream|"
5000	"|surface in m^2|"
70	"|length in m|"
0.50	"|degree of permeability|"
0	"|if line is internal [1] otherwise [0]|"
"C"	"|label upstream|"
2000	"|surface in m^2|"
25	"|length in m|"
0.60	"|degree of permeability|"
1	"|if line is internal [1] otherwise [0]|"
"C1"	"|label upstream|"
4500	"|surface in m^2|"
60	"|length in m|"
0.60	"|degree of permeability|"
1	"|if line is internal [1] otherwise [0]|"


## Final relation

I have compressed all the files here: Data_and_Results_v_assigned.zip

It is possible to rielaborate the single input data: renaming it in input_system.dat and moving it in the same folder of storm_sewer.exe. Here is the complete design with all the lines, I composed it copying parts of the results found previously:

***************************************************************************
*               PROGRAMMING TO DESIGN A STORM SEWER SYSTEM                *
*                     USING LINEAR RESERVOIR MODEL                        *
***************************************************************************
(Version 0.9.2)

Software open source by Nicola Rainiero, under GPLv3 license
\\--->  rainnic.altervista.org  <---//

___________________________________________________________________________
The system is defined by input_system.dat

First value of v0                          v0  =  40 m^3/ha
Coefficients of IFD curve                  a   =  51.4 mm hour^-n
n   =  0.375
n'  =  0.5
Gauckler-Strickler roughness coefficient   KS  =  75 m^(1/3)/s
Numbers of lines to design                 N   =  4
Tolerance value                            MIN =  0.005
___________________________________________________________________________
SUMMARY OF LINES INSERTED
Label         Surface       Length        PHI           INT/EXT
-            ha             m          -              1/0
A           0.29           50          0.4             0
B           0.2            25          0.5             0
B1          0.3            45          0.5             1
C           0.2            25          0.6             1
C1          0.45           60          0.6             1

_______________
Line from A
L           S aff.        S tot.        PHI tot.          Kc
m             ha            ha             -               -
50            0.29          0.29          0.400           4782

Line dimensioned by fixing the speed in  1 m/s

VO            U            Q           A'        VOP=A'L       D      y/D
m^3/ha       l/s,ha         l/s         m^2           m^3        m       -
40.00       119.550       34.670      0.035        1.733
45.98       104.008       30.162      0.030        1.508
45.20       105.796       30.681      0.031        1.534
45.29       105.587       30.620      0.031        1.531
45.29       105.587       30.620      0.031        1.531      0.30    0.45

For line from A:
D       y/D      v       Q       i         TAU
m        -      m/s     l/s      -        N/m^2
0.300    0.45   1.000   30.62  0.006171     4.2

_______________
Line from B
L           S aff.        S tot.        PHI tot.          Kc
m             ha            ha             -               -
25            0.2           0.2           0.500           7472

Line dimensioned by fixing the speed in  1 m/s

VO            U            Q           A'        VOP=A'L       D      y/D
m^3/ha       l/s,ha         l/s         m^2           m^3        m       -
40.00       186.797       37.359      0.037        0.934
44.67       167.269       33.454      0.033        0.836
44.18       169.117       33.823      0.034        0.846
44.23       168.940       33.788      0.034        0.845
44.23       168.940       33.788      0.034        0.845      0.30    0.48

For line from B:
D       y/D      v       Q       i         TAU
m        -      m/s     l/s      -        N/m^2
0.300    0.48   1.000   33.79  0.005822     4.2

_______________
Line from B1
L           S aff.        S tot.        PHI tot.          Kc
m             ha            ha             -               -
45            0.3           0.5           0.500           7472

Line dimensioned by fixing the speed in  1 m/s

VO            U            Q           A'        VOP=A'L       D      y/D
m^3/ha       l/s,ha         l/s         m^2           m^3        m       -
41.69       179.227       89.614      0.090        4.033
49.75       150.175       75.087      0.075        3.379
48.45       154.227       77.114      0.077        3.470
48.63       153.649       76.824      0.077        3.457
48.60       153.731       76.866      0.077        3.459
48.60       153.731       76.866      0.077        3.459      0.30    0.94
48.60       153.731       76.866      0.077        3.459      0.40    0.59

For line from B1:
D       y/D      v       Q       i         TAU
m        -      m/s     l/s      -        N/m^2
0.400    0.59   1.000   76.87  0.003368     3.6

_______________
Line from C
L           S aff.        S tot.        PHI tot.          Kc
m             ha            ha             -               -
25            0.2           0.9899999     0.491           7203

Line dimensioned by fixing the speed in  1 m/s

VO            U            Q           A'        VOP=A'L       D      y/D
m^3/ha       l/s,ha         l/s         m^2           m^3        m       -
46.79       153.938      152.399      0.152        3.810
50.64       142.239      140.817      0.141        3.520
50.35       143.065      141.635      0.142        3.541
50.37       143.007      141.577      0.142        3.539
50.37       143.007      141.577      0.142        3.539      0.40    0.94
50.37       143.007      141.577      0.142        3.539      0.50    0.68

For line from C:
D       y/D      v       Q       i         TAU
m        -      m/s     l/s      -        N/m^2
0.500    0.68   1.000  141.58  0.002299     3.3

_______________
Line from C1
L           S aff.        S tot.        PHI tot.          Kc
m             ha            ha             -               -
60            0.45          1.44          0.525           8238

Line dimensioned by fixing the speed in  1 m/s

VO            U            Q           A'        VOP=A'L       D      y/D
m^3/ha       l/s,ha         l/s         m^2           m^3        m       -
47.13       174.805      251.719      0.252       15.103
57.61       142.982      205.895      0.206       12.354
55.70       147.883      212.952      0.213       12.777
56.00       147.107      211.834      0.212       12.710
55.95       147.229      212.010      0.212       12.721
55.96       147.210      211.982      0.212       12.719
55.96       147.210      211.982      0.212       12.719      0.50    0.94
55.96       147.210      211.982      0.212       12.719      0.60    0.70

For line from C1:
D       y/D      v       Q       i         TAU
m        -      m/s     l/s      -        N/m^2
0.600    0.70   1.000  211.98  0.001779     3.1

___________________________________________________________________________
SUMMARY

Line from   L           ST      D      y/D      v      Q       i      TAU
-       m          m^2      m       -      m/s    l/s      -     N/m^2
A     50.00     2900.00  0.300    0.45   1.000  30.62  0.00617  4.233
B     25.00     2000.00  0.300    0.48   1.000  33.79  0.00582  4.172
B1    45.00     5000.00  0.400    0.59   1.000  76.87  0.00337  3.639
C     25.00     9900.00  0.500    0.68   1.000 141.58  0.00230  3.307
C1    60.00    14400.00  0.600    0.70   1.000 211.98  0.00178  3.102



## Related Content:

### Nicola Rainiero

A civil geotechnical engineer with the ambition to facilitate own work with free software for a knowledge and collective sharing. Also, I deal with green energy and in particular shallow geothermal energy. I have always been involved in web design and 3D modelling.