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# Working Principles

## EPA-SWMM 5.0

SWMM 5.0 is a dynamic rainfall-runoff simulation model, released by the environmental protection agency of The United States of America,

  used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. The runoff component of SWMM operates on a collection of subcatchment areas that receive precipitation and generate runoff and pollutant loads. The routing portion of SWMM transports this runoff through various drainage network components:

  > - a system of pipes,
  > - channels,
  > - storage/treatment devices,
  > - pumps, and
  > - regulators.

EPA has recently extended SWMM 5 to explicitly model the hydrologic performance of specific types of low impact development (LID) controls, such as:

> > - porous pavement,
> > - rain gardens,
> > - green roofs,
> > - street planters,
> > - rain barrels,
> > - infiltration trenches, and
> > - vegetative swales.

> SWMM 5.0 has its own, easy to use graphical user interface (Shown below)

> EPA SWMM 5.0 Desktop

### Downloading and Installing SWMM 5.0

EPA SWMM 5.0 can be downloaded from US-EPA web site . The software is public domain, therefore free to use.

It works on Windows and Linux (use with Wine ). Should work fine on Mac OS X (with Wine) too, but this was not confirmed at the time of writing.

### SWMM 5.0 Input file format

SWMM 5.0 has a text-based input file format. When you build a network model on the SWMM 5.0 Desktop and save it, the software in-fact saves a text based input file. This file has extension inp (e.g. `StorageEx.inp`). The format of the file is self-explanatory and looks like the following:

    [TITLE]

    [OPTIONS]
    FLOW_UNITS           LPS
    INFILTRATION         CURVE_NUMBER
    FLOW_ROUTING         DYNWAVE
    START_DATE           10/28/2011
    START_TIME           00:00:00
    REPORT_START_DATE    10/28/2011
    REPORT_START_TIME    00:00:00
    END_DATE             10/28/2011
    END_TIME             06:00:00
    SWEEP_START          01/01
    SWEEP_END            12/31
    DRY_DAYS             0
    REPORT_STEP          00:01:00
    WET_STEP             00:01:00
    DRY_STEP             00:01:00
    ROUTING_STEP         0:00:01
    ALLOW_PONDING        NO
    INERTIAL_DAMPING     PARTIAL
    VARIABLE_STEP        0.75
    LENGTHENING_STEP     0
    MIN_SURFAREA         0
    NORMAL_FLOW_LIMITED  SLOPE
    SKIP_STEADY_STATE    NO
    FORCE_MAIN_EQUATION  H-W
    LINK_OFFSETS         DEPTH
    MIN_SLOPE            0

    [EVAPORATION]
    ;;Type       Parameters
    ;;---------- ----------
    CONSTANT     0.0
    DRY_ONLY     NO

    [RAINGAGES]
    ;;               Rain      Time   Snow   Data
    ;;Name           Type      Intrvl Catch  Source
    ;;-------------- --------- ------ ------ ----------
    Gage1            VOLUME    0:03   1.0    TIMESERIES ABM10yrs2hrs

    [SUBCATCHMENTS]
    ;;                                                 Total    Pcnt.             Pcnt.    Curb     Snow
    ;;Name           Raingage         Outlet           Area     Imperv   Width    Slope    Length   Pack
    ;;-------------- ---------------- ---------------- -------- -------- -------- -------- -------- --------
    A2               Gage1            J4               96.9     40.80    1000     4.13     0
    A1               Gage1            J1               33.8     29.24    1000     4.13     0
    A3               Gage1            J3               50.7     32.17    1000     4.13     0
    A4               Gage1            J10              30.0     25.17    1000     4.13     0
    A5               Gage1            J9               25.5     10.00    1000     4.13     0
    E1               Gage1            J8               34.9     0        1000     1.86     0

    [SUBAREAS]
    ;;Subcatchment   N-Imperv   N-Perv     S-Imperv   S-Perv     PctZero    RouteTo    PctRouted
    ;;-------------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
    A2               0.01       0.1        0.05       0.05       25         OUTLET
    A1               0.01       0.1        0.05       0.05       25         OUTLET
    A3               0.01       0.1        0.05       0.05       25         OUTLET
    A4               0.01       0.1        0.05       0.05       25         OUTLET
    A5               0.01       0.1        0.05       0.05       25         OUTLET
    E1               0.01       0.1        0.05       0.05       25         OUTLET

    [INFILTRATION]
    ;;Subcatchment   CurveNum   HydCon     DryTime
    ;;-------------- ---------- ---------- ----------
    A2               90         0.5        7
    A1               90         0.5        7
    A3               90         0.5        7
    A4               90         0.5        7
    A5               90         0.5        7
    E1               70         0.5        7

    [JUNCTIONS]
    ;;               Invert     Max.       Init.      Surcharge  Ponded
    ;;Name           Elev.      Depth      Depth      Depth      Area
    ;;-------------- ---------- ---------- ---------- ---------- ----------
    J2               45.633     1.8        0          0          0
    J5               47.381     1.8        0          0          0
    J6               41.909     1.8        0          0          0
    J8               23.459     3          0          0          0
    J9               37.689     2          0          0          0
    J10              32.424     2          0          0          0

    [OUTFALLS]
    ;;               Invert     Outfall    Stage/Table      Tide
    ;;Name           Elev.      Type       Time Series      Gate
    ;;-------------- ---------- ---------- ---------------- ----
    J12              15.649     FREE                        NO

    [STORAGE]
    ;;               Invert   Max.     Init.    Storage    Curve                      Ponded   Evap.
    ;;Name           Elev.    Depth    Depth    Curve      Params                     Area     Frac.    Infiltration Parameters
    ;;-------------- -------- -------- -------- ---------- -------- -------- -------- -------- -------- -----------------------
    J11              27.159   1.8      0        FUNCTIONAL 500     0        0        0        0
    J3               36.437   1.8      0        FUNCTIONAL 500     0        0        0        0
    J4               52.853   1.8      0        FUNCTIONAL 500    0        0        0        0
    J1               55       1.8      0        FUNCTIONAL 500     0        0        0        0
    J7               29.589   1.8      0        FUNCTIONAL 500     0        0        0        0

    [CONDUITS]
    ;;               Inlet            Outlet                      Manning    Inlet      Outlet     Init.      Max.
    ;;Name           Node             Node             Length     N          Offset     Offset     Flow       Flow
    ;;-------------- ---------------- ---------------- ---------- ---------- ---------- ---------- ---------- ----------
    T4-1             J9               J10              117        0.02       0          0          0          0
    T4-2             J10              J11              117        0.02       0          0          0          0
    T4-3             J11              J8               60         0.02       1.5        0          0          0
    T1-1             J1               J2               242        0.02       1          0          0          0
    T1-2             J2               J3               400        0.02       0          0          0          0
    T2-1             J4               J5               288        0.02       1          0          0          0
    T2-2             J5               J6               288        0.02       0          0          0          0
    T2-3             J6               J3               288        0.02       0          0          0          0
    T3-1             J3               J7               428        0.02       1          0          0          0
    T3-2             J7               J8               342        0.02       1.0        0          0          0
    T5               J8               J12              235        0.01       0          0          0          0

    [XSECTIONS]
    ;;Link           Shape        Geom1            Geom2      Geom3      Geom4      Barrels
    ;;-------------- ------------ ---------------- ---------- ---------- ---------- ----------
    T4-1             CIRCULAR     2                0          0          0          1
    T4-2             CIRCULAR     2                0          0          0          1
    T4-3             CIRCULAR     2                0          0          0          1
    T1-1             CIRCULAR     1.2              0          0          0          1
    T1-2             CIRCULAR     1.2              0          0          0          1
    T2-1             CIRCULAR     2                0          0          0          1
    T2-2             CIRCULAR     2                0          0          0          1
    T2-3             CIRCULAR     2                0          0          0          1
    T3-1             CIRCULAR     1.5              0          0          0          3
    T3-2             CIRCULAR     1.5              0          0          0          2
    T5               RECT_OPEN    .4               3          0          0          1

    [LOSSES]
    ;;Link           Inlet      Outlet     Average    Flap Gate
    ;;-------------- ---------- ---------- ---------- ----------

    [TIMESERIES]
    ;;Name           Date       Time       Value
    ;;-------------- ---------- ---------- ----------
    ;2hr
    2hrRainfall                 0:00       0.00
    2hrRainfall                 0:01       0.12
    2hrRainfall                 0:02       0.12
    2hrRainfall                 0:03       0.12
    2hrRainfall                 0:04       0.12
    2hrRainfall                 0:05       0.12
    2hrRainfall                 0:06       0.13
    2hrRainfall                 0:07       0.13
    2hrRainfall                 0:08       0.13
    2hrRainfall                 0:09       0.14
    2hrRainfall                 0:10       0.13
    2hrRainfall                 0:11       0.14
    2hrRainfall                 0:12       0.15
    2hrRainfall                 0:13       0.15
    2hrRainfall                 0:14       0.14
    2hrRainfall                 0:15       0.16
    2hrRainfall                 0:16       0.16
    2hrRainfall                 0:17       0.16
    2hrRainfall                 0:18       0.17
    2hrRainfall                 0:19       0.17
    2hrRainfall                 0:20       0.17
    2hrRainfall                 0:21       0.17
    2hrRainfall                 0:22       0.18
    2hrRainfall                 0:23       0.19
    2hrRainfall                 0:24       0.19
    2hrRainfall                 0:25       0.2
    2hrRainfall                 0:26       0.2
    2hrRainfall                 0:27       0.2
    2hrRainfall                 0:28       0.21
    2hrRainfall                 0:29       0.22
    2hrRainfall                 0:30       0.23
    2hrRainfall                 0:31       0.23
    2hrRainfall                 0:32       0.24
    2hrRainfall                 0:33       0.25
    2hrRainfall                 0:34       0.26
    2hrRainfall                 0:35       0.27
    2hrRainfall                 0:36       0.28
    2hrRainfall                 0:37       0.29
    2hrRainfall                 0:38       0.3
    2hrRainfall                 0:39       0.31
    2hrRainfall                 0:40       0.33
    2hrRainfall                 0:41       0.35
    2hrRainfall                 0:42       0.37
    2hrRainfall                 0:43       0.39
    2hrRainfall                 0:44       0.41
    2hrRainfall                 0:45       0.43
    2hrRainfall                 0:46       0.46
    2hrRainfall                 0:47       0.5
    2hrRainfall                 0:48       0.53
    2hrRainfall                 0:49       0.57
    2hrRainfall                 0:50       0.62
    2hrRainfall                 0:51       0.67
    2hrRainfall                 0:52       0.74
    2hrRainfall                 0:53       0.81
    2hrRainfall                 0:54       0.91
    2hrRainfall                 0:55       1.02
    2hrRainfall                 0:56       1.17
    2hrRainfall                 0:57       1.34
    2hrRainfall                 0:58       1.58
    2hrRainfall                 0:59       1.89
    2hrRainfall                 1:00       2.34
    2hrRainfall                 1:01       2.1
    2hrRainfall                 1:02       1.73
    2hrRainfall                 1:03       1.45
    2hrRainfall                 1:04       1.24
    2hrRainfall                 1:05       1.08
    2hrRainfall                 1:06       0.96
    2hrRainfall                 1:07       0.86
    2hrRainfall                 1:08       0.78
    2hrRainfall                 1:09       0.7
    2hrRainfall                 1:10       0.65
    2hrRainfall                 1:11       0.59
    2hrRainfall                 1:12       0.55
    2hrRainfall                 1:13       0.51
    2hrRainfall                 1:14       0.48
    2hrRainfall                 1:15       0.45
    2hrRainfall                 1:16       0.43
    2hrRainfall                 1:17       0.39
    2hrRainfall                 1:18       0.38
    2hrRainfall                 1:19       0.36
    2hrRainfall                 1:20       0.34
    2hrRainfall                 1:21       0.33
    2hrRainfall                 1:22       0.32
    2hrRainfall                 1:23       0.3
    2hrRainfall                 1:24       0.29
    2hrRainfall                 1:25       0.27
    2hrRainfall                 1:26       0.26
    2hrRainfall                 1:27       0.26
    2hrRainfall                 1:28       0.24
    2hrRainfall                 1:29       0.24
    2hrRainfall                 1:30       0.23
    2hrRainfall                 1:31       0.22
    2hrRainfall                 1:32       0.22
    2hrRainfall                 1:33       0.21
    2hrRainfall                 1:34       0.2
    2hrRainfall                 1:35       0.2
    2hrRainfall                 1:36       0.19
    2hrRainfall                 1:37       0.18
    2hrRainfall                 1:38       0.18
    2hrRainfall                 1:39       0.18
    2hrRainfall                 1:40       0.17
    2hrRainfall                 1:41       0.17
    2hrRainfall                 1:42       0.16
    2hrRainfall                 1:43       0.16
    2hrRainfall                 1:44       0.15
    2hrRainfall                 1:45       0.15
    2hrRainfall                 1:46       0.15
    2hrRainfall                 1:47       0.15
    2hrRainfall                 1:48       0.14
    2hrRainfall                 1:49       0.14
    2hrRainfall                 1:50       0.14
    2hrRainfall                 1:51       0.14
    2hrRainfall                 1:52       0.13
    2hrRainfall                 1:53       0.13
    2hrRainfall                 1:54       0.13
    2hrRainfall                 1:55       0.13
    2hrRainfall                 1:56       0.13
    2hrRainfall                 1:57       0.12
    2hrRainfall                 1:58       0.12
    2hrRainfall                 1:59       0.12
    2hrRainfall                 2:00       0.11

    ;Rainfall Data
    ABM10yrs2hrs                0:00       0
    ABM10yrs2hrs                0:03       0.36
    ABM10yrs2hrs                0:06       0.38
    ABM10yrs2hrs                0:09       0.40
    ABM10yrs2hrs                0:12       0.42
    ABM10yrs2hrs                0:15       0.45
    ABM10yrs2hrs                0:18       0.48
    ABM10yrs2hrs                0:21       0.52
    ABM10yrs2hrs                0:24       0.56
    ABM10yrs2hrs                0:27       0.61
    ABM10yrs2hrs                0:30       0.67
    ABM10yrs2hrs                0:33       0.74
    ABM10yrs2hrs                0:36       0.82
    ABM10yrs2hrs                0:39       0.93
    ABM10yrs2hrs                0:42       1.08
    ABM10yrs2hrs                0:45       1.27
    ABM10yrs2hrs                0:48       1.54
    ABM10yrs2hrs                0:51       1.94
    ABM10yrs2hrs                0:54       2.58
    ABM10yrs2hrs                0:57       3.75
    ABM10yrs2hrs                1:00       6.33
    ABM10yrs2hrs                1:03       4.75
    ABM10yrs2hrs                1:06       3.07
    ABM10yrs2hrs                1:09       2.22
    ABM10yrs2hrs                1:12       1.71
    ABM10yrs2hrs                1:15       1.39
    ABM10yrs2hrs                1:18       1.16
    ABM10yrs2hrs                1:21       1.00
    ABM10yrs2hrs                1:24       0.88
    ABM10yrs2hrs                1:27       0.78
    ABM10yrs2hrs                1:30       0.70
    ABM10yrs2hrs                1:33       0.64
    ABM10yrs2hrs                1:36       0.58
    ABM10yrs2hrs                1:39       0.54
    ABM10yrs2hrs                1:42       0.50
    ABM10yrs2hrs                1:45       0.47
    ABM10yrs2hrs                1:48       0.44
    ABM10yrs2hrs                1:51       0.41
    ABM10yrs2hrs                1:54       0.39
    ABM10yrs2hrs                1:57       0.37
    ABM10yrs2hrs                2:00       0.35

    [REPORT]
    INPUT      NO
    CONTROLS   NO
    SUBCATCHMENTS ALL
    NODES ALL
    LINKS ALL

    [TAGS]

    [MAP]
    DIMENSIONS 0.000 0.000 10000.000 10000.000
    Units      None

    [COORDINATES]
    ;;Node           X-Coord            Y-Coord
    ;;-------------- ------------------ ------------------
    J2               5415.068           1893.131
    J5               6566.084           1307.978
    J6               6360.316           1809.538
    J8               5138.567           3802.918
    J9               4418.378           2889.821
    J10              4424.808           3153.462
    J12              5312.184           5063.248
    J11              4752.751           3571.429
    J3               5595.115           2336.819
    J4               6823.294           1140.791
    J1               4778.472           1417.292
    J7               5325.044           3102.020

    [VERTICES]
    ;;Link           X-Coord            Y-Coord
    ;;-------------- ------------------ ------------------
    T4-2             4739.891           3397.812
    T4-3             5035.683           3571.429
    T4-3             5042.113           3706.464
    T3-2             5337.905           3732.185

    [Polygons]
    ;;Subcatchment   X-Coord            Y-Coord
    ;;-------------- ------------------ ------------------
    A2               9137.862           940.587
    A2               9302.164           1556.721
    A2               8390.285           2526.106
    A2               7379.825           2567.182
    A2               7429.116           1400.634
    A1               4086.563           458.062
    A1               4160.500           975.615
    A1               4669.837           950.970
    A1               5548.856           1452.093
    A1               5581.716           310.190
    A1               4867.000           195.178
    A3               6297.935           2800.132
    A3               6946.737           3271.194
    A3               7907.907           3139.752
    A3               7940.767           3410.852
    A3               7293.018           3745.043
    A3               6971.382           4602.045
    A3               6585.271           4429.527
    A3               6420.969           3714.811
    A3               5955.091           2959.011
    A4               3550.123           3206.322
    A4               3342.244           2942.475
    A4               2918.491           3086.392
    A4               2478.747           3030.424
    A4               3070.403           4013.851
    A4               3686.044           3917.907
    A5               4226.039           1863.728
    A5               3682.356           1607.877
    A5               3442.496           1815.756
    A5               3554.430           1975.662
    A5               3466.482           2207.527
    A5               3826.272           2647.271
    A5               4337.974           2719.229
    A5               4689.769           2567.318
    E1               4365.046           4144.795
    E1               4518.867           4808.151
    E1               4586.164           5202.318
    E1               4481.613           5204.819
    E1               3818.829           4472.268
    E1               3722.900           4062.388

    [SYMBOLS]
    ;;Gage           X-Coord            Y-Coord
    ;;-------------- ------------------ ------------------
    Gage1            9936.709           6075.949

## How SWMM5-EA exploits the input file

Problems of metaheuristics [1] involve solving a problems with various input parameters. For example a problem of calculating optimal sizing of a number of detention storages involve running SWMM 5.0 model with different values for detention storage sizes. Example 1 is such a problem. How SWMM5-EA facilitates this process of running SWMM with different values for a set of variables is by using a ‘template‘ system. SWMM5-EA marks a number of locations in the input file with special `space-holders` (We use symbols like `@!v1!@`). For example the [STORAGE] section of our swmm input file:

    [STORAGE]
        ;;               Invert   Max.     Init.    Storage    Curve                      Ponded   Evap.
        ;;Name           Elev.    Depth    Depth    Curve      Params                     Area     Frac.    Infiltration Parameters
        ;;-------------- -------- -------- -------- ---------- -------- -------- -------- -------- -------- -----------------------
        J11              27.159   1.8      0        FUNCTIONAL 500     0        0        0        0
        J3               36.437   1.8      0        FUNCTIONAL 500     0        0        0        0
        J4               52.853   1.8      0        FUNCTIONAL 500     0        0        0        0
        J1               55       1.8      0        FUNCTIONAL 500     0        0        0        0
        J7               29.589   1.8      0        FUNCTIONAL 500     0        0        0        0

is templated like:

    [STORAGE]
        ;;               Invert   Max.     Init.    Storage    Curve                      Ponded   Evap.
        ;;Name           Elev.    Depth    Depth    Curve      Params                     Area     Frac.    Infiltration Parameters
        ;;-------------- -------- -------- -------- ---------- -------- -------- -------- -------- -------- -----------------------
        J11              27.159   1.8      0        FUNCTIONAL !@v1@!     0        0        0        0
        J3               36.437   1.8      0        FUNCTIONAL !@v2@!     0        0        0        0
        J4               52.853   1.8      0        FUNCTIONAL !@v3@!     0        0        0        0
        J1               55       1.8      0        FUNCTIONAL !@v4@!     0        0        0        0
        J7               29.589   1.8      0        FUNCTIONAL !@v5@!     0        0        0        0

This is done by user by simply blocking the number that need to be a place-holder and pressing a button (See figure below)

> How to create place-holders in a SWMM input file.

Then the optimization engine will fill these place-holders with relevent values during each evaluation step.

[1] | Metaheuristic methods optimizes a problem by iteratively trying to improve a candidate solution with regard to a given measure of quality. The Evolutionary computation method used in SWMM5-EA is a metaheuristic method.

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- previous |
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