Runoff from One Watershed for a 100 Year Simulation with SWMM 5 Statistics for Peak, Mean and Total Runoff

Introduction:  This set of blogs uses the 1000 year rainfall/runoff/hydraulics model that you can download at http://swmm2000.com/forum/topics/1000-year-simulation-with-rainfall-in-swmm-5 to show the inner workings of SWMM 5 and by extension InfoSWMM and H2oMap SWMM using a QA/QC version of SWMM 5 with extended graphics.   I always hope that seeing the inner workings of a SWMM 5 feature helps to understand the code, sensitivity and importance of a parameter.   It also helps show sometimes when a parameter is not important.  

Discussion:  In this blog we look at the Runoff total over the 100 year period, graph the runoff (Figure 1) and show the Mean, Total and Peak Runoff using the Statistics Command in SWMM 5.   The Frequency plots shown in Figure 1 are made using event separation time of 6 hours.  The number of Runoff Events over the 100 year period is 11,144 events.   The details of the simulation are shown in Figure 2.

Figure 1.   Runoff from One Watershed for a 100 Year Simulation with SWMM 5 Statistics for Peak, Mean and Total Runoff

Figure 2.  Details of the Simulation Watershed

[TITLE]

[OPTIONS]

FLOW_UNITS           CFS

INFILTRATION         GREEN_AMPT

FLOW_ROUTING         DYNWAVE

START_DATE           01/01/2500

START_TIME           00:00:00

REPORT_START_DATE    01/01/2500

REPORT_START_TIME    00:00:00

END_DATE             12/31/2599

END_TIME             23:00:00

SWEEP_START          01/01

SWEEP_END            01/30

DRY_DAYS             0

REPORT_STEP          01:00:00

WET_STEP             00:15:00

DRY_STEP             00:30:00

ROUTING_STEP         0:01:00

ALLOW_PONDING        NO

INERTIAL_DAMPING     NONE

VARIABLE_STEP        0.75

LENGTHENING_STEP     1

MIN_SURFAREA         0

NORMAL_FLOW_LIMITED  BOTH

SKIP_STEADY_STATE    NO

FORCE_MAIN_EQUATION  H-W

LINK_OFFSETS         DEPTH

MIN_SLOPE            0

; Added Parameters for QA/QC

MAX_PROCESSORS       NO

BYPASS               YES

ThetaStorage         NO

MAX_ITERATIONS       8

MIN_ITERATIONS       2

TOLERANCE            0.001000

RELAXATION           0.50

AREAWEIGHT           1.00

HYDRAULICWEIGHT      1.00

DWF_GLOBAL           1.0

RDII_GLOBAL          1.0

DEPTH_UNITS         

SaveAllData          NO

[FILES]

SAVE RAINFALL "C:\Users\Robert E Dickinson\Desktop\Desktop_July2012\RainFall.rff"

[EVAPORATION]

;;Type       Parameters

;;---------- ----------

MONTHLY      .1     0.1    .1     0.15   0.2    0.3    0.191  0.3    0.2    0.1    0.05   0.05 

RECOVERY     soil

DRY_ONLY     YES

[RAINGAGES]

;;               Rain      Time   Snow   Data     

;;Name           Type      Intrvl Catch  Source   

;;-------------- --------- ------ ------ ----------

RainGage         VOLUME    1:00   1.0    FILE       "D:\100_years_rainfall.dat" user       IN  

[SUBCATCHMENTS]

;;                                                 Total    Pcnt.             Pcnt.    Curb     Snow   

;;Name           Raingage         Outlet           Area     Imperv   Width    Slope    Length   Pack   

;;-------------- ---------------- ---------------- -------- -------- -------- -------- -------- --------

MySubCatchment           RainGage         Storage          10       10       100      0.5      0                       

[SUBAREAS]

;;Subcatchment   N-Imperv   N-Perv     S-Imperv   S-Perv     PctZero    RouteTo    PctRouted

;;-------------- ---------- ---------- ---------- ---------- ---------- ---------- ----------

MySubCatchment           0.02       0.05       0.05       0.1        25         OUTLET   

[INFILTRATION]

;;Subcatchment   Suction    HydCon     IMDmax   

;;-------------- ---------- ---------- ----------

MySubCatchment           4          1          0.25     

[OUTFALLS]

;;               Invert     Outfall    Stage/Table      Tide

;;Name           Elev.      Type       Time Series      Gate

;;-------------- ---------- ---------- ---------------- ----

Outfall          0          FREE                        NO

[STORAGE]

;;               Invert   Max.     Init.    Storage    Curve                      Ponded   Evap.  

;;Name           Elev.    Depth    Depth    Curve      Params                     Area     Frac.    Infiltration Parameters

;;-------------- -------- -------- -------- ---------- -------- -------- -------- -------- -------- -----------------------

Storage          1        9        0        FUNCTIONAL 10       0        0        0        0       

[CONDUITS]

;;               Inlet            Outlet                      Manning    Inlet      Outlet     Init.      Max.     

;;Name           Node             Node             Length     N          Offset     Offset     Flow       Flow     

;;-------------- ---------------- ---------------- ---------- ---------- ---------- ---------- ---------- ----------

VENANT           Storage          Outfall          500        0.013      0          0          0          0        

[XSECTIONS]

;;Link           Shape        Geom1            Geom2      Geom3      Geom4      Barrels    Culvert Code  Transition Multipler

;;-------------- ------------ ---------------- ---------- ---------- ---------- ---------- ---------- ---------- ----------

VENANT           CIRCULAR     3                0          0          0          1          0          0          0        

[LOSSES]

;;Link           Inlet      Outlet     Average    Flap Gate

;;-------------- ---------- ---------- ---------- ----------

[POLLUTANTS]

;;               Mass   Rain       GW         I&I        Decay      Snow  Co-Pollut.       Co-Pollut. DWF      

;;Name           Units  Concen.    Concen.    Concen.    Coeff.     Only  Name             Fraction   Concen.  

;;-------------- ------ ---------- ---------- ---------- ---------- ----- ---------------- ---------- ----------

tn               MG/L   1          0.0        0.0        0.0        NO    *                0.0        0.0      

[LOADINGS]

;;Subcatchment   Pollutant        Loading  

;;-------------- ---------------- ----------

[INFLOWS]

;;                                                 Param    Units    Scale    Baseline Baseline

;;Node           Parameter        Time Series      Type     Factor   Factor   Value    Pattern

;;-------------- ---------------- ---------------- -------- -------- -------- -------- --------

Storage          FLOW             ""               FLOW     1.0      1.0      1      

[DWF]

;;                                Average    Time     

;;Node           Parameter        Value      Patterns 

;;-------------- ---------------- ---------- ----------

Storage          FLOW             2          "Hourly"

[HYDROGRAPHS]

;;               Rain Gage/     

;;Name           Month            Response R        T        K        IA_max   IA_rec   IA_ini 

;;-------------- ---------------- -------- -------- -------- -------- -------- -------- --------

MANY             RainGage       

MANY             All              Short    .1       1        1        1        .01      0      

MANY             All              Medium   .05      3        3        1        .01      0      

MANY             All              Long     .01      5        10       1        .01      0      

[RDII]

;;Node           Unit Hydrograph  Sewer Area

;;-------------- ---------------- ----------

Storage          MANY             1        

[PATTERNS]

;;Name           Type       Multipliers

;;-------------- ---------- -----------

soil             MONTHLY    .01   .10   1     2     1     .10 

soil                        .01   .10   1     2     1     .1  

Hourly           HOURLY     0.191 0.236 0.251 0.302 0.400 0.463

Hourly                      0.703 1.000 0.876 0.670 0.491 0.456

Hourly                      0.400 0.358 0.274 0.290 0.373 0.385

Hourly                      0.468 0.596 0.640 0.543 0.403 0.364

[REPORT]

INPUT      YES

CONTROLS   NO

SUBCATCHMENTS ALL

NODES ALL

LINKS ALL

[TAGS]

[MAP]

DIMENSIONS 747573.697 247745.801 753800.907 251809.529

Units      Feet

[COORDINATES]

;;Node           X-Coord            Y-Coord          

;;-------------- ------------------ ------------------

Outfall          747879.187         247930.516       

Storage          750522.255         249213.382       

[VERTICES]

;;Link           X-Coord            Y-Coord          

;;-------------- ------------------ ------------------

[Polygons]

;;Subcatchment   X-Coord            Y-Coord          

;;-------------- ------------------ ------------------

MySubCatchment           747856.752         247967.907       

MySubCatchment           747726.887         248390.794       

MySubCatchment           747597.022         248813.681       

MySubCatchment           747221.312         249101.864       

MySubCatchment           747337.291         249659.456       

MySubCatchment           747484.496         250917.382       

MySubCatchment           749812.998         251702.471       

MySubCatchment           753039.238         251624.814       

MySubCatchment           753965.941         250721.110       

MySubCatchment           753517.852         247990.342       

[SYMBOLS]

;;Gage           X-Coord            Y-Coord          

;;-------------- ------------------ ------------------

RainGage         750276.915         250966.450