LA RIERETA

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LA RIERETA
LA RIERETA
MODELING AND SOLUTIONS
FOR FLOODING PROBLEMS
USING SWMM 5.0
PRESENTATION
This work is under a bigger perspective witch the objective is to
solve urban drainage problems at La Riereta Basin .
This basin suffers from flooding events mainly due to the
impermeability of its ground.
Many measures will be proposed from different aspects of urban
drainage theories but, all of them are going to be based on
modeling using SWMM 5.0.
DESCRIPTION
La Riereta is an urban basin
located at one of the most urban
areas in Barcelona called San Boi
de Llobregat.
The basin is reported to have
high slopes an there are hardly
any green areas inside its limits.
The aproximate area of La
Riereta is 18 ha and there are
register of xxx mm near its outfall
due to flood.
Source: Grupo Flumen UPC
LA RIERETA
OUTFALL
DISCRETIZATION
The basin’s drainage was defined by analyzing a topographic map
witch presents the streets heights, pipes heights and direction of
flow identifying its patterns.
This is a very important step to develop the modeling correctly and
to get the diagnosis.
To get the discretization the basin’s limits were designed
considering the areas that are responsible to contribute with flow
to the outflow point.
DISCRETIZATION
The same idea was applied to select the sub-basins.
For each area that supposed to be one sub-basin, an identification
of its pipes was made and if these pipes contributes to the
discharge of the basin, then it was consider one sub-basin.
If the sub-basin has more than one pipe that contributes to the
basin’s discharge, the pattern assumed is that the flow goes to the
pipe with the biggest slope.
The final topologic design contains 12 sub-basins and are showed
below:
DISCRETIZATION
OUTFALL
DISCRETIZATION
The area located between
Francesc Macia, Viuda
Vives, Cerdanya y Mallorca
streets (sub-cuenca LR004)
is not supposed to be
included at the basin by
considering all the
criterions explained, but
this area is reported to
contribute to La Riereta.
Calle
Cerdanya
Calle
Malorca
Source: Googlemaps
DISCRETIZATION
The drainage network is conformed by a major
drainage sewer, placed at Calle de Torre Figueres –
Calle de Jaume – Calle de la Rutula, starting at Calle
Mossen Cinto Verdaguer and discharging at the control
point. In addition, has been considered a secondary
sewer placed in Carrer de Francesc Macia, that
receives conduit contributions from Calle del Pintor
Fortuny.
MODELING WITH SWMM
MODEL´S CONTRUCTION
With the topologic schema defined, SWMM EPA model has been
implemented, including subcatchment, nodes, conduits and
information of its dimensions.
From the available information the requested variables and parameters
were defined : areas, wides, mean of slopes surface, impermeability
percentage, roughness coefficients and storage depth for impermeable
and permeable areas, infiltration model parameters, invert elevation
and depth, diameters and conduits dimension’s, and manning
coefficients for conduits. In the same way, the average slope of the
sub-basins was determined.
Width was determinate considering the contribution length for each
sub-basin, between the basin head and outfall, following the
consolidated drainage pattern.
PRE-CALIBRATION RESULTS
With the first modeling, the observed and modeled volume difference were defined,
using the curve number (CN) method and a constant rainfall abstraction. The
following graphs shows the hydrograph using the CN method and a 3 mm/hr
constant rainfall loss:
HIDROGRAMAS EVENTO ELIAS
HYDROGRAPHS FOR ELIAS RAINFALL EVENT
0.5
0.45
0.4
Caudal (m3/s)
DISCHARGE (m3/s)
OBS
MOD CN
MOD -3mm
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
50
100
150
Time (min)
Tiempo
(min)
200
250
300
PRE-CALIBRATION RESULTS
HYDROGRAPHS
FOR EFREN
RAINFALL
EVENT
HIDROGRAMAS
EVENTO
EFREN
HIDROGRAMAS
FIDEL
HYDROGRAPHS
FOR FIDELEVENTO
RAINFALL
EVENT
0.5
0.3
OBS
MOD CN
0.45
MOD -3mm
OBS
MOD CN
MOD -3mm
0.4
0.25
Caudal (m3/s)
0.2
DISCHARGE (m3/s)
DISCHARGE (m3/s)
Caudal (m3/s)
0.35
0.15
0.1
0.3
0.25
0.2
0.15
0.1
0.05
0.05
0
0
0
50
100
150
Tiempo
(min)
Time
(min)
200
250
300
0
50
100
150
Tiempo
(min)
Time
(min)
200
250
300
CALIBRATION
First Efren and Elias rainfall events were chosen for calibration
and Fidel was elected for Validation. It was made because
these two first rainfalls presents only one peak while Fidel
shows doble-peak and the 3 of them have the same amount as
well.
CALIBRATION
Efren
Intens idad
0.50
25
0.40
0.30
30
0.20
118
109
100
91
82
73
64
55
50
0.20
60
0.10
70
0.00
Tiempo (min)
Caudal (m3/s)
0.30
40
0.40
40
37
30
34
0.50
31
20
28
0.60
25
193
181
169
157
145
0.70
22
Tiempo (min)
133
121
109
97
85
73
61
49
37
25
0.00
1
30
0
19
0.10
25
Caudal
10
16
0.20
13
20
Elías
Intens idad
10
0.30
46
0.00
37
0.10
40
1
35
1
15
Caudal (m3/s)
0.60
20
Tiempo (min)
Intensidad mm/h
0.40
Caudal (m3/s)
10
13
Intensidad mm/h
0.70
15
28
0.50
5
0.80
10
7
0.60
0.90
4
0
1.00
5
19
Caudal
Intensidad mm/h
Intensidad
Caudal
0
10
Fidel

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