La Riereta Catchment Sant Boi de Llobregat

Summary Contents 1. Introduction... 2 2. Group presentation... 3 3. The project... 4 3.1. Objective... 4 3.2. Study Area... 4 4. Methodology... 6 4.1. Initial data... 8 5. Model implementation... 12 5.1. Calibration and validation of the model.... 15 6. Determination of the storm design... 23 7. Diagnóstico hidráulico escenario TR = 15 años... 26 8. Solutions for Rehabilitation... 31 9. Conclusion... 38 1

1. Introduction Hydro Latin America is a course borned of the EuroAquae consortium and organized by the Universidad Politècnica de Catalunya. The course proposes the promotion of the global vision for a sustainable management of urban water through the international experience of teamwork with the participants students, according the key concepts and using the modeling tools, and encouraging the critical analysis. This year, the 2016 edition of Hydrolatinamerica takes place in Universidad Nacional de Ingeniería, in Lima, Peru. Figure 1. Universidad Nacional de Ingeniería, Perú In this context, it is developed the hydrologic and hydraulic study of La Riereta urban catchment, using the Stormwater Management Model (SWMM). 2

2. Group presentation. Name Country Professional Information University Age Mail Lilian Yamamoto Brazil Civil Engineering Student Universidade Federal do Rio de Janeiro 23 tenolil6@aquacloud.net Martín Pez Argentina Hidryc Resources Engineering Universidad Nacional del Litoral (UNL) 26 pezmar6@aquacloud.net W. Enrique Amaya T. Colombia Sanitary Engineer Universidad de Santo Tomás - Tunja 26 ninajho6@aquacloud.net Sergio Esquivel Puente México Civil Engineering Universidad Autónoma de Nuevo Léon 29 esquser6@aquacloud.net Figure 2. Hydrolatinamerica 2016 - Team 2 3

3. The project 3.1. Objective The course project consist on a sewer rehabilitation process of a urban catchment called La Riereta. To carry out this process a hydrological and hydraulic model will be built up using the EPA Storm Water Management Model (SWMM 5.0). 3.2. Study Area The urban catchment is located in Sant Boi de Llobregat, which is a town near to Barcelona. Figure 3. Location of the study area (Google, 2016). This catchment has a surface area of 15ha approximately. Moreover, it presents high indexes of impermeability due to is mainly inserted in the old historic center of the city. 4

Figure 4. Surface of study area in 3D, using software Surfer 9.0. Figure 5. Old Historic Center of Sant Boi de Llobregat (Google, 2016). 5

In adittion, the catchment slope varies from high to medium values and the drainage of the roofs discharges directly to the street through downspouts. Additionally a group of inlets distributed in the streets ensure the collection of the generated runoff after the rainfall occurs. Figure 6. Google street view of Sant Boi. 4. Methodology The model used in this study is the Stormwater Management Model (SWMM) developed by the U.S. Environmental Protection Agency (EPA). The SWMM model, is a dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. 6

Figure 7. Urban wet weather flows. 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 a system of pipes, channels, storage/treatment devices, pumps, and regulators. SWMM tracks the quantity and quality of runoff generated within each subcatchment, and the flow rate, flow depth, and quality of water in each pipe and channel during a simulation period comprised of multiple time steps. Running under Windows, SWMM 5 provides an integrated environment for editing study area input data, running hydrologic, hydraulic and water quality simulations, and viewing the results in a variety of formats. These include color-coded drainage area and conveyance system maps, time series graphs and tables, profile plots, and statistical frequency analyses. SWMM accounts for various hydrologic processes that produce runoff from urban areas. These include: 7

time-varying rainfall. Evaporation of standing surface water. Rainfall interception from depression storage. Interflow between groundwater and the drainage system. Infiltration of rainfall into insaturated soil layers. SWMM accounts for various hydrologic processes that produce runoff from urban areas. These include: Design and sizing of drainage system components for flood control. Sizing of detention facilities and their appurtenances for flood control and water quality protection. Flood plain mapping of natural channel systems. Designing control strategies for minimizing combined sewer overflows. Evaluating the impact of inflow and infiltration on sanitary sewer overflows. In this way, to meet project objectives, some tasks are carried out as follows: 4.1. Initial data On site of HydroLatinAmerica was available a data about La Riereta for the study area recognition and evaluation. Among them, there is an AutoCAD file that presents the division of urban properties, the description of the drainage network with the localization of manholes and their elevations, conduits dimensions, flow directions and an outlet point previously defined, as showed in figure 4. 8

Figure 8. Autocad date of La Riereta. 4.2. Basin discretization In order to build up a simple model but representing with accuracy either in SWMM, it was made a discretization of catchments and subcatchments based on the definition of their limits. These delimit the contribution areas for each outlet node for the drainage system and it was made from the topographic characteristics and flow directions in pipes. Then, it was possible to obtain 33 subcatchments, which can be observed at next figure. 9

Figure 9. Limits of the catchments and the subcatchments. The runoff with were obtained considering the subcatchment as asymmetric planes of contribution to the outlet. The expression used were: Where: W : Runoff with : Length of flow A : areas of asymmetric planes A : Sub-basin total area L A 1, 2 W S k 2 S k A2 A1 A 10

Table 1. Subcatchment summary Name Area Width %Slope Rain Gage Outlet SUB13 0.37 125.03 4.22 1 N81 SUB18 0.23 68.93 4.86 1 N-4 SUB1 0.54 129.62 1.4 1 N-8 SUB2 0.39 144.63 3.44 1 N-55 SUB3 1.1 219.65 2.59 1 N-127 SUB4 0.78 202.75 4.83 1 N-8 SUB5 0.49 131.12 4.45 1 N4 SUB6 0.62 127.06 1.2 1 N-45 SUB7 0.08 43.93 3.92 1 N-42 SUB8A 0.4 141.25 3.32 1 N-57 SUB9 0.92 225.06 4.71 1 N-52 SUB10 0.48 162.21 2.04 1 N-47 SUB11 0.29 77.04 1.61 1 N-27 SUB12 0.4 83.81 5.94 1 N-16 SUB14A 0.34 94.62 3.09 1 N-18 SUB15 0.23 87.19 3.04 1 N-11 SUB16 0.16 78.4 2.53 1 N-4 SUB17 0.17 65.55 6.12 1 N-11 SUB19 0.21 73 7.35 1 N-6 SUB21 0.33 64.21 3.48 1 N-75 SUB22 0.2 66.24 11.92 1 N-15 SUB23 0.36 82.44 0.34 1 N-15 SUB24 0.76 144.63 1.75 1 N-30 SUB20 0.9 310.88 3.86 1 N-13 SUB26A 0.56 62.17 4.02 1 N-31 SUB27A 0.47 135.17 9.33 1 N-66 SUB28A 0.53 91.92 2.83 1 N-82 SUB28B 0.54 97.46 2.83 1 N-84 SUB27B 0.28 95.96 9.33 1 N-70 SUB8B 0.34 77.73 3.32 1 N-56A SUB26B 0.31 69.62 4.02 1 N-30 SUB25 0.67 221.68 1.07 1 N-33 SUB14B 0.29 85.82 3.09 1 N-30 4.3. Collect of data Furthermore, it was defined, from the AutoCAD file, the main drainage system based on the most relevant conduits dimensions and their tracing. A collect of information about the slopes, the areas, the lengths and the flow's width of which 11

subcatchment was made. There were absence of some information, like manhole's elevation and the cross section's dimensions of some conduits that were arbitrated based on an interpolation between the others information given. 5. Model implementation It was developed the topology of the model in SWMM, creating the subcatchments group. Then, it was possible to represent the integration of the subcatchments with their respective output nodes with drainage system. By a visual analysis, suported by an orthophoto, it was determined the impermeability percentage of the subcatchments. The majority of the system conduits has a circular and rectangular cross sections and made of concrete, because of that the roughness coefficients is 0.013. The next table presents the characteristics from the conduits. Table 2. Conduit properties Name Node Inicial Node Final Cross Section Length %Slope Roughness Hyd. Depth C1 N81 N-9 CIRCULAR 49.7 6.1165 0.013 0.5 C2 N-9 N-16 CIRCULAR 36 5.8344 0.013 0.5 C3 N-16 N-25 CIRCULAR 40.8 4.4062 0.013 0.5 C4 N-25 N-26 CIRCULAR 44 2.9581 0.013 0.4 C5 N-26 N-27 CIRCULAR 32.1 1.8338 0.013 0.4 C6 N-11 N-17 CIRCULAR 32.2 3.8744 0.013 0.5 C7 N-17 N-18 CIRCULAR 35.7 2.6844 0.013 0.5 C8 N-18 N-27 CIRCULAR 35 4.688 0.013 0.5 C9 N-27 N-30 CIRCULAR 71.1 1.9697 0.013 0.5 C10 N-4 N-11 CIRCULAR 51.3 5.9442 0.013 0.5 C11 N-6 N-13 CIRCULAR 52.9 4.6895 0.013 0.6 C12 N-13 N-19 CIRCULAR 38.1 2.5336 0.013 0.6 C13 N-19 N-20 CIRCULAR 46.6 1.6726 0.013 0.6 C14 N-20 N-30 CIRCULAR 43.3 2.9429 0.013 0.6 C15 N-15 N-22 RECT_OPEN 55.3 1.1947 0.013 0.3 C16 N-22 N-33 RECT_OPEN 58.4 2.4206 0.013 0.3 C17 N-70 N-33 CIRCULAR 71.1 10.7064 0.013 0.5 C18 N-33 N-31 CIRCULAR 51.1 1.601 0.013 0.4 C19 N-31 N-30 CIRCULAR 55.5-1.1973 0.013 0.6 C20 N-30 N-49 CIRCULAR 48.4 5.8109 0.013 1 12

Name Node Inicial Node Final Cross Section Length %Slope Roughness Hyd. Depth C21 N-49 N-51 CIRCULAR 54.9 5.8094 0.013 1 C22 N-51 N-52 CIRCULAR 30.4 5.6746 0.013 1 C23 N-42 N-47 CIRCULAR 43.6 4.5897 0.013 0.4 C24 N-47 N-52 CIRCULAR 61.2 10.2927 0.013 0.3 C25 N-52 N-53 CIRCULAR 47 1.2533 0.013 1 C26 N-53 N-127 CIRCULAR 28.7 1.2545 0.013 1 C27 N-127 N-54 CIRCULAR 31 1.2259 0.013 1 C28 N-54 N-50 CIRCULAR 34.6 1.214 0.013 1 C29 N-50 N-8 CIRCULAR 48.9 1.1821 0.013 1.2 C30 N-45 N-5 RECT_OPEN 92.8 8.8208 0.013 0.4 C31 N4 N-5 CIRCULAR 33 1.4335 0.013 0.6 C32 N-5 N6 CIRCULAR 33 2.525 0.013 0.6 C33 N6 N7 CIRCULAR 47.3 2.579 0.013 0.6 C34 N7 N-8 CIRCULAR 41.1 2.5251 0.013 0.6 C35 N-8 N9 CIRCULAR 45.9 0.4833 0.013 1.2 C36 N9 OUT1 CIRCULAR 50.1 2.1606 0.013 1.5 C37 N-75 N-15 RECT_OPEN 54.7 11.398 0.013 0.3 C38 N-84 N-83 CIRCULAR 55.1 1.623 0.013 0.5 C39 N-83 N-82 CIRCULAR 51.8 2.296 0.013 0.5 C40 N-82 N-70 CIRCULAR 80.8 6.3802 0.013 0.5 C41 N-56 N-56A CIRCULAR 47.7 6.55 0.013 0.4 C42 N-56A N-52 CIRCULAR 27.7 18.2041 0.013 0.4 C43 N-67 N-68 CIRCULAR 18.8 0.8937 0.013 0.6 C44 N-68 N-69 CIRCULAR 36.1 1.1164 0.013 0.6 C45 N-69 N-70 CIRCULAR 24.7 8.1402 0.013 0.5 C46 N-55 N-54 RECT_OPEN 52.6 5.6516 0.013 0.4 C48 N-57 N-56 CIRCULAR 46.4 1.1009 0.013 0.4 C49 N-66 N-67 CIRCULAR 77.5 3.2589 0.013 0.6 As described in item 4.3, the data collected is inserted in SWMM to establish the node s elevation based on possibly the lowest elevation, and the depth máximum by the difference between the terrain elevation and the invert elevation. The next table presents the characteristics from the nodes. Table 3. Node properties Name Invert Elevation Máx Depth N81 33.39 1.5 N-9 30.36 1.65 N-16 28.26 1.6 N-25 26.46 1 13

Name Invert Elevation Máx Depth N-26 25.16 1.5 N-27 24.57 1.6 N-4 31.56 1.4 N-11 28.52 1.3 N-17 27.27 0.8 N-18 26.21 0.8 N-6 28.67 1.3 N-13 26.19 1.4 N-19 25.23 1.55 N-20 24.45 1.6 N-30 23.17 1.9 N-15 26.25 1 N-22 25.59 1.3 N-33 23.33 3.1 N-70 30.9 1.6 N-31 22.51 3.4 N-49 20.37 2.79 N-51 17.18 3.44 N-42 23.82 1.1 N-47 21.72 1.5 N-52 15.46 4 N-53 14.87 3.57 N-127 14.51 3.3 N-54 14.13 3.05 N-50 13.71 2.72 N-45 24.38 0.9 N4 16.7 1.9 N-5 16.22 3 N6 15.39 2.93 N7 14.17 2.58 N-8 13.13 2.3 N9 12.91 1.84 N-75 32.45 1.3 N-84 38.33 1.1 N-83 37.43 1.5 N-82 36.04 2.3 N-56 23.54 1.5 N-56A 20.42 1.7 N-67 33.47 1.55 N-68 33.3 1.55 N-69 32.9 1.55 N-55 17.1 0.9 N-66 35.99 1.55 N-57 24.05 1.5 14

Name Invert Elevation Máx Depth OUT1 11.83 1.5 5.1. Calibration and validation of the model. For calibration and validation of the model, there are three rain events which contains flow measurements at the outlet point of the catchment: Susana, Jordi and Efren. Figures X and X below show these events and the measured flow. Figure 10. Susana rain event. 15

Figure 11. Jordi rain event. 16

Figure 12. Efren rain event. Due to the catchment high impermeability seems valid to consider constant the value of run off loss. In this way, the effective precipitation of the three events mentioned above was determined leaving an intensity of 3mm/h for each hydrograph. The next figures shows the hydrograph of total precipitation and effective precipitation. 17

Figure 13. Average loss percentage. Figure 14. Average loss percentage. 18

Figure 15. Average loss percentage. The calibration consisted in an iterative process which the hydrologics parameters are varied to succeed the minimization of the difference of the maximum flow, the peak time and the volume between the simulated hydrograph and the observed one of the registered events. For calibration, it was considered the Susana and Jordi events. The final parameters - Para todas las subcuencas: %Imperv=100, N-Inperv=0.015, N-perv: - ; Dstore-Inperv=0; Dstore-Perv=0; %Zero-Imperv=90. - Para todos los conductos: n=0.013 19

Q [m 3 /s] 2016 LIMA, PERU The results of the calibration shown in the next figure. 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 20 40 60 80 100 t [min] Measured Flow Simulated Figure 16. Hydrograph results of the calibration. Susana event. The next table shows a summary of the errors for each event. Table 4. Summary of errors for Susana event. 20

Q [m 3 /s] 2016 LIMA, PERU 1.10 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 20 40 60 80 100 120 140 160 180 200 220 240 t [min] Measured Flow Simulated Figure 17. Hydrograph results of the calibration. Jordi event. Table 5. Summary of errors for Jordi event. 21

Q [m 3 /s] 2016 LIMA, PERU 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 Measured flow Simulated 0.10 0.05 0.00 0 50 100 150 t [min] Figure 18. Hydrograph results of the calibration. Efrén event. Table 6. Summary of errors for Efrén event. Percent error variables previous are within ranges of acceptable error. Once calibrated and simulated the example, proceed a calculating hietograma for a return time (TR) of 15 years in order to under simulate the critical conditions. 22

6. Determination of the storm design To determinate the project rain, it were used IDF Barcelona - Fabra curves (Serie 1972-1993). The family of IDF curves is represented by the following expressions: Where: I: intensity [mm/h] : Recurrence [years] : Duration of rain [min] : Dependent coefficients of rain duration. The duration of the rain (tr) was adopted in order to result greater than the concentration time (tc) of the basin which was estimated by the following equations: (SCS, 1973) Where: L: length of the basin [m] CN: Curve number (SCS) 23

S: average slope of the basin [m/m] (California Culvert Practice, 1942) Where: L: length of the longest water course [m] H: stretch between the head and the outlet of the basin [m] Where: C: runoff coefficient of the rational method L: length of surface flow [m] S: surface slope [m/m] (Federal Aviation Administration, 1970) In the next Table, obtained concentration times (tc) and adopted rain duration (tr). 24

Table 7. Obtained concentration times (tc) and adopted rain duration (tr). Figure 19. Design rain obtained for a recurrence period of 10 years and a rain duration of 1 hour. 25

7. Diagnóstico hidráulico escenario TR = 15 años The hydraulic simulation of the sewerage system in the study area was carried out using the SWMM 5.0 software. The simulation was performed using a hietograma with a return period of 15 years. The modeling results are reported at the time of peak hydrograph simulation: Table 8. Node flooding of hydraulic diagnostic Node Hours Maximum Rate Hours of maximum Total Flood Volume Flooded CMS Flooding 10^6 ltr N-25 0.08 0.122 00:30 0.02 N-26 0.09 0.047 00:26 0.008 N-27 0.1 0.277 00:30 0.058 N-18 0.01 0.028 00:29 0 N-15 0.18 0.264 00:30 0.08 N-22 0.01 0.078 00:22 0 N-33 0.25 1.026 00:30 0.446 N-47 0.02 0.073 00:29 0.003 N-52 0.01 0.043 00:30 0.001 26

Figure 20. Node Flooding. 27

Figure 21. Capacity full flow. At the performance of the simulation, it was possible identify some critical conduits which has a pressure flow in it and presents overflow at the manholes, as it was shown in previous tables. It can be observed below the profiles with the information about the system saturation at the critical conduits. 28

Figure 22. Profile N81 N30. Figure 23. Profile N75 N30. 29

Figure 24. Profile N30 OUT1. Figure 25. Profile N45 OUT1. 30

Figure 26. Profile N42 N52. 8. Solutions for Rehabilitation Rehabilitation sewer system is assigned activities increased diameter and slope changes in the collectors not operating free flow, maintaining the constructive type of piping material. Then the pipe sections that have been modified are presented, increasing its hydraulic capacity and slope. 31

Table 9. Pipes with increasing diameter and slope Name Node Inicial Node Final Shape Length Roughness %Slope Existing %Slope Rehabilitation Hyd. Depth Existing Hyd. Depth Rehabilitation C4 N-25 N-26 CIRCULAR 44 0.013 2.9581 2.9581 0.4 0.6 C5 N-26 N-27 CIRCULAR 32.1 0.013 1.8338 1.8338 0.4 0.6 C9 N-27 N-30 CIRCULAR 71.1 0.013 3.6206 1.9697 0.5 0.8 C15 N-15 N-22 RECT_OPEN 55.3 0.013 1.1947 1.1947 0.3 0.6 C16 N-22 N-33 RECT_OPEN 58.4 0.013 3.7078 2.4206 0.3 0.6 C18 N-33 N-31 CIRCULAR 51.1 0.013 1.601 1.601 0.4 1 C19 N-31 N-30 CIRCULAR 55.5 0.013 0.9178 1.1973 0.6 1 C20 N-30 N-49 CIRCULAR 48.4 0.013 3.378 5.8109 1 1 C22 N-51 N-52 CIRCULAR 30.4 0.013 5.6746 5.6746 1 1.2 C24 N-47 N-52 CIRCULAR 61.2 0.013 10.2927 10.2927 0.3 0.4 C25 N-52 N-53 CIRCULAR 47 0.013 1.2533 1.2533 1 1.2 C26 N-53 N-127 CIRCULAR 28.7 0.013 1.2545 1.2545 1 1.5 C27 N-127 N-54 CIRCULAR 31 0.013 1.2259 1.2259 1 1.5 C28 N-54 N-50 CIRCULAR 34.6 0.013 1.214 1.214 1 1.5 C29 N-50 N-8 CIRCULAR 48.9 0.013 1.1821 1.1821 1.2 1.5 C35 N-8 N9 CIRCULAR 45.9 0.013 0.4833 0.4833 1.2 1.5 C37 N-75 N-15 RECT_OPEN 54.7 0.013 11.398 11.398 0.3 0.4 In all, the hydraulic capacity of 15 pipes (diameter) was increased and the slope of 2 sections. The material of the pipes in concrete circular section remains. In order to improve the slope reverse to the flow direction of conduit C -19, it was decided to increase the depth of the manhole or node N -30. The results of the optimized hydraulic modeling is as follows: 32

Figure 27. Node flooding of rehabilitation. 33

Figure 28. Link capacity full flow of rehabilitation. According to the above graphs, it can be seen that with optimization performed, any well presents rebozamiento and total piping works free flow, with a maximum depth between 80 and 100 %. Table 10. Pipes with increasing diameter and slope Existing System Rehabilitation Efficiency of Rehabilitation (%) Node Flooding 9 0 100 Link (Capacity Full Flow) 14 0 100 Optimized profiles sections are presented. 34

Figure 29. Profile N81-N30. Figure 30. Profile N75-N30. 35

Figure 31. Profile N30-OUT1 Figure 32. Profile N45-OUT1 36

Figure 33. Profile N42-N52. Increased hydraulic capacity of the pipeline will not generate problems of considerable decrease in depth to crest tube. 37

9. Conclusion Through the Hydrolatinamerica event, it was possible to develop the hydraulic and hydrologic model of the La Riereta s drainage system. It was possible to represent satisfactorily the hydrologic answer of the basin, however with excessive volumes due to have included an area bigger than the real contribution area. The error percentage of the calculated hydrograph in relation to the observed one, in general is about 26.36%. We can affirm that is an acceptable value for the calibration of a hydrodynamic model. To achieve a bigger reliability at the model calibration, it requires include the topology of the urban drainage system in its totality, in order to simulate input and resorted times of the flow which drains the sewage system. The construction of a hydrodynamic model with more approximation with the reality requires more productive time, considering that it has to have a discretization more detailed of the urban basin. In general, it has augmented the hydraulic capacity of 15 conduits (diameters), as well as the slope of 2 conduits. The conduit s material has been preserved in concrete and the circular and rectangular cross section. 38