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HydroUrbanBCN. Sant Boi de Llobregat Urban Drainage System. Team 5: Irem Oc Waiteng Luen Alex Poins Andres Emen. Outline. Introduction Objectives La Riereta Catchment Model Set-up La Riereta Model Calibration and Validation Drainage Network Diagnosis for T = 10 years
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HydroUrbanBCN SantBoi de Llobregat UrbanDrainageSystem Team 5: IremOc WaitengLuen Alex Poins AndresEmen
Outline • Introduction • Objectives • La RieretaCatchmentModel Set-up • La RieretaModelCalibration and Validation • Drainage Network Diagnosis for T = 10 years • Dryweatherflowanalysis • Conclusion
La RieretaUrbanCatchment 1. Introduction
1. Introduction • La Riereta (17 Ha) is located in the historical part of SantBoi de Llobregat, Catalonia, Spain. • Highly impervious (88%), slopes 1% - 7% • Rainfall and Runoff Events have been made in the sub-catchment. • Combined type sewer system (42 manholes)
La RieretaUrbanCatchment 2. Objectives
2. Objectives • To analyze the combined sewer network in the La Riereta urban catchment for a design storm of 10 years return period and 1 hour duration. • Toanalyzethesewersystembehaviourduringdry-weather and its improvement EPA SWMM 5.0 as a hydro- informatictool.
La RieretaUrbanCatchment 3. La RieretaCatchmentModel Set-up
3. La RieretaCatchmentModel Set-up 3.1. Catchment and Network Identification and Discretisation • Two basic criteria: (1) Each sub catchment of 1 Ha approx, and (2) rainfall collection path
3. La RieretaCatchmentModel Set-up 3.2. HydrologicParameters • W: width, A: area, L: the mean flow path length. • Land use was estimated from satellite images, to determine the Manning´s Coefficient (Pervious 0.15 – 0.24; Impervious 0.02) • Impervious model, the losses were assumed as a constant value in the hyetograph.
3. La RieretaCatchmentModel Set-up 3.3. HydraulicParameters • Inverts and rim values from AUTOCAD • Manning Coefficient for concrete pipes as 0.016
La RieretaUrbanCatchment 4. LA RIERETA MODEL CALIBRATION AND VALIDATION
4. ModelCalibration and Validation 4.1. ModelCalibration and Validation Data • Three assigned rainfall events: St. Jordi, St. Elias and St. Susana. Variables to calibrate: total volume, peak discharges and lag time.
4. ModelCalibration and Validation 4.2. Data Validation based on Mass Conservation Principle • The St. Elias rainfall event may contain errors as the constant loss from this event (11.33 mm/h) is much higher than the values from the other events. • Acceptable range of 3 to 7 mm/h
4. ModelCalibration and Validation 4.3. Model Calibration with Jordi Rainfall Event • St. Jordi rainfall event was used to calibrate the La Riereta model. Parameters: 4.3.1. Constant Loss • Directly subtracted from the rainfall time-series. Initial value: 3.69 mm/h. Trial and error process to minimize the error between simulated and real volume at the outlet.
4. ModelCalibration and Validation 4.3.2 Sub-catchment Width • Increased until the error in the peak discharge (31%) and lag time (0%) are acceptable
4. ModelCalibration and Validation 4.3.3 Sub-catchment slope • Increased until the error in the peak discharge is less than 25%.
4. ModelCalibration and Validation 4.4. Validation
La RieretaUrbanCatchment 5. DRAINAGE NETWORK DIAGNOSIS FOR 10 YEARS RETURN PERIOD DESIGN STORM
5. Drainage Network Diagnosis 5.1. Design of 10 Years Return Period Storm for 1 hour Duration • The Barcelona-Fabra Intensity-Duration-Frequency (IDF) for 1 hour duration and 10 years return period.
5. Drainage Network Diagnosis 5.2. Design storm simulation and results
La RieretaUrbanCatchment 6. DRY WEATHER FLOW ANALYSIS
6. DryWeatherFlowAnalysis 6.1. Dry Weather Flow simulation Toogeneral!!
6. DryWeatherFlowAnalysis 6.1. Dry Weather Flow simulation • Flows assigned to each sub- catchment inlet • Necessary to achieve a minimum velocity of 0.7 m/s once per day
6. DryWeatherFlowAnalysis 6.2. Dry Weather Flow simulation Results • Velocity at 8h00 (peak). Results without changes in the network:
6. DryWeatherFlowAnalysis 6.2. Dry Weather Flow simulation Results • Changes: • The network can no longer be used for rainfall drainage system • Longitudinal slopes not enough for initial flows • Cross sections, smaller and egg-shaped • Manning coefficient´s is reduced since the pipes are changed from Concrete to PVC.
La RieretaUrbanCatchment 7. conclusions
7. Conclusions • Only one rainfall event available for calibration • Successfully calibrated and validated with rainfall and discharge data from the Jordi and Susana rainfall events respectively. • For a 10 years return period design storm occurs important floods. • Rehabilitation to achieve self- cleansing is almost possible but unavailable for being used as a drainage system. • A more detailed analysis is demanded