Presentation on theme: "Andre Filipe Santini Fernando González Mónica Álvarez Huarita Nancy G. Ballesteros Quilo."— Presentation transcript:
Andre Filipe Santini Fernando González Mónica Álvarez Huarita Nancy G. Ballesteros Quilo
Discretization and model definition to work; Determination of model parameters; Calibration and Validation; Diagnosis of the current drainage capacity; Solution approach through holding tanks; Conclusions and Recommendations.
General Identify problems of flooding and inadequate, and solve problems with holding tanks at strategic points, using the hydrological - hydraulic SWMM 5.0 program. Specific Discretization of the basin; Determination of effective rainfall; Determination of roughness coefficients of the sewer; Model calibration and validation of hydrological-hydraulic; Designing adequate numbers of holding tanks and locate them in the most critical flooding areas to prevent flooding in La Riereta. Disseminate findings and recommendations.
Located in the old town of Sant Boi de Llobregat, near Barcelona; Drainage area approximately 17 Ha; High percentage of impervious areas; High average surface slopes; Variable diameter circular ducts; Tubes composed primarily of concrete; Combined sewer system;
18 sub-catchment area; Total of Ha; Areas ranging between 0.28 to 1.65 Ha.
Sub-catchment Nodes Conduits Rain
Slopes: Were obtained using the coordinates of the CAD file supplied, ranging from 0.6 to 6.6%. Roughness: During the calibration we changed the roughness of the Basin from 0.02 to and for the duct to to evaluate the results.
The model was calibrate with two rain events, Efren and Fidel, for the validation we used Elias.
The analysis of the results obtained in the calibration step weren´t good enough; To improve our results we should redefine the sub- catchment, making new delimitation of areas; However due to lack of time to improve the results we proceed with the next step, diagnosis and solution.
Once we calibrate and verify the model, we proceed with a diagnosis of the drainage basin; To do that we define a storm design from an IDF curve;
We used the IDF curve familie from Barcelona to evaluate the storm design. The storm design is built from the IDF curve according to the method of alternating blocks
T= 10 years
ALTERNATING BLOCK METHOD
This design storm is to introduce in the SWMM model in order to evaluate how the current sewage system behaves facing a rain with a recurrence time of 10 years.
NODE Hours Flooded (h) Maximum Rate (CMS) Time of Occurrence (h) Total Flood Volume (10 6 l) Maximum Pondep Depth (m) : : : : : : : : : : TOTAL FLOOD3.99 Critical nodes 52, 33 and 36
MAIN AFFECTED AREAS
Once identified the critical nodes, is proposed as a solution to use Storage Units upstream those nodes. Storage unit in Japan.
According to the problems identified in the diagnostic phase, we propose solutions to prevent flooding in the problem areas. In order to this we placed storage reservoirs that can act at the time of the flood and reduce risks; In this regard, solutions of this kind were raised for those nodes that had major problems; The reservoirs were placed upstream the problematic nodes in order to reduce the peaks and avoid drowning. In this sense, four reservoirs were placed.
Storage UnitArea (m2) Max. Depth(m) DEP DEP DEP DEP DEP 1 DEP 2 DEP 3 DEP 4
Location scheme in plant reservoirs
The dimension were obtained after a trial & error process, in which one we adopted different dimensions until we get such dimension that solve those problems. We to deal with the width limitation of the street in some areas. We adopted Linear Reservoirs; Having defined the dimensions and evacuation structures necessary (orifices and weir), we proceeded to run the SWMM 5.0 model, and following results were obtained.
NODE Hours Flooded (h) Maximum Rate (CMS) Time of Occurrence (h) Total Flood Volumen (10 6 l) Maximum Pondep Depth (m) : : : : : : TOTAL FLOOD0.71
Observing the data obtained in the stage of Diagnosis and compared with those shown above, we see that there is a decrease in the volume spilled and also the most problematic nodes (36, 33 and 52) does not generate overflows. DIAGNOSISSOLUTIONDECREASE (%) Total Flood Volumen ( 10 6 l )
As an example, we shown the results for Node 52. The figure below shows the dimensions of it.
By entering the reservoir in the scheme of the basin, were generate an attenuation of the hydrograph. The Figure shows the hydrographs before and after placing the reservoir NODE 52 DIAGNOSTICSOLUTIONVariation (%) Peak Flow (m3/s) Peak Time (h) 0:35:000:40:00
The calibration of the model present percentages of high variation in relation to the comparison of pick flow and volume between hydrograms observed and calculated. On the event Efren, the difference of pick flow between hydrogram observed and calculated is close to 13%, while the event Fidel this difference is close to 9%. In relation to the volumes, there are important differences, being itself close to 24% for the event Efren and the 30% for the event of Fidel. In the stage of diagnosis, by introducing the design storm, there generate flooding on varies sectors of the catchment. The nodes more affected are the 36, 33 and 52. The total volume flood is close to 4000 m3. In function of the problems detected, we planted like a solution put reservoirs upstream of the nodes where flooding exist. In this sense we put 4 reservoirs with areas on plant between 300 m2 and 900 m2.
The presence of this reservoirs generate that the nodes affected in the stage of diagnosis decrease, also, the critic nodes 36,33 and 52 don’t have more flooding. The decrease of volume flood its almost 85% In function to this values, we considerate acceptable the design of structure of storage. However for bigger precipitations to the design it is possible that comeback to generate inconvenient on some nodes and reservoirs. In function of the result obtain on the stage of calibration and validation we believe convenient realize a new discretization of the basin with the object of generate an acceptable calibration and validation of the model. With respect to the reservoirs designed, they are able to retain the volumes needed to prevent flooding in the critical nodes, however their capacity is achieved almost entirely. Therefore it is believed appropriate to review the design of the data with the aim of having a free volume of the same at least 15%.