DIAGNOSTIC AND ASSESSMENT OF A URBAN BASIN SEWER SYSTEM at Riereta, Sant Boi de Llobregat, SPAIN

AVANCE REPORT

Presentation Nº 1: “HYDRO LATIN AMERICA 2011”

Cochabamba. July 2011

Team Nº 4:

Juliana Martins Bahiense julianamba@gmail.com Brazil

Juan Pablo Brarda jpablo145@yahoo.com.ar Argentina

Ronald Herbas Vargas ronald_herbas.var@hotmail.com Bolivia

Cinthya Segales Cruz roxana_1389@hotmail.com Bolivia

STUDY AREA DESCRIPTION AND LOCALIZATION

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Sant Boi de Llobregat is located in the metropolitan area of Barcelona, in Barcelona province, Cataluña.

It has 82,428 inhabitants (INE 2009) and it occupies an area of 22 km2.The analysis area in this study is the urban watershed of La Riereta, located at old municipality of Sant Boi de Llobregat. It has an area of approximately 15.5 ha.

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At the standpoint of urban drainage, one of the main features of the basin is its high rate of impermeabilization which causes a significant increase on stormwater runoff.

Current state of sewerage system, concerning ducts sizes and antiquity, aggravates this problems.

1 – Increasing in volume

2 – Flow accelaration

3 – Runoff peak increasing

STUDY AREA DESCRIPTION AND LOCALIZATION

OBJETIVES

Hydrological and hydraulic behavior evaluating and diagnosing of an existing sewerage network in Riereta region, Sant Boi de Llobregat, through the use of EPA SWMM computer program.

• Determine in a given year, the probability of overcapacity occurrence in the network, to a certain series of precipitation;• Determine flooding volumes in the study area for that series;• Determine peak flow rates registered during the series;• Estimate flooding permanence during this period;• Determine vulnerable areas of flooding-related phenomena in the study area;• Assess safety level in existing sewer system for a given time of recurrence (TR), identifying maximum TR which do not have surface flooding occurrence and existing network works with free surface.

GeneralGeneralObjetive Objetive

Particular Particular ObjetiveObjetive

Based on available information

Topographic information of

the region

Urban parcelling

layout

Existingnetwork

sewerage

METHODOLOGICAL USED PROCESS

Satellite images support:

Characterization of impervious areas. Discharge form of roofs and buildings.

Definition of basins and

urban sub-basins

METHODOLOGICAL USED PROCESS

SUB-BASIN:SUB-BASIN: Definition of hydrological characteristics parameters

PPRROOCCEESSSS

LINKS: LINKS: Definition of hydraulic characteristics parameters

Construction of drainage topological schemeAnalysis of meteorological events - Construction of design rainfall.

Calibration and validation of model based on available hydrological information. Chosen events were Jordi, Fidel and Martina, recorded in the basin study.

Diagnosis of drainage system considering a design rainfall with 10 years TR and duration of one hour.

Determination of effective hyetographs to estimate runoff, regarding that runoff losses (PL) are constant. It can speed up the calibration process. Valid assumption for urban watersheds due to its fast response time.

Fulfill the objectives for Team No. 4.

METHODOLOGICAL USED PROCESS

GANT DIAGRAMGANT DIAGRAM

SHORT WATERSHED CHARACTERIZATION

• Riereta basin is located in the old town of Sant Boi de Llobregat, in the metropolitan area of Barcelona.

• The study basin is a urban type basin and has an area of about 15.5 ha.

• It presents high impermeabilization levels and it is completely urbanized. The houses are old.

• The terrain is extremely rugged with slopes ranging between 4% and 0.5%.

• Some of the distinctive characteristics of sewer system are: Combined sewer system; Concrete ducts with mostly circular sections and diameters ranging between 300 mm and 1200 mm; Linking ducts through concrete inspection chambers;

Satelyte image with basin delimitation. It can be viewed the high impermeabilzation hate

18 Subbasins18 Subbasins0.65 – 1.25 ha0.65 – 1.25 ha

SHORT WATERSHED CHARACTERIZATION

NETWORK SYSTEM

HYDROLOGICAL PARAMETERS DETERMINATION

CHARACTERISTIC WIDTH “W”:CHARACTERISTIC WIDTH “W”:

Given that real basins are not rectangular neither have symmetric and uniform properties, it is necessary to adopt a process that permit to estimate characteristic width to general situations.

Sk = (A2 – A1) / A W = (2 – Sk) * l

Sk = Correction factor; 0 ≤ Sk ≤ 1A1 = Area at one side of drainage

channelA2 = Area at other side of drainage

channelA = Total areal = Lenght of main drainage channel

Name Area [Ha]

Length [m]

A1 [Ha] A2 [Ha] SkW1 [m]

Slope [%]

Area Impervious

[%]

"n" Manning Imperv

"n" Manning Perv

SubC1 1,153 214,00 0,282 0,872 0,295 364,870 4,86% 84,770 0,015 0,250

SubC2 0,979 223,00 0,306 0,676 0,185 404,745 3,81% 87,735 0,015 0,250

SubC3 0,659 142,00 0,273 0,384 0,056 276,119 2,42% 86,345 0,015 0,250

SubC4 0,539 123,00 0,251 0,289 0,019 243,663 3,82% 79,961 0,015 0,250

SubC5 0,562 130,00 0,276 0,284 0,004 259,480 1,75% 88,871 0,015 0,250

SubC6 0,667 198,00 0,274 0,392 0,059 384,318 3,26% 90,301 0,015 0,250

SubC7 0,852 141,00 0,374 0,477 0,052 274,739 3,82% 91,205 0,015 0,250

SubC8 1,460 203,00 0,510 0,953 0,222 361,036 2,52% 79,326 0,015 0,250

SubC9 1,007 123,00 0,351 0,655 0,152 227,304 3,58% 84,001 0,015 0,250

SubC10 0,975 131,00 0,378 0,597 0,110 247,656 3,10% 89,094 0,015 0,250

SubC11 0,808 128,00 0,171 0,637 0,233 226,176 2,88% 98,921 0,015 0,250

SubC12 0,686 112,00 0,224 0,465 0,121 210,504 2,48% 100,000 0,015 0,250

SubC13 0,947 140,00 0,410 0,539 0,065 270,970 1,81% 97,395 0,015 0,250

SubC14 0,866 193,00 0,314 0,553 0,120 362,937 0,35% 94,264 0,015 0,250

SubC15 0,861 139,90 0,363 0,498 0,068 270,357 0,38% 94,025 0,015 0,250

SubC16 0,640 128,00 0,317 0,322 0,003 255,680 1,20% 94,532 0,015 0,250

SubC17 0,667 122,00 0,296 0,370 0,037 239,486 3,52% 91,455 0,015 0,250

SubC18 1,078 145,00 0,348 0,710 0,181 263,755 1,39% 85,055 0,015 0,250

TOTAL 15,406  

SSUUBB--BBAASSIINNSS

HYDROLOGICAL PARAMETERS DETERMINATION

Cota (msnm)

Tramo D(mm) TI SI TF SF Long.(m) So.(%) "n" Rugosidad

2-6 600 33,941 32,141 29,971 28,671 53,81 6,45 0,013

6-13 600 29,971 28,671 27,593 26,593 52,77 3,94 0,013

13-19 600 27,593 26,593 26,777 25,227 37,95 3,60 0,013

19-20 600 26,777 25,227 26,047 24,447 46,65 1,67 0,013

20-21 600 26,047 24,447 25,201 23,454 34,39 2,89 0,013

21-30 600 25,201 23,454 25,073 23,173 9,74 2,89 0,013

30-48 600 25,073 23,173 25,178 22,554 22,55 2,75 0,013

15-22 300 27,25 26,25 26,889 25,589 55,27 1,20 0,013

22-33 400 26,889 25,589 26,427 23,327 58,67 3,86 0,013

82-70 500 38,342 36,042 32,496 30,696 81,44 6,56 0,013

70-33 500 32,496 30,696 26,427 23,327 70,54 10,45 0,013

33-31 400 26,427 23,327 25,909 22,509 51,14 1,60 0,013

31-48 400 25,909 22,509 25,178 22,554 55,46 -0,08 0,013

11-17 500 29,818 28,518 28,071 27,271 39,88 3,13 0,013

17-18 500 28,071 27,271 27,013 26,213 35,92 2,95 0,013

18-27 500 27,013 26,213 26,174 24,574 35,02 4,68 0,013

27-29 400 26,174 24,574 25,178 22,87 60,08 2,84 0,013

29-48 500 25,178 22,87 25,178 22,554 11,17 2,83 0,013

48-49 1000 25,178 22,554 23,6 20,368 38,06 5,74 0,013

49-51 1000 23,6 20,368 20,625 17,197 55,19 5,75 0,013

51-52 1000 20,625 17,197 19,459 15,459 30,24 5,75 0,013

47-52 300 23,225 21,725 19,459 15,459 61,5 10,19 0,013

52-53 1000 19,459 15,459 18,443 16,816 47,98 -2,83 0,013

53-127 1000 18,443 16,816 17,836 16,073 28,68 2,59 0,013

127-54 1000 17,836 16,073 17,199 15,294 30,07 2,59 0,013

54-50 1000 17,199 15,294 16,465 14,396 34,7 2,59 0,013

50-8 1200 16,465 14,396 15,432 13,132 48,79 2,59 0,013

7-8 600 16,748 14,18 15,432 13,132 41,19 2,54 0,013

8-9 1200 15,432 13,132 14,758 12,91 45,96 0,48 0,013

CCOONNDDUUCCTTSS

HYDRAULIC PARAMETERS DETERMINATION

NSubC1

SubC2

SubC3

SubC17

SubC4

SubC6

SubC5

SubC7

SubC8

SubC18

SubC16

SubC13

SubC12

SubC11

SubC10

SubC9SubC14

SubC15

NSubC1

SubC2

SubC3

SubC17

SubC4

SubC6

SubC5

SubC7

SubC8

SubC18

SubC16

SubC13

SubC12

SubC11

SubC10

SubC9SubC14

SubC15

D18

D8

D15-14

D9

D10

D11

D12

D13-16

D6- 7

D3

D4

D2 D1

NSubC1

SubC2

SubC3

SubC17

SubC4

SubC6

SubC5

SubC7

SubC8

SubC18

SubC16

SubC13

SubC12

SubC11

SubC10

SubC9SubC14

SubC15

NSubC1

SubC2

SubC3

SubC17

SubC4

SubC6

SubC5

SubC7

SubC8

SubC18

SubC16

SubC13

SubC12

SubC11

SubC10

SubC9SubC14

SubC15

D18

D8

D15-14

D9

D10

D11

D12

D13-16

D6- 7

D3

D4

D2 D1

NSubC1

SubC2

SubC3

SubC17

SubC4

SubC6

SubC5

SubC7

SubC8

SubC18

SubC16

SubC13

SubC12

SubC11

SubC10

SubC9SubC14

SubC15

D18

D8

D15-14

D9

D10

D11

D12

D13-16

D6- 7

D3

D4

D2 D1

SWMM MODEL SCHEME

CALIBRATION OF MODELIt is necessary to identify the parameters to be considered for calibration. It is known to use the MPLC with which values are not required pervious area (assuming the entire area impervious), second volume in depression will not be necessary. On that basis, the parameters used for the iterative process are:•Loss constant in mm / h [Pl]•Characteristic width in m [W]•"n" Impervious surface area Manning,•"n" Manning duct of the sewer system.The calibration is carried out with the event Fidel and validated for the events Martina and Jordi.

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DIAGNOSTIC AND ASSESSMENT OF A URBAN BASIN SEWER SYSTEM at Riereta, Sant Boi de Llobregat, SPAIN

AVANCE REPORT

Presentación Nº 1: “HYDRO LATIN AMERICA 2011”

Cochabamba. Julio de 2011

Team Nº 4:

Juliana Martins Bahiense julianamba@gmail.com Brazil

Juan Pablo Brarda jpablo145@yahoo.com.ar Argentina

Ronald Herbas Vargas ronald_herbas.var@hotmail.com Bolivia

Cinthya Segales Cruz roxana_1389@hotmail.com Bolivia