Alternative Drainage Techniques : Infiltration

Team 3

Ariel Marcelo Ravelli (Argentina)Lina Mabel (Chile)

Vinícius de Mello Moutinho (Brasil)

• Theme Presentation• Case of Study• Rain and Modeling• Adopted Solution• Results

Theme Presentation

Drainage Alternative Forms

•Trenches

•Storage Rooftops

•Permeable Pavement

•Infiltration Basins

Case of Study La Riereta basin, Saint Boi Llobregat

Basin 100% impermeable

1% to 7% average slopes

Area of 18 ha

Unitary Drainage System

SubCatchmentTotal Area

(m²)Permeable Area (m²)

L (m) Width % per. %imp %slope

1 9627,97 308,34 173,56 330,93 3,20% 96,80% 1,64%

2 6714,73 528,12 149,72 272,77 7,87% 92,13% 1,64%

31 6630,54 62,82 174,72 349,44 0,95% 99,05% 3,48%

4 19994,75 151,16 266,13 473,10 0,76% 99,24% 1,54%

5 17776,41 0,00 223,07 431,95 0,00% 100,00% 2,61%

6 13875,27 690,36 152,7077 263,94 4,98% 95,02% 3,75%

7 9769,22 0,00 103,39 169,39 0,00% 100,00% 0,91%

8 11239,69 28,19 149,67 237,82 0,25% 99,75% 4,19%

9 24536,38 121,50 154,46 247,59 0,50% 99,50% 4,26%

10 19494,04 0,00 206,32 355,79 0,00% 100,00% 1,07%

11 7302,09 0,00 183,82 367,64 0,00% 100,00% 3,30%

12 10973,80 1155,76 101,39 154,63 10,53% 89,47% 1,74%

13 10827,35 2960,82 127,58 188,33 27,35% 72,65% 5,96%

14 8397,599 0 120,1996 214,40 0,00% 100,00% 4,42%

[1] These subcatchments had it´s width calculated as symmetrical, W= 2*L, while the others were calculated as asymmetrical, W=(2 - Sk) x L, Sk= (A2 – A1)/ A

Subcatchments Features

Rain and Modeling

Rain and Modeling

3 Rains: Jordi, Fidel and Martina

Rain and Modeling

Calibration : Fidel

First Round Last Round

Rain and Modeling

Validation : Jordi

Error: peak: 0.4% volume: 34%

Project Rain

0

50

100

150

200

250

0:00

0:05

0:10

0:15

0:20

0:25

0:30

0:35

0:40

0:45

0:50

0:55

1:00

Time (min)

Inte

ns

ity

(m

m/h

)

Project Rain

Reduced Project Rain

Project Rain

Full Rain Reduced Rain

Local Problem

************************** Volume Volume

Flow Routing Continuity hectare-m 10^6 ltr

************************** --------- ---------

Dry Weather Inflow ....... 0.000 0.000

Wet Weather Inflow ....... 0.466 4.664

Groundwater Inflow ....... 0.000 0.000

RDII Inflow .............. 0.000 0.000

External Inflow .......... 0.000 0.000

External Outflow ......... 0.270 2.699

Internal Outflow ......... 0.190 1.896

Evaporation Loss ......... 0.000 0.000

Initial Stored Volume .... 0.000 0.000

Final Stored Volume ...... 0.006 0.063

Continuity Error (%) ..... 0.130

Solutions

• Reduce Impermeable Area

• Combined Solution

Solutions

• Reduce Impermeable Area from 100% to 0%

************************** Volume Volume

Flow Routing Continuity hectare-m 10^6 ltr

************************** --------- ---------

Dry Weather Inflow ....... 0.000 0.000

Wet Weather Inflow ....... 0.088 0.883

Groundwater Inflow ....... 0.000 0.000

RDII Inflow .............. 0.000 0.000

External Inflow .......... 0.000 0.000

External Outflow ......... 0.072 0.716

Internal Outflow ......... 0.009 0.088

Evaporation Loss ......... 0.000 0.000

Initial Stored Volume .... 0.000 0.000

Final Stored Volume ...... 0.007 0.066

Continuity Error (%) ..... 1.396

Solutions

• Combined Solution

• Imper. Area – 60%

• CN – 60

• Infiltration Basin

• Shallow Trenches

Solutions

Solutions

Total Volume Reduction : 88%

Conclusions

100% to 0% we still had a flood, an amount of 0.46% of the inicial flood.

Combined solution, we were able to reduce the soil impermeability from 100% to 60%, and using the infiltration basin and the trenches, we reduced the total flood from 1.896 x 106 to only 0.230 x 106 ltrs, a total reduce of 88%

Problems

Good Management Required