Detecting Changes in Stormwater Runoff due to LID Installation. Asal Askarizadeh

Transcription

1 Detecting Changes in Stormwater Runoff due to LID Installation Asal Askarizadeh

2 Urbanization Increase of impervious surfaces Impacts on hydrology at the catchment scale

3 Low Impact Development (LID) Enhancing retention and infiltration capacity of watershed Change in the response of watershed to rain events Restoring disturbed hydro-ecology of urbanized catchments Some examples of LID

4 How can LID deployment affect stormwater runoff? Type and combination of deployed LIDs

5 How can LID deployment affect stormwater runoff? Percentage of watershed area covered by LIDs

6 How can LID deployment affect stormwater runoff? Spatial configuration of LIDs within the watershed

7 Main research goal Detecting changes in stormwater runoff due to LID installation

8 Multiple factors affect runoff R=Runoff R=f(Precipitation, Infiltration, Evapotranspiration, Drainage Characteristics) Research motivation Low Impact Development R=g(Drainage characteristics)

9 Research Objective: Develop a method to detect change in stormwater runoff due to LID installation Conjecture: The Instantaneous Unit Hydrograph method can detect change in stormwater runoff due to LID installation

10 Instantaneous Unit Hydrograph (IUH) A mathematical way of representing the runoff generated by a watershed in response to a unit volume of excess rainfall event Isolate effect of LID on stormwater runoff

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12 Research Plan First step: Numerical experiment to test IUH method (synthetic data from SWMM5) Second step: Application of IUH method to data rich systems (field data from LSBC)

13 First step: Numerical experiment to test IUH method Calibrate a HYDROLOGICAL MODEL to an URBAN WATERSHED Simulate runoff from the URBAN WATERSHED for a test storm under two conditions: Without LID With LID Can we detect change in stormwater runoff with the IUH method?

14 Fitting IUH model to the simulated runoff time-series Statistically test posterior IUHs parameters

15 HYDROLOGICAL MODEL: Storm Water Management Model (SWMM) Schematic representation of LID in SWMM5

16 URBAN WATERSHED: Compton Creek Highly urbanized watershed in Los Angeles Total area: 22.6 sq. mile Percentage of imperviousness: 62% Compton Creek

17 First Test: WATERSHED RESPONSE to installation of porous pavement (8% by area)

18 WATERSHED RESPONSE Precipitation (in) Runoff prior LID installation (in) Runoff post LID installation (in) Time (hr)

19 As expected our synthetic data shows that installing porous pavement: Delays rising limb of the hydrograph Reduces peak flow Reduces runoff volume Slightly longer recession Can we detect change in stormwater runoff with the IUH method?

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22 Conclusion IUH can detect LID installation in Compton watershed Future Work Numerically investigate sensitivity of IUH to LID type, combination, percentage of coverage and configuration in Compton Watershed Use IUH to determine if runoff in Little Stringybark Creek (Melbourne, Australia) changed after extensive on-the-ground implementation of LID Application of method to the possible LID project data in CA

23 Hydrological Modeling Economic Analysis Statistical Analysis Stanley Grant Brett Sanders Jean-Daniel Saphores Amir Aghakouchak Tim Fletcher Martha Sutula Ashmita Sengupta

24 Thank you!