Measurement and Estimation of Evapotranspiration from Urban Green Spaces in New York City

Transcription

1 Measurement and Estimation of Evapotranspiration from Urban Green Spaces in New York City KIMBERLY DIGIOVANNI, FRANCO MONTALTO, STUART GAFFIN PHILADELPHIA LOW IMPACT DEVELOPMENT SYMPOSIUM TUESDAY, SEPTEMBER 27, 2011 SESSION 34

2 Ecosystem Services and Hydrologic Restoration Stormwater management Reduction of the Urban Heat Island (UHI) effect Energy Savings Air pollution mitigation Carbon sequestration Image NRC (2005) Image (top) Church et al (1995), (bottom) USDA-FIA (2000)

3 Objective Directly measure evapotranspiration (ET) rates from a variety of engineered urban green spaces, or green infrastructure technologies, and a historically undisturbed forest in a temperate urban environment

4 Monitoring Sites URBAN PARK BIORETENTION AREA 1 BIORETENTION AREA 2 BIORETENTION AREA 3 BIORETENTION AREA 4 GREEN ROOF

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6 Period of Monitoring Record Urban Park Bioretention Area 1 Bioretention Area 2 Bioretention Area 3 Bioretention Area 4 Green Roof Precipitation Soil Moisture Lysimeter Mass Drainage from Lysimeter

7 Methods WEIGHING LYSIMETER SOIL WATER DEPLETION

8 Weighing Lysimeters Measured actual evapotranspiration (AET) is derived utilizing a mass (water) balance approach, given by the following equation: where P is precipitation, D is drainage below the root zone, R is surface runoff, ET is evapotranspiration and ΔS the change in storage During dry periods, the precipitation, drainage and runoff terms become zero reducing the above equation:

9 Methods: Weighing Lysimeters

10 Soil Water Depletion Technique Adaptation of the water balance where n r = number of layers to the depth of the effective root zone, ΔS i = the thickness of each layer in mm, θ 1 and θ 2 = volumetric water contents on the first and second date of sampling respectively in m 3 m -3, R e = rainfall that does not runoff the area (mm), W d = drainage from the zone sampled (mm), Δt = time interval between the first and second sampling dates (Jensen, Burman et al 1991)

11 Calculation Results URBAN PARK BIORETENTION AREA 1 BIORETENTION AREA 2 BIORETENTION AREA 3 BIORETENTION AREA 4 GREEN ROOF

12 Urban Park

13 Urban Park: Weighing Lysimeter Evapotranspiration (mm/day) Evapotranspiration Lysimeter Mass Lysimeter Mass (kg) /8/2011 9/9/2011 9/10/2011 9/11/2011 9/12/2011

14 Bioretention Area 1

15 Bioretention Area 1: Weighing Lysimeter Evapotranspiration (mm/day) Evapotranspiration 1 Lysimeter Mass 0 8/25/2011 8/30/2011 9/4/2011 9/9/2011 9/14/ Lysimeter Mass (kg)

16 Bioretention Area 1: Soil Water Depletion Evapotranspiration (mm/day) /25/2011 8/30/2011 9/4/2011 9/9/2011 9/14/2011

17 Bioretention Area 2

18 Bioretention Area 2: Weighing Lysimeter Evapotranspiration (mm/day) /1/2010 3/2/2011 6/1/2011 8/31/2011

19 Bioretention Area 2: Soil Water Depletion Evapotranspiration (mm/day) /25/2011 8/30/2011 9/4/2011 9/9/2011 9/14/2011

20 Bioretention Area 3

21 Bioretention Area 3: Soil Water Depletion Evapotranspiration (mm/day) /1/ /20/2010 1/9/2011 2/28/2011 4/19/2011 6/8/2011

22 Bioretention Area 4

23 Bioretention Area 4: Soil Water Depletion Evapotranspiration (mm/day) /14/ /3/2010 1/22/2011 3/13/2011 5/2/2011 6/21/2011 8/10/2011

24 Green Roof

25 Green Roof: Weighing Lysimeter 8 Evapotranspiration (mm/day) /15/2009 1/1/2010 7/20/2010 2/5/2011 8/24/2011

26 Green Roof: Soil Water Depletion Evapotranspiration (mm/day) /15/2009 1/1/2010 7/20/2010 2/5/2011 8/24/2011

27 Discussion SOIL WATER DEPLETION VS. LYSIMETER BIORETENTION AREA 2 GREEN ROOF

28 /5/11 8/10/11 8/15/11 8/20/11 8/25/11 8/30/11 9/4/11 9/9/11 9/14/11 Volumetric Water Content (m3 /m3) Lyaimeter Mass (kg) Bioretention Area 2: Soil Water Depletion vs. Lysimeter

29 Bioretention Area 2: Soil Water Depletion vs. Lysimeter 8 ET by Water Depletion (mm/day) Lysimeter ET (mm/day)

30 Green Roof: Soil Water Depletion and Lysimeter Evapotranspiration (mm/day) /15/2009 1/1/2010 7/20/2010 2/5/2011 8/24/2011

31 Green Roof: Soil Water Depletion vs. Lysimeter 8 ET by Water Depletion (mm/day) R² = Lysimeter ET (mm/day)

32 Green Roof: Lysimeter Mass and Volumetric Water Content Volumetric Water Content (m 3 /m 3 ) P ~ 3.5 mm 0 7/1/2011 7/3/2011 7/5/2011 7/7/ Lysimeter Mass (kg)

33 Green Roof: Composite Evapotranspiration

34 Implications Water Stormwater Annual P = 1080 mm Annual ET = 610 mm Stormwater Retention Annually % (With seasonal variation) For 500 m 2 green roof = 300,000 L (80,000 gallons) Energy Latent heat 595 cal/g For 500 m 2 green roof = 45,000 MJ Comparison to background

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36 Conclusions and ongoing work Longer studies covering season Development of predictive models for estimation of ET from different types of urban green spaces Characterization of transpiration

37 Acknowledgements National Science Foundation NSF GRFP NSF RAPID Grant CBET NYDOS & DEC NYCDPR - Nandan, Bram, Jeff, Jackie, Jamie, Sean ECFS Howard Waldman Columbia NYCSWCD - Tatiana Cooper Prof. Cataldo Adams Environmental Systems, Inc. JPL and Universal Supply Nathan, Stephen, Scott, Ben, Jeff, Ryan, Zach, Allison, Vikki, A.J., etc.

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39 Monitoring Setup Climatic monitoring P, Temp, RH, u, R s Weighing lysimeter setup 0.6 m x 1.2 m replica section M, θ, Q (qualitatively) June 2009 Present 5 minute data intervals

40 Observation period Alley Pond Precipitation 8/4/2011 through current (with two week gap) Lysimeter Nashville Precipitation 7/25/2011 through current Lysimeter 7/25/2011 through current Colfax Precipitation 7/25/2011 through current Lysimeter 12/2/2010 through current Furmanville Sagamore and Cruger Precip 9/12/2009 through 9/8/2011 (continuous) Soil Sensors 10/22/2010 through 5/22/2011 Fieldston Precipitation 2008 through curent (with gaps) Lysimeter 6/09/2009 through current (continuous) Soil sensors 8/30/2009 through current (with gaps)