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Plant Surveys of Bioinfiltration Units at the Edison Environmental Center and Implications for Design

Thomas P. O’Connor, P.E., BCEEEnvironmental EngineerEdison, NJ

EPA Bioinfiltration Research and Demonstration Controls

• Adjacent to Permeable Pavement Research and Demonstration site

• Receives parking lot and roof runoff• Instrumented with water content reflectometers based on time domain reflectometer technology

• Media primarily sand – choice after extensive testing• Plants: drought, inundation and salt tolerant• Six side-by-side units – three surface areas in duplicate:

Middle units design close to NJDEP guidance (11:1 watershed to surface area); smaller are half surface area (20:1) while larger are twice surface area (5:1)

• Plastic sheeting separates units and surrounding area to ~ 1.2 m depth

2

3https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100BXHW.txt

= WCR location (2 depths)

= Thermistor location (3 depths)

22:1

Note: Not to Scale

Curb Cut

Asphalt11:1

5.5:1

7.1 m

7.1 m

7.1 m

3.7 m

14.9 m7.5 m

2.9 m 2.9 m

14.9 mRoof Runoff (from adjacent building) [0.28 ha]

42.7 m

Sidewalk

Drainage Area: Surface Area

N

4

5

Bioinfiltration units during construction

T T T

G

S

G

G

S

S

S SNote: Diagram is not to scale. T=small tree, S=shrub, G=grasses (not turfgrass), sedges, and rushes. Shrub numbers are approximate and will depend on species. See next slide for species list. Some of the grass area may be planted in herbaceousplants, species and locations to be determined.

TTT

G

S

G

G

S

S

SS

Bioinfiltration units over timebefore initial survey

7

5/3/2010

5/15/2012

6/11/2010

11/1/2012

Media: 0.86 m

0.25 m

0.38 m

= WCR

Underlying Soil

Gravel: 0.10 m

0.48 m

0.10 m

2.9 m 2.9 mInlet:“Front” “Back”

8

Minimum root depth blueberry /

winter berry 0.41 m

Minimum root depth bayberry 0.51 m

Note: Not to scale8

Media 90% sand (United States Golf Association concrete sand) and 10% sphagnum peat moss by volume; organic content 1.1% test lost on ignition.

Plant growth assessment of shrubs• Conducted December, 2012

– Document plant survivability– Measure Basal Area at three heights (base, 0.6m

and 1.4 m)– Measure height– Assess shading

• Review ancillary data for period since planting – Rainfall statistics– Soil moisture – Calculate reference crop evapotranspiration

9

Number of shrubs per bioinfiltration unit (BU) –

some plants did not survive

10

BUNumber

BU Size

Location Number Measured (Planted-2010)Bayberry Blueberry Winter-berry

1 Small West 1 (1) 1 (1) 2 (2)2 Medium West 3 (3) 3 (3) 6 (6)3 Large West 9 (11) 9 (11) 6 (7)4 Large East 9 (11) 11 (11) 6 (7)5 Medium East 3 (3) 1 (3) 5 (6)6 Small East 1 (1) 1 (1) 2 (2)

Brown et al. 2015

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2010 Mar Ap

rM

ay Jun Jul

Aug

Sep

Oct

2011 Mar Ap

rM

ay Jun Jul

Aug

Sep

Oct

2012 Mar Ap

rM

ay Jun Jul

Aug

Sep

Oct

0

25

50

75

100

125

150

175

250

275

300

450

475

500

Mon

thly

Dep

th (m

m)

Mar: 284 mm

Aug: 478 mm* Record

Rainfall Deficit Rainfall

Reference Evapotranspiration

Rainfall and reference crop evapotranspiration (ET0)

Monthly ET0 –Monthly Rainfall= Rainfall Deficit

WCR monitoring locations media saturation

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Total of 91 events analyzed with complete data from all WCR locations.

Period of analysis: 2010-2012 growing seasons (April to October).

When saturation not frequent, the change in soil moisture was attributed to direct rainfall.

Bayberry growth closer to inlet and in smaller bioinfiltration

units better than in large units

13

14

Winterberry height closer to inlet and in smaller bioinfiltration

units taller than in large units

Also effect of shading

E – EastW – WestF – Full SunS – Shade

15

Mean Plot of Basal Area @ 0.6 m (cm 2) grouped by Shadingblueberry 23v*27c

Mean Mean±0.95 Conf. Interval

Shaded Full Sun

Shading

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24Ba

sal A

rea

@ 0

.6 m

(cm

2 )

Basal Area @ 0.6 m (cm 2): F(1,24) = 11.176, p = 0.0027

Blueberry growth in shade better than full sun

Conclusion and discussion for shrub study

• Be mindful of rain fall deficit• May not have uniform surface infiltration• Smaller controls may provide better function than oversized control– greater plant survivability and robustness– continue to infiltrate even when flooded

16

Follow-up plant survey• Conducted June – August 2018 by summer intern• Grasses

– Indian grass Basal area at height of 10 to 15 cm conducted over three week period

• Shrubs and woody vegetation at DBH (1.4 m) only• Height of shrubs woody vegetation• Recruitment – identification of new woody vegetation

17

18

8/14/2018

19

Shrub and woody vegetation

20

Shrub and woody vegetation and grasses

Statistical Analysis Multivariate ANOVA

• Multivariate Analysis of Variance (MANOVA)–Bayberry height (cm) and diameter largest branch

(cm)–Categorical: Surveys and BU sizes

21

22

Observations

• No winterberry observed• No service berry in BU 6, not measured in BU 5

–Cause deer damage • One dominant bayberry in BU2, use to be three• Bayberry appears to be spreading, shoots observed• Bitter Panicum high density in BU 3 and 4; observed on BU 2, 5 and 6; not in BU 1

• Bitter Panicum is adapted to “low soil moisture” and does not perform well in shade” (USDA)

• Indian grass “best in deep, well-drained floodplain soils” (USDA)

23

2018 Survey Implications

• Bayberry taking over shrub habitat• Bayberry “success” in BU4 potentially due to shading• Grasses indicative of soils moisture evaluation (Brown et al. 2015)– Indian grass more dominant in smaller BU and

toward front, while Bitter Panicum dominates back of BU 3 and 4 where plants rely on direct rainfall

• “Recruitment” plants prefer front of larger BU or smaller BU

• Results consistent with previous findings: Smaller BU controls have more robust plant growth

24

Hurricane Irene Response

25

Swale to Storm Drainage Pipe

26

Swale to Storm Drainage Pipe

27

28

September 8, 2011 Flooding of Bioinfiltration Units

Comparison of Hurricane Irene to September 8, 2011

29

Hurricane Irene Totals and Intensity

•Peak hourly rainfall intensity was 44.4 mm/hr (1.75 in/hr)

•Discharge to storm drainage pipe first occurred after 95.7 mm (3.77 in) of rain had fallen

30O’Connor and Amin (2015)

Annual reduction in roof discharge to existing EEC

storm sewer system

•Mean annual rainfall for New Jersey is 1,100 mm (45 in) (Robinson, 2013)

•For typical year, approximately 2.9 x 106 L (7.6 x 105 gal) infiltrate through biofiltration units from roof of adjacent building

31

References • R. Brown, T. P. O’Connor and M. Borst (2015). “Divergent Vegetation Growth Patterns

Relative to Bioinfiltration Unit Size and Plant Placement” ASCE’s Journal of Sustainable Water in the Built Environment (JSWBE), Vol. 1, No. 3. (http://ascelibrary.org/doi/abs/10.1061/JSWBAY.0000796)

• T. P. O’Connor and M. Amin (2015). “Rainwater Collection and Management from Roofs at the Edison Environmental Center” ASCE's JSWBE, Vol. 1, No. 1. (http://ascelibrary.org/doi/abs/10.1061/JSWBAY.0000792)

• https://plants.usda.gov/factsheet/pdf/fs_sonu2.pdf

PARS Environmental performed the first survey in December 2012. Nicholas Lund, a volunteer intern from Montclair University, performed the Spring/Summer 2018 survey. Internship was in partnership with US EPA Region 2.

32

Acknowledgements

Questions?

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DisclaimerThe USEPA, through its Office of Research and Development, funded and managed, or partially funded and collaborated in, the research described herein. It has been subjected to the Agency’s peer and administrative review and has been approved for external publication. Any opinions expressed in this paper are those of the author(s) and do not necessarily reflect the views of the Agency, therefore, no official endorsement should be inferred. Any mention of trade names or commercial products does not constitute endorsement or recommendation for use.