STORMWATER INFILTRATION TRENCH RETROFIT UPDATE

Transcription

1 STORMWATER INFILTRATION TRENCH RETROFIT UPDATE John Komlos, Ph.D. Bridget Wadzuk, Ph.D. Andrea Welker, Ph.D. Robert Traver, Ph.D. Nicolas Pazlopez Tobias Müller (Nave Newell, Inc.) Civil and Environmental Engineering - Villanova University Villanova Urban Stormwater Partnership 1

2 Aged Infiltration Trench 6ft 10ft 13ft 2

3 Aged Infiltration Trench Constructed Aged in 2004 Infiltration Trench Collecting stormwater from top deck of parking garage (~20,400 ft 2 ) (blue) Infiltration trench (surface area ~130 ft²) (red) Designed with drainage area to SCM surface area of 160:1

4 Recession rates at lowest depth range 0-0.3m Aged Infiltration Trench Lewellyn, C., Lyons, C., Traver, R., and Wadzuk, B. (2015). "Evaluation of Seasonal and Large Storm Runoff Volume Capture of an Infiltration Green Infrastructure System." Journal of Hydrologic Engineering, /(ASCE)HE ,

5 Aged Infiltration Trench Pictures were taken in July 2007 (rainfall: 0.9 )

6 Goals of This Study Examine how failure occurred in an infiltration trench. Redesign the infiltration trench to improve longterm operation. Quantify the performance of the infiltration trench retrofit.

7 Excavation of the old infiltration trench (IT) took place in October/November 2015

8 Excavation

9 Excavation 1ft perforated inflow pipe

10 Excavation Aggregate and Geotextile were covered with a dark layer silty soil

11 We had 2 weeks for in-situ forensic analysis between the excavation of old trench and installation of retrofit

12 Infiltration Trench Retrofit Design Constrained environment: Limited space for stormwater control measure (SCM) implementation Collect stormwater from less of parking deck (~5800 ft 2 ) (blue) Infiltration trench (~130 ft²) (red) Designed with drainage area to surface area of 45:1 Pretreatment system to filter out suspended solids (Contech Jellyfish ) Storage volume is provided with a modular stormwater system (R-Tanks HD, ACF Environmental) 12

13 Construction of IT Retrofit

14 Construction of IT Retrofit R-Tanks: 90% porosity compared to 40% for commonly used stone aggregates Allows for practical maintenance.

15 Construction of IT Retrofit Pretreatment - Jellyfish

16 The Jellyfish Filter from Contech Engineering Solutions

17 Future Work bypass pipe splitter Box runoff from parking deck Jellyfish inlet to infiltration trench flume overflow

18 Water Quantity Performance 18 Water Depth in Trench (ft) July 25, storm Drain Down Time = 4 hr Time July 25, storm event Drain Down Time = 4.5 hr Inflow (cfs) IT Inflow (cfs) It Depth (ft)

19 Volume Infiltrated 19 Volume infiltrated through August ,000 gallons

20 Infiltration Trench Recession Rates Original vs Retrofit at 0 to 1 ft water depth: 20

21 Water Quality Performance Total Suspended Solids (TSS) = Particle Size > 0.45µm 70.8% ± 15.8% Removal (n=7) (n=2) (n=2) (n=2) (n=1) (n=1) (n=1) (n=1) 21

22 Water Quality Performance Total Dissolved Solids (TDS) = Particle Size < 0.45µm 33.0% ± 23.6% Removal (n=7) (n=2) (n=2) (n=2) (n=1) (n=1) (n=1) (n=1) 22

23 Infiltration Trench Retrofit Pretreatment Filter Filter membranes before and after 5 months of operation 23

24 Sediment that clogged old Infiltration Trench: Sediment collected on Jellyfish filter: A-Inlet Manifold (n=2) Jellyfish Filter Clay 15.5% (±0.7) Silt 52.5% (± 0.7) Sand 32.0% (± 1.4) Silt 41% Clay 7% Sand 52% (Silt) Loam - 30% Organic Matter Loam 30% Organic Matter 24

25 Conclusions: Failure of the old infiltration trench was caused by sediment (mostly silt) buildup in multiple locations. Infiltration trench retrofit reduced runoff volume effectively with no decrease in recession rates observed to date. Pretreatment filter provided 78% TSS reduction and 33% TDS reduction. Future Work: Continue to monitor infiltration trench w.r.t water quantity and water quality. Quantify the size of solids retained/removed by Jellyfish prefilter using the LISST Portable XR (a portable laser diffraction particle size analyzer by Sequoia Scientific, Inc.) 25

26 Acknowledgments PA Department of Environmental Protection Growing Greener program Villanova Urban Stormwater Partnership (VUSP) William Penn Foundation Villanova Facilites Contech (Jim Lenhart and John Pedrick)

27 Question? John Komlos Villanova University

28 Construction of IT Retrofit