jm ca lunch n learn pdh pres feb15afisher/post/drywell/torrent/... · pressure and infiltration...

4/1/2015

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www.torrentresources.com 1


Presenter

Jim Mayer, M. ASCE• Civil Engineering/Development/Construction since 1996

– City Engineering

– Consultant/PM

– Developer/PM

– Design/Build Contractor/PM

– Technical Marketing Engineer

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Continuing Education (PDH Credits)

THIS PRESENTATION QUALIFIES FOR PROFESSIONAL DEVELOPMENT HOURS


Questions?

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Torrent Resources Profile

• Employee owned

• Started in 1972 as McGuckin Drilling

• General Engineering Contractor with offices in Phoenix, AZ

and Ontario, CA

• Licensed in AZ, CA, NM, NV, OR, and WA

• Specialize in the design, fabrication, and installation of

engineered drywells for deep stormwater infiltration

• Installed more than 75,000 drywells in six western states

• Revolutionized the drywell industry with the MaxWell®


Definition of Drywell

• Basic Drywell

– Hole in the ground filled with rocks to receive untreated stormwater runoff

– Cannot maintain or clean

– Used since the Roman Empire

• Engineered Drywell (MaxWell ®)

– A engineered device that pre-treats stormwater prior to infiltration

– Easy to clean and maintain

– Around since the 1970’s

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Evolution of Stormwater Management

• Stormwater Management Theory has Changed:

– Let it flow off site (throw it away)

– Creates many problems

– Decentralized approach (LID)

• Capture it

• Treat it

• Infiltrate it


Typical Stormwater Hydrographs

Additional runoff due to impervious

• The Impact of Development

VOLUMEINFILTRATED

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• Example of the Impact of Development

– Decrease in infiltration ±35%

– Increase in runoff ± 45%

Hydromodification


Stormwater Management

• Detention/Retention

– Manage stormwater

• Regionally

• Locally

– Water Quality Volume

• Capture, treat, infiltrate first ¾”

– Dispose of stormwater in X hours

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Stormwater Detention/Retention

YOU’VE PROVIDED

DETENTION/RETENTION.

NOW WHAT?


Stormwater Disposal

• Shallow Infiltration

• Deep Infiltration

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Stormwater Disposal

• Shallow Infiltration

– Typically <10’ below finished grade

– Stormwater released here will typically not reach permeable soils

– Very large footprint

– Susceptible to sediment loads/easily impacted

– Become “tanks” without regular maintenance

– Add drywells to failed systems


• Manmade Shallow Infiltration

Stormwater Disposal

Susceptible to sediment loading Easily impacted Cannot be maintained

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Stormwater Disposal

• Natural Shallow Infiltration

– “Bioswale”

– Rain garden

– Infiltration trench

Susceptible to sediment loading Easily impacted Cannot be maintained


Stormwater Disposal

• Deep Infiltration is Best

– Deeper soils typically equate to higher infiltration rates

– Average depth to permeable soils is 45’- 65’

– Provides temporary volume storage

– Taller water column increases pressure and infiltration rate

• 1’ of depth ≈ 0.43 PSI

– 69’ of depth ≈ 30 PSI pressing down

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• California’s drought has been getting progressively worse

• Stormwater infiltration can replenish our aquifers

• More drinking water available in times of drought

Why Infiltrate?

DROUGHT


Why Infiltrate?

• Subsidence is a direct result

of groundwater withdrawal

• Infiltration can help prevent

future subsidence

SUBSIDENCE

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Drywells Defined

• Basic Drywell

– Hole/chamber filled with rock

– Low tech

– Easily impacted

– Not maintainable


Drywells Defined

• Engineered Drywell

– Pre-treatment device

– Engineered design

– Site specific

– Installed by experienced

professionals

– Technique is as important

as the components

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Class V Underground Injection Control (UIC) Well

• Authorized by rule (40 CFR 144)

– No EPA permit necessary

• Must not endanger aquifer

• Must be registered for inventory purposes

• Must be constructed, operated, and closed properly

– States have primacy (ADEQ)


MaxWell ® IV

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• Single chambered design

– Settling chamber for TSS removal

– Mesh filter

– Shielded inlet

– Capture of floating hydrocarbons

– Gravel pack is protected

– Can drill depths up to 120’ to reach

permeable soils

– Number of drywells based on perc

rate and mitigated volume

MaxWell ® IV


MaxWell ® Plus

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MaxWell ® Plus

• Dual chambered design

– Flow between chambers is restricted

– Increased residence time = more

effective settling

– Extends the service life of secondary

chamber – insurance policy

– Stormwater gets treated twice prior to

infiltration

– Number of drywells based on perc rate

and mitigated volume


• Reliable/maintainable mechanism for

stormwater infiltration

• Average infiltration rate (0.5 CFS)

• Putting it in perspective

– >13,400 GPH infiltration rate

– >646,000 gals in 48 hours

Meeting the Infiltration Deadline

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• Unsightly • Stagnant water = foul odor• Can endanger health

– Breeding ground for mosquitoes• West Nile Virus• Encephalitis• Dengue (den-gee)

• Dispose of stormwater quickly

Standing Water


Advantages of Engineered Drywells

• Effective pre-treatment

• Help meet design requirements

• Easy to maintain

• Long service life

• Easy and fast to construct

• Small footprint

• Easy to retrofit

• Simple to add to other systems

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Hydrocarbon & Organic Capture

• Absorbent pad floats on surface

• Provide complete control and

capture of hydrocarbons

• Polymer beads capture up to

27X original volume



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Envibro® System

• Unparalleled Protection

– Used where fuel is stored/dispensed

– Beads swell and cut off flow

– Automatic operation

– Provides large capture volume

– Prevents subsurface contamination

– Maximum flow rate of 0.178 cfs


Bead Pack Preparation

Each Envibro System

bead pack is assembled

at Torrent Resorces

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Design Assistance

• Torrent will assist with design

• Get us involved early in the design process


Design Assistance

• What Torrent Offers

– Design “partners”

– Help meet design requirements

– 40+ years of drilling experience and data

– Creative solutions

– Customizable drop-in details

– Collaborate

• Direct phone• Direct e-mail • www.designmydrywell.com• [email protected]

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Design Assistance

• www.designmydrywell.com

– Complete form and e-mail is sent


Design Assistance

• Our database is huge

– Drilling data

– Perc rate data

• Well known/respected throughout

construction community

• Work with soils engineers in

uncharted territory

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Other Benefits

LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN

– USGBC offers two Sustainable Site Credits

• Credit 6.1: Stormwater Design – Quantity Control

– maintain pre-development rate and volume for 1-yr, 24-hr and 2-yr, 24-hr storms

• Credit 6.2: Stormwater Design – Quality Control

– treat 90% of average annual rainfall and 80% removal of TSS load


Installation

DRILLING AND CONSTRUCTINGA DRYWELL

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Installation

• All Work is Self Performed

– All aspects of work completed by Torrent

– All equipment is owned and maintained by Torrent

– Quality assurance and pride in construction (ESOP)

– Torrent is a one stop shop focused on customer’s needs


Installation

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Installation

VideoVideo


Installation

• 4’ diameter lower shaft for well construction and gravel pack

• 6’ diameter upper shaft for precast concrete liner construction

• Drill to 120’ to reach permeable soils

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Installation

• Safety First


Installation

• Geotextile fabric prevents the migration of fines into boreholes

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Installation

• Building a drywell


Installation

• Completing the gravel pack

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Installation

• Lowest piece of concrete liner is perforated


Installation

• Setting the cone sections to final grade

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Installation

• Installation of crossover pipe


Installation

• Completion of crossover pipe

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Installation

• Backfill with 2 sack slurry to grade

– Locks components in place

– Prevents subsidence


Installation

• Protect the drywell from sediment and debris during remaining site work

• Remove when all site work is complete

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Installation

• Tying into UG Storage

– Large detention system

feeding into MaxWell ® Plus


Installation

• Completed MaxWell® IV in residential area

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Installation

• Completed MaxWell® Plus in residential area


Installation

• Completed MaxWell® IV in a residential area

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Installation

• Completed MaxWell® Plus in commercial area


Installation

• Glen Oaks Project - MaxWell® Plus in Los Angeles, CA

• Built in right of way

• Alleviate flooding

• Meter to track stormwater recharge

http://hbteam.org/featured-projects/trees-as-bio-swales/

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Installation

• Downtown Los Angeles


Installation

• MaxWell® Plus in Ontario, CA

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Installation

• Constructing a MaxWell® Plus at LAX

• Installed with a renovation project

• No nearby storm drain

• Constructed in 3 days

• Tiny footprint


California Installations

• LA County Natural History Museum

• City of Anaheim Utilities Service Center

• Fullerton City Yard

• Santa Barbara Bowl

• Alhambra Mixed Use Project

• Anaheim Regional Trans Intermodal Center

• Palisades Garden Walk

• Harbor UCLA Medical Center

• Arcadia Methodist Tower

• Pomona College, Claremont

• UCLA Film Archive Project

• Santa Monica Infiltration Project

• Town of Apply Valley Street Improvements

• 1000 Grand

• Olympic & Olive

• Birch Hills Golf Course

• Olympic & Broadway

• Oak Valley Retail Center, Beaumont

• Columbia Elementary School, El Monte

• North Fontana Park

• Church of the Nazarene, Hemet

• La Quinta Fire Station #32

• Crenshaw Plaza, Baldwin Hills

• UCLA Graduate Student Housing, Westwood

• Freeway Commerce Center, Mira Loma

• Citizens Business Bank Arena, Ontario

• Toberman Village, San Pedro

• Covina Citrus Condominiums, Covina

• Victorville City Hall

• Coastal Walk Condos, Huntington Beach, CA

• UCSD Parking Garage

• LAX Terminal 1 Modernization

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• Arizona: Retention and infiltration is mandatory

• California: Use LID and infiltration unless hardship

• Oregon: Drywells are widely used

• Washington: Drywells are widely used

• Montana: Drywells are slowly being introduced

• Utah: Drywells are increasing in popularity

• Existing drywell programs: NJ, CT, PA, NC, IN

• Biggest trend: Changed the way we view stormwater. Treat like a valuable resource…stop “throwing it away”.

Infiltration Approvals & Trends


Southern California Projects

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Metro Phoenix Projects


Maintenance

System Maintenance is

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Maintenance

• Regular maintenance will allow for a long service life

• Torrent can maintain all types of drainage features

• Inspect after first year


Maintenance

Clean the drywell when 15% of the original chamber volume is

filled with silt and debris

www.cleanmydrywell.com

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Retrofit Old Drywells

What to do when an old drywell stops working?


Retrofit Old Drywells

• Utilizing a failed Drywell

– Re-drilling a failed drywell is normally not an option

– Surrounding soils are usually impacted and cannot be remediated

– Better to move over 25’ and drill a new drywell

– Convert the impacted well into the primary settling chamber creating a MaxWell ® Plus System

– This is known as a “tie-in”Secondary

Primary

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• Drywells have been studied for decades

– MAG & EPA – Phoenix, AZ

– Tucson Water Study – Tucson, AZ

– USGS Report 93-4140 – Fresno, CA

– HydroSystems Study – Chandler, AZ

– Bouwer Study – Phoenix, AZ

– Graf ADEQ – Phoenix, AZ

– Elk Grove – City of Elk Grove, CA

– Water Augmentation Study – Los Angeles, CA

Drywell Studies


MAG / EPA Study

DRYWELL STUDY

Conducted by:

Funded by:

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MAG / EPA Study

• 5-Acre commercial

development originally

served by 5 drywells

• Monitoring wells

installed to evaluate

the quality of treated

stormwater


MAG / EPA Study

• MAG / EPA Determination

– “Overall, there is no indication that storm runoff has degraded

groundwater quality at the site.”

– “…overall, the use of drywells for disposal of storm runoff from

commercial areas does not pose a substantial threat to the quality

of groundwater in the Phoenix urban area”

– Study confirms soil as an effective filtration medium

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• HydroSystems, Inc. Study

(Independent Third – Party Drywell Monitoring Study)

– Chandler Arizona

– Commercial Setting

– Performed by HydroSystems, Inc of Phoenix Arizona

HydroSystems Study


HydroSystems Study

• Project Particulars

– 24.3 total acres

– 19.7 improved acres

– 4.6 landscaped acres

– 100% of stormwater runoff

retained on site

– Entire site drains to central basin

containing a single MaxWell ®

Plus System

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HydroSystems Study

• Study Description

– 7/28/2010 – 2/27/2011

– 17 recorded events

– 7.47” total rainfall

– A 92% average TSS removal

– 3,800,000 gallons recharged

– Positive results


HydroSystems Study

• Conclusions

– “…quality of the stormwater that was processed through the MaxWell™ Plus Drainage System positively exceeded expectations.”

– “…supports the use of the MaxWell™ Plus Drainage System for the efficient treatment and recharge of stormwater runoff in commercial areas.”

– “…does not pose a significant threat to the quality of underlying groundwater.”

– “…significant portion of stormwater runoff to be recharged into the subsurface instead of being routed to…”

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Water Augmentation Study

LOS ANGELES BASIN

WATER AUGMENTATION STUDY

PHASE II FINAL REPORT SUMMARY

THE LOS ANGELES AND

SAN GABRIEL RIVERS WATERSHED COUNCIL

2000 – 2007

http://www.usbr.gov/lc/socal/reports/LASGwtraugmentation/report.pdf



• Reason for Study

– Is it safe/effective to infiltrate urban stormwater into aquifer?

• Estimated 500,000 AF stormwater available annually

• Stormwater BMPs varied

• Land use at test sites varied

• 7 year study period

• Results positive

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• Study Conclusions

– “…no evidence of groundwater quality degradation from the infiltration of stormwater.”

– “…suggested that groundwater quality at the six monitored sites was stable or improved for most constituents.”

– “…no apparent trends to indicate that over the long-term, stormwater infiltration will negatively impact groundwater.”

– “…implement decentralized stormwater management practices to advance infiltration in existing and new developments.”

– “Soil appears to be very effective in removing TSS and bacteria from stormwater.”



Elk Grove Drywell Study

• Drywell specific study

• Study began Fall 2014

• 2-year study

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Deep Infiltration is Proven

• Deep Infiltration Performs

– Engineered drywells are an excellent choice as either…

• Stand-alone BMP (volume or flow based)

• Compliment to other stormwater treatment trains

– Engineered drywells are effective at pre-treatment…

• Increased TSS removal with longer residence times

• Floating hydrocarbons removed with absorbent media

• Metals removed along with TSS


The Proof is in the Testing

• Constant head percolation testing

– Perc test wells after construction

– Saturate well and stabilize flow rate

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• Constant head percolation testing

– Flow in = Flow out

– Provides “real world” perc rate

– May reduce the number of drywells designed

– Cost savings



• Distribution Center

– Design

• 425,000 cubic feet total

• 5 basins

• 35 drywells per design

– Installation/Testing

• Install 10 drywells and perc

• Very permeable

• Added only 2 drywells

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• Torrent Delivers

– Torrent Resources has been designing, drilling, and installing stormwater drywells since 1972

– Engineered drywells have been proven effective at pre-treating and infiltrating stormwater

– Installed >75,000 MaxWell drywells throughout six states in the greater Southwest; 99% of which are still in operation

– Torrent Resources maintains an extensive database, which helps with design and estimating

– Run camera down every 100th drywell as QC measure

– 5-year warranty on parts and workmanship

The Proof is in Our History


Conclusions

• Stop throwing stormwater away

• LID is here to stay

– Capture

– Treat

– Infiltrate

• Deep infiltration is best

– Drywells

• Cost less

• Work better

• Last longer

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Question and Answer


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Olympic & Olive Installation


Olympic & Olive Installation

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LAX Installations

• A – 8100 Westchester Blvd

• B – LAX Cup Project SUSMP

• C – American Airlines SUSMP

• D – Southwest Terminal 1 Rehab


Why Infiltrate?

• Surface water represents only 1% of the water on earth

• Only 0.3% of that is readily available

• Infiltrate and use aquifer as storage

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Municipal Recharge Well

• Designed to continuously recharge

treated water into the vadose zone

• Recharge up to 1,000 AF annually

per well (325 million gallons/year)

jm ca lunch n learn pdh pres feb15afisher/post/drywell/torrent/... · pressure and infiltration...

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