Glenoaks Bioswales and Dry Well City Right of way Project On-Site Stormwater Diversion Project


The Glenoaks Bioswales & Dry Well Project was the most cost effective project funded by Prop O. The flooding occurs on Glenoaks, the bioswales and dry wells are located on Glenoaks and divert the stormwater directly into the ground for groundwater recharge. Dry Wells and NOT containers or cisterns, the chambers are open at the bottom to allow the stormwater to flow freely into the ground, and have open capacity depending upon soil type. Much of the soil in the San Fernando Valley is sandy in texture and the water flows through the soil quickly and deeply.

The City is currently building a Source Point Water Capture system at a 3500 ft. long median on Woodman Avenue with a State Grant, and lesser LADWP funding. These projects compared to other construction are resulting in less expense for greater water capture.

Download a PDF of our presentation of LABT’s work on Pro O

What are Dry Wells?

Dry well systems recharge the groundwater, which is what we desperately need to accomplish. The City has historically used single chamber dry wells that eventually become filled with sediment and debris, and are rendered useless. The Glenoaks Project is the first City Right of Way construction of the Double Chamber dry well system. The first chamber essentially screens the sediments and the stormwater flows into the second chamber for percolation into the ground. The first chamber can be cleaned, which is recommended on a five year basis. Torrent Resources is the Arizona based contractor who built our system.

Glenoaks Quick Facts

Funded by: Prop O Grant Funds, $500,000
Location: On Glenoaks Blvd. north of Sunland Blvd., CD #6
City Partners: BOE, Prop O Division; BOS, Watershed Protection; Public Works
Site Conditions: Approximate 280 acre feet of stormwater flows from neighboring watershed to 4 block area of Glenoaks Blvd., southern border of Sunland Blvd.
Estimated Stormwater Capture: Over 30 acre feet of stormwater annually
The most “cost effective” of all Prop O Projects (Dollars per acre feet of stormwater diverted into groundwater), quoting Mark Gold of Prop O Committee.
Stormwater Capture: Based on water capture capacity of each Dry Well, site soil percolation rate and saturation point, it is estimated that each Dry Well will take in 1.1 acre feet of stormwater multiplied by 26 rain events annually, or 28.6 acre feet of stormwater capture. The Bioswales calculation is not finalized, but is estimated to easily capture over an additional 4 acre feet of stormwater.

Project Scope Constructed By LABT
Six bioswales in City Right of Way, the first with the City’s new standard plans installation of four new double chamber Dry Wells, by Torrent Resources Sidewalk removals, soil removals from dry well installations, street piping, building of catch basins, and street and sidewalk restoration and improvements Parkway planter box with stormwater capture piping and drainage areas 14 hazardous trees removed, replaced with fourteen 36” box trees.

Entry Level Landscape Construction Job Training
Provided job training for eight young adults

Media Gallery

1 concrete cutting for drywells 2ft bs perc of sw note water mark 2ft bs sw cap 4ft bs percolation of sw 5ft bioswale excava depth bioswale excava bioswale excavation bottom liner is permeable cloth bs interior wall framing cactch basin and warped gutter 2 catch basin and warped gutter install catch basin concrete pour catch basin install 2 catchh basin completed 2ft bs completed 4ft bs completed bs completed curbs w coring caps completed warped gutter and catch basin concrete demolition for bioswales concrete demolition concrete finishing concrete liner install 2 concrete liner install 3 concrete liner install concrete liner installation 4 concrete pouring concrete removal drainage drywell drilling 2 drywell drilling 3 drywell drilling drywell inlet from catch basin drywell system flooding flooding2 framed bs walls and curbing gravel install inlet concrete coring 2ft bs inlet concrete coring 4ft bs interior of drywell LABT Catch Basin Install non-permeabale liner install Picture1 piping from catch basin to drywell on dora street restoringsidewalks slurry install for street restoration slurry install soil and plant install stormwater capture in action stormwater measurement meter street sdwlk restoration for drywells strt sdwlk rest for dw sw cap in ac swlk concrete finishing tree planting