City of Palmdale using drywells as water quality BMP
Historically, drywells have been used in many different ways to manage stormwater. For instance, a drywell can be used to drain away stormwater that collects in a basin or tank within a specified time period, such as 36, 48, or 96 hours. Drywells can also be used in line, in a dynamic way, to manage flows generated by a particular design storm. However, the City of Palmdale has been using drywells as a water quality BMP.
The latest example of this can be seen at Yellen Park on the South side of Avenue S near Hillcrest Avenue in Palmdale. The scope of work includes a new parking lot, landscaping, sidewalks, storm drains, and a reconfigured detention basin designed to hold over 32 acre-feet of stormwater.
The grades in the parking lot were designed to convey stormwater to the south to a curb inlet, which is connected to a new storm drain that outlets into the 15’ deep detention basin. While these are all typical design techniques, what makes this design unique is the catch basin, located in the gutter before the curb inlet, that is connected to a MaxWell Plus. In this configuration, the drywell provides a maintainable mechanism to treat the low flows, dry weather flows, and the “first flush” first flush of all storms, which tends to include the heaviest concentrations of oil, grease, sediment, and debris.
“The MaxWell® Plus Drainage System is a dual-chambered infiltration BMP that pre-treats stormwater twice for constituent removal prior to infiltration. The product offers field-proven efficiency, and has become the standard of quality utilized by numerous municipalities in California and Arizona and the overwhelming choice of specifying civil engineers in the private sector. This popular model, as seen in the Yellen Park project, is best used in large paved areas when connected with underground storage tanks or where there is an abundance of silt, sediment and debris runoff.”
DRYWELLS WILL IMPROVE YOUR PROJECT’S CAPACITY FOR AQUIFER RECHARGE.
TO LEARN HOW, CONTACT US TODAY.