Santa Monica Alleys Get a Green Makeover

September 20, 2018 4:00 PM
by Delana Gbenekama

If you live or work in Santa Monica, then you’ve most likely traveled our bustling streets and seen City construction crews working alongside milling and concrete trucks in nearby alleys. This year, as part of the City’s annual Alley Renewal Program, the Street and Fleet Services Division of the Public Works Department is resurfacing 13 alleys in need of major repairs. Crews began repairs in February and will continue renewing these high-priority alleys through December 2018. 

Three of the alleys were reconstructed with gutters crafted from pervious concrete, which will absorb urban runoff (rainwater and nuisance water) from city streets. This helps prevent polluted runoff from draining into the ocean and improve the water quality at our local beaches. It also helps reduce flooding and ponding during storm events. Over time, the water percolating through the pervious concrete gutters will help replenish Santa Monica’s groundwater supply, contributing to the City’s goal of achieving water self-sufficiency.

The table below lists the alleys that are being reconstructed for 2018:

Alleys Slated for Reconstruction in 2018

Status

15th Court (pervious gutter)

1500 block

Complete

11th Court (pervious gutter)

1500 block

Complete

Euclid Court (pervious gutter)

1500 block

Complete

20th Court

1100 block

Complete

22nd Court

1110 block

Complete

Lincoln Court

1500 block

Complete

11th Court

600 block

Complete

11th Court

500 block

Complete

19th Court

900 block

Complete

Stanford Court

800-1037 block

Complete

24th Court

2210-2311 block

Will be complete by end of 2018

Georgina Place North

100-399 block

Will be complete by end of 2018

Lincoln Court

2500 block

Will be complete by end of 2018

The Street and Fleet Services Division works closely with the Civil Engineering Division to install pervious gutters. Based on monitoring data at the storm drain outfalls, Civil Engineering identifies the drainage basins that discharge to locations along the ocean shore where water quality is poor. The Street and Fleet Services Division installs pervious concrete gutters if alleys are being reconstructed within these drainage basins.

Below is a summary of how pervious concrete gutters are installed:

  1. Remove the existing pavement from the alley, and then adjust the alley elevation to allow for proper drainage. Adjust the underground utility boxes so they are positioned at the proper elevation.*
  1. Install the new asphalt pavement and allow it to cure.*
  1. Use a milling machine and backhoe loader to cut and excavate the trench for the gutter. Install rock at the bottom of the trench before placing a filter fabric on top of the rock. The filter fabric prevents fine particles from clogging the void spaces in the rock and subsequently allows unconstrained infiltration of runoff into the underlying soil.
  1. Pour the pervious concrete. Install a plastic liner on top of the concrete to allow the concrete to cure.

*The renewal process for alleys that do not receive pervious concrete gutters is summarized in steps one and two.

The Alley Renewal Program is funded by the City’s Capital Improvement Program budget. The pervious concrete gutters are funded by the Clean Beaches and Ocean Parcel Tax, also known as Measure V, which was passed by Santa Monica voters in 2006 to reduce urban runoff and implement best management practices to improve water quality in the Santa Monica Bay.

Authored By

Delana Gbenekama
Equity and Communications Program Manager