Potrero Canyon — Landscaping (Weeding, Brush Clearance, Irrigation) Updates


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5/21/24:  A toxic herbicide, “Cheetah Pro,” was broadly sprayed over large portions of the Park, destroying native plants and greenspace and harming the Park’s biodiversity.  PPCC has submitted a letter expressing serious concerns and requesting that another, less toxic compound be used in the Park and that the use of Cheetah Pro be halted until we learn more about its permissive use. See Letter re Herbicide Use at Potrero Canyon.

5/1/24:  The conditions described below (cracks and fissures in trails; overgrown brush blocking trails) have been remedied.

4/9/24:  Large cracks and fissures have reappeared during the past few months in the Friends St. trail and other Park trails. Overgrown brush is also blocking trails.  These conditions have arisen following storms in the past several months.  RAP Maintenance Supervisor Robert Buenrostro advises that he has observed the conditions and has asked staff to work on the ruts and cracks throughout.  He has also reached out to Kristin Ly of BOE, who states that she will have the landscaping contractor trim back the overgrown brush.

10/23/23:  BOE and CD11 have further investigated the standing water conditions described below.  BOE has now installed additional measures to mitigate the flow of water from a concentrated area, including an additional new drainage pipe to disperse the water more evenly and more plantings to absorb the water.  BOE will monitor the conditions in the coming weeks and months to determine if further measures are needed.

8/11/23:  BOE reports that (1) it has now planted additional native plants which are absorbing some of the water flowing from the pipe above the main service road (described below); (2) the pool of standing water is now significantly drier; (3) BOE will continue to investigate options to mitigate the water drainage.

8/4/23:  The source of the standing water on the main road, as referenced in posts below (7/1, 7/7, 7/20), remains unidentified.  BOE explains that the pipe projecting from the slope (from which water is flowing) may be a subdrain, previously installed during earlier grading projects in the canyon in order to channel any subgrade water.  BOE will place additional plants in the slope area to absorb some of the water, while it considers other options to mitigate minor water drainage.  Vector Control is expected to be contacted quarterly to monitor standing water in the Park.

8/4/23:  The water on the main road referenced in posts below (7/26, 7/30) has receded.  We are advised that this condition is intermittent, resulting from run-off from the required watering of plants on the slopes above the road.  Watering for longer periods of time is needed to preserve the plants due to the highly compacted soil.  The run-off typically recedes after a day.  It is expected that watering in this area will be reduced or eliminated depending on rainfall.  BOE and the landscape contractor have examined sprinklers in some Park areas and will replace any broken sprinkler heads that are identified.

7/30/23:  Water continues to flow onto the main service road from an unidentified source, resulting in another pool of standing water at a different location on the main road, below the Friends St. trail.  RAP and/or BOE have been asked to investigate, to fix the problem, and, if needed, to request assessment and treatment of the standing water by Vector Control.

7/26/23:  Park project manager Kristen Ly advises that BOE’s landscape contractor has been notified and is investigating reports of ongoing water flowing and sprinklers working needlessly.  She explains that some water can be expected in the riparian area running through the Park, as BOE is undergoing testing of the pump station.

7/20/23:  Vector Control Executive Director Aaron Arugay advises that he and his team recently inspected the water on the main service road (described below) and treated several areas where the water is standing. They suggest periodic monitoring.  A leak with an unidentified source persists.

7/12/23:  Brush clearance on the canyon slopes is now complete.  Weeding in other areas by the BOE contractor is ongoing.

7/7/23:  Brush clearance by the RAP contractor is ongoing, with several canyon slope areas cleared substantially to date.

7/7/23:   After community outreach due to observation of water on the Park’s main service road (described below), LA County Vector Control Executive Director, Aaron Arugay, advised that he and his team are familiar with Potrero Canyon and have inspected other areas in the Park on several occasions in the recent past.  He will have Vector Control staff examine the site and treat the area, if needed, sometime next week.

Regarding the source of the water, BOE had ruled out any problem on City/RAP property or on one of the Alma Real residential properties above the rim, but Kristen Ly (Park project manager) has been attempting to reach out to an adjacent rim property owner to ascertain whether the source may be coming from that property; we don’t know the status of those efforts to date.  We will continue to monitor.

7/1/23:  A large pool of water has been present for more than a week on the Park’s main service road beyond the lookout point at the south end of the canyon.  RAP and BOE have been alerted and BOE has investigated the condition and possible sources of the problem.  BOE advises that the water is not due to an irrigation leak on Park property or from over-watering but may be due to conditions on private residential property along the canyon rim.  We have asked BOE to continue to investigate the source and have also requested that RAP alert Vector Control to treat the standing water. We will continue to monitor.

7/1/23:  Some brush clearance has taken place, but large areas along canyon slopes have not yet been cleared and crews have not been observed recently working in the canyon.  Residents continue to report hearing fireworks exploding in the canyon nightly. We have asked for a status update from RAP and have stressed the importance of clearing all brush in time for the July 4th holiday, when we can expect more fireworks and increased wildfire risk.  We will continue to monitor.

6/23/23:  The landscape contractor, Waste Unlimited, has also spent the week clearing encroaching weeds along both sides of the main service road, and along walking paths within the Park.

6/21/23:  RAP Maintenance Supervisor Robert Buenrostro informs us that the brush clearance contract has been awarded to Waste Unlimited, which will commence work this week.

6/20/22:  RAP Maintenance Supervisor Robert Buenrostro advises that in regard to brush clearance on the canyon slopes, RAP has not yet had a bid from a contractor but is continuing to seek bids.  We have notified RAP and CD 11 that brush clearance must occur well in advance of the July 4th holiday, due to fire risk from fireworks (see 6/20/23 entry under Park Signage and Use).

5/18/23:  The contractor is continuing to work on setting up the pump station at the mouth of the canyon.  When completed, recycled water will be pumped through the riparian zone.  Completion is expected this summer.  Until then, BOE will need to continue irrigating some canyon areas in or near the riparian zone, in order to preserve plants.  This may result in temporary pooling of water on nearby trails, which BOE advises cannot be avoided.  The PCOC will monitor and request that Vector Control continues to regularly treat any areas of standing water.

5/18/23:  BOE’s landscape contractor is engaging in daily weeding, focusing primarily on the canyon’s basins.  This is an ongoing project and will take years before invasive weeds can be fully controlled (estimated five-year project).  Meanwhile, weeds such as wild mustard are proliferating and in some cases protruding onto narrow Park trails. Cindy Simon (PPCC Area 6 Representative) has offered to form a group of volunteers to help with the weeding efforts.  We have asked CD 11 to secure permission for this group to begin assisting the contractor and we are hopeful that our volunteers will be permitted to begin helping soon.  In addition, required brush clearance along the canyon slopes has begun and must be continued by a contractor for RAP (to be hired).  We are told that brush clearance is expected to be completed by July 4th.  A primary goal of brush clearance is to ensure that native plant species are preserved to the extent possible.

4/11/23:  The contractor is working on irrigation testing and fixes and is also weeding and clearing brush on an ongoing basis.  We have asked BOE, via project manager Kristen Ly at the recent Community Safety Town Hall, to maintain an ongoing interface with LA County Vector Control and ensure that water which may seem standing is in fact sufficiently moving and not creating an unsafe breeding ground.

3/31/23:  See report of 3/7/23 meeting between PCOC members and LAFD staff, including the Brush Clearance Unit, regarding brush clearance, weeding and related landscaping and safety concerns for the Park:  Brush Clearance Report.

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