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Memorandum HELIX Environmental Planning, Inc. 7578 El Cajon Boulevard Suite 200 La Mesa, CA 91942 KatieB@helixepi.com 619.462.1515 tel 619.462.0552 fax www.helixepi.com

Date: March 29, 2016

To: Catherine Rom, City of San Diego

Cc: Shelby Howard, HELIX Environmental Planning, Inc.

From: Summer Schlageter, Biologist HELIX Environmental Planning, Inc. Bruce McIntyre, Principal Planner HELIX Environmental Planning, Inc.

Subject: Post-maintenance Report for the Nestor Creek Channel Emergency Maintenance Project – Map 134

HELIX Proj. No.: SDD-24.25

Message:

This memo documents the pre- and post-maintenance conditions associated with emergency maintenance in an earthen bottom, riprap-lined channel located at 1760 Palm Avenue, San Diego (See Figures 1 and 2). The information on the biological resources affected by the emergency maintenance area is based on a pre-maintenance survey conducted by Dudek on November 13, 2015, and a post-maintenance inspection conducted by HELIX Environmental Planning (HELIX), immediately following completion of the maintenance on February 6, 2016. The information is also based on the results of monitoring conducted by HELIX during the maintenance activities.

PRE-MAINTENANCE CONDITIONS

The vegetation communities which existed prior to maintenance are depicted in Figure 3. Photographs contained in Attachment A illustrate the pre-maintenance area. The channel was unvegetated, and had accumulated trash, debris, sediment, and loose vegetation.

Vegetation communities adjacent to and along the channel were disturbed lands, disturbed Arundo-dominated wetland, and disturbed freshwater marsh.

No sensitive plant or animal species were observed or detected during the pre-maintenance survey.

MAINTENANCE DESCRIPTION

The maintenance occurred on February 5 and 6, 2016. The maintenance involved excavation of sediment, debris, and vegetation from an earthen riprap channel segment. The maintenance took place along approximately 65 linear feet of channel with a bottom width of 15 to 22 feet and a top width of 28 feet.

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Memorandum (cont.) HELIX Environmental Planning, Inc. 7578 El Cajon Boulevard Suite 200 La Mesa, CA 91942 619.462.1515 tel 619.462.0552 fax www.helixepi.com

Maintenance on February 4 involved preparing the site including installing a pump and hose upstream behind a sand bag berm approximately 3 feet high and 2.5 feet deep placed across the bottom of the channel upstream of the work area. Water from the concrete channel upstream was diverted downstream of the work limits. An excavator was the primary piece of equipment used in the maintenance. Crews used the excavator to remove vegetation and silt build up from within the channel and deposit it into a haul truck for removal from the site. The Urban Corps of San Diego County were also on site raking trash and removing vegetation from the channel with hand-held tools. Maintenance activities on February 5 involved continual removal of vegetation and debris adjacent to the channel using an excavator. The debris was then loaded into a haul truck for removal from the site. The Urban Corps of San Diego County were on site removing trash and raking vegetation from within the channel using hand-held tools. The project impacted 0.02 acre (65 linear feet) of wetland waters of the U.S. (disturbed freshwater marsh) within the earthen-lined section of Nestor Creek through the removal of accumulated sediment and vegetation. The project also temporarily impacted 0.002 acre of non-wetland waters of the U.S. of Nestor Creek by the sandbag berm. An estimated 62 cubic yards of sediment and vegetation were removed during the maintenance. All equipment and material were removed upon completion of the work. MAINTENANCE MONITORING

HELIX biologists were present throughout the maintenance activity. Monitoring was conducted by HELIX biologist Talaya Rachels, on February 5, and by HELIX biologist, Laura Moreton, on February 6, 2016. Total impacts to jurisdictional areas were 0.02 acre of wetlands waters of the U.S. (disturbed freshwater marsh). Throughout the maintenance, the biological monitors confirmed that the maintenance was confined to the pre-determined area, and that appropriate Best Management Practices were implemented to protect against excessive erosion and impact to adjacent areas.

POST-MAINTENANCE CONDITIONS

Upon completion of the maintenance, the maintained area was devoid of vegetation, as illustrated in the photographs contained in Attachment B.

If you have any questions or comments on this memo, please contact me or Shelby Howard.

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FIGURE 1

Regional MapNestor Creek Channel (MMP Map 134) - Emergency Channel Maintenance

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Vicinity MapNestor Creek Channel (MMP Map 134) - Emergency Channel Maintenance

SOURCE: USGS 7.5-Minute Series - Imperial Beach Quadrangle.

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FIGURE 2

Figure 3 (MMP Map 134)

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Biological Resources and ImpactsNestor Creek Channel (MMP Map 134) - Emergency Channel Maintenance

SOURCE: SANDAG Imagery 2015; Helix 2015; City of San Diego 2015; California Coastal Commission, 2012.

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Channel Survey Area

Coastal ZonesCoastal Commission Appealable AreaCoastal Commission Permit JurisdictionCoastal Zone BoundaryDefferred Certification AreaNon Appealable Area 1Non Appealable Area 2

ImpactsChannel Maintenance Impact AreaAccess/Staging Area

Jurisdictional DelineationACOE/RWQCB/CDFWCDFW OnlyVegetation CommunitiesDEV, DevelopedDL, Disturbed LandsDW_ARU, Disturbed Wetland (Arundo-dominated)

FWM_CC, Fresh Water Marsh (Concrete-Lined)

OW_CC, Open Water (Concrete-Lined)dFWM, Disturbed Fresh Water Marsh

MMP Map 134; Figure 3

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Channel Survey Area

ATTACHMENT A

Nestor Creek Channel Emergency Channel Maintenance, MMP Map 134

Photograph Log

Photograph 1: Looking downstream (west) from the center of the concrete lined section of the channel toward the west end of MMP Map 134; Figure 3.

(November 13, 2015; 10:14am)

Photograph 2: Looking south within the north end of the Access/Staging area in MMP Map 134; Figure 3 .

(November 13, 2015; 10:29am)

Photograph 3: Looking south towards the earthen channel impact area and adjacent properties from the staging area in the northwest end of MMP Map 134; Figure 3.

(November 13, 2015)

Photograph 3: Looking northeast at the properties adjacent to the proposed emergency impact area (see Arundo on right side of photo) at the northwest end of MMP Map 134; Figure 3.

(November 13, 2015)

Photograph 4: Looking upstream from the northern end of the Access/Staging area towards disturbed freshwater marsh and adjacent properties in MMP Map 134; Figure 3.

(November 13, 2015; 10:21am)

G\PROJECTS\S\SDD-ALL\SDD-24_Stormwater\25_As-needed O&M_Emergency Support\Nestor Map 134\Photos During and Post-construction Photograph Log

NESTOR CREEK CHANNEL EMERGENCY MAINTENANCE, MMP MAP 134

Attachment B

Excavator clearing channel (facing north).February 5, 2016

Excavator clearing channel (facing south).February 5, 2016

G\PROJECTS\S\SDD-ALL\SDD-24_Stormwater\25_As-needed O&M_Emergency Support\Nestor Map 134\Photos During and Post-construction Photograph Log

NESTOR CREEK CHANNEL EMERGENCY MAINTENANCE, MMP MAP 134

Attachment B

Bypass pump hung above channel.February 5, 2016

Cleared channel (facing north).February 5, 2016

G\PROJECTS\S\SDD-ALL\SDD-24_Stormwater\25_As-needed O&M_Emergency Support\Nestor Map 134\Photos During and Post-construction Photograph Log

NESTOR CREEK CHANNEL EMERGENCY MAINTENANCE, MMP MAP 134

Attachment B

Removal of trash and vegetation from within the channel using hand-held tools.February 6, 2016

Debris loading into dump truck for removal from site.February 6, 2016

G\PROJECTS\S\SDD-ALL\SDD-24_Stormwater\25_As-needed O&M_Emergency Support\Nestor Map 134\Photos During and Post-construction Photograph Log

NESTOR CREEK CHANNEL EMERGENCY MAINTENANCE, MMP MAP 134

Attachment B

Cleared downstream portion of channel.February 6, 2016

Cleared channel (facing south).February 6, 2016