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EMERGENCY LAGOON MOUTH RESTORATION AT

LOS PEÑASQUITOS LAGOON

2015 SUMMARY REPORT

Prepared by: Los Peñasquitos Lagoon Foundation ACOE Permit Number: SPL-‐‑2007-‐‑01134-‐‑RRS Coastal Development Permit No. 6.07.021.A1 401 Water Quality Cert. No. 07C-‐094

February 12, 2016

Summary Report 2015-‐ Restoration of the Ocean Inlet at Los Peñasquitos Lagoon ACOE Permit Number: SPL-‐2007-‐01134-‐RRS Coastal Development Permit No. 6.07.021.A1 401 Water Quality Cert. No. 07C-‐094

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1 EXECUTIVE SUMMARY Los Peñasquitos Lagoon (LPL) is a relatively small coastal salt marsh (510 acres) located in the northern portion of San Diego County and is part of the Torrey Pines State Reserve. LPL receives perennial freshwater flows and storm runoff from a 60,000-‐acre watershed comprised of three sub-‐watersheds: Carmel Valley, Los Peñasquitos Canyon and Carroll Canyon. Listed as a Marsh Preserve within the Torrey Pines State Reserve, LPL is afforded the highest level of protection by the State of California. LPL provides critical habitat to Federally and State Listed Species that include the Light-‐footed Clapper Rail (Rallus Longirostris Levipes), Western Snowy Plover (Charadrius alexandrinus nivosus), Belding’s savannah sparrow (Passerculus sandwichensis beldingi), Nuttall’s Lotus (Lotus nutallianus) and Coulter’s goldfields (Laesthenia glabrata ssp coulteri). LPL also serves as an important refuge for migratory bird species using the Pacific Flyway, while also providing habitat to other marine, terrestrial and avian species native to coastal salt marshes along the Southern California Bight. LPL contains Essential Fish Habitats and is the closest coastal lagoon to the only two Areas of Special Biological Significance (ASBS) located offshore of San Diego County. LPL also serves as a natural system for flood control for surrounding urban areas and provides water quality improvements for the coastal waters.

Large, fast-‐moving waves generated by winter storms in the North Pacific move sand and cobbles into the Lagoon’s inlet area via storm surge, wave activity and high tides. While the initial deposit of sand can be removed by outflows from the lagoon, the cobbles remain. These cobbles form a sill that facilitates future sediment deposition in the lagoon inlet during subsequent winter swells and high tides. Evidence indicates that the LPL’s inlet to the ocean had remained open year round historically. However, land use change, including urban encroachment, during the last two centuries has reduced the lagoon’s ability to flush out sediment after storm events, constrained the lagoon inlet to a fixed location south of its historic location, and introduced perennial freshwater input from the watershed. Though tidal exchange has improved with the construction of the new lower bridge at North Torrey Pines Road (a.k.a. Historic Highway 101), reductions in the LPL’s tidal prism and closures still occur as large volumes of marine sediment are still deposited within the inlet area and lagoon channels.

Decreased tidal prism and extended inlet closures at LPL can impact both aquatic and terrestrial habitats, impact native and migratory species, pose risks to nearshore coastal water quality, impair the Lagoon’s Beneficial Uses, and threaten nearby urban infrastructure vulnerable to flooding. Water quality parameters (e.g. dissolved oxygen and salinity) degrade during extended inlet closures once they are no longer exposed to tidal mixing from ocean waters. Impacts to water quality can occur rapidly during periods of warm temperatures typical of summer months, resulting in fish kills and loss of invertebrate communities. Since 1995 all three of the Lagoon’s three main tributaries became perennial, providing a new type of impact to Lagoon environs during extended closures as impounded water becomes hyposaline. As a result, LPL has experienced rapid habitat conversion as areas of historic salt marsh located in the eastern portion of the Lagoon have been displaced by brackish and freshwater


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habitats. In addition to loss of salt marsh habitats, year round inputs of freshwater from the watershed have also raised serious public health risks due to vector-‐borne disease. LPL is also a known location of mosquito breeding habitat for Culex tarsalis, the species known to transmit West Nile Virus (WNV) in southern California. Documented cases of WNV have occurred in both wild and sentinel avian populations, as well as within human populations located near the Lagoon.

Since 1985, the Los Peñasquitos Lagoon Foundation (LPLF) has performed mechanized lagoon inlet openings. Through adaptive management and stakeholder coordination, LPLF has been successful in maintaining the inlet at LPL while producing multiple benefits in a cost effective manner. The inlet at Los Peñasquitos Lagoon closed on 3/31/15 with subsequent inspections indicating that it would most likely not reopen under natural conditions (See Figure 1-‐1 to Figure 1-‐3). The inlet remained closed until it was breached on April 22nd. Excavation of the main channel and inlet area commenced on 4/23/15 and continued through to 5/1/2015 with no work occurring over the weekend. Water quality (dissolved oxygen) rebounded quickly once tidal circulation was restored. It is estimated that more than 30,000 cubic yards of excavated material (i.e. sand and cobbles) was hauled to Torrey Pines State Beach for disposal south of the inlet.

Figure 1-‐1. View of the closed inlet at Los Peñasquitos Lagoon, looking west toward Torrey Pines State Beach. Photo taken by

M. Hastings on 4/9/15.

Figure 1-‐2. View of the closed inlet at Los Peñasquitos Lagoon looking southeast from the lower bridge that spans the inlet.

Photo taken by M. Hastings on 4/9/15.


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Figure 1-‐3. Panoramic view of the closed inlet at Los Peñasquitos Lagoon. Photo taken by M. Hastings on 4/9/15.

2 PERMIT COMPLIANCE Prior to excavation and disposal activities, LPLF performed monitoring of water quality, sensitive bird species surveys, and grain size analysis of beach spoils pursuant to permit requirements and conditions. Beach disposal of sand was performed outside of grunion spawning dates specified by California Department of Fish and Wildlife.

2.1 Water Quality Water quality data indicated decreasing DO levels within the Lagoon during the extended closure that lasted from March 31st until the inlet was mechanically breached on April 22nd. DO levels quickly dropped below 5 mg/l on April 1st (See Figure 2-‐1), indicating stressful conditions for aquatic species and triggering the project’s special biological conditions set by its Coastal Development Permit (6-‐07-‐021-‐A1) that allow for mechanical excavation of the inlet. DO dropped below 2 mg/l just before April 4th and remained below 5mg/l, for the most part, after April 13th. Once tidal circulation was restored within Lagoon channels, water quality parameters quickly improved (See Figure 2-‐2). Salinity levels also were affected by the extended inlet closure due to perennial inputs of dry weather flows of freshwater from the urbanized watershed, remaining below 26 ppt and often dropping toward 23 ppt (See Figure 2-‐3). Salinity levels rebounded quickly to 30-‐32 ppt after the inlet was breached and even increased to 33 ppt after the main inlet was reconnected to the ocean (See Figure 2-‐4).

Figure 2-‐1. DO and water levels within LPL after inlet closure on 3/31/15. Note the rising water levels due to perennial dry

weather inputs of freshwater from the Lagoon’s tributaries in conjunction with declining DO due to the lack of tidal mixing from ocean waters. Graphic by TRNERR.


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Figure 2-‐2. DO and water levels within LPL after the inlet breach on 4/22/15. Note the quick drop in water surface elevation

followed by the restoration the diurnal tidal signal in conjunction with DO levels that shows restored tidal mixing within Lagoon channels. Graphic by TRNERR.

Figure 2-‐3 View of surface levels (red line) and salinity (yellow line) captured at Monitoring Station W2, located at the railway bridge within the northern channel. Salinity levels decline following the closure on 3/31/15 due to dilution from continuous

freshwater inputs from the watershed and lagoon boundaries. Graphic by TRNERR.

Figure 2-‐4. View of surface levels (red line) and salinity (yellow line) captured at Monitoring Station W2, located at the railway bridge within the northern channel. Once the inlet is breached, surface levels drop and eventually follow the tidal signal of low

and high tides. Salinity rises quickly once tidal circulation is restored, going from brackish to marine with regard to salinity concentrations. Graphic by TRNERR.


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2.2 Resource Agency Notification & Monitoring Results Notification & Submission of Pre-‐ and Post-‐Activity Sampling Forms Agency notification and pre-‐opening and post-‐opening monitoring forms were submitted to the regulatory agencies as a requirement of project permits (See Appendix 1). The San Diego County Department of Environmental Health (DEH), California State Parks (CSP) Lifeguards, and CSP Rangers were contacted to assure that beach advisory signage would be in place and that the necessary water quality sampling and beach safety precautions would be implemented. Sensitive Bird Species Surveys Pre-‐maintenance surveys for sensitive bird species indicated that no listed species were present within the project area or evidence of nesting activity adjacent to the project site. This was most likely influenced by the extended closure that resulted in much of the Lagoon’s mudflats, sand bars, high marsh and transitional areas being inundated for almost a month. Surveys were conducted on April 9th and April 20th. Monitoring for presence of sensitive bird species was also conducted daily during inlet restoration efforts to assure that there would not be “take” or other impacts to sensitive species. Equipment operators were briefed on limits of the work area and areas of sensitive habitats to assure that there would be no impacts to vegetated areas, especially those used for nesting by Belding’s savannah sparrow that occur adjacent to the project site. Grain Size Analysis Grain size analysis was performed prior emergency maintenance efforts to determine suitability for beach disposal of sediment excavated from the inlet area. Composite samples were created from sediment cores taken at four separate locations within the project area on March 17th (See Figure 2-‐5). The composite samples were sent an outside laboratory to determine grain size analysis and sorting using laser particle analysis. Results were provided to Army Corps of Engineers (ACOE) on April 9th with the composition of all four samples ranging from 98.5% -‐ 98.9% sand and gravel (See Appendix 2 for complete results and statistics).


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Figure 2-‐5. Locations of sediment samples taken within the project area and submitted for grain size analysis.

Graphic developed by Coastal Environments.

Turbidity Monitoring Beach disposal of excavated material (i.e. sand and cobbles) is performed to reduce project cost and provide sand nourishment along Torrey Pines State Beach, which experiences a great deal of erosion due to large wave events during winter months. A majority of the material spoiled on the beach is placed along the waterline so that incoming tides can disperse the sand piles. Sand is dispersed horizontally along the nearshore area usually during one complete tidal cycle. During the project, photo and observational monitoring of the disposal area was performed from the coastal bluff near Lifeguard Tower #4 and on the lower bridge at N. Torrey Pines Road to assess potential water quality impacts due to offshore turbidity from an elevated viewpoint. Monitoring results indicate that beach disposal activities did not result in offshore turbidity beyond levels that occurred naturally to both the north and south of the project area due to nearshore currents and rip tides (See Figure 2-‐6 to Figure 2-‐8).

Locations of four sediment samples.


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Figure 2-‐6. Turbidity monitoring during disposal of sand on Torrey Pines State Beach. Photo by M. Hastings 4/29/15.



Grunion Monitoring Disposal of sand on Torrey Pines State Beach occurred outside of scheduled (closed) grunion runs for April 2015. Therefore, monitoring for presence/absence of grunion was not conducted.


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3 SUMMARY OF WORK PERFORMED

3.1 Project Footprint, Equipment Staging Area and Access Points The project’s footprint and work areas are provided in Figure 3-‐1. In general, excavation and stockpiling of spoils occurred between Transect A1 and the deep-‐water mark located between Transect D and Transect E2 in the northern channel. Excavated material (i.e. sand and cobbles) was loaded onto articulated rock trucks and hauled out to Torrey Pines State Beach for disposal with some disposal occurring within the inlet area to restore a remnant dune area.

When not in use, heavy equipment was staged along the coastal bluff adjacent to N. Torrey Pines Road (See Figure 3-‐2 -‐ Figure 3-‐4) as required by project permits with spill prevention tarps and buckets placed under equipment (See Figure 3-‐5). Access to the Lagoon was provided by a sand ramp built at the staging area that allowed equipment to descend to Torrey Pines State Beach and enter LPL fromunder the lower bridge at N. Torrey Pines Road (See Figure 3-‐6 and Figure 3-‐7).

Figure 3-‐1. Project Footprint. Jones & Stokes 2007.


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Figure 3-‐2. Equipment Staging Area and Access to Project Area. Google Earth 2010.

Figure 3-‐3. Equipment Staging Area Project Area, viewing north along N. Torrey Pines Road. Photo by M. Hastings 4/22/15.


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Figure 3-‐4. Equipment Staging Area Project Area, viewing south along N. Torrey Pines Road. Photo by M. Hastings 4/22/15.

Figure 3-‐5. Equipment staging area with spill prevention tarps and bucket. Photo by M. Hastings 4/23/15.

Figure 3-‐6. Access ramp used by heavy equipment to enter and exit staging area along N. Torrey Pines Road. Photo by M.

Hastings 4/22/15.


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Figure 3-‐7. Equipment getting ready to enter LPL under the lower bridge along N. Torrey Pines Road. Photo by M. Hastings

4/22/15.

3.2 Excavating the Inlet Please refer to Figure 3-‐1 with regard to locations of transects referenced in this sub-‐section. Work began on 4/22/15 and consisted of cutting a channel from Transect A1 to Transect A2 to provide a conduit for lagoon outflows once the inlet was breached and breaching of the inlet at 9:38 am. Equipment worked along Transect A2 until lagoon waters drained and two excavators proceeded to the deep-‐water mark located near Transect E2 and began to excavate the main channel. Excavation in this area of the Lagoon continued through to 4/24/15 with spoils stockpiled for loading and hauling activities that would commence on 4/27/15. Excavation of the inlet area continued on 4/27/15 through to 5/1/15 with heavy equipment working from Transect E2 and Transect D towards Transect A1 depending on water levels within the inlet due to tides. Efforts from 4/27/15 -‐ 5/1/15 included loading, hauling and disposal of excavated spoils and are briefly summarized below.

Day 1 -‐ April 22nd Two PC-‐400 excavators and a wheeled front loader were brought to the project site on April 21st and staged near the LPL inlet. Work began at 7:00 am with initial efforts consisting of cutting an outflow channel on Torrey Pines State Beach at Transect A1 up to Transect A2 within the Lagoon (See Figure 3-‐8 and Figure 3-‐9). This channel would help to direct the discharge of water impounded within the LPL once the inlet was breached (See Figure 3-‐10). Once the channel was completed, the inlet was breached at 9:38 am, releasing impounded waters to drain the Lagoon (See Figure 3-‐10 -‐ Figure 3-‐13) and permit access of heavy equipment back to Transect E2. Once water levels dropped, the two excavators proceeded to the deep-‐water mark located near Transect E2 and began to excavate the main channel. Excavated spoils were stockpiled and would be loaded onto trucks the following week to haul and dispose of the sand on Torrey Pines State Beach.


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Figure 3-‐8. Excavating a channel west of the inlet at Los Peñasquitos Lagoon to direct lagoon outflows. Photo by M.

Hastings on 4/22/15.

Figure 3-‐9. Excavating a channel toward the impounded water at Los Peñasquitos Lagoon. Photo by M. Hastings on 4/22/15.

Figure 3-‐10. Getting ready to release impounded water within Los Peñasquitos Lagoon by breaching the inlet. Photo by M. Hastings on 4/22/15.


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Figure 3-‐11. Breaching the inlet to release impounded water within Los Peñasquitos Lagoon. Photo by M. Hastings on 4/22/15.

Figure 3-‐12. View of water exiting Los Peñasquitos Lagoon shortly after the inlet was breached. Photo by M. Hastings on

4/22/15.

Figure 3-‐13. View of water exiting Los Peñasquitos Lagoon later in the day after the inlet was breached. Note the expanded

with as channel banks erode due to outflow. Photo by M. Hastings on 4/22/15.


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Day 2 (April 23rd) & Day 3 (April 24th) Day 2 and Day 3 consisted of excavating the inlet area and stockpiling spoils to be hauled out to Torrey Pines State Beach the following week. Initial efforts on Day 2 focused on continued excavation of the deep channel near Transect E2 as shown in Figure 3-‐14 and Figure 3-‐15. By Day 3 excavation continued toward Transect D in both the north and southern channels (See Figure 3-‐16 and Figure 3-‐17).

Figure 3-‐14. Excavating at the deep-‐water mark in Los Peñasquitos Lagoon near Transect E2. Photo by M. Hastings on 4/23/15.

Figure 3-‐15. Close up view of excavation at the deep-‐water mark in Los Peñasquitos Lagoon near Transect E2. Photo by M.

Hastings on 4/23/15.

Figure 3-‐16. Excavating in the northern channel at Los Peñasquitos Lagoon near Transect D. Photo by M. Hastings on 4/24/15.


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Figure 3-‐17. Excavating near the southern channel at Los Peñasquitos Lagoon near Transect D. Photo by M. Hastings on

4/24/15.

Day 4 (April 27th) -‐ Day 8 (May 1st) Additional equipment was brought in over the weekend to facilitate efforts to excavate and haul sediments out of the inlet area at LPL. The additional equipment consisted of three 45-‐ton articulated rock trucks and a D6 Dozer. Since the inlet had closed to tidal circulation on Saturday April 25th, initial efforts on Monday (April 27th) focused on clearing the inlet area between Transect A1 and Transect A2 to release impounded waters (See Figure 3-‐18 and Figure 3-‐19). Once the water levels dropped within the Lagoon, excavation continued within the inlet area along with loading of excavated spoils from the previous week onto the rock trucks to be hauled and disposed of on Torrey Pines State Beach (See Figure 3-‐20 and Figure 3-‐21).

Figure 3-‐18. Excavating the inlet area near the bridge at Los Peñasquitos Lagoon. Photo by M. Hastings on 4/27/15.


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Figure 3-‐19. Excavating the inlet area west of the bridge at Los Peñasquitos Lagoon. Photo by M. Hastings on 4/27/15.

Figure 3-‐20. View of inlet work that included excavation and stockpiling of spoils in Los Peñasquitos Lagoon. Photo by M. Hastings on 4/27/15.

Figure 3-‐21. Loading of excavated spoils near Transect E2 in Los Peñasquitos Lagoon. Photo by M. Hastings on 4/27/15


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During Day 5 through to Day 8, efforts continued to focus on excavating the inlet area and hauling spoils to Torrey Pines State Beach. While work areas were more or less dictated by water levels within the Lagoon due to high tides in the morning, the overall progression was to work from Transect E2 toward Transect A1 as summarized in Figure 3-‐22 to Figure 3-‐33.

Figure 3-‐22. Excavating between Transect A2 and Transect B in Los Peñasquitos Lagoon. Photo by M. Hastings on 4/28/15.

Figure 3-‐23. Loading excavated spoils near Transect D in Los Peñasquitos Lagoon. Photo by M. Hastings on 4/28/15.

Figure 3-‐24. Loading excavated spoils near Transect D at the southern channel in Los Peñasquitos Lagoon. Photo by M. Hastings

on 4/29/15.


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Figure 3-‐25. Loading excavated spoils near Transect B in Los Peñasquitos Lagoon. Photo by M. Hastings on 4/29/15.

Figure 3-‐26. Excavating and stockpiling between Transect D and Transect B in Los Peñasquitos Lagoon. Photo by M. Hastings

on 4/30/15.

Figure 3-‐27. Excavating and stockpiling near Transect D in the northern and southern channels. Loading spoils near Transect A.

Photo by M. Hastings on 4/30/15.


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Figure 3-‐28. Panoramic view of work within the inlet area of Los Peñasquitos Lagoon. Photo by M. Hastings on 4/30/15.

Figure 3-‐29. Loading near Transect A1 during high tide when access to the Lagoon was limited. Photo by M. Hastings on

5/1/15.

Figure 3-‐30. Excavating and loading near Transect B within Los Peñasquitos Lagoon. Photo by M. Hastings on 5/1/15.

Figure 3-‐31. Panoramic view of Los Peñasquitos Lagoon inlet during loading of excavated spoils to be hauled to disposed on Torrey Pines State Beach. Photo by M. Hastings on 5/1/15.


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Figure 3-‐32. Finishing up excavation of the inlet at Los Peñasquitos Lagoon near Transect A2. Photo by M. Hastings on 5/1/15.

Figure 3-‐33. Excavating the remainder of the sand spit that grows off the southern abutment of the bridge that spans the inlet

at Los Peñasquitos Lagoon. Photo by M. Hastings on 5/1/15.

3.3 Grain Size & Sediment Volume Removed from the Lagoon Inlet It is estimated that approximately 26,000 cubic yards of sand was removed from the inlet area at LPL with an estimated 25,575 cubic yards of sand hauled to Torrey Pines Beach for disposal. Excavated material consisted of 98.5% to 98.9% sand based on the results of grain size analysis performed in the project area prior to maintenance activities. As shown in Table 3-‐1, grain size within the inlet area tends to be greater than 95% sand. Table 3-‐2 provides annual amounts of sand removed from LPL’s inlet from 2008 – 2015, including both 2013 and 2014 that required multiple efforts due to beach nourishment in Solana Beach and Encinitas that occurred in the spring of 2012 under the Regional Beach Sand Project II. Please refer to the annual summary reports for 2013 and 2014 for more information.


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Table 3-1. Grain size analysis results at LPL inlet 2009-2015

Year Core Median Grain Size (mm)

% Sand % Silt % Clay Sample Location

2009

1 0.30 97.71 1.61 0.68 LPL 1. Inlet

2 0.27 98.38 1.10 0.52 LPL 2. Western Basin on Transect B

3 0.21 96.85 2.31 0.84 LPL 3. Main Channel Near Transect D

4 0.20 93.29 5.27 1.44 LPL 4. Southern Channel Near Transect E2

2010

1 0.35 98.67 0.91 0.41 LPL 1. Inlet




2011

1 0.31 99.55 0.45 0.00 LPL 1. Inlet




2012

1 0.25 96.47 2.62 0.91 LPL 1. Inlet




2013

1 0.30 98.56 0.96 0.48 LPL 1. Inlet




2014

1 0.26 98.54 1.01 0.45 LPL 1. Inlet




2015

1 0.22 98.6 0.98 0.47 LPL 1. Inlet


3 0.22 98.5 1.06. 0.45 LPL 3. Main Channel Near Transect D



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Table 3-2. Cubic yards removed annually from the inlet at Los Peñasquitos Lagoon using heavy equipment.

Date of Inlet Maintenance

Type of Inlet Maintenance

Cubic Yards Removed Annually 1

Total Cubic Yards Removed to Date

4/30/08 – 5/09/08 Emergency Opening 32,400 32,400





5/13/13 – 5/17/13 Emergency Breach 5,000 128,633






1 Estimates based on truck load counts with the average haul amount at 25 cubic yards per truck load.

4 RESULTS AND CONCLUSIONS Benefits to Los Peñasquitos Lagoon and Torrey Pines State Beach The restoration of the tidal prism at LPL provided benefits both within the Lagoon and along Torrey Pines State Beach. Within the Lagoon, water quality (e.g. dissolved oxygen, salinity, pH and temperature) was restored to levels required for the health and survival of aquatic species that include fish species valuable to recreational fisheries (e.g. California halibut and anchovy) and invertebrates that provide a food source to both local and migratory bird species. Restoring the tidal prism also helped to protect the Belding’s savannah sparrow (Passerculus sandwichensis beldingi), a State-‐listed endangered species. This bird nests within LPL’s high marsh habitat, defined as the area just above tidal influence. During extended inlet closures, rising water levels caused by perennial flows of freshwater from the watershed can inundate the upper marsh, causing nests to be abandoned. By lowering levels of freshwater within the Lagoon, the project was also successful in helping protect Nuttall’s Lotus (Lotus nutallianus) and Coulter’s goldfields (Laesthenia glabrata ssp coulteri), two 1B – listed plant species considered by the California Native Plant Society to be rare, threatened or endangered in California. Lowered water levels also restored valuable foraging habitat for two federally endangered birds,


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Ridgeway’s rail (Rallus obsoletus -‐ formerly referred to as Light-‐footed Clapper Rail (Rallus Longirostris Levipes)) and Western Snowy Plover (Charadrius alexandrinus nivosus). In addition, foredune and beach habitat is restored within the inlet area using excavated sand that is placed along eroded vegetation banks and on top of cobble substrate exposed by wave propagation and surge within the inlet during winter months. Project benefits along Torrey Pines State Beach generated by beach disposal of sand excavated from the LPL’s inlet include the following:

• Covering of exposed riprap located along an eroded bluff that separates Torrey Pines State Beach and public parking spaces along N. Torrey Pines Road to improve public access and safety, as well as to serve as a soft buffer to reduce further erosion of the bluffs from winter waves, storm surge and extreme tide events.

• Re-‐contouring of sand placed along the upper beach to mimic the profile of a coastal dune extending from the lower beach to the bluffs to increase the total area of available beach for public use and improved access from N. Torrey Pines Road.

• Creation of potential spawning habitat for grunion caused by sand placement along portions of the lower beach that had been predominately cobblestones.

• Improved beachsafety along Torrey Pines State Beach through the creation of a beach access ramp for emergency vehicles traveling on N. Torrey Pines Road.

Photo-‐documentation of inlet status before and after tidal circulation was restored is provided below:

Figure 4-‐1. View of the closed inlet at Los Peñasquitos Lagoon on 4/9/15. Photo by M. Hastings.


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Figure 4-‐2. View of the closed inlet at Los Peñasquitos Lagoon looking southeast from the lower bridge that spans the inlet.

Photo taken by M. Hastings on 4/9/15.

Figure 4-‐3. Panoramic view of the closed inlet at Los Peñasquitos Lagoon on 4/9/15. Photo by M. Hastings.

Figure 4-‐4. View of the inlet at Los Peñasquitos Lagoon after inlet work was completed. Looking west toward the ocean. Photo

by M. Hastings on 5/1/15.

Figure 4-‐5. View of the inlet area at Los Peñasquitos Lagoon after inlet work was completed, looking southeast from the lower

bridge along N. Torrey Pines Road. Photo by M. Hastings on 5/1/15.


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Figure 4-‐6. Panoramic view of the restored inlet at Los Peñasquitos Lagoon on 5/1/15. Photo by M. Hastings.

Figure 4-‐7. View from the north parking lot of eroded remnant dune and beach habitat scoured by incoming swells and waves

propagating through the inlet during winter months. Photo by M. Hastings on 2/3/15.

Figure 4-‐8. View from north parking lot of restored beach and dune habitat. Photo by M. Hastings on 5/1/15.


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Figure 4-‐9. View of eroded bluffs adjacent to public parking along N. Torrey Pines Road prior to the project, typical after winter

months that erode large sections of Torrey Pines State Beach. Photo by M. Hastings 4/21/15.

Figure 4-‐10. View of the same section of bluffs following beach nourishment efforts using excavated sand from the inlet area hauled to Torrey Pines State Beach for disposal south of the inlet to avoid re-‐introduction into the inlet area. Photo by M.

Hastings 5/11/15.

Reductions in Populations of Culex tarsalis -‐ Freshwater Mosquito that Transmits West Nile Virus The project was successful in reducing mosquito-‐breeding habitat for Culex tarsalis by restoring the lagoon’s ocean inlet and tidal prism, achieved through breaching of the inlet and re-‐connecting the Lagoon’s main channel with the ocean. A post-‐project site inspection indicated that surface levels within the eastern portion of LPL were observed to be below the bank of the tidal channels, indicating connectivity with the ocean and adequate drainage for the eastern portion of the Lagoon. Continuous measures of water levels within the Lagoon’s main channel also indicated that the tidal influence had been restored as measured elevations of water levels within LPL corresponded to water levels indicative of the low and high range indicative of the corresponding tidal cycles.

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