STP 62. Upper Newport Bay Ecosystem Restoration Project .

STP 62. Upper Newport BayEcosystem Restoration Project –Three Years of Post-ConstructionMonitoringLawrence Smith, USACE LADJane Grandon, USACE LAD (in memoriam)Rachel Woodfield, Merkel & Associates

STP 62. Upper Newport Bay Ecosystem Restoration Project – Three Years of Post- 2014Construction MonitoringINTRODUCTIONNewport Bay is located on the southern California coast, approximately 40miles south of Los Angeles. From the harbor entrance Newport Bay extendsabout 3.5 miles north northeastward. Newport Bay is a combination of twodistinct units, termed "Lower Bay" and "Upper Newport Bay” (UNB),divided by the narrows at Pacific Coast Highway (PCH) Bridge. The752‐acre Lower Bay, where the majority of commerce and recreationalboating exists, is heavily developed (predominantly as residential properties)and is a deep basin coastal lagoon. The 1,000‐acre UNB is a drowned rivervalley, geologically much older than the Lower Bay, and is largelyundeveloped. Much of UNB is included in the Upper Newport BayEcological Reserve, managed by the California Department of Fish andWildlife (CDFW).Upper Newport Bay is one of the largest coastal wetlands remaining insouthern California. Natural habitats within UNB include open marinewaters, intertidal mudflats, cordgrass‐dominated low salt marsh,pickleweed‐dominated mid salt marsh, high salt marsh, salt panne, riparian,freshwater marsh, and upland. UNB supports an impressive number anddiversity of birds, particularly during fall and winter when shorebirds andwaterfowl arrive from their northern breeding grounds. Upper Newport Bayalso supports several endangered bird species and an endangered plant. Thesubtidal and intertidal waters of UNB provide important habitat for marineand estuarine fishes.

STP 62. Upper Newport Bay Ecosystem Restoration Project – Three Years of Post- 2014Construction MonitoringRESTORATION NEEDBy the end of the 20th century, the ecological diversity and functionality ofUNB was increasingly threatened by sedimentation from the surroundingurbanized watershed. The primary source of freshwater and sediment loadsto UNB is San Diego Creek, which drains approximately 85 percent of the98,500‐acre San Diego Creek watershed. Sediment from the San DiegoCreek watershed had increasingly filled open water areas within UNB. Thissedimentation decreased the extent of tidal inundation, diminished waterquality, degraded habitat for endangered species, migratory water birds, andmarine and estuarine fishes. It also resulted in navigation problems in UNBmarinas and navigation channels. If sediment deposition within UNB hadbeen allowed to continue, the remaining open water areas would haveeventually evolved into mudflats, and later, marsh or upland habitat,resulting in a loss of ecological diversity.

STP 62. Upper Newport Bay Ecosystem Restoration Project – Three Years of Post- 2014Construction MonitoringPROJECT IMPLEMENTATIONThe restoration project was initiated in 2006. The first phase was conductedfrom April 2006 to July 2009. The second phase was conducted fromNovember 2009 to October 2010. The total cost of restoration wasapproximately 37.4 million. Key project features included expansion anddeepening of two sediment control basins (Basin I/III and Basin II),deepening of channels around five restoration islands, creation of three largemudflats, relocation of a least tern nesting island, installation of maintenanceaccess at the two nesting islands, and installation of interpretive signs andbuoys.POST‐RESTORATION MONITORINGIn order to detect and document the long‐term development processesfollowing the restoration, the ACOE prepared the Post‐restorationMonitoring Program for the Upper Newport Bay Ecosystem RestorationProject. The program outlines ten years of biological and physicalmonitoring. The schedule for the various monitoring events is providedbelow.

STP 62. Upper Newport Bay Ecosystem Restoration Project – Three Years of Post- 2014Construction MonitoringRESULTSArea of habitats within the UNB study area (March 2013).HabitatHectares AcresSouthern coastal salt marsh145.5359.6Freshwater marsh5.714.1Mule fat scrub0.20.4Southern willow scrub0.61.4Coastal sage scrub1.63.9Disturbed0.20.4Non‐native vegetation2.35.8Salt panne0.71.8Intertidal mudflat68.3168.8Eelgrass0.20.6Open water100.5248.4Unvegetated1.12.6Unvegetated nest site1.63.8Urban/developed0.51.1

STP 62. Upper Newport Bay Ecosystem Restoration Project – Three Years of Post- 2014Construction MonitoringComparison of key habitats (ha.) within the UNB study area duringYears 1, 2, and 3.Habitat201120122013Southern coastal salt marsh141.6144.4145.5Intertidal mudflat74.372.068.3Open water99.298.8100.5The habitats of primary interest in relation to the effect of the restorationwork were salt marsh, mudflat, and open water. Year 3 found a continuedreduction in the amount of mudflat. This was due primarily to the expansionof salt marsh onto the mudflat.Water quality monitoring in Year 2 (2012) showed that dissolved oxygen(DO) is depressed at depth to levels that are considered to be biologicallydetrimental. Continual water quality monitoring performed with deployedinstruments over a six‐month period in 2005 found hypoxic events to bemost closely tied to increased freshwater discharge, low solar radiation, andreduced bottom water circulation during neap tide series. This program wasnot continual monitoring, it is not possible to determine for how long andover what area hypoxic conditions continue to occur post‐restoration,however the dredging project should have resulted in improved watercirculation and reduced residence time in the upper portions of UNB.

Upper Newport Bay Ecosystem Restoration18 October 2010 Project Summary Period of Contractual Construction: November 2005 to October 2010Period of Dredging Construction: April 2006 to September 20102.35 million cubic yards (mcy) dredged, 2.2 mcy removed from the bay and 0.15 placed in‐bayConstructed the following:o Widened and deepened 2 Sediment Control Basins (Unit II and Unit I/III) to ‐17.2 feet MLLW (‐20 feetMSL)o Deepened 5 shallow island restoration channels (Shellmaker Island, Middle Island, New Island, HotdogTern Island, and New Least Tern Island) to ‐2.2 feet MLLW (‐5 feet MSL)o Restored 3 mudflats (Shellmaker, 23rd Street, Bullnose West) at ‐1.5 ft to 4.3 ft MLLWo Relocated 1 tern nesting island (relocated Skimmer Island to New Least Tern Island)o Provided maintenance access ramps to 2 nesting islands (New Least Tern and Hotdog)o Provided interpretive signs and buoysPhase 1 Contractor was DD‐M Crane and Rigging dredged 1.737 mcy from April 2006 to July 2009Phase 2 Contractor was RDA, Contracting Inc. dredged 613 kcy from January 2010 to September 20101.05 mcy removed from Unit II Basin (DD‐M Phase 1 removed 865 kcy; RDA Phase 2 removed 186 kcy)905 kcy removed from Unit I/III Basin (DD‐M Phase 1 removed 494 kcy; RDA Phase 2 removed 411 kcy)92% disposed offshore at LA3 and 1% nearshore at Newport Beach7% disposed in‐bay for construction of nesting islandsApproximately 5,000 tug and scow trips passed underneath PCH without incident (from 1,685 DD‐M tug andscow trips to LA3, 680 RDA tug and scow trips to LA3 and numerous tug and scow maneuvers)2 to 4 scows were in use at any one time for construction, 7 different scows ranging from 1000 cy capacity to3000 cy capacity2 Brusco tugs pushing and towing the scows through the harbor. Roland, Terri L., or Cleo hauled scows offshoreStaging areas were Lower Castaways and Northstar Beach1,558,000 cy were disposed at LA3 under Phase 1, 565 days of actual dredging for an average production of2,750 cy per dredge day, over a period of 1,183 days. Primary dredge was a 5 cy clamshell bucket mounted onthe CB‐3 Crane Barge, with some of the dredging performed by 10‐inch hydraulic dredge “Pelican”.613,000 cy were disposed at LA3 under Phase 2, 175 days of actual dredging for an average production of 3,500cy per dredge day, over a period of 240 days. Primary dredge was a Cat 385 excavator mounted on the CB‐3Crane Barge, with a minor amount of dredging performed by 10‐inch hydraulic dredge “Pelican”.An amphibious excavator was used to: complete the shallow dredging at Middle Island and Shellmaker IslandRestoration Channels; construct the maintenance access ramps at New Least Tern Island and Hotdog TernIsland; and excavate the Skimmer Island to mudflat elevation. In December 2009 there was an incident wherethe excavator, while being parked on the mudflat for the day, turned over into the bay. No injuries and noenvironmental damage occurred. It took a few days to bring the excavator upright.

3189/04-99N LIOrange CountyLos Angeles County?ISan Bernardino CountyIOrangeRiverside CountyCountyPACIFIC hambersOCEANSOURCE: CORPS 1998GroupNOT TO SCALESan Diego CountyPROJECT LOCATIONFigure 1.2-1

3184109-99Santa s:1) Elevation in Feet (MLLW Datum)2) Sources and Dates of Survey Data: Topography: USGS Newport Beach Quadrangle, 1981 Bathymetry :Lower Bay: U.S. Army Corps of Engineers, 1989Upper Bay (Excluding Unit 1 Basin) :Coastal Frontiers Corp., September 1992Upper Bay, Unit 1 Basin Only :Orange County, EMA, March 1992De AnzaNPacific Ocean Harbor Entrance hambersGroupSource: Corps 1993LOCATION OF PLACES IN NEWPORT BAYFigure 1.2-2

Design Refinements. Design refinements prior to start of construction include:Sept. 20041. The unit II basin side slopes were steepened to reduce the loss of mudflat habitat.2. The unit II basin was reduced in size to reduce the loss of mudflat habitat.3. A newly created mudflat was added at 23rd Street to offset loss of mudflat habitat in thetwo basins.4. A second newly created mudflat was added to the Bullnose West area to offset loss ofmudflat habitat in the two basins, replacing the prior Bullnose design.5. Design for the removal of previously dredged materials from Shellmaker Island to restorewetlands functions was modified to avoid salt marsh bird's beak (Cordylanthus maritimusmaritimus) a federal and state-listed endangered plant species.6. Provisions were detailed to provide access to Hot Dog Island for California Departmentof Fish and Game maintenance activities including provisions for keeping the islandisolated from people and their pets.7. Provisions were detailed to provide access to the new California least tern-nesting islandfor California Department of Fish and Game maintenance activities including provisionsfor keeping the island isolated from people and their pets.8. The Shellmaker Island dendritic channel was deleted from the project to prevent potentialimpact to sensitive plant and animal species occurring in the nearby salt marsh.9. New design for the California least tern nesting island with removal of all underlyingmaterial to project depth to provide disposal site for excavated material.10. Scour protection feature were added to mouth of San Diego Creek.11. Restoration of the side channel for Shellmaker Island will not include the southernportion of the channel that is already subtidal. This reduces the amount of dredgingrequired and avoids impacts to salt marsh bird’s beak located adjacent to this section ofthe channel.12. Restoration of wetlands in the Northstar Beach area was redesigned to provide optimalarea of intertidal mudflats, while avoiding existing structures.Design Refinements. Design refinements during construction include:2005-201013. Northstar Beach area removed from project14. 23rd Street mudflat design enlarged to offset loss from removal of Northstar Beach andredesigned to avoid freshwater riparian corridor that grew in area previously designed tobe mudflat; access channel to main channel added to design.15. Subtidal channel around New Least Tern Island deepened and widened, cordgrasstransplanted as mitigation for lost vegetation.16. Dike segmented.17. Mudflats under Skimmer Island left in place to offset mudflat losses.