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Chapter 2: The Study Area Rancho Palos Verdes, California Feasibility Report Chapter 2. The Study Area The Rancho Palos Verdes Study Area, located along the south central section of the Palos Verdes Peninsula, is shown on Figure 2-1. It lies along the southwest margin of the Los Angeles coastal plain and is bounded on the south and west by the Pacific Ocean. The overall Study Area encompasses the 7-1/2 mile coastline of the City of Rancho Palos Verdes, located about 25 miles south of the City of Los Angeles in Los Angeles County, California. Specific emphasis during this Feasibility Study has been directed at the areas of Abalone Cove and Portuguese Bend, with a focus on Portuguese Bend Cove. Bathymetry The offshore bathymetry is shown in Figure 2-2. The Palos Verdes shelf in general, gradually slopes from the shoreline to a depth of approximately-250 feet MLLW. The width of the shelf varies from four miles off Palos Verdes Point, to one and one-half miles off of the Study Area, to 13 miles off Los Angeles and Long Beach Harbors. The shelf slopes to the San Pedro Basin via the San Pedro Escarpment. The San Pedro Basin, located between the Palos Verdes Peninsula and Catalina Island, is at a depth of approximately-3,000 feet MLLW. Other major bathymetric features include the Redondo Canyon to the northwest and the San Pedro Valley to the south. Topography From the shoreline bluffs to about 1,200 feet at the crest of the hills, the area topography consists primarily of rolling hills that range from a 10% slope to more than a 35% slope. The Study Area's physical characteristics, shown in Figure 2-3, include two of the most spectacular promontories on the Southern California coast— Inspiration Point, a unique marine habitat, and Portuguese Point, an active landslide mass. The shoreline, backed by a pronounced sea diff, is characterized by rocky, gravelly, narrow beaches covered by coarse materials such as cobbles, and rocky headlands. Landslide Description The following sections present information to describe the landslide conditions in the Portuguese Bend area and adjacent areas. The information reflects studies accomplished as part of this feasibility study by the City of Rancho Palos Verdes, other studies, and the Corps of Engineers analysis of the study results. The detailed information on these studies and analysis are presented in the Geotechnical Appendix • 2-1 ;.I,.a 1 - '�-;;r T�� <.Cftte �n I 1 + II cc T710.0eZIR,, ),I.,\ir, , ,:r,. ,r. , ,, , . t_,,,.. r,! , _ -, :/i.j A ,..1 . 1 li- .—— C—' ?-—.."e......'1-Ar'4"-.1-Dig3 - I•3 a ~' nt1 � 171 W 4• •d'Yj ,.1� l fr4,1. �,• l•'l. rwra (Q 30 Ill It I:4 + 1 r v w �`� .. f 1 ' ry r //I i', % I -- °a *.r f1• r11(ill l,. /� I 1h:4• t r•14 Ij�'--•;�_ /j' 1.4 41.1 /A. /1/ 9 �p /'' 9 .VI ,. N Irnn 1�/�/i+ l %, ; �/ Ir .G ` '1 g .-- r ''8 ' I Sid '� \) I{ " ,.� e ii_ill.A I [. i 1 D I11i' _•RA , •„� 1. ..x'.1.=! i- , /' .. d .- 4 ..., .4 1'. II �r.��--=..p . to , e 1 �•�• �� ).”:1 0 03 ar to ` /!r- 1 i • L4f-`Sr ! n r I Y 1. .tiw �1•�'I I (�• ` , 1 i�,-. ;f2 CP �.ri �■fZ-Li S/�Nll ffiiiliiyk� ••.I �' r. rR AO can ,i _ ',„ `�I( ��`'� �w'r+e" ' aNri�1 f t • • 0 '� _ 1 f.%d` + .. Vti, A IP a n"J� �f"1! 4 4'1li e tf` T� •D• •, I ,,,� c ,I rI �.'\1. , _ {7 /14�' rNy i a e ..:,---;1r. f t , rr ' i t PP w1k4 �� xar.,/ 1.� ..,.. %, ,.ti 1-• o r ' t • !� ;t •` 19yi ,( i, Fiii .-,- .gi' -.s'T1�1F1 W!�� it t `� .;ii �� r 9 &J'L Al tib, l )' ,i 'iJewpoitt„„yo y� 'll 14!i+.�.. +t .� r�{, Mm'1� YytiN;f ., . r• G I •C r Iti'� 1%/f,.�•' v 1.IhnrE'+1.,Yn�. •'�,14‘ '+.-. ' 1 :'ar� 1'�..4. `�`s � 1 r ..•'�.�/��t,/! a��t 6,0'....),,m., i4::: ‘,1, i. , •� r�L I ,I �.�,.��' r rpt (�'� II p�'i r' _Y a it! '1 1 - - L4 7..'F't r, , - -.: - � ' Y�•,1_w_.til. ,„.. j ��. , .. .. i iii)1.0,_ .Jr I= , .m.1 fMIv. ,bin.:.l.A,If .. 0 ,0 4111. Geomorphology • The City of Rancho Palos Verdes lies along the southern slope of the Palos Verdes Peninsula in Southern California. The land mass may be described as a northwest-trending dome located at the southwest edge of the Los Angeles Basin. It is bordered on the south by the Pacific Ocean and on the north by the broad plain of the Los Angeles Basin. The Palos Verdes Hills are a block of bedrock squeezed upward into a dual-plunging anticline between the Palos Verdes Fault and the offshore San Pedro Basin Fault. The Mesozoic Catalina Schist forms the core of the anticline. Overlying this is the middle-to-late Miocene Monterey Formation. The Monterey Formation consists of Altamira Shale overlain by Valmonte Diatomite and in turn by Malaga Mudstone. Basalt dikes, sills, and volcanic tuff is present within the Altamira Shale. Portions of the tuffs have been altered to form bentonitic clays, rich in the clay mineral montmorillonite. The thickest of these bentonitic tuff beds is called the Portuguese Tuff. During the Pliocene, the Palos Verdes Hills were uplifted and exposed as an island. Sediments were deposited along the north and northeast flanks of the island, gradually filling in the basin, and the Palos Verdes Hills became a peninsula,joined to the Los Angeles Basin. The Peninsula continued its rise from the sea during the Pleistocene, and a series of 13 wave cut benches were eroded on the hills as a result of eustatic sea level changes, giving the Palos Verdes Peninsula its distinctive profile. Modem wave erosion has carved a steep, nearly vertical sea cliff up to 150 feet high along most of the shoreline. From the coast, the elevation rises approximately 1,480 feet over • one mile to the crest of the Palos Verdes Hills, which marks the crest of the Palos Verdes anticline. Land rises from the shoreline in a series of gentle benches and steep rises to the crest of the hill. This topography has been highly modified by the recent and current landslides. Geology The bedrock of the Palos Verdes Peninsula consists of a core of Mesozoic-Age Catalina Schist, overlain by the Monterey Formation as shown in Figure 2-4. It has a gentle to moderate dip, approximately 15 to 30 degrees toward the south on the seaward side. The rock has smaller folds within the limbs of the anticline that forms the Palos Verdes Hills. The Monterey formation has been divided into three suvordinate units or members. The oldest unit is the Altamira Shale which is overlain by the Valmonte Diatomite, which is, in turn, overlain by the youngest of the three members, the Malaga Mudstone. The Altamira shale is the most prominent member of the Monterey Formation exposed in Ranchos Palos Verdes. It consists of beds of tuffaceous shale, siltstone, tuff, and tuffaceous siltstone that are intruded by basaltic dikes and sills, as well as tuffs. The tuffs can form distinct marker beds. One of these, the Portuguese Tuff, has an average thickness of about 55 feet and is an important marker bed in the Study Area. Many of the tuff beds have been altered to bentonite day. The betonite composition and thickness of the Portugese Tuff make it a nearly perfect aquiclude. Groundwater migrates downward until reaching the tuff, which prevents continued downward migration. Borings drilled within the landslide often find local groundwater perched on top of the betonite. 1110 2-3 Figure 2-4. Bedrock Geology • =t_:'- r o"* 111-=- - .- ate:-. 1 Y —.—~— ——_— ._ - GJ cel'' IrmW.lfn� ---------4-;---11-'-f-----2-a-----7---------1- -tea-==-----'--:,../j.......: ',;;•. .............................u1..\ \� lllllli3s. N.m .:J.; \Y� 1C- s-'-'-'; -'---- --------- .744.:St'';: N:::::::::,.:'::.?44.1j,:;:,;;i.............:"..",-:..,-: Z'j'A::; /1''' CowNe w iafl nwntDN '-•' p ••••••••••• i _•.. .:� i 3 MMnm I.W.e•NudYm. IrNDLlOen pNv '.nYe•yF4s .\ � -_`r OYo<es Paa gr.vn...Wb.t MMM1CNt <i;; .\\ � r:-'.f N. r..norn.p•faY4 Sewn• ' ��, •e..'l.SA. • Sferi. _ �� Ma01, R..pl.m YIMI•<N. IMdfYe. r=b3 .t.c t.ZJ n Yb Cr.r1Y nlgflrcS. 1 •'r.- tWI TVll.c.a .ic4. nt MO 41.41. b...4 .; - e•ml IAY. .t.Tull ....0,pl 1,...,•••Tuft ' v 'MarW.adc ScM• YINNi PiH`. c� Mrt• GIs.ScN.t ,y, -, ce4.cla r4 $Mlnr<..We...r..ea0•MIt 0 4,2 1 7 2 Aepn.l.r• r 14.10(�f. 1:....30,,1:....30,, • • W Wlf.t•...diW Yr•fy.plJe•icYaf pY.ecvr..l ai.ella+ Polon!RM., Landslides Coastal portions of the Palos Verdes Hills have undergone periodic, recurrent landslide activity over the last 600,000 years. A majority of the landslides that have occurred in the past 120,000 years have been within a two-square-mile area (1,100 acres) of the City of Rancho Palos Verdes. Subsequent to the Portuguese Bend landslide which began in 1956, two additional landslides, Abalone Cove and Klondike Canyon, occurred within the Ancient Landslide Complex. These landslides and the Complex, are delineated in Figure 2-5. The Abalone Cove landslide, reactivated in 1974, consisted of slide debris from the ancient Pleistocene landslide, that was re-mobilized. Sliding was first notice at the toe of this slide, and over the next two years progressed inland to Palos Verdes Drive South. By 1980, the active sliding had propagated inland of Palos Verdes Drive South, with a maximum area of about 80 acres. Subsequent to the initiation of ewatering wells in 1980, most of the movement of the Abalone Cove had stopped. • 2-4 ::•':::C,4.144'.44';:;;;,..:.4714. ::. <:�'r. c•�' rk,,,h.yy14'4 •\:•, .'/•::(i •.3 •..••••• r, 0. 1'4;z]:1+ ��t7. -,• . �: � .i d.. .• :•' r'.. is;'t !� why ry.��.} i .•.,. ,�,�.}:�';�: ' + ;• ''7v �:• �+s (,r-•. .. 'v��'' ii 1.- •.•,• .: I• n ,% t .4'-'s. • :. \ •^.. '�{�,..,,>•y.1 :Y •'1' '- :N' • ii ;,,11<. AiAvl;),(4 Y`�`'hf" •,�',r 1s,•,. •sites' r•r`Y 4t ' (t.Eth/, �•% k kA? y:� •'' ,..A ', �.sp�.� 4r ,' 1,...'/:"'T/'� ; ',;t; ,r^,,�.v..•• , ,.) • �:,, �5.,.., stt:.... c• •••'•.. iorf•''S;�-. ,4: .t, 92.,..•,:.:'. !: 1 I.. 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' r "+' . •Ti ,.. �: ::Z �+ .1 5I •,.if: r. .. • . .�: .ft:::!',•,.+ stit'c..{` =: • 1.= - v • �+// .i t ! ��• t • • `d • t � / gJ 13 ';A3 • ' •[,ei " • 1112 ( k I l.....1.;**,1113/4.01),'; , • * os ��_ Tom•. , -/� i lilt=.i ;•'h. _ jai.• i a<""r ., Sb o ff a. +'_+ '711. .-i• ..• +;. )1 f aha '�". :1' •�. '�. �►N. l'''.•',;..'. • .{d 17) '� a1''...:••;....;' • t��/if '' 1/I U0 !!' 4 111 iii, ' . t.. a ..tt ...7► '_ �'"�itif. • ', .,«�'.',r�, •t 1 .i ilii �'" 'A'5::Z7IN::�yi sE•.:•10.. 'L-� > Z' ••i �;� i' �•, ��;' 1. : ' 11 '..::I. °�:. ,..�/. y., i •`N W4 I if �1 I:• .. r .ter:: • li t. '� a ft s ji 4; .`,-,•,„.. :'i '• ..-;.•:•N inti 'r. ”- it I, ...60/1..1.14). a G./ •' 7 ,. ;•'= '` �< .; !. a, • Table 2-1 shows the rates of landslide movement at Portuguese Bend, primarily from May 1984 to January 1997 at specific monitoring stations (survey monuments). The monitoring stations locations are shown in Figure 2-7. The survey monument locations show the approximate location of points at which Los Angeles County and other City monument data was collected. The J locations are County monuments, some of which have been discontinued or destroyed. The PB locations are City monuments, and locations not shown have also been discontinued or destroyed over time by the ongoing land movement. J and PB locations overlap at some locations. The rate of movement at almost every location is both horizontal and vertical, and varies directionally as well; however, the rates shown are for horizontal movement only. As shown in Table 2-1, the landslide movement decreased from May 1984 to 1991. Since that time, rates have been erratic seasonally, and have recently begun to increase. Current overall average movement is 7.6 feet per year. The fastest overall average annual rates of movement in feet per year are in the seaward subslide at PB40/J2 (25.55), in the upper central subslide at PB29/J-13A (14.90) and in the lower central subslide at PB08/J3B (14.46). The slowest overall rates of movement are found at Smuggler Cove PB04/J4A(1.05), and in the upper portion of the landslide including PB18 and PB19 (at 1.60 and 2.06, respectively). Other upper subslide locations also show a degree of slowing. During the feasibility study, the local sponsor also placed ten GPS stations in the surf • zone at about-five feet MLLW in an attempt to identify the extent of the land movement into the ocean. These station locations are shown in. Figure 2-8. The measurements identified the rates of movements shown in Table 2-2 and Table 2-3 for 1996 and 1997. Location of the Slide Plane and Seaward Toe of the Slide The shoreline along the ancient landslide remained essentially the same until the re- activation of the currently active Portuguese Bend Landslide. Until 1956, the shoreline was marked by a fairly wide, sandy beach that was the Portuguese Bend Clubhouse and a wooden pier. It also included exposed low-lying rocky areas providing tide pools and other intra tidal habitats.After reactivation, the Portuguese Bend Landslide mass advanced over this area destroying the Clubhouse and pier, and covering the pristine intra tidal and sandy beach habitat and recreation areas. The current shoreline is a steep bluff (80-to-100 feet high)that descends to a narrow strip of cobble beach. The bluffs continued erosion by wave action removes accumulations of fine grained material from the shoreline. The location of the active Portuguese Bend Landslide Slide Plane and the seaward toe of this plane were analyzed by geologists under contract by the City of Rancho Palos Verdes. The conclusions of these geologist indicate that the toe of the slide plane appear to be near the present shoreline. The location of the active toe was investigated using side-scan sonar and seismic surveys. In addition, three borings were taken along the shoreline shown, in Figure 2-7, and measurements of eight GPS monuments placed along the shoreline, shown in Figure 2-8. • 2-7 1.,, ..,..„.• , , ,-. (:( ..---' , ' .,, 1...,'i i 0,4., to• .-. , .::.i'. :r- , i , / 1) / ..•' -'` 91.1- - •. ',A/c.,. 4'C.S . ,, • t.. i.1 MC'', . / • Ar ' 4,.. . .' 0.). '''' • s.i.A ,'..' .40 :, . t.‘1,. P1/2 \—' "...\'' " 4.,-;:e...-::';"--7,.....::•'''..`...--.-.,f,W4,'1' ...•.)k /tli > • ' .? \).> ‘''•,• ..,14.73 . 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P - r,a- • , ,.1 •• . .- c ---zf...1 , • " c•,•.'•••••• •,'" *%,44 .\-•....11% • '11,i,t1•-'1',., : 2 „•.c.-' ',/:',....;f,, :"' ,4,-3'7. .. ..•>• <'\.) p.ii-N - sP-M'-"4'I- (•...,,(-'; - ' • '\...; T'.'...7... '•,-4, ' , •>/>•'. \_..--••,,,:, N,-.*-:)izp f&_;.r.,:c.,..,....,s,„,,,i-ji , ' V 1-,../..1S.:'S. -;''', *-, ` \ ',.‹i.,/x N' / -7' r' '• ,.. , '•lif."-- ' ;:- •''[.,,?‘" " ".11,-,‘ ..../.'0'•• •/\ 2....'V ,'' • I • 4,. \-n ".1\'`::::. ; i:;:);.!., •..//41-:•,: ;7•./71 spe'..'"''..S) ! ''' (//4) :.'''). --*-4y,,:: 1 • \\;;.,1 \.%';',;,;•,(•• •0;11,-./N.,,,,:i! .?•".e(C,.,, .. :•!,..,.t.• • 4//... / • • •,;./.../- 0-, .;. . ' c.i...rP-0 \,..'''.1,.1/4/1 / •: •-•-,-;//iti7,1./ i f/,•//•:•:::i,_./../(...'..,'.. ••y(<; ',.:.I • •• . • ••' • •-i:.!-::c..-e... ...„.u....4,4 / 0 " 7 • • Measurement Survey Monument Locations at Portuguese Bond Dates pr.94 Site 1.18 1.2 1.38 1-4A ISA I-7A Blakeley I.8A 1.IA 1.10 J-12 D•2 OaY.. I.l3A 1.16 1.19 1.21 1.22 1994 Sit. (PS-13) (P5-40) (PS-08) (P8-04) (PB-II) (P3O7) (PB-14) (PS-22) (P939) (P324) (P8-29) (P9-03) (P5.26) (P3201 P?-06 P8-09 PB910 PS-12 P2-18 PS-19 PS-25 PS-27 PS-41 I01-b76 . - - - 6.18 - • - • - • - - • - • - • - • . 0 25 • • • - • - • - • - 13 Sep 80 - - 9.71 . . - - - 13 Mry 829.25 - • • • I Nov82 . • - 7.34 - • - - - - - ' - - . 16 May 84 21.60 41.29 28.64 1.44 27.61 13.22 23.38 10.36 14.06 • 20.71 38.81 - - - - • - - - - - 11 Sep 84 . 19.13 37.51 26.99 1.66 26.21 12.61 - • 27.35 9.52 12.59 • 17.86 - 35.29 - - • - - • - - 151cm 85 28.17 42.54 31.54 1.27 29.94 12.90 • - 31.22 8.32 12.10 - 18.40 33.72 • - - - - - - • 17 Jul85 - 37.35 28.89 1.21 27.31 11.68 13.11 - 27.68 7.36 9.98 • 15.44 34.82 - - • 151=86 16.35 32.13 32.05 1.22 23.18 9.29 8.88 • 23.05 4.34 6.08 • 11.68 28.89 - • - - - • - - • - - • - 9 Jun 86 26.07 50.46 • 215 37.40 17.01 15.75 - 36.97 7.46 I I.C8 9.18 18.22 45.62 - - • - • - - • I Oct 86 17.61 31.19 22.93 0.17 25.08 12.14 9.30 - 21.84 4.63 6.69 7.17 11.22 29.91 - - - - - - - - - - • - - 25 I=87 • 28.01 20.03 0.13 18.23 8.29 7.20 • 16.23 2.87 3.59 3.47 6.32 • - • - • - - - • - - - 6 Apr 87 11.93 3287 23.78 1.30 16.80 8.17 7.32 12.25 13.39 1.00 1.39 0.98 3.24 12.63 1.24 - - - - - - 81u187 10.29 23.99 17.75 0.34 13.20 6.47 5.29 10.11 10.64 0.72 1.26 1.06 2.89 10.18 1.02 - - • - - - - • - - • 4 Noe 81 7.14 18.07 13.10 0.86 9.62 4.69 4.20 7.18 7.98 0.90 0.85 0.99 2.56 7.72 1.07 - - - - - • - • - 7 Mar 88 5.12 25.12 15.73 - - - 4.02 5.17 - 0.47 1.24 1.47 2.60 4.89 1.24 - - • - - - • 21 Jun 68 1.11 14.32 5.38 1.85 2.96 1.65 1.49 0.72 2.32 0.57 0.52 0.62 0.98 0.75 0.40 - - - - • - • - - - 6 Oct 88 1.03 9.51 4.44 0.14 2.64 1.54 1.26 1.31 2.53 0.65 1.33 0.70 1.18 1.27 0.86 • - - - • - - - 25 Jan 89 1.19 8.59 3.62 0.47 2.24 1.39 1.25 1.00 1.96 0.51 0.37 0.69 0.85 1.11 0.63 1.12 - • - • - - - 26 Jun 89 • 10.61 4.35 0.52 2.46 1.34 1.25 1.19 1.76 0.58 0.53 0.55 0.64 1.13 end 2.16 - - - 'D C 29 Mar 90 1.34 11.59 5.66 0.65 2.54 1.34 1.21 1.36 1.89 0.35 0.66 0.54 0.95 1.43 2.00 • - - - (1) 25Nou91 1.70 14.06 • 0.86 2.93 1.33 1.33 1.69 2.21 0.30 0.24 0.36 end 1.66 2.52 CO a) 18 Aug 92 2.13 16.45 7.09 2.58 4.38 2.38 2.13 2.4] 3.36 0.45 0.37 0.20 2.41 5 57 0.13 3.20 • - U) 4Oct94 2.98 . . and • .nd .nd . 1.86 4.17 0.15 0.15 j el 10 Oct 94 • - 1.79 • 5.11 • 0.93 3.58 . . - • 1.79 4.65 26.16 • - 0) 29 Nov 94 2.11 • 1_63 1.43 • 350 0.07 • 1.43 0.07 - 0.26 <0.00 0.13 4.20 • -t 0 309w94 0.26 1.29 • 1.22 - • 1.50 4.07 6.15 - • I Dec 91 • . 3.65 . . end . . . • . . • - - 3.65 7.30 . <0.00 - • Ca 14 Mor 95 5.63 • 4.50 5.01 9.45 3.62 • • - 2.71 18.84 • 4.77 • 8.86 3.76 13.23 • C 15 Mar 95 - 2.36 5.52 3.09 • 10.49 • 1.14 2.00 - 16 Mar 95 10.95 40.15 12.02 - 21.93 14.60 _ 12.78 18.25 - • - 12.78 - • 16.43 28.50 14.93 E a) 27 Apr 95 7.91 30.68 • 2.29 • 7.88 • 11.56 . • 10.52 - 6.20 7.55 15.28 5.09 6.96 11.17 • - 161un 95 - 1.31 - 6.28 - 5.04 - - - - • 2.92 4.16 6.71 - • 0 10 Aug 95 4.59 4.41 • 4.65 - - _ - - 4.31 8.72 2.26 2.72 4.31 - 2 N 19Aug95 - - • 0.86 - 2.83 - - - - 3.27 2.13 - • - - - - - • 9Sep95 3.04 - - 1.04 • 2.78 - 3.53 - 3.52 • 2.09 3.48 6.21 1.46 2.07 4.75 - 6.54 CO 190c195 3.47 16.39 0.40 9.79 2.86 • - . 3.31 • - 2.25 2.71 5.63 7.60 - - • - C 28 Oct 95 _ . - 8.00 3.16 1.98 7.67 - - 1.24 1.64 3.07 • 5.84 CO 21=96 2.80 0.67 5.99 2.10 - - - - - 2.01 2.31 5.29 4.75 - - - - O 181cn 95 - 14.69 - - 4.71 2.65 5.23 • 2.10 1.56 - - - - 1.10 1.19 232 9.37 3.77 N 2914.96 3.35 . - - - - - - - . 2.83 - - . - - - - 0 I O Air 95 3.07 - 1.03 6.51 3.50 5.32 2.80 - - 1.34 4.99 2.40 3.16 5.93 4.96 1.28 L76 3.31 6.84 4.31 LL 20 Jun 96 2.80 - - 036 5.63 2.56L95 2.46 5.14 • _ _ _ - - - - 29 Aug 96 216 - • 0.46 4.99 2.01 4.25 2.40 - - L64 4.05 138 2.03 4.59 3.74 1.25 1.58 2.37 5.63 3.86 CO V.' 1 15 Oct 96 2.16 - - 0.97 4.71 - - - - - • - 1.79 1.95 4.16 3.65 - - - - N 211 +97 3.68 - • 0.73 8.15 2.76 - - • - 2.40 3.01 6.91 5.84 - - - d .71 ID 29 Jan 97 _ - - • - • _ • 1.55 2.19 - 5r.b97 0.46 0.06 TOTAL 205.44 587.68 303.74 32.56 341.92 16737 119.62 44.41 320.92 61.96 84.93 83.30 135.71 312.87 6.46 22.95 45.06 61.56 30.89 43.46 90.72 100.22 20.76 26.78 58.83 67.83 39.25 Acg.Rote 6.63 25.55 14.46 1.05 12.25 5.59 5.44 4.04 12.84 3.26 4.47 3.33 7.98 14.90 0.92 2.87 3.47 8.79 2.57 3.10 6.48 7.71 1.60 2.06 4.40 11.31 6.54 in ltlyr 2-9 IIITable 2-1 b. Rates of Landslide Movement at Portuguese Bend GPS MEASUREMENTS CITY OF RANCHO PALOS VERDES REDEVELOPMENT AGENCY � -"" ic: . .:..«.,....... Q,.' a...,x i.ii <...$.3l.. ........ Z4,).;S'•v.L •h,..">",...._. <...xa<.. > Z,ao;.r a ca..... _ ....,.. . ill Total Period 1 Last Period MOVEMENT GPS DATE DATE HORZ. VERT W" DATE DATE HORZ. VERT Monuments BEGIN END FT. FT1 BEGIN END FT. FT ww w ., - rm c . .. :i.., Abalone Cove il`J"at ABO1 BASE •••• 0.0 0.0 %i.`£ •••• 0.0 0.0 ABG2 08/16/94 01/15/98 0.0 0.0 :? 01/29/97 01/15/98 0.0 0.0 A803 10/04/94 01/15/98 0.0 0.0 01/29/97 , 01/15/98 0.0 0.0 A804 10/04/94 01115/98 0.2 0.1 <e 01/29/97 01/15/98 0.0 0.0 ABO5 10/04/94 02/18/97 0.1 0.0 .µ 01/29/97 02/18197 0.0 0.0 A806 08/16/94 09/12/98 0.3 0.2 01/15/98 09/12/98 0.2 0.2 ABO7 10/04/94 09/12/98 0.3 0.2 07109/98 09/12/98 0.0 0.0 A1308 08/16194 09/12198 0.3 0.1 07/09/98 09/12/98 0.0 0.0 A1309 08/16/94 09/12/98 0.2 0.1 3•1 01/15/98 09/12/98 0.2 0.1 AB11 08/16/94 01/21/97 0.1 0.0 s 01/18/96 01/21/97 0.1 0.0 AB12 10/04/94 01/15/98 0.1 . 0.0 01/29/97 01/15/98 0.0 0.0 AB 13 10/04/94 01/15/98 0.2 0.1i 10/19/97 01/15/98 0.0 0.0 •• • • AB 14 08)16/94 01/16/98 0.0 0.0 10/19/97 01/I6/98 1 0.0 0.0 AB15 08/15/94 t 10/19/97 0.1 0.0 m 03/12/97 4 10119/97 0.0 0.0 AB16 10/04/94 09/12/98 0.1 0.1 i 01/16/98 09/12/98 0.0 0.0 AB17 08/15/94 01/16/98 0.0 0.0 01/29/97 01/16/98 0.0 0.0 AB18 08/15/94 01/16/98 0.0 0.0 ▪ 01/29/97 01/16/98 0.0 0.0 AB19 08/15/94 01/16/98 0.0 0.0 , ▪ 01/29/97 01/16/98 0.0, 0.0 AB20 08/16/94 01116/98, 0.0 0.0 'I:i 03/12/97 01/16/98 0.0 0.0 4 AB2I 08/16/94 03/12/97 0.0 0.0 II 03/16195 03/12/97 0.0 0.0 AB22 08/16/94 07/23/97 0.2 0.0 '~4' 01/21/97 07/23/97 0.2 0.0 AB23 09/17/97 09/12/98 0.1 0.3 '„`' 01116 09/12/98 0.1 0.5 AB24 4 03/12/97 09/12/98 0.1 0.0 03/12/97 09/12/98 0.1 0.0 AB50 01/16/98 01/16/98 0.0 • 0.0 01/16/98 01/16/98 0.0 0.0 ...._. ,,,,X, ?.,,.M...�..s .`Y'.� ` :.fsixa..;.....o..o a .:5i ..x.........n....w' '$...n1. aki...".,a a...a Portuguese Bend PB04 10/04/94 11/06/98 4.2 1.2 em, 09/12/98 11/06/98 0.1 0.0 • PB05 10/04/94 10/19/95 3.5 0.3 I 03/16/95 10/19/95 2.0 0.1 PB06 08/16/94 11/06/98 13.3 2.3 ys 09/12/98 11/06/98 0.3 0.0 • PB07 10/04/94 11/06/98 16.6 1.0 i- 09/10/98 11/06/98 0.5 0.0 • 08 06 ' 09/12/98 11/06/98 0.4 0.1 • Sc 11l____5:8/16/ 4 11/06/98 6� . 09/12/98 11/06/98 0.4 0.1 • PB10 08/16/94 11/06/98 34.8 4 5.7 09/12/98 11/06/98 0.9 0.3 PB11 08/16/94 11/06/98 40.5 7.4 09/12/98 11/06/98 1.1 0.3 • PB12 08/16/94 11/06/98 29.1 2.0 + 09/10/98 11/06/98 0.8 0.2 • P813 08/16/94 11/06/98 18.3 1.8 09/12/98 11/06/98 0.5 0.1 • PB14 08/16/94 11/30/94 0.0 0.0 A 10/10/94 11/30/94 0.1 0.0 PB15 08/16/94 12/01/94 0.0 0.0 11/30/94 12/01/94 0.0 0.0 .--,- 11-07-98 III 2-11 Table 2-1c. Rates of Landslide Movement at Portuguese Bend . III :,.='f.z"--:-'-;ViS;7:-t ' .::71,;;t....1Q:....'..2•1....,z;'7,',-.... .›x.1,:,7'4',,z:z:::g.- -'1-7IFfki7::'''''zig-7,::::•'4+-7-Z.5:',a7'",i'::itt^7: 1.71:ZiFi'gii,`EAti•Sz' Total Period Last Period MOVEMENT ; MOVEMENT GPS DATE DATE HORZ. VERT Pi DATE DATE HORZ. VERT Monuments BEGIN END FT. FT. s BEGIN END FT. FT. PB16 08/16/94 03/12/97 9.6 1.7 '1 08/29/96 03/12/97 2.0 0.4 PB18 08/16/94 11/06/98 8.0 2.0 v 09/11/98 11/06/98 0.2 0.1 • PB19 08/16/94 11/06/98 10.6 1.7 ` 09/11/98 11/06/98 0.3. 0.1 • PB20 03/14/95 11/06/98 25.9 3.5 0 09/11/98 11/06/98 0.8 0.1 • PB21 10/04/94 11/06/98 24.0 3.4 5.iL 09/1I/98 11/06/98 0.7 0.1 • PB22 10/04/94 11/06/98 303 ! 4.1 -- 09/11/98 11/06/98 0.8 0.2 • P823 10/04/94 10/19/97 12.6 i 1.1 02/05/97 10/19/97 3.5 0.5 PB24 10/04/94 , 11/06/98 16.6 2.9 ' 09/12/98 11/06/98 0.4 0.0 • PB25 10/04/94 11/06/98 17.3 1.2 .S 09/11/98 11/06/98 0.4 0.0 - P826 10/04/94 11/06198, 14.1 1.3 is 07/09/98 11/06/98 0.3 0.1 - PB27 10/04/94 11/06/981 40.4 4.8 i10. 09/11/98 11/06/98 1.1 0.3 • PB29 08/16/94 11/06/98 22.3 6.0 /: ' 09/12/98 11/06/98 0.6 0.1 • PB34 10/19/95 10/19/95 0.0 0.0 t. 10/19/95 10/19/95 0.0 0.0 PB38 12/04/97 11/06/98 4.5 0.0 s. 07/09/98 11/06/98 1.0 0.0 - P339 03/16/95 03/16/95 0.0 0.0 03/16/95 03/16/95 i 0.0 0.0 P840 1 03115/95 01/18/96 15.25.5 10/19/95 01/18/96 j 3.7 1.3 PB41 03/15/95 02/05/97 10.1 0 1.6 08/29/96 02/05/97 2.9 0.2 P1342 03/15/95 03/16/95 0.0 0.0 `-w 03/15/95 03/16/95 0.0 0.0 P843 08/28/96 11/05/98 32.1 0.0 09/12/98 11/05/98 1.3 0.0 • • P1345 01/21/97 11/05/98 24.7 0.7 r+x 09/12/98 11/05/98 ; 1.1 0.2 • PB46 0 01/21/97 11/05/98 31.6 2.7 *w 09/12/98 11/05/98 1.5 0.2 • PB51 12/04/97 11/06/98 0.4 1 0.13 09/11/98 11/06/98 0.1 0.0 • P853 12/04/97 11/06/98 6.2 1.2 % 09/11/98 11/06/98 0.5 0.1 • PB54 12/04/97 11/06/98 0.6 0.2 09/11/98 11/06/98 0.0 0.0 • P855 01/21/98 11/06/98 5.9 1.I `1 09/11198 11/06/98 0.6 0.1 • z.‘.-.1.i....• =' Vie. ,,,.-- , ^ •.r:x ,.Vr"m Beach Points 806 11/25/96 11/04/98 0.0 0.1 01/28/98 11/04/98 0.0 0.0 - B1300 07/23/97 10/19/97 0.0 0.1 '00: 09/18/97 I0/I9/97 0.1 0.0 3802 1 07/22/97 10/19/97 7.9 1.4 a'a 09/18/97 10/19/97 2.3 0.5 BB06 07/22/97 10/19/97 0.2 0.3 09/18/97 10/19/97 0.1 0.3 8808 07/22/97 12/13/97 5.3 1.8 10/19/97 12/13/97 2.8 0.9 81309 07/23/97 01/28/98 3.5 1.1 `+ 12/13/97 01/28/98 0.1 0.0 BB10 07/23/97 11104/98 0.1 0.6 _:• 01/28/98 11/04/98 0.1 0.0 BB20 12/13/97 11/05/98 1.5 0.1 12/13/97 11/05/98 1.5 0.1 • 8821 I2/13/97 11/04/98 0.4 0.4 .+s: 01/28/98 11/04/98 0,0 0.1 • B1322 12/13/97 11/05/98 8.2 1.3 4. 12/13/97 11/05/98 0.5 2.1 • 8B23 12/13/97 I 11/04/98 3.0 0.1 I`` 01/28/98 11/04/98 2.9 0.1 • BB25 12/13/97 Ir 11/04/98 5.8 0.5z 01/28/98 11/04/98 5.8 0.6 • 1 I I E i i: ! I i i 1 2-12 4111 • Figure 2-8. GPS Stations - �P ax..A of»-� y�Hi P.1. • :� :.:711......... •a Ila E' ° r. r.. •!H. ..� �� -�_ Via•. �1:ll .I ,,i ..,_::::i......, - ��_ Il_xt s— LC'I.,)15.4a......-=.--,--_''� .<Z. --'•'A'•°-• psi:C ..: • ....... . %. ,, • • J / 4)..-'..:'/-- / , 'T' J/J £. 2...- esu 1:-' 710_- • I • 0 4/3 s0111•4111)0111•0111•4111)S � Q sw.su-•t 80ar. S . • oc f'eir . 0 2-13 1110 Table 2-2. 1996 Beach Point Landslide Movement Beach Net Horizontal Rate Horizontal Total Point Movement(ft) Move (ft/day) Net Bearing Dates Days B02 0.018 0.001 S 39° 17' W 9/28/96 to10/24/96 26 B03 0.016 0.001 N 64°26' E 9/28/96 to 10/24/96 26 B05 0.020 0.001 S 15° 08' E 9/28/96 to 10/24/96 26 B06 0.031 0.001 N 60° 16'W 9/28/96 to 10/24/96 26 B07 0.526 0.020 S 06° 32' E 9/28/96 to 10/24/96 26 B08 0.015 0.001 N 84° 17'W 9/28/96 to 10/24/96 26 B09 0.034 0.001 N 00°44' E 9/28/96 to 10/24/96 26 B10 0.027 0.001 N 81°27'W 9/28/96 to 10/24/96 26 Table 2-3. 1997 Beach Point Landslide Movement • Beach Net Horizontal Rate Horizontal Total Point Movement(ft) Move (ft/day) Net Bearing Dates Days B06 0.046 0.000 S 76° 54' E 11/25/86 to 1/28/98 429 BBOO 0.034 0.000 S 76° 54' E 7/23/97 to 10/19/97 88 BB02 7.865 0.088 S 05°44' W 7/22/97 to 10/19/97 89 BB06 0.158 0.002 N 09° 32'W 7/22/97 to 10/19/97 89 BB08 5.279 0.037 S 09° 09' W 7/22/97 to 12/31/97 144 BB09 3.498 0.019 S 16° 59' W 7/23/97 to 1/28/98 189 BB10 0.066 0.000 S 57° 19'W 7/23/97 to 1/28/98 189 BB21 0.425 0.009 N 29° 55' E 12/13/97 to 1/28/98 46 BB23 0.105 0.002 S 22° 51'W 12/13/97 to 1/28/98 46 BB25 0.064 0.001 S 17° 53' W12/13/97 to 0/28/98 46 III 2-14 Corps of Engineers Analysis of Slide Plane Toe • Based on review of these studies, the Corps of Engineers Geotechnical Branch indicated that the location of the active slide plane cannot be defined with great accuracy at this time because of inherent drilling and sampling problems. The Corps of Engineers analysis of the field investigation shows potential slide plane and toe locations shown in Figure 2-9. The Corps agrees that the findings of the side-scan sonar and seismic studies appear to show stable undisturbed bedrock located 400 feet offshore. However, there are several concerns regarding the location of the slide plane and toe within 400 feet from the shoreline. The Corps of Engineers also agrees that at the present shoreline, the borings define the slide surfaces as no deeper than about-40 feet MLLW and as shallow as the beach itself. The Corps analysis indicates that the present beach can be considered an active surface because the slide mass can move across it and therefore because of varying rates of slide movement and coastal erosion , the location of the toe of the slide has been variable over the last few decades (reaching as far as 200 feet offshore), and may or may not be coincident with active or presently inactive slide surfaces. The Corps of Engineers concludes that the shoreline borings indicate that the slide planes could dip offshore, inferring that unstable foundation conditions exist well beyond the 100 foot distance from the shoreline. In addition, the historic maximum southward extent of the shoreline was approximately 200 feet seaward of the current shoreline. At this time, there is no data to suggest that this represents the maximum possible seaward location of the toe. Continuing Monitoring of Landslide Movement The City of Rancho Palos Verdes is continuing to monitor the landslide movement including the installation of additional GPS stations along the shoreline of Portuguese Bend. The results of these studies indicate some sections of the shoreline show little or no movement, with one particular station showing continuing movement. The City intends to continue the monitoring of these stations to further determine the limits of the active slide plane toe. Landslide Stabilization Plans Since its reactivation, many efforts have been made to stabilize the landslide, including grading, dewatering wells, drainage improvements, construction of caissons or"shear pins," and construction of gabions to reduce erosion of the toe. The effectiveness of these efforts are complicated by multiple factors contributing to the continued movement. However, it appears that there has been reduction in slide movement as a result of some of these efforts. The most significant factor causing continuous movement is the presence of groundwater within the landslide. The water causes a reduction in the strength of the bentonite days, due to adsorption of the water by smectites within the day. Groundwater also reduces the effective stresses along the rupture surface, and increases the weight of the landslide material. Because of the complexity of the various factors causing the landslide, there will be some degree of uncertainty on whether the landslide can be permanently stabilized. • 2-15 19 co C N 300- I`- Seaward Subsilde---- --� 51p 13 • O 200- PIves w N 100- els a cn 1:1 Holocene Belmont o _j L c-3 A — • -9L"16 w"labl-22— ---- . - f .- - 3 /- Porlvevele lull .— —�' -- - D. 100 _ _ --- r __ — — T,n. 1 O Vicinity of Bedrock 0 About 400 Feet Offshore rt 0 0 • 0 0,. . r I� Coastal Processes And Shoreline Conditions This Section describes the coastal processes pertinent to the Study Area and sediment budget conditions. Topics covered include tidal levels, extreme and daily wave climates, nearshore circulation, and the transport, deposition and erosion of sediment. It also includes analysis of potential sediment sources such as the Portuguese Bend Landslide, local creeks and storm drains, and erosion of local cliffs. It also identifies sediment sinks, and the overall sediment budget for the Study Area. Further information and details on these topics are presented in Appendix B, Coastal Engineering, Design, and Cost Estimates. Climate The climate of coastal southern California is generally considered to be of a semi-arid Mediterranean type. Ocean-landmass temperature variations result in daytime wind patterns dominated by onshore winds, nightly patterns dominated by offshore flows. Exceptions occur during occasional winter storms, where wind directions vary, and during Santa Ana conditions when winds are usually out of the northeast. The National Weather Service provides summary weather statistics for the southern California area by geographic location. Statistics for Long Beach (closest available data to project site) indicates an average wind speed of 6.3 miles/hour, with an average wind direction of WNW. Daily highs average 74° F and daily lows average 54° F. Average annual precipitation is 12 inches (NWS, 1998). 11, Storms Ocean swells affecting the Study Area are generated by three basic meteorological phenomena: northern Pacific extra-tropical cyclones, eastern north Pacific tropical cyclones, and extra-tropical_storms_.in_the_southern_hemisphere. Extra-tropical cyclones regularly form in the north Pacific from October through May. These storms usually track across the Pacific in an easterly direction. These storms have been responsible for the largest waves affecting the Study Area. The 1982-83 and 1988 winter storm seasons resulted from a series of extra-tropical cyclones which produced severe conditions responsible for widespread destruction along the Southern California Coast. Tropical storms or tropical cyclones develop in the warm waters off the west coast of Mexico during May through November. The tropical cyclones usually track west to northwest, but have been known to veer to various directions.An average of eight or nine tropical cyclones per year attain hurricane strength in the eastern north Pacific. These hurricanes weaken and dissipate as they reach the cooler waters of more northern latitudes. If these systems stall or track into an appropriate wave window, fairly large waves can propagate into southern California. Although extremely rare, tropical systems can track up all the way into the southern California area, as evidenced by the tropical storm of September 1939. During the southern hemisphere winter, large intense low pressure systems move from west to east across the south Pacific. Locally, these storms can generate very large waves. 110 2-17 For the most part, this activity occurs from May to October. These waves travel northward across the equator and into the southern California area. Wave periods are typically long, 16- to-22 seconds. Wave heights reachingsouthern California typicallyare small (two-to-four feet); ' however, in some instances they can be ten feet or larger. Tides Tides along the southern California coastline are of the mixed semi-diurnal type. Typically, a lunar day consists of two high and two low tides, each of different magnitude. The lower-low normally follows the higher-high by about seven to eight hours, whereas the next higher-high (through lower-high and higher-low waters)follows in about 17 hours. The National Ocean Service (NOS), collected tide measurements at the Los Angeles Outer Harbor in establishing tidal datums of the 1960 to 1978 tidal epoch. Tidal characteristics are shown in Table 2-4. Table 2-4. Tidal Characteristics -Los Angeles Outer Harbor Reference Elevation (Ft/MLLW) Highest Observed Water Level (1/27/83) 7.96 Mean Higher High Water(MHHW) 5.52 Mean High Water(MHW) 4.77 Mean Tide Level (MTL) 2.86 • Mean Low Water(MLW) 0.95 Mean Lower Low Water(MLLW) 0.00 Lowest Observed Water Level (12/26/32) -2.59 Water Levels The variation of water levels along the shoreline is due principally to astronomical tides (ie. tides driven by the moon, sun and planets), storm surge driven by spatial variation in barometric pressure, wind and wave setup, and inter-annual large scale oscillations in the circulation and temperature distribution of the Pacific, commonly referred to as the El Nino Southern Oscillation (ENSO). Prediction of astronomical tides is well established and validated by observation. The contribution of the other components to water levels are more random in occurrence, although not entirely independent, and more variable both spatially and temporally. Flick(1991) estimated the ten largest positive tidal residuals at a relatively wave sheltered location in southern California to range from 0.84 to 1.06 feet over a 30-year period of record. Flick(1991) also demonstrated that the joint occurrence of the largest residuals with the highest astronomical tides and/or highest waves were rare, although the analysis 2-18 • subjectively filtered residuals having durations shorter than one and one-half days. Wave setup and setdown along the beach profile varies from a minimum near the wave breaker location and a maximum at the shoreline. Linear wave theory predicts maximum setup of about 4%to 5% of wave height Surf beats or infragravity waves are thought to be the result of non-linear transformation of energy across the surf zone. This phenomenon is not precisely understood but is generally observed with a magnitude of one to several feet during severe wave events. Long-term changes in sea level from the "greenhouse"effect, tectonic forces, and other localized ground movement are relatively small by comparison to the other components of sea level. The National Research Council (Marine Board, 1987) considered three plausible future sea level rise scenarios along the coastline of North America: 0.5 meters, 1.0 meter, and 1.5 meters by the year 2100 (relative to 1986). Past trends at Los Angeles show a sea level rise of 0.004 feet per year with a standard error of 0.0017 ft/yr for the period between 1950 and 1986 (NOAA, 1988). If past trends are projected into the future for Los Angeles, a sea level rise of 0.2 feet would be expected over the 50-year evaluation period. Currents In the nearshore region, Iongshore energy flux calculations and observations indicate a net longshore flow to the southeast with a northwest reversal during times of southern swell. Sediment plumes observed in the nearshore zone indicate local cross shore and complex circulation patterns. Measurements made seaward of the-100 ft isobath indicates mean 4110 offshore surface flow with mid-level and bottom flow to the northwest. Figure 2-10 shows general circulation in the Southern California Bight Noble (1994) states"A poleward flowing undercurrent, the California Countercurrent, also enters the Southern California Bight along the continental margin from the southern boundary. This undercurrent causes currents along the slope off Palos Verdes to flow toward the northwest." A year-long study of circulation patterns on the Palos Verdes Shelf was begun in May 1992 (Noble, 1994). Four moorings were deployed on the shelf and upper slope. The moorings contained current meters located near the surface, at mid-depth, and near bottom. Noble (1994) states "The mean currents flow generally along the isobaths toward the northwest at all mid-depth and near bottom sites. Mean surface currents are offshore. However there is considerable variability in the average flow field for individual months." • • 2-19 Figure 2-10. General Circulation -Southern California Bight III - \. • 14°C .-I - f:,. • / Santa Barbara a : _ Los Angeles _ -;- os, Verdes } insul '',-2,..._-_,,_--}„.. .."' .-.T_ _.- ..-E7-'_ :'t-.,,,z, ZtlNi:.\ �• • _`. _ � ..---- 15°C 15°C • ; :i-2 p _ � ►. .--San Diego ' � 2} U.S. r�_ _F _ - Tijuana MEX. lior 16°C •Prevailing Winds 'y . ° `�-' ii.....-i, -. lb\ - -4— Surface Water Flow ¢ �=._* ► Ensenada Mid-depth Water • = _• _ Flow . . -_ F `\\\y (Below 200 m) _r. �� . 17°C �n�. ::. ;‘ Freshwater Inflow := . , --- Average Water Temperature -ii _ g- °. ~.:jam . • at 10 m `. - � •i 2-20 0 Wave Exposure The Study Area is sheltered from deep ocean waves by the offshore Channel Islands and by the extension of headlands located on the Pacific Coast. Four wave windows exist as shown on Figure 2-11.A southerly window located between the Baja California Coastline and Santa Catalina Island extends from 147°to 170°. A southwesterly window located between Santa Catalina Island and San Nicholas Island extends from 217°to 240°.A westerly window located between Santa Barbara Island and Santa Rosa Island extends from 245°to 277°. A northwesterly window located between Point Conception and Santa Cruz Island extends from 289°to 293°. Local Seas and Swells There are no wave gauges in the immediate vicinity of the project site. Buoy 46025 located in 2,800 feet of water midway between Catalina and Anacapa Islands provides the best source of measured nondirectional data offshore of the project site. Significant wave height and dominant period statistics are available from April 1982 through October 1993. Wave heights during this period range from 0.3 ft-to-26 feet, with periods ranging from less than 2.3 seconds to greater than 25 seconds. • A few directional wave data sets were researched and the directional wave data from Buoy 46025 from 10/1/92 to 4/30/93 were selected as the directional data set best representing local seas and swell. Wave heights of one to three feet and wave periods ranging from two to 25 seconds are typical of the daily wave conditions atthe_Ranchopalos.Verdes coast. The site normally experiences wave heights of four to six feet a few times a year. Extreme Waves Extreme wave data are available from hindcast and measurements. The selected data set represents a time period that extends from 1904 to 1988, and is presented in Table 2-4. The data set is derived from four sources described in Appendix B, Coastal Engineering, Design and Cost Estimates. S 2-21 6 Figure 2-11. 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' .•• to-- o•• .- - - ,-,"44 e• +• ••4•0•0P -- 4444w .. _ _ ♦••• •f4•••••••.•••eO♦_: - -►•e••e•••••• % - _ ' ao•••°o••f.a°•.+04•te _ ;: ..4• •e••o• _ =:•iiiiiiiii♦ i. ii4 : ' - ...,.. o-e0•4••. , . _s••••o•.•o•o40e•4• - --. . .d :. .414f••O•s•.Oo •• e❖o • ,s44•44 44••e ••••4 •4 :�••e❖••o•❖.❖.❖.•o••• • • • • L • • • • • • .•44•e•.•4 • ••4 •o •••_ i•••••f•• •••f••••f•••4•• ►•••s••oo�iooziii+iiiii, = • • -•°• ••• ••••if••••••°ii• ,�•oio••oi•iF•04•e•4+• e• - �•• • ••4 • •�• • • s 4•ef4+i•4.4eioon •��a•4ie•••4+r.•P•:.i•S:14a.•oe• ❖+ . =- e••4.0.0••4•••eoeeo••••• Ns,• -•- ... i ••sil•ff°••°••• ii ••iei +ii.ei•eiii �.- -- '�@oe •e• ..••••f40•cw•c, •4e•••i••4••o••e••e4••444•+ •4••!•• •4 ' !•••••••••••e•Of•••••••••4••••••f.# . • - - _ _- • _ - _ 4444•G•❖•••••••••••••••••••e••e0.4S•*-.: -:.' 5 :+40t.4,„s•.•4•4...0•... ••4,4.•.•4•• -?ANFI,ER-BANK - _ • -•- `••••••i•i • Table 2-5. Extreme Wave Conditions H. T Az Date (ft) (sec) (deg) Reference 9 Mar 1904 17.9 12.0 225 1 8 Mar 1912 17.5 11.5 270 1 16 Dec 1914 13.0 9.9 180 1 28 Jan 1915 16.3 11.8 205 1 1 Feb 1915 16.5 12.4 280 1 26 Jan 1916 14.0 9.6 250 1 1 Feb 1926 12.6 16.0 260 1 6 Apr 1926 11.8 13.8 270 1 6 Dec 1937 11.6 16.4 270 1 15 Sep 1939 26.9 14.0 205 1 20 Jan 1943 16.2 10.8 180 1 13 Mar 1952 11.7 11.7 250 1 6 Jan 1953 16.0 19.2 260 1 27 Jan 1958 18.1 13.5 270 2 5 Apr 1958 25.1 17.5 293 2 10 Feb 1960 18.3 18.5 294 2 11 Feb 1963 19.5 13.5 269 2 • 7 Feb 1969 15.6 14.5 284 2 7 Dec 1969 14.4 20.5 276 2 29 Aug 1972 12.7 17.5 156 3 16 Jan 1978 18.6 16.5 284 2 20 Feb 1980 15.6 14.5 255 2 23 Jan 1981 15.4 17.5 265 2 29 Jan 1981 21.5 15.5 269 2 24 Sep 1982 11.1 15.5 158 3 1 Dec 1982 20.4 10.5 293 2 27 Jan 1983 21.0 20.5 283 2 13 Feb 1983 17.1 16.5 275 2 2 Mar 1983 23.6 18.5 263 2 Nov 1984 15.5 17.0 262 4 Dec 1985 21.4 17.0 262 4 Dec 1986 12.0 15.0 280 4 Mar 1987 15.6 15.0 260 4 Jan 1988 33.1 15.0 265 4 Marine Advisors 2 Pacific Weather Analysis, Extratropical Combined Sea and Swell 3 Pacific Weather Analysis, Tropical Storm Swell Affecting South Facing Beaches 4 Begg Rock Waverider Buoy data, direction averaged from WIS and Kent data • 2-23 Deep Water Extreme Wave Frequency 411 A return period analysis of the extreme storm wave heights was performed using the partial duration series of 25 storms over a period of 88 years using ACES 1.07e (USACE, 1996). Population parameters were estimated by the method-of-moments. A Fisher Tibbets Type I distribution provided the "best fit"to the data. The results are shown in Table 2-6. Table 2-6. Return Period for Unsheltered Deep Water Waves Return Period Significant Height (Years) (Feet) 2 10.4 5 15.8 10 19.3 25 23.8 50 27.2 100 30.5 Nearshore Extreme Wave Frequency 411, The deepwater waves were transformed to nearshore depths of 100 feet using O'Reilly coefficients as described in Appendix B. An extrema) analysis was done on the results of the transformed wave data to determine significant wave height return periods offshore of the site. These data are presented in Table 2-7. Littoral Cells The Santa Monica Cell extends from Point Dume to Palos Verdes Point (USAGE 1986). The northwestern part of this cell (Malibu area) is characterized by rocky headlands and seasonal pocket beaches. The central portion of this cell (Will Rogers to Torrance) is characterized by year-around sandy beaches which were artificially widened and compartmentalized by beachfills and coastal structures (groins,jetties, and breakwaters). The southeastern portion of this cell (Palos Verdes Region) is characterized by rocky headlands and pocket beaches. 2-24 I Table 2-7. Nearshore Extreme Wave Distribution (Depth of 100 feet, MLLW) Return Period Wave Height (years) (feet) 2 5.2 5 7.7 10 9.9 25 13.2 50 15.9 100 - 18.8 The Palos Verdes Subcells extend from Palos Verdes Point to Point Fermin, a distance of approximately 12 miles (USAGE 1986). This region is characterized by rocky headlands and pocket beaches. The San Pedro Cell extends 31 miles from Point Fermin to the city of Corona Del Mar just southeast of the Newport Submarine Canyon (USAGE 1986). This cell has been extensively modified by man. Major watersheds have been dammed reducing sediment yield. 4111 The extensive breakwaters constructed for Los Angeles and Long Beach Harbors have reduced wave energy, thereby reducing sediment transport in this area. Jetties protecting Alamitos Bay, Anaheim Bay and Newport Bay also have modified cell dynamics (USAGE 1986). The following discussion will focus on the Palos Verdes Subcells, With information provided on the Santa Monica and San Pedro Cells when pertinent. Control Volume A control volume has been established in order to study sediment flux within the area of study, Figure 2-12. The control volume extends from Long Point to Whites Point, and from the 0 ft MLLW contour to the-100 ft MLLW contour. Evaluation of the change in sea floor elevation between three dates will aid in the understanding of sediment accretion and erosion patterns. Potential sediment sources (material into the control volume)and sediment sinks (material out of the control volume)are highlighted below and discussed in detail further in this section. Potential sediment sources include: beachfills, the Portuguese Bend landslide material, local streams and storm drains, bluff erosion, littoral flux of material into the control volume from outside the boundaries, and the Whites Point Outfall. Potential sediment sinks include offshore and downcoast loss of sediment out of the . control volume. 2-25 , li�Jryd ►C I ;/•• :�N. : 4`•,.�, is r , ' pF �ts ' ., r � �� MEND 4:.• R. 1 °a11� �.�� //y • tl �> 44:.x.;4 i zg/.! / ''-,Aiii7.0 SOS 11° k'y`; • f{4• �` '` 1� '* N •{.•a.•fx {A ,- ',../, '.f.-N-.::-;''''.....4..a: 4'....,• . -... .jr-.•-.L.. :.''',.- .--- ,-,... ..It_. i.• ‘ 77,_.... 5.4.: ,\ .r 1 •r ! r ti - Y .r Il v.-.:Y,. .1t "P " ,/t ff. ,),.,1 g _ • .. ,�.;;\ tin .S' ‘ :-.i— i' .\ •., ,'" '�• r j/r _ .r....�: A• \:•-/ .**.I,;..te::1;.*:::.r� , 4.• ▪ �. rI• .W',. ,•,s, 1 c \ ©4 •� •iN•'''' '�;., • -'. s , ,:,�+i. .•s"�i ^-SL-ter .mo i .'t:. 1 y 7..;4.•;_-....,74,,,,,,, �._. ... + ,l \ \\_Nf -,��-_ ! ..' + ,•.+ •'^;. �.�• r•rp•r\ ',•Wt .M �'rt.'If1, '►•r. `-La •./ .�4 44 �,•. i. <. .tr � t • .T•'=.7 w ��5.-kiro, ' �w •.C;,r..A1�- S- • ' ^�:�.,'�� '•. ,•.�'..:.•!' � 1�./ 'i '�,- .I� ,� •'�'•il-...`t•`. 1 'AP,'" .a„ �nl�i 4. 4.000..._. „,,,,,..0 :/,1 , , �7/ISHIf aP 1+( v• si� svw-r� ay I �} s x 114 - , ^l',91,4;(.;' `l',� �.f:U-' •,.� c e' r .• r .. +L+. ,_ �p 'elm.. .�`'' tli!w►' .rso r • • '\' '4 • /+ ♦ py 9 tea. n.a^.ii•ua+J t Y • L trt . •,t '� \-1/4'_..,V,,AL, '.oma .,Pram.-r.N.r. % rJ,r• r.,ad. F•♦err. ♦♦♦ �a�. :i�i LL ��\ ��-•-44' �:li •�.-,'....'%Iv`.��y-�.�rti .�'�i1,'_'. .INi Eiger I P sl A ."gicarc7,t t,,, ..0%--!-- ;_-, -,.. - riA...r-v. t-gt 4V- 11fr "Il LIMITS OF CONTROL VOLUME r '! :',.res +7'a.:w� / J 1. -44=U.1-7.:•-•,A,i A ♦ Y .. f .- :L"A hw rte. 4 ,•F IS -100 FT MLLW CONTOUR ♦y, , r .•.L•• -+ o FROM LONG PT. TO WHITES PT. r-/ ..'+='_ :,.,C ,o', .. +ti43,t. j '•' kl LEGENDS ��ss� DRAINAGE AREA BOUNDARY �� OFFSHORE LOSS AND ''�I PT FERMIN —-—-—-— CREEK. ETC DOWNCOAST TRANSPORT (fib DRAINAGE AREA NUMBER 4.000----Bow AMOUNT OF MATERIAL IN/OUT OF SUBCELL OR CONTROL VOLUME •89.000 AMOUNT OF MATRIAL RETAINED IN CONTROL VOLUME ;bra STREAM AND BLUFF CONTRIBUTION • ! t LANDSLIDE CONTRIBUTION :1:la .11, • + Sediment Sources Beachfill Minor amounts of sand have been imported for the private beach adjacent to the Portuguese Bend Club. A thin sand layer has been deposited on top of the existing cobble beach. Dates and amounts are unavailable but discussions with local officials indicate an infrequent import of small quantities. For purposes of this report it is assumed that the beach fill contribution into the control volume is negligible. Landslides Leighton and Associates, (1997) states "Charles Abbott and Associates, Inc. (1997) conducted a study to determine the total volume of[Portuguese Bend] landslide material lost due to wave erosion. The study determined that 5,834,000 cubic yards of landslide material has been eroded from the landslide toe since the reactivation of the Portuguese Bend Landslide."The calculation period is 1956 (reactivation)to 1995, a 40-year period. Dividing the total accumulation by the time period yields a rate of 145,850 cubic yards a year we will use 146,000 cubic yards a year. Kayen, et al (1994) states "Other landslide along the margin at Abalone Cove and Pt. Fermin have contributed relatively insignificant amounts of material to the shelf." Stream Contribution • In order to estimate the amount of sediment yield of the drainage areas in the Rancho Palos Verdes area under study, PSIAC(1968)was used. This publication delineates a very broad method for sediment yield estimation in the Pacific Southwest Region, and is recommended to be used on areas no smaller than ten square miles. The area that drains into the control volume was determined from a topographic nap.The drainage area is approximately 10.7 square miles. The study drainage area was broken down into six smaller drainage areas, as follows: Area 1: Extends from Palos Verdes Point to the southern border of Palos Verdes Estates (includes Lunada Bay). Area 2: Extends from southern border of Palos Verdes Estates to Point Vicente. Area 3: Point Vicente to Inspiration Point(includes Long Point and Abalone Cove). Area 4: Inspiration Point to Bunker Point(includes Portuguese Bend). Area 5: Bunker Point to Sea Bench. Area 6: Sea Bench to White's Point(includes Royal Palms Beach Park). Stream sediment yield analyses for each area are shown in Table 2-8. 2-27 Table 2-8. Stream Yields Stream Yield Drainage Area (cubic yards a year) 1 2,739 2 1,639 3 3,699 4 2,953 5 631 6 1,339 Bluff Erosion Coastal bluffs within the study have the potential to contribute material to the littoral zone. The same six reaches used for stream yield were used for bluff erosion. The analysis of sediment yields from bluff erosion is presented in Appendix B, Coastal Engineering, Design and Cost Estimates. The results are shown in Table 2-9. Table 2-9. Rancho Bluff Erosion Estimates Reach Length (ft) Sediment Yield (cubic yards a year) 1 7400 1850 2 9400 2350 3 16700 4175 4 8800 2200 5 4300 1075 6 5800 1450 Historic Volume Change Within Control Volume Digital data was obtained from the National Oceanic Survey(NOS) for 1933 and 1976 surveys. The NOS surveys extend from Torrance Beach to Los Angeles Harbor, and from the shoreline to well beyond-100 ft MLLW depths. The Corps of Engineers conducted a 2-28 • hydrographic survey in July 1995 which extended from Long Point to Whites Point and from the shoreline to a depth of-100 ft MLLW. Volume changes between consecutive surveys are shown in Table 2-10. Table 2-10. Control Volume Change Net Volume Change Annual Accumulation Surveys Compared (cubic yards) (cubic yards/year) 1933 to 1976 +3,252,000 +162,6001 1976 to 1995 +220,600 +11,600 1933 to 1995 +3,472,600 +89,0411 ' Assumes accumulation occurred between 1956 and 1976 Figure 2-13 indicates the change in bottom depth between the 1933 and 1976 NOS surveys. Areas of greater than 3 foot gain are shown adjacent to Smugglers Cove, Portuguese Bend, and downcoast to White's Point to about the -60 foot isobath are visible. Figure 2-14 indicates the change in bottom depth between the 1976 NOS survey and the 1995 USACE survey. Accretion depths of greater than three feet are shown at Portuguese Bend, with greater than three feet of erosion at Bunker Point. It is possible that much of the material that had accumulated on the reef at Bunker Point and reefs to the southeast, were removed by the severe storms of 1982, 1983 and 1988. Sediment Sinks Man-Made Structures Breakwaters, groins and jetties affect se-. - nt transport. Depending upon length and location, jetties and groins can reduce, divert or even block sediment flow. Two existing coastal structures are found in the Portuguese Bend area. A groin was constructed at the eastern end of Portuguese Bend Beach on top of natural rocks in the 1920s. In 1976, the groin was extended further seaward to reduce the down coast transport of eroded sediment. Although the groin seems to be effective in retaining some cobble material, it's effect is negligible in regards to the scope of the sand and fine grain sediment being considered for this report. • 2-29 Figure 2-13. Isopachs: 1933-1976 Surveys 4111 1NIOd S3111-11 mQ iU m m p . • b-I ,t it A -- ;i1).,,, ' -'...4/ ti 7;CJ Je pihyitr pip. ttllI .,:. ,:r i' 4 ..,"41.i, 'C'r C / 1,7 • }13:. :'t J:. :::,,I, W ; r.:. i, W / 1` 2e ').?f •1 6 • ,4i ;ice t:.% F 1„:: '''' iiq;n it t.1f j. .", 8 dam! 1 t l ,ye•o" , a itQJ Z'4 t j f. o f • tp J2 u B% f • i=.I .. Itl -t fJr /l. Q c•• LL a ::4 N , Z — _ri 1 11 '14 F F J «. b t R, V. 2-30 • • • VJ v O I /I1.1 ...•... :Ci .J JV '` PORTUGESE RENO c.? .::::0';' ,- .:Si.• '.t.2 a 2q f o �„ DiOY .7wVF:41( �I ‘4 1.Nil a I.0 SS z.005 3.555 4.e0e -n _ �`^ts � "74 4� 4 't'•�\ .°� SCALE 1" •1 S@0' 0 • M fs <•;Ezf.. fD • `��. r .:>.. �a to ;3s: i; ciiS . :i�;^• e° >a=xw ,• -a 20 ..a \ ."S 3' a�y N NOTE, CONTOURS SHOWN ARE FROM JULY 1995 CORPS SURVEY. AND ARE AT 10 FT INTERVALS Sry+• "1.-3.,•-•'''': (p LEGEND. �;. +"' `� " + .1.., ,� N > 3 FT GAIN _�iz .4w I.na. I____ 0 TO 3 FT LOSS 4.1 ,Y` > -3 FT �' _I! LOSS Plate 6: Iscpachs: 1976-199S Surveys A 744-feet-long, trend gabion structure was constructed along the Portuguese Bend shoreline east of Inspiration Point in July 1988. The gabion was constructed to protect a . portion of the landslide from wave erosion and to mitigate down coast transport of the sediment debris. Observations indicate that the gabions did reduce sediment erosion of the landslide as evidenced by decreased water turbidity in the immediate nearshore area. The gabions experienced structural deformation from wave attack and landslide movement and were completely destroyed within one year of construction. Headlands Headlands can partially or completely block sediment flow. Observation of the coastline between Abalone Cove and Cabrillo Beach indicate no permanent sandy beaches created by headland induced accumulation. Headlands within the Study Area at Portuguese Point and Inspiration Point permanently retain small amounts of material. Submarine Canyons Submarine canyons function as sediment sinks for material transported in the littoral zone. No submarine canyons are located close enough to shore to affect sediment transport within the Study Area. Longshore Energy Flux and Transport Potential Table 2-11 presents the estimates of sediment transport potential based on considering wave climate. The estimate provides an understanding of the potential volumes of sand which could be moved if sediment was available. The results indicate a total net potential of moving about 107,000 cubic yards of material to the southeast a year. Sediment Budget Figure 2-15 summarizes the quantification of sediment sources and sinks affecting the control volume. The following sources are included: stream and bluff erosion, Portuguese Bend landslide erosion, and an estimation of material being transported into the control volume from around Point Vicente and Long Point. Because of the orientation of the coastline to Palos Verdes Point north, the net transport in this region will be to the northwest and therefore not impact our Study Area. Beachfill material is considered negligible. The landslide contribution is estimated to be 146,000 cubic yards a year. Streams and bluffs contribute 4,000 cubic yards a year into the control volume from Areas 1 and 2, and 18,000 cubic yards a year from Areas 3 through 6. The total stream and bluff contribution falls well below the net potential transport rate of 107,000 cubic yards a year calculated in Section 5.4. This indicates that before the Portuguese landslide was activated in 1956, most if not all of the material that entered the control volume was transported out of the control volume. Based on this, it is assumed that the 1933 hydrographic survey was probably similar to conditions in 1956 prior to initiation of the slide. The historic rate of accretion within the control volume will therefore be the amount of material 2-32 '.� accumulated from 1933 to 1995, divided by 39 years (1956 to 1995). This rate of accumulation is 89,000 cubic yards a year. Table 2-11. Longshore Energy Flux Center Transport Rate Band Azimuth (cubic yards a year) 7 135 173.3 8 158 2,417.5 9 180 6,651.5 10 203 1,562.6 11 225 -1,979.2 12 248 -28,918.3 13 270 -83,329.8 14 293 -3,321.5 15 314 -0.0 • GROSS 128,353.7 NET SE -106,743.9 Note: band widths were 22°, -is SE transport, +is NW transport • 2-33 IP ' • 40" fri: me..1 v. i, g• -..., • i 4, .)00 4-..N., 4.,4..., „.:±1,1*NJ t .... . •,.., r.,.. , \ - . ‘, ...,,_ sz,,,,,.._ 4.- 4ft..111-01A\NI..1.... . nth e y 4 4\ 4. 'k24? ' .,-(? - ' "It'.`,,s't C.• f i•1 •el ' 'r' ..t...._• ef....0.4le --- ...,4e.‘.),tw•••'<? Loil.' - , .._. 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W IF,/ ,411111101. 4 ' • VI .1.4 Tre, . /020•04,-,1 =N. N.,...\444.. ,s.. • •1y 5"- — •-\.-, Mf; •• ,, it- -....,e,N _IL.714-... ..m..., al-. .i, , • V .ftiA. „hi p,-,., , ,".•....t. ivotx,Ifi ,„, !,,,,.-,..L.,a.,.., A, . '- , ,.. 4,-1 ,,N,. . - - ••• marl , I ...16 twi Cf)a„s....-- • . 5k/t ''st-z-, .0..04, ,...,,;, _ vird _me.. -- -- tv- „A , ,71 IS/4 •--. ,111, ,... 1 s '.\ ... Nit. 1 %A .... yfj,'.-./••:- . 1 40.0,k•egride'L...)".' ....,••711 Q IV%i / Ili •a c ' CC, '••• ' ' - ..,...., ,.. .,ict imbrimar•T, 4.4 Rant -. .....1‘, ''''...-tz`Wk.•is ad oriiisl■iloIIII Nem IV ,z: 4,,. .4r ;.- • ',‘• ,,... .i L'4 in me Ji,o am mulo fision rt •/ I 4 ' cary,. - ALgritrii,.0.:"'" *'-:-V ...maw was.mg loi ••• L.3cz? ** /// ‘,. ..kir.7,-4.• 4,1.. .torumiAr...I..%6.....thy rib= 7 4:6 LIMITS OF CONTROL VOLUME a. • / • / .1.:444'..': v,''A'vi..1Z1v1;''.Wrix",,X.14'..., - - • 1.0.6• i , .1.4.1.111.MIR is am ii..... r4. IS -100 FT MLLW CONTOUR •. 1 , agurv-..sullillelilt"): , (n • .."/ ,.r.7 V ,..49miNur.2. .,4 s... 0 FROM LONG PT. TO WHITES PT. .. •e ..111)%•.;1 J. C / • ..-1 '....s-",'Q:• "......'40rje :',..I'''''' 141i C) 7g. qi,. err d i''-'" ' %.-V•ik.': ' 0 •.. r •4.,-: ir. .It 0 LEGEND 1 • ..7,7 •: em, .*•.. /i4 sommmmomm. DRAINAGE AREA BOUNDARY OFFSHORE LOSS AND PT FERMIN —-—-—-— CREEK. ETC DOWNCOAST TRANSPORT A- co 0 DRAINAGE AREA NUMBER 4,000—opp.. AMOUNT OF MATERIAL IN/OUT OF SUBCELL OR CONTROL VOLUME •eq.000 AMOUNT OF MATRIAL RETAINED IN CONTROL VOLUME /11M, STREAM AND BLUFF CONTRIBUTION LANDSLIDE CONTRIBUTION .• (1) • In order to balance the sediment budget, an additional 79,000 cubic yards a year of material would have to be removed from the control volume. It is assumed that some of this material is carried downcoast and out of the control volume and some of this material (mostly fines) is deposited offshore of the control volume. Table 2-12 summarizes the sediment budget. Assuming the landslide contribution rate remains constant, the values shown are predicted to occur for future without project conditions. Table 2-12. Sediment Budget Source Rate (cubic yards a year) Stream and bluff contributions +22,000 Landslide contribution +146,000 Calculated accumulation in control volume *89,000 Longshore and offshore transport out of control volume -79,000 Note: + = Entering C.V., -= Leaving C.V., *= Remains in C.V. • Seismicity The Study Area lies along a broad boundary that separates the Pacific plate from the North American plate, in a seismically active area associated with the San Andreas Fault Zone that lies some 50 miles north. The Los Angels region is geologically complex, and almost 100 active faults have been identified in the area, some of which are shown in Figure 2-16. The nearest active fault zones are the Palos Verdes, the San Pedro Basin, and the Newport- Inglewood fault zones, all located within ten miles of the City of Rancho Palos Verdes. Sediment Characteristics The Portuguese Bend area was known for its hard rock reef prior to becoming covered by sediment from the Portuguese Bend landslide. Currently the hard rock reef is consistently covered by landslide sediment. The sediments in the Portuguese Bend area consist of sand, silt, and clay sized material. A detailed marine sediment analysis, including over 90 samples from the five foot isobath to the 60 foot isobath, was performed in the Portuguese Bend area to determine sediment grain size, sediment thickness, sediment compactness, and sediment contamination. There is a fairly wide range of silt and clay fraction content in the Study Area. Sediments with the lowest silt and clay fractions occur along the coast and in the shallow and • 2-35 Figure 2-16. Earthquake Faults0. \ mss / , c..% • S moo`./e/ o°/,�oa� ;oo// Io��os -c \ Looe • S L \ o0 raG� Few••. 9°•t oo�do• ` N----::-----------------------------‘ ._. -- I-- �/, Hollywood Fault Malibu CoostFault . '...••.......—_ S;erro �— Fault • ' 1 1-1-71-11.777771-,. • sonic Monica of odre Fou/ ).c.., Ione A .,...\----o, - Redondo \s I y kh/f/ier F \ N Canyon \ ! 9� o�/f Fault i o S . N. \ L \ °a o %\• \ e, °P \ \ ` saes • °Gi ao , \ ` �; i i�� • e o o \ °6\ \ o ♦ ~a\ \os o - •Gi o -•\ '`° \ \ m \ i .•\ \ \ \ \ \ \ `, N. \ \ i \ .o° \ \ .... 0 9i \ Catalina \ 0 �� ,� °��° Island .STUDY AREA \\ • °° \ _ \1 '" \ - N - ` �\o 0<. \ 1 `1 °"o \co o 2-36 • intermediate depths of Portuguese Bend near the southeast part of the area. There is a general trend of increasing silt and clay in the offshore direction from east to west, with sediment in the central part of the Bend characterized by a high percentage of silt and clay (50% for most samples). See Figures 2-17, 2-18 and 2-19. The thickness of sediment covering underlaying hard rock in the nearshore Portuguese Bend area is shown in Figure 2-20. In general, sediment in the nearshore (less than -25 feet MLLW) area is less than five feet thick. Sediment further offshore (greater than -30 feet MLLW) is 10 feet and thicker. The sampling taken found no evidence of compaction or cementation of sediment covering the underlaying hard rock reef. The grain size of the materials that reflect the composition of the Portuguese Bend landslide are mostly silty sand with occasional gravel and cobbles. The mineralogy of the landslide materials reflects the composition of the underlying rocks of the Altamira Shale member of the Monterey Formation, and includes siliceous shale, siltstone, diatomite, and volcanic tuff and bentonite. Also included are metamorphic rock fragments from the Catalina Schist which have a distinctive metamorphic mineral assemblage, including glaucophane. Offshore The mineral composition of bottom sediments taken from offshore and to the southeast is very similar to the onshore samples. Many have an oxidized surface sediment layer ranging in color from brown to tan overlying greenish-black sediment containing unoxidized organic matter, suggesting that the area offshore is subject to episodes of rapid sediment deposition 110 from a terrestrial source. Suspended sediment in the surf zone is also oxidized and identical in color. Sediment Chemical Contamination Offshore Contamination The marine pollution problem offshore the Palos Verdes Peninsula has been well documented in several sources. For 55 years, treated wastewater has been discharged off Palos Verdes through the Los Angeles County Sanitation District's Joint Water Pollution Control Plant (JWPCP) sewer outfall at Whites Point. The world's largest manufacturer of DDT discharged its processed waste into the sanitation District's sewers from the 1950s to 1971. Prior to the early 1970s, before improved pollution source control and wastewater treatment practices, the discharge is reported to have significantly altered the Palos Verdes shelf environment. Sediments off the Peninsula were reported to contain elevated levels for heavy metals, DDT, and PCBs in the surface sediments to 20 centimeters in depth near the discharge. • 2-37 ' • 118 23'W 118 22'W 118 21'W 118 20'W 118 19'W 118 18'W •• - Disaggregated Grain• Size ,- 1992 USGS data, 1990 fi/V Vantuna data . ., cr'",04 .....„. . c -,... •ti- . 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' .-kt.41\‘ "'lt •,.....,•-,in -•,•N••,A•i s:. o' :3• ...'.f•••."•\b•-:r.,v, v.• ..1 i-tZ.:.V,-§•'."......• ..4.:' ' .` N,*.0.`kw.:11..•-;liEf Mercator Proleollon al 33.7 N."NAP27 '.. t);...g .'z'NI:.;;- .•4, ,,-,, 4.*tit:k:f.:. -. .••,..---. • ,•.......m-, •..,..s..:,.\• •.,\s• I,•••<:.7.•.:. •••• c ',;•••- I..' '•,,h.\- .,- N,,.. ;.,,.,,•::,: c 118 18'W , •,0.1 .,,,,;,, •tt-,, , .,,, ,,...!-. 1 18 20'W 118 21.W Zt., /t1; 118 22'W 118 23'W 0 0 ..i• • • • z F7. ,, U 2 PROJECT N o LIMITS Li i a xs� \� AREA 1 �. - jy,rle: _ 'REA 2 '�~+~' MAJOR CONTOURS AT 18 FOOT INTERYALS LC '1"'r!\" •..... HOLECENCE SEDIMENT THICKNESS CONTOUR (DILL) I al -- ASSUMED HOLOCENE EOIMENT THICKNESS / HA6ITAT RECOVERY/IMPACT AREAE IN •r -1I8 FT CONTOUR DEPTH IN FEET ILLY N ^ CD .' 5' SEDIMENT THICKNESS IN FEET 4 I AREA 4 01 at AREA 3 6. ..~�--^. a .1111. M lo: \ -�,'). ;` AREA 5 -..e A y 134. N. '21,,,..,„ �FTtiA�i N M rF O NOTES. 1. HOLOCENE SEDIMENT THICKNESS OVER BEDROCK (CONTOUR INTERVAL 6 FT) . SOURCE. R.F. DILL ET AL. 1995 .. •�� n■ MAO■■vmm wni�m mar. 2. USAGE JULY 1995 HYDRO SURVEY CONTOURS AT 10 FT INTERVALS. MEWL=�•ry•o.t..vw.■ lid PLATE 3. LAND CONTOURS FROM 08-95 AERIAL SURVEY AT 10 FT INTERVALS. SEDIMENT THICKNESS SUPPLIED RV THE CITY OF RPV. RECOVERY/IMPACT AREAS The sediment affected by effluent from the Whites Point outfall occurs as an asymmetrical, elongated oval shaped mound some 50-to-60 meters (160-200 feet) offshore on I Figure 2-21. The effluent-affected mound thins the continental shelf, northwest of the outfall, g both offshore(out to the 500-meter depth contour) and inshore(to the 30-meter depth). The actual distribution and depth of offshore contamination varies with the contaminant, but, in general, peak contamination is closest to the outfall. The contamination footprint typically extends in a northwesterly direction with contamination concentration decreasing as the distance from the outfall increases. The highest concentrations of most contaminants are buried 20-to-30 centimeters. (50-76 inches) along the 60.meter isobath. Sediment quality off the Peninsula has improved significantly since the discharge of DDT was discontinued in 1971, and since improved treatment technology and control of contaminant sources has significantly decreased the amount of heavy metals entering the ocean through the JWPCP. It must be noted that recent laboratory experiments with continental shelf sediments off the Palos Verdes Peninsula (Quensen et al, 1998) report that DDE, the most prevalent metabolite of DDT present in the sediment, is readily dechlorinated to a less toxic form, DDMU, by anaerobic marine bacteria. This is contrary to the commonly held notion that DDE is recalcitrant, and implies that the commonly held notion that DDE poses a long-term environmental risk of bioaccumulation should be re-evaluated. Currently, the Federal Government has a lawsuit against chemical corporations that were involved in the discharges through the JWPCP at Whites Point(United States of America et al, v. Montrose Chemical Co►poration of California, et. aL). The contaminated shelf offshore was designated as a site for Superfund investigation by the Environmental Protection Agency in July 1996. EPA has recently prepared a draft report evaluating the current and future ecological risk posed by the contaminated site. Nearshore Contamination All of the existing, ongoing monitoring of contaminated marine sediment has been performed in depths of 30 to 500 meters. As part of the sediment surveys performed for this feasibility study, contaminant sediment analysis was performed on nearshore sediment samples in the Study Area. Vibra-cored sediment samples were taken at five nearshore locations, 7.6 to 7 meters in depth, in Portuguese Bend and one location in Smugglers Cove. These six samples were further divided into an upper, middle, and lower subsample. All 18 subsamples were analyzed for heavy metals, pesticides, and organic pollutants as per EPA/USACOE. Chemical analysis of sediment show that cadmium and nickel occurred at all vibra- cored locations in concentrations that could cause possible environmental effects as defined by Long et al. 1993; i.e., the concentrations exceed the effects range-low(ERL) level. The highest concentrations of these metals were found in the upper and middle layers of sediment 2-42 Figure 2-21. Area of Highly-Contaminated Sediment II . . %......i.t 40. .r I ,, I ..... .... i Pou e$ t �+. t valO9 Veld °. S. • loo m.��` ,tea i, .,A 42(: ° ° Q` � . 6,o m. �°° Los Angeles •c Harbor -••••.N... V N r 'A...N A • N` Area of Highly Contaminated` , Sediment ....--11 - ♦ • 0 is_ 3 ' I- £ Kilometer$ . • 2-43 in the central part of Portuguese Bend. No metal concentrations, however, exceeded the effects range-medium (ERM) level at any locations. DDT and its derivatives (i.e., 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT, and Total DDT)were also detected in vibra-cored samples. DDE concentrations exceeded the 27 ppb ERM level at all but one vibra-core location. Levels that exceeded the ERL level of 2.2 ppb occurred at all locations. DDE was found in the upper, middle and bottom vibra-core sediment subsamples. Cores from the farthest east, however, showed an increasing pattern of total DDT from top to bottom; westernmost cores had the opposite pattern. Sediment rates and/or vertical mixing of sediment(by physical and/or biological processes) may explain the observed patterns. It should be noted that the contamination levels found in the nearshore cores taken in Portuguese Bend were similar to contaminated sediment levels in Santa Monica Bay and several times less than the levels found in and near the effluent-affected contaminated mound offshore the Peninsula. Economic and Social Conditions The City of Rancho Palos Verdes was incorporated in 1973, and by general City law it operates under the Council/City Manager form of government. The City encompasses 12.3 square miles of hilly inland and seven and one-half miles of coastline. One-third of the total land and three-quarters of the immediate coastline land is vacant. The area is a very desirable place to live, with its scenic views of the Los Angeles Basin and the Pacific Ocean, and its usually clean air. Despite the history of landslide occurrences and the continuing landslide movement, some of the existing residential properties have been sold several times since the current landslide activity began. The buyers had full knowledge of the potential and • continued landslide damage, but still found the area attractive. In some cases, dwellings have • been purchased that were obviously damaged, and may continue to be damage prone. Major Land Uses Major land uses in the Rancho Palos Verdes Study Area are residential and open- space recreation. Agriculture includes about ten acres on the Portuguese Bend landslide,just • inland of Palos Verdes Drive South. Institutional use consists of the Wayfarer's Chapel on the western edge of the Abalone Cove landslide adjacent to Palos Verdes Drive South. There is a commercial horse stable in the western portion of Abalone Cove, and a City park, parking lot, and beach. There is a vegetable and flower stall along the road near the park, but otherwise commercial and industrial land use is discouraged. In July 1984, a building construction moratorium was enacted in the City of Rancho Palos Verdes for the landslide areas. There may be limited future residential development in the Portuguese Bend Club area, which borders the current landslide. If the moratorium were to be lifted for the areas adjacent to the 260-acre Portuguese Bend active landslide area (and Abalone Cove and Klondike Canyon landslide areas), development in those areas may occur. No development in the Portuguese Bend landslide area is expected in the future. 2-44 • The area seaward of Palos Verdes Drive South is designated as a coastal zone, and subject to Hazard Zone Codes, therefore, no new subdivision development is expected to occur there, with or without the moratorium. The area below Palos Verdes Drive South is limited to recreational uses and facilities. Development plans for the Abalone Cove public park and beach area consist of an increase in parking spaces at the top of the access trail down to the beach. Longer-term City plans propose public environmental protection and related recreation uses for the landslide area below Palos Verdes Drive South at Smuggler's Cove and Portuguese Bend Cove, once the earth movement is stabilized. In 1996, the City of Rancho Palos Verdes signed a Natural Communities Conservation Plan (NCCP)Agreement which formalized the City's interest in participating in the NCCP Program. The NCCP Program was established by the State of California with the National Community Conservation Act of 1991. The goal of the NCCP Program is to elicit voluntary participation of local entities in the comprehensive management and conservation of habitat for multiple wildlife species in their jurisdictions. NCCPs are intended to result in land use plans and management programs for the long-term protection of designated habitats and their component species. The ultimate objective is to provide for regional protection and perpetuation of natural wildlife diversity in a given area covered by the Plan, while allowing compatible land use and appropriate development and growth. Because of the many species that are dependent on California Coastal Sage Scrub, the State of California's developed guidelines to protect Coastal Sage Scrub habitat in five southern California counties (San Diego, Orange, Riverside, San Bernardino, and Los Angeles)through the NCCP Program. Coastal sage habitat on the Palos Verdes Peninsula • falls within a"sub-region" of the larger Southern California Coastal Sage Scrub Planning Area effort. The Cities of Rancho Palos Verdes and Rolling Hills Estates, and Los Angeles County are currently involved in the planning effort, along with the CDF&G and the USFWS, and environmental groups. A conceptual plan is being developed which includes alternative coastal sage scrub habitat preserves to be considered in the Palos Verdes Peninsula NCCP. Parts of the preserves, when formally identified, are expected to occur within the feasibility Study Area and/or the bluffs above the Portuguese Bend Project area. Demographics The population in the City of Rancho Palos Verdes was 36,577 in 1980, and 41,659 in 1990. The median household income was $79,797 in 1989, compared to the Los Angeles County median household income of$34,965. A majority of the owner-residents of the area are college-educated and employed in professional and managerial occupations. The total 1986 Rancho Palos Verdes labor force was 20,807, of which 20,234 were employed, an unemployment rate of 2.8%. The major road through the Study Area is Palos Verdes Drive South, a significant east-west link. About eight- tenths ighttenths of a mile of Palos Verdes Drive South is in the active landslide area, and is subject to on-going repair. Other roads in the area are private, maintained by local Homeowners Associations, except for a short length of roadway in the Seaview area of Klondike Canyon above Palos Verdes Drive South. S 2-45 The City of Rancho Palos Verdes provides limited bus service for residents on a call-in basis. Utilities are provided to residents of the Study Area by various companies—water is • provided by the California Water Company; electricity by Southern California Edison; natural gas is by the Southern California Gas Company; and telephone service by General Telephone. The Rancho Palos Verdes main sewer lines along Palos Verdes Drive South are owned and maintained by the Los Angeles County Sanitation District. Recreation Open space recreation is the principal land use in the Study Area.At Portuguese Bend the area above Palos Verdes Drive South (PVDS) is used for horseback riding, hiking, biking, viewing, and picnicking activities. The Rancho Palos Verdes City Recreation Department provides open space areas for organized nature study programs. Most of the recreation below Palos Verdes Drive South is oriented to beach use. Approximately 51,000 persons each year visit the public beach in the Abalone Cove Park and adjacent shoreline areas for sunbathing, swimming, and some skin diving. There are plans to increase parking spaces to 175 spaces. The rock pools around Portuguese Point and Inspiration Point, although impacted by the sediment and turbidity from landslide debris erosion, still provide marine life viewing, gathering, and nature study opportunities. Despite awkward access (the areas are steep and uneven, and are fenced off due to hazardous conditions) and diminished aesthetics, Smugglers Cove and Portuguese Point continue to be visited by recreational users for gathering, swimming and sunbathing, and a field archery dub has established a range below Palos Verdes Drive South on the landslide berm. Recreational use occurs at the Portuguese Bend Club beach, although deterioration of • the private beach due to the adjacent landslide has diminished its use, and periodic beach nourishment is required. A popular junior lifeguard program has had to be relocated, and it has become much less popular-as-a swimming beach. It is now used mostly for family picnics and barbecues by its 200 member families. A City park had been proposed for Portuguese Bend, and a plan was being explored by the City of Rancho Palos Verdes to include improved beach and inland area access, hiking, biking and equestrian trails, a protected skin-diving area, a small golf course and driving range, and two parking lots. Studies in cooperation with Fish and Wildlife Services to provide habitat for the endangered gnatcatcher are ongoing. Environmental Conditions This section presents the environmental conditions in the Study Area. Information is presented on air and water quality, biological resources, sediment quality, aesthetics and cultural resources that exist in the Portuguese Bend area and adjacent areas. Further information describing the area resources citing specific sources of information and analysis are presented in the inclosed Draft EIS/EIR and appendices to that document. 1111, 2-46 Air Quality The Study Area is located in the southwestern coastal area of the South Coast Air Basin (SCAB). The SCAB, shown on Figure 2-22, consists of the non-desert portions of Los Angeles, Riverside, and San Bernardino counties and all of Orange County. It covers an area of approximately 6,600 square miles, bounded on the west by the Pacific Ocean; on the north and east by the San Gabriel, San Bernardino, and San Jacinto Mountains; and on the south by San Diego County. The potential for adverse air pollution conditions in the SCAB is high, particularly during the period from June through September. Poor ventilation caused by generally light winds and shallow vertical mixing is frequently insufficient to disperse the large quantities of emissions generated in the basin. In addition, the plentiful sunshine of the area provides the requisite energy to convert oxides of nitrogen (NOx) and reactive organic compounds (ROC), which consist of hydrocarbons and related compounds, into ozone. At the present time, the SCAB is in "extreme" non-attainment for the NAAQS for 03, "serious" non-attainment for the NAAQS for CO and PM,o, non-attainment for the NAAQS for NO2, and in attainment of the NAAQS for SO2. The Air Resources Board (ARB) also designates areas of the state as either in attainment or non-attainment of the CAAQS. An area is in non-attainment if the CAAQS has been exceeded more than once in three years. At the present time, the SCAB is in "severe" non-attainment for the CAAQS for 03, NO2, and CO, non-attainment for the CAAQS for PM,o, and in attainment of the CAAQS for SO2 (SCAQMD 1994). • The maximum pollutant concentrations measured at various monitoring stations maintained by the South Coast Air Quality Management District(SCAQMD)within the SCAB from 1991 through 1993 are provided in Table 2-13 and characterize the background air quality of the Study Area. The North Long Beach location is the closest air quality monitoring station to the Study Area, located approximately eight miles to the east. Generally, concentrations of photochemical smog, or 03, are highest during the summer months and coincide with periods of maximum solar insolation. Inert pollutant concentrations (those pollutants other than 03) tend to be the greatest during the winter months when extended periods of reduced wind conditions and surface-based temperature inversions occur. 2-47 40 Figure 2-22. South Coast Air Basin and Monitoring Stations X 1 •` i I -. • SANTA CLARITA(2) L _.f 1 I LAKE GREGORY ri Loa Mpdn Co. • San Bon a•Soo Co. RESEDA• BURBANK• • ' //�'�" PASADENA•• AZUSA t • FONTANA LOS ANGELES,NO.MAIN GLENDORA / • • • SAN BERNARDINO r BEVERLY MILS• ) ••• POMONA f • r UPLAND • REDLANDS 1,.OS ANGELES• •PICO RIVERA / - r-----L--—: _ _ "`" LYNWOOD WEST LOS ANGELES, • WHITTIER' • RIVERSIDE(2)• I HAWTHORNE • LA HABRA J'" _I •I ,`1f NOACO 1 •ANAHEIM NORTH LONG BEACH• LOS ALAMITOS \ • PERRIS I • HEMET • � Rivaaid�Co. Orem*Ca L \ •COSTA MESA ) • • EL TORO / LAKE ELSINORE TORO/ AVALON il :- IECEHD 11111111 South Coot Air Basin • Air Uo,Iorin0 Station i ' SCALE i 1 10 S o t0 MILES . ilk 2-48 • • • Averaging NUMBER()F DAVS NUMBER OF DAYS Pollutant/bfonitoring 71me MAXIMUM CONCEum i1oN BY YEAR FEDERAL STANDARD EXCEEDED.* STATE STANDARD EXCEEDED" Cr • Station (unlit) ., ,, .. ••• .'• (D OZONE IV North LongIi 'l I•hour 0.11 0.13 0.14 0 6 I 4 � 19 IS (ppm) W NITROGEN DIOXID North Long beach Annual 0.041 - b.b34 b:036 0 0 0 NA NA NA As ang Desch 1.hour 0.028 0.18 0.20 NA NA NA 2 0 0 K Nosh f (ppm) 3 SULFUR DIOXIDE c 3 North Long heath Annual 0.004 0.004 0.004 0 0 0 NA NA NA -0 (ppm) 0 North Long beach 24-hour 0.618 0.026 0.014 0 0 0 0 0 0 (ppm) North Long beach I•hour 0.14 0.11 4.05 NA NA NA 0 0 0 (ppm) CARRON MONOXIDI, CCD C N North Long Reach -hour 'h.3 - 8.1 a.9• 0 0 0 I U 0 ...i A CO (ppm) N North Long Beach l•hour 14.0 10.0 9.0' 0 0 0 0 0 0 to ,may (ppm) co PM10 W •Oy, Nonh Long beach Annual 36.4' 36.6' 33.8 NA l A NA i 1 i 3 (geometric) N (PRlm3) 5. Nonhl.ong Deng-- Annual 39.8• 38.6' 37.4 1 0 0 NA NA NA rr (arithmetie) S (1l[ho/ms) (D North Lung DeaDead24. ur 92 67 86 0.0% 0.0% 0.0% 23.6% 19.3% 19.7% A0) (p8/ms) - (D ore : NA a Not applicable. Q. • a Data presented are valid,but Incomplete In that an insufficient number of valid data points were collected to meet the EPA and/or the ARD criteria for C representativeness. •• - Annual avenging periods are reported as either being exceeded or not being exceeded. PM,0 24-hour standard exceedance,measured as percentage of time 0 samples exceeded standard. Percentage Is used because PMto sampling is not performed on a daily basis. .4C Sources: ARE 1992,1993;SCAQMD 1994. South Coast Air Basin Emissions The total air emissions that occurred in the SCAB during 1993 are displayed in Table 2- 14. The SCAB emissions inventory is periodically updated to forecast future emissions inventories, to analyze individual control measures, and for input data to regional air quality modeling. The inventory emissions are reported to the ARB; they compile the information from all air districts pursuant to Section 39607(b) of the California Health and Safety Code.The 1993 inventory represents the most current emissions data available for the SCAB (SCAQMD 1997). Table 2-13 shows that the largest contributors to air pollutants in the SCAB are mobile sources. On-road motor vehicles account for 55% of the VOC, 66% of the NOR, and 81% of the CO emitted in the SCAB. Table 2-14. 1993 Base Year Average Annual Day Emission Inventory South Coast Air Basin (Tons/Day) VOC NO,, SO,, PM„ CO Stationary Sources Fuel combustion 11 136 8 10 65 Waste burning 1 3 2 2 17 Solvent use 331 0 0 1 0 Petrol. Process, storage, and transfer 58 8 11 2 5 Aft- Industrial Process 17 6 2 20 1 Miscellaneous 32 1 0 344 11 Total Stationary 450 154 23 379 99 Mobile Sources On-road vehicles 676 794 25 27 5,682 Off-road vehicles 114 246 31 15 1,264 Total Mobile Sources 790 1,040 56 42 , 6,946 TOTAL I 1,240 I 1,194 I 79 I 421 I 7,045 Source: SCAQMD 1997. All values reported as rounded in the 1997 Air Quality Management Plan. Water Quality Water column temperatures in the ocean vary with depth and time of year. The upper portion of the water column is strongly thermally stratified from about May to October, reaching an average maximum surface temperature of about 19 degrees Celsius (C) from July to September. During this period, the temperature changes by approximately five degrees C over the upper 20 meters of the water column. The minimum water temperature (approximately 14 degrees C) occurs in late winter. 2-50 •" • The recurring oceanographic phenomenon known as El Nino occurs periodically in the South Pacific and occasionally effects Southern California waters by increasing marine water temperature, especially during fall and winter, by several degrees. The quality of the marine water in the Southern California Bight is monitored by various agencies for a variety of reasons (NRC 1990); however, the quality of water in the Study Area has not been specifically monitored and the area is not known to have any site-specific water quality problems other than the obvious turbidity problems in Portuguese Bend. Incidental to the marine biological surveys conducted for this Study dissolved oxY9en, pH, temperature, and salinity were recorded. The readings for surface and bottom ocean water are shown in Table 2-15 and Table 2-16. Table 2-15. Surface Water Quality Measurements Dissolved Temp. Salinity SITE 02(mI/1) pH (°C) (parts/thousand) Portuguese Bend' 9.7, 8.9 7.9, 8.0 19, 17 35.1, 34.9 Abalone Cove' 9.3, 8.9 7.9, 8.0 19.7, 17.3 34.5, 34.9 Lunada Bay2 8.9 8.0 17.3 34.9 Palos Verdes Pt.3 10.1 8.0 19.0 34.5 1 The first reading was taken on August 1995,the second was taken in December 1995. • 2 Only one reading taken in December 1995. 3 Only one reading taken in August 1995. Table 2-16. Subsurface Water Quality Measurements Dissolved Temp. Salinity SITE 02(mI/1) pH (°C) (parts/thousand) Portuguese Bend' 10, 8.6 7.9, 7.9 16, 17.1 34.6, 34.9 Abalone Cove' 9.3, 8.6 8.0, 7.9 18.5, 17.1 34.8, 34.9 Lunada Bay2 8.6 7.9 17.1 34.9 Palos Verdes Pt.3 11.6 7.9 15.5 34.1 The first reading was taken on August 1995,the second was taken in December 1995. 2 Only one reading taken in December 1995. 3 Only one reading taken in August 1995. These measurements are all consistent with those found under natural, open ocean conditions in the Southern California Bight(Eganhouse and Venkatesan, 1993). • 2-51 Coastal Zone Biological Resources Coastal Vegetation 110. The vegetation in the undeveloped areas of the Study Area can be classified as California coastal scrub (also known as coastal sage scrub). Characteristic shrub species of this vegetation type are California sagebrush, white and black sage, California buckwheat, toyon., !aural sumac, and prickly pear cactus. The dominant understory herbs are typically wild oats and red brome. The area within the active landslide has vegetation that is highly disturbed. The constantly shifting land surface and fissures keep the vegetative community in a seral stage. This constant disturbance has also allowed weedy, opportunistic plants to invade the site, such as, sweet fennel, pepper tree, castor bean, and Russian thistle. Coastal Wildlife Natural, undisturbed Coastal sage scrub provides suitable habitat for a variety of wildlife species adapted to both open chaparral and desert scrub. Brown (1982:11) provides a list of wildlife species typical of Coastal sage scrub (Type 133.2— California Coastalscrub). Bradley (1980) provides detailed abundance and distribution data on birds of the peninsula. The Study Area, however, has been disturbed by the recent landslide and urban development; as such, the Study Area does not possess the wildlife diversity that would be associated with a well-developed, natural coastal sage scrub community. This is evidenced by surveys performed for other Projects in the Study Area. Many of the species observed or expected are typical of disturbed habitats in the early seral stages • (e.g., ground squirrel, cottontail, racoon, morning dove, song sparrow, raven, fence lizard, and side-blotched lizard). For this analysis, the wildlife species listed in the references cited above are assumed to occur in the Study Area. Marine Biological Resources The Study Area has two basic habitat types for marine biological resources: (1) soft- bottom habitat, which includes sandy beaches and sandy, subtidal areas, and (2) hard-bottom habitat, which includes the rocky intertidal and rocky subtidal reefs. The Study Area investigated for marine biological resources examined the Portuguese Bend Cove and adjacent areas including Rocky Point and Abalone Cove. Figure 2-23. The sedimentation, severe erosion of landslide debris, and excessive turbidity appears to have resulted in the smothering and degradation of the hard rock reef habitat in the area. Non- affected upcoast areas, such as Rocky Point, has a healthy biological community that is typically associated with hard rock reefs of Southern California. (The Rocky Point area, - therefore serves as a "reference site"which is used in evaluating the present conditions and expected restoration benefits at Portuguese Bend). As such, the Corps of Engineers contracted the Chambers Group and Vantuna Research Group to perform marine biological • 2-52 • i 0 / . 1 Palos Verdes Pt. \ "' G Lunada Bay \ G vG " I \ \\\ .i.,71 W ‘ ) . . a Palos Verdes Hills N N v e W e. A1.44 G e, Qom, O.' A QK' Q'c'• : . ... .s a\o J• A�¢,,e <�we 40" ip 0 L......--- ..y....416._ . ,go.jiti.zo .\,• A,,,. • ‘?"11"1E1%, e'te CO -II � co _ Berra co N♦, c0 F !Ga ��Nautical Miles NC 4,4 9-40 m qa„ 44 eN `fir �` A intertidal Surveys Beach Seines ..1, G Gill Nets % Diver fish Surveys "" Diver Subtidal Surveys =Otter Trawls so of `p\ surveys in the Study Area. Appendix A of the Draft EIS/EIR presents the findings of these studies. The following summarizes the findings on the type of flora and fauna existing in the Study Area. Chapter 3 of this Feasibility Report presents information and analysis of the different conditions and quality of the three major areas as part of defining the opportunities for restoration. Marine Vegetation Sandy Intertidal and Subtidal. In the sediment-laden Portuguese Bend turf-like mats of green algae formed the predominant marine vegetation; the branching coralline green algae and green algal mats are the common vegetation on the sandstone and unstable substrate common in the area. The encrusting brown algae was also common on suitable cobble substrate. In the sediment-laden Portuguese Bend area, giant kelp and associated understory plants were only observed in a few areas where rock had been exposed above the sediment layer. Abalone Cove, which has a moderate amount of turbidity and sediment relative to the dense covering at Portuguese Bend, has a low density of giant kelp and sparse growth of understory vegetation. Rocky Intertidal. Surveys performed in rocky intertidal areas of the Study Area indicate that the marine plants are typical of southern California rocky intertidal areas. Areas with rocky intertidal habitat(e.g., Palos Verdes Point) have marine plants typical of the open coast. Branching coralline algae, feather boa kelp, surf grass, encrusting red algae, and green algae are all common plants of the rocky intertidal. Rocky Subtidal. Surveys performed in the rocky subtidal areas in the Rocky Point reference area included in the Study Area confirm that sediment-free and turbidity-free areas are dominated by the giant kelp and has understory plants that are typical of the giant kelp forest community as described in Foster and Schiel (1985) and Murray and Bray (1993:332). The giant kelp forms a dense overstory with other marine plants like feather boa kelp, bladder chain kelp, palm kelp, and the brown algae forming the understory plants. The Portuguese Bend area was essentially absent of giant kelp. Marine Invertebrate Animals Intertidal. The sandy intertidal beach in southern California is dominated by beach hoppers, and the isopod in the upper intertidal; the middle and lower intertidal is characterized by sand crabs, and the clam. The rocky intertidal habitat of the Pacific Coast, in general, and Southern California in particular, has been extensively studied and documented. Similarly, throughout the world a marked vertical zonation occurs in the distribution of rocky intertidal animals in southern California. 2-54 The splash and high tide zone is characterized by the barnacles, limpets, the gray • littorine snails, and the striped shore crab. The characteristic animal of the mid-tide zone is the California mussel. Although this zone is dominated by mussels, representatives of nearly every invertebrate phylum are found attached or crawling within the mussel beds. In the Study Area hermit crabs, goose neck barnacles, red barnacles, chiton, aggregating sea anemone, and the stripped shore crab were common in this zone. The most readily identified animal of the low tide zone is the purple sea urchin, turban snails, and ochre, or common starfish. Subtidal. In the sandy, soft bottoms of southern California, the epifauna (motile species adapted to cling to surfaces) dominate shallow depths; these species are primarily suspension feeders (e.g., sea pen). In water deeper than 30 feet, the number of epifaunal animals declines, and those epifauna that are found there are carnivores or scavengers such as sea stars, sand star, elbow crab, and ophiuroids, or brittle stars). The reverse is true for infaunal animals (animals that burrow into the sediment) in subtidal soft bottoms, and their numbers increase with depth. In shallow waters (<45 feet)the infauna are predominately amphipod crustaceans and ostracods; in deeper waters (>45 feet) the predominate infauna are polychaete worms which establish tubes or burrows in the relatively stable, deep soft bottom sediment; e.g., the tube worm. A site specific infauna survey was conducted to determine if the infauna community had substantially changed since it was surveyed in 1990. The survey indicate that there is little change in the tube-building infaunal community off Portuguese Bend. Macroinvertebrate surveys of soft-bottom areas indicate that frequent deposition of eroded sediment probably retards the establishment of some epifaunal animals that would normally be expected in Southern California soft-bottoms like the tube worm, the sea pansy, and the sea pen. The hard rock subtidal community is dominated by giant kelp, and its biological community are best categorized as a kelp forest community. As such, in areas not adversely affected by heavy sedimentation and turbidity, the invertebrate animals found in the Study Area are typical of those found in southern California kelp forest. The giant kelp forest is inhabited by a species-rich invertebrate fauna. Literally hundreds of species have been recorded in this habitat type. The diversity of morphologies, feeding types, and behaviors make it difficult to provide a general overview of the species present. Forster and Schiel (1985:55-69) provides a general overview of the invertebrate animals that are common in the kelp forest, and that publication is incorporated by reference, as per 40 CFR 1502.21. As a brief summary, the kelp forest is typically rich in filter/suspension/detritus feeders like sponges, anemones, corals, sea cucumbers, clams, and mussels. Grazers like sea urchins, abalone, isopods, amphipods, and sea snails are all common. Among the predators, 2-55 • sea stars, crabs, spiny lobster, octopus, and squids are all regular inhabitants of the kelp • forest. In short, the species abundance and richness of a healthy kelp forest is among the highest in nature. In the sediment-laden, turbid Portuguese Bend area, the giant kelp community has been adversely affected by these conditions. Turbidity decreases light penetration which reduces plant production and reduces the food source of grazing species. The sediment load causes direct burial and smothering of sessile invertebrates, and clogging of gills and scouring of all animal invertebrates. As a result, surveys of the kelp communities in Portuguese Bend reveal a depauparate invertebrate community. Abalone Cove, which is moderately impacted by sedimentation, has less species diversity and abundance than the relatively unaffected Palos Verdes Point area. Marine Fishes Cross and Allen (1993) provide a detailed description of the distribution, life history, and migration of marine fishes in the Southern California Bight, including pelagic fish and fish associated with hard and soft bottom habitats. The following discussion is based largely on that report and on the marine biological surveys performed for this Study. It should be noted that in this analysis, as previously stated, it is assumed that all marine fish that are typical of Southern California hard- and soft-bottom habitat are expected to occur in suitable habitat in the Study Area. Soft Bottom Fish. The dominant fish of the soft-bottom habitats in Southern California are the left-eyed flatfish (e.g., California halibut and sanddab); right-eyed flatfish (e.g., turbot); and toungfish (e.g., California toungfish. These fish have evolved to adapt to the soft bottom. Their depressed body form with their eyes on one side allows them to easily bury themselves in sediment to hide from predators. Love et al. (1986) reported on the dominant marine fish of the nearshore of southern California; their surveys include the above species, as well as, the queenfish,white croaker, northern anchovy, and fan tailed sole. Otter trawl surveys performed for this Study indicate that yellow sculpin, midshipman, and California scorpionfish were also abundant in soft bottom areas of the Study Area. Rocky Intertidal Fish.The rocky intertidal areas are a turbulent and hostile environment for fish. There they have to cope with waves, surge, and fluctuations in temperature, salinity and dissolved oxygen caused by changing tides. Only a few species are thought to be typical residents of rocky intertidal areas of Southern California: wooly sculpin, rockpool blenny, and California dingfish. These fish spend all but their larval existence in the intertidal and shallow subtidal areas. Rocky Subtidal Fish.As previously mentioned for subtidal plants and invertebrates, the hard rock subtidal community is dominated by giant kelp, and its biological community is best categorized as a kelp forest community. As such, in areas not adversely affected by 2-56 heavy sedimentation and turbidity, the marine fish found in the Study Area are typical of those found in southern California kelp forests. The giant kelp forest is inhabited by a diverse and abundant fish fauna. Over 120 species are known to occur in southern California kelp beds; this represents almost 23% of the known marine fishes of California. Fedler et al. (1974), Foster and Schiel (1985:69) and Cross and Allen (1993:507) provide an overview of the marine fish that are common in the kelp forest, and that publication is incorporated by reference, as per 40 CFR 1502.21. The following is a brief summary of those reports and the results of surveys performed for this Study. . Diver surveys performed for this Study indicate that Selema, Rock wrasse, and California sheephead were also abundant in the kelp forest areas of the Study Area. As mentioned previously, the Study Area includes the sediment-laden, turbid Portuguese Bend area. The giant kelp community and associated fishes in that area have been adversely affected by these conditions. Turbidity decreases light penetration which reduces plant production and reduces the food source of grazing species. Also, the sediment load causes clogging of fish gills. Fish surveys performed in the Study Area reveal a depauparate fish community in Portuguese Bend when compared to the unimpacted area of Palos Verdes Point. Surveys of Abalone Cove indicate that, even though only moderately impacted by • sedimentation, it also has less fish species diversity than the relatively unaffected Palos Verdes Point area. Pelagic Fish. These open ocean marine fishes move and/or migrate through the Study Area and are not identified with either soft or hard bottom habitat. In the Southern California Bight, these species include: mackerel, anchovy, Pacific bonito, yellowtail, blue shark, white seabass, and swordfish. Gill net and beach seine surveys performed for this Study indicate that topsmelt, queenfish, and grey smoothhound were also abundant pelagic fish that move through the Study Area. Threatened and Endangered Species USFWS provided the Corps of Engineers with a list of Federal threatened and endangered species and a list of numerous other"sensitive"species, described in Table 2-17. The discussion below will, however, concentrate only on those species listed or proposed under the Federal Endangered Species Act. The other"sensitive" species have no legal protection under the Endangered Species Act. 2-57 Table 2-17 Federal Listed or Proposed Threatened, Endangered Species (Known or reasonably expected to occur in the Study Area) Common Name Scientific Name Status Lyon's pentachaeta Pentachaeta lyonii Endangered' Glaucopsyche lygdamus Palos Verdes blue butterfly palosverdesensis Endangered El Segundo blue butterfly Euphilotes battoides allyni Endangered Brown pelican Pelecanus occidentalis Endangered' California least tern Sterna antillarum browni Endangered' Peregrine falcon Falco peregrinus anatum Endangered' Polioptila califomica califomica California gnatcatcher Threatened Perognathus longimembris pacificus Pacific Pocket Mouse Endangered 'This species is also listed as Endangered by the State of California. Lyon's Pentachaeta. This plant grows primarily along the coastal sage scrub/grassland edge. It was historically known to occur on the Palos Verdes peninsula, but has not been 410. documented there recently. The primary reason for this species decline has been extensive urbanization. Palos Verde Blue Butterfly. This is a coastal subspecies of the more widely ranging silvery blue butterfly(G. I. australis). The decline of most endangered butterflies can be attributed to the lost of the host/foodplant on which these butterflies use exclusively during one or more life stages (Thelander 1994:419). The larval host/foodplant for the Palos Verdes blue- the rattlepod (Astragalus trichopodus var. lonchus)- has been heavily impacted by urbanization, overgrowth by weeds, and weed control practices. Females lay their eggs on the host plant during February to April, and the eggs hatch about a week later. The larvae feed on the seeds and flowers and quickly pass through five larval phases. When fully grown the larvae pupate on the host plant seedpods or under decomposing leaves at the base of the plant New butterflies emerge the following February or March, synchronized with the appearance the host plant's flowers (Thelander 1994:426). This species was presumed to be extinct(it had not been seen in more than ten years) when it was re-discovered on the grounds of the Defense Fuel Support Point(a Department of Defense facility) in San Pedro. This population was observed using deerweed (Lotus scoparius), as well as rattlepod as a foodplant(Nelson 1994). Both larval host plants have the potential to occur in the inland portions of the Study Area. 2-58 110 El Segundo Blue Butterfly. This species was once widespread throughout the southern coast of Los Angeles County. It is now believed to be limited to a few acres near El Segundo and a larger area on the west of Los Angeles International Airport. The larval host/foodplant for this species is the dune buckwheat(Eriogonum parvifolium); this host/foodplant can be found along the coastal bluffs in the Study Area (USFWS 1996). Brown Pelican.The California brown pelican is a frequent visitor and sometime year- long resident along the California coast. Although they can be found anytime of the year, they are most conspicuous in the late spring through the fall after the breeding season (February- May) on Anacapa and the Santa Barbara Islands (Briggs et al. 1987). Birds appearing in early spring are most likely migrants from coastal Mexican colonies. Pelicans forage for surface fish, particularly anchovies (Engraulis mordax), in the open ocean. Pelicans are extremely tolerant of human activity at day-time roost and are often seen roosting and loafing on breakwaters, piers, buoys, harbors wharves, and the shoreline all along the California Coast. They are not tolerant of disturbances on night roost, however, and are known to quickly flush from roost at the slightest disturbance(Jacques and Anderson 1987). No night-time roost are known to occur in the Study Area. California Least Tern. This seabird migrates from Mexico and Central and South America to coastal south-central California to breed. During their stay in California, the birds forage for fish in the nearshore coastal waters and embayments. Birds typically nest in small colonies. The nest usually occurs in the open expanse of lightly colored sand or dirt or dried mud next to lagoons or estuaries or on open sandy beaches. The nest generally consists of merely a small depression or scrape in the soil or sand lined with pebbles or sea shell fragments. Nesting usually concludes by mid-August, with post-breeding groups still present into September-(USFWS 1980): USFWS document that least tems have been observed foraging within the Study Area; they speculate that the birds represent adults from the Terminal Island colony and birds from more northerly breeding sites (USFWS 1996:52). Peregrine Falcon.The American subspecies of the peregrine falcon originally ranged throughout North America. Its numbers greatly declined due to increased use of chlorinated hydrocarbon pesticides (DDT) following World War II (Hickey 1969). In California there were approximately 100 breeding pairs in 1946. By 1969 there were fewer than ten breeding pairs (Herman 1971). In 1975, eight nesting pairs were confirmed and six successfully fledged young (Fyfe et al. 1976). In 1980 the number of known breeding pairs in California had increased to 50-60 pairs (USFWS 1982). The population's recovery from near extinction has been dramatic over the past 25 years that the USFWS has proposed to remove the falcon from the Endangered Species list(63 FR 45446, Aug. 26, 1998). 2-59 As in other parts of its almost worldwide range, birds nest typically on ledges or sheer cliff faces a thousand or more feet above the surrounding landscape. In urban areas, birds use skyscrapers as nest sites; USFWS report a breeding pair using the Vincent Thomas Bridge in San Pedro (USFWS 1996:53). Breeding pairs remain near territories throughout the year. However, non-territorial adults and immature birds are far-ranging and travel hundreds of miles in search of their main prey— other birds, especially pigeons, songbirds, shorebirds, waterfowl, and seabirds (USFWS 1980a). No known nest sites occur in the Study Area; however, the Study Area is probably used as foraging habitat for these birds. California Gnatcatcher. This small songbird is a resident of Southern California coastal sage scrub. Because of the extensive loss of habitat in southern California, the gnatcatcher was listed as threatened in 1993. Atwood et al. 1995a (as cited by USFWS 1996:54) reported 26-to-56 breeding pairs of gnatcatchers on the Palos Verdes Peninsula during 1993 through 1995. In the Study Area, they report seven breeding pairs in 1993, seven in 1994, and three in 1995 (Atwood et al. 1995a and 1995b). Due to the number of species that are dependant on California Coastal Sage Scrub, the State of California's has developed guidelines to protect Coastal Sage Scrub habitat through the Natural Communities Conservation Plan (NCCP) Process in the Southern California Coastal Sage Scrub Planning Area (see CDF&G 1993). The intent of the guidelines • is to elicit voluntary participation of local entities with Coastal Sage Scrub habitat in their jurisdictions. The goal being to provide for regional protection and perpetuation of natural wildlife diversity in coastal sage scrub areas while allowing compatible land use and appropriate development and growth. The City of Rancho Palos Verdes has recently (1996) signed a NCCP Planning Agreement which formalized the City's interest in participating in the NCCP planning efforts. Pacific Pocket Mouse. This is the smallest of the 19 races of the little pocket mouse (P. longimembris). Members of this species inhabit arid regions over much of the western United States. Pocket mice, in general, are more closely related to kangaroo rats in that they are nocturnal, seed eaters with fur-lined cheek pouches for transporting seeds back to burrows (Thelander 1994:67). This subspecies is adapted to coastal habitats with open, shrubby vegetation, including coastal strand, coastal dunes, weedy vegetation on river alluvium, and coastal sage scrub. For burrowing it requires areas with fine-grained sandy soil. Like kangaroo rats, it eats mainly seeds, and appears to supplement its diet with leafy material and insects. This species once extended along the coast from Marina del Rey and El Segundo in Los Angeles County to the Mexican Border. However, from 1940-to-960, populations declined rapidly under coastal development. After a collection was made in 1971, no confirmed sighting 2-60 ` jai of this species was made until a small population was located in 1993. It is believed that other populations may exist in suitable habitat, but this species is difficult to trap and subject to widely fluctuating population levels (Thelander 1994:67). Potentially suitable habitat may exist in the Study Area. As covered in the section on the California gnatcatcher, the City of Rancho Palos Verdes in1996 signed a NCCP (Natural Communities Conservation Plan)Agreement which formalized the City's interest in participating in the NCCP Program. The NCCP Program was established by the State of California with the National Community Conservation Act of 1991 (Fish &Game Code Section 2800 et seq.). The goal of the NCCP Program is to elicit voluntary participation of local entities in the comprehensive management and conservation of habitat for multiple wildlife species in their jurisdictions. NCCPs are intended to result in land use plans and management programs for the long-term protection of designated habitats and their component species. The ultimate objective is to provide for regional protection and perpetuation of natural wildlife diversity in a given area covered by the Plan, while allowing compatible land use and appropriate development and growth (Calif. Resources Agency 1997). Because many species are dependant on California Coastal Sage Scrub, the State of California developed guidelines to protect Coastal Sage Scrub habitat in five southern California Counties under the NCCP Program (see CDF&G 1993). The five counties are San Diego, Orange, Riverside, San Bernardino, and Los Angeles. Coastal sage habitat on the Palos Verdes Peninsula falls within a "sub-region"of the larger Southern California Coastal Sage Scrub Planning Area effort. The City of Rancho Palos Verdes, the City of Rolling Hills estates, and the County of Los Angeles are currently involved in the Planning effort with CDF&G, the USFWS, and other environmental organizations. A conceptual plan which includes alternative coastal sage scrub habitat preserves to be considered in the Palos Verdes Peninsula NCCP is under development. Parts of the preserves, when formally identified, are expected to occur within the Feasibility Study Area and/or the bluffs above the Portuguese Bend Project area. Aesthetics The Study Area is highly scenic when vistas and views are directed from high points on land toward the ocean. For areas outside the active landslide, the landscape appears as gently rolling hillsides with much open space. The area within the Portuguese Bend landslide provides an ocean view that is often marred by the fairly consistent sediment plume from the eroding bluff. After major storms, the turbidity plume extends miles offshore and downcoast. The landward viewer sees a landscape with scattered residential units and hillsides that are in various stages of erosion cause by the moving landmass. 2-61 Cultural Resources idik Ethnography The Native American group who lived in the area prehistorically is known as the Gabrielino. The name, as given to them by the Spanish, comes from Mission San Gabriel. Tongva is the name the Gabrielino have for themselves. The Tongva occupied prehistorically a geographical area which extended from Topanga Canyon in the northwest to Aliso Creek in the south, and included most areas in what we know today as Los Angeles and Orange Counties (Bean and Smith 1978:538). The Tongva are a Uto-Aztecan linguistic stock speaking peoples who were first contacted by the Spanish in the mid-16th century and later subjugated by Spanish Franciscan padres during the establishment of the California mission system in the mid 18th century. The Tongva had villages along the coast where they exploited marine resources. Inland villages were located near major potable water sources.Trade was carried out with groups on the Channel islands and as far east as central Arizona. Based on ethnographic studies, several Tongva villages were located on Palos Verdes Peninsula including Chowig-na, Tovemungna and Chowi(Johnston 1962:93). Prehistory Archaeological dating of prehistoric sites in California has established human occupation in the area beginning with southward migration of big game hunters at least 10,000 years before present. Regional prehistory of the area is based on decades of research and is generally divided into four periods. They are defined as follows: • Paleo-Coastal Period (ca. 10,000 to 6000 B.C.). This period was marked by small groups subsisting on marine and terrestrial species. The number of sites (and therefore data) for this period is very limited due to the very small populationat that time, and several thousand years of erosion and deposition. Millingstone Period (ca. 6000 to 2000 B.C.). This period was characterized by the addition of groundstone (handstones and milling slabs)to the tool assemblage. This was a product of greater reliance on hard seed products. Mortars and pestles were added to the assemblage by the end of the period. There is a higher frequency of more stable settlements as evidenced by the presence of well developed middens. Intermediate Period (2000 B.C. to A.D. 500). This was a period of increased technological innovation. This period was time of increasing population size, interregional exchange, and a greater focus on marine resources. Late Period (A.D. 500 to European Contact). This period was marked by the creation of large permanent villages and extensive trade with the Channel Islands. A time of increased diversity of craft items and manufactured goods and greater political and societal complexity. 2-62 History The first European explorers to visit the area were Cabrillo in 1542 and Vizcaino in 1602. The establishment of missions by the Spanish, including Mission San Gabriel Arcangel in 1771, was the beginning of Spanish colonization of California. Juan Jose Dominguez was granted 75,000 acres on Palos Verdes Peninsula in 1784 by the Spanish governor. In the early 19th century, the ownership of Rancho Palos Verdes came into the hands of the Sepulveda family. The land was used primarily of cattle grazing. The coves and inlets in the Study Area were used as anchorages for 19th century whaling ships, while at least one area in the project vicinity was the site of a whale oil processing station. Jotham Bixby became owner of a large portion of Rancho Palos Verdes in 1882 (Colombo 1991:14). In the early 1900s, Japanese Americans began renting coastal land for the cultivation of vegetables. The end of World War II saw extensive land sales for the purpose of developing residential communities. Today, there are four incorporated cities on the peninsula (Columbo 1991:14). Archeological Sites An archival records search at the Regional Archeological Information Center at the University of California, Los Angeles on December 18, 1996, and a review of archeological project files located at the Los Angeles District indicate that 12 cultural resource surveys had been conducted in the proposed project vicinity. The most recent formal survey was performed in 1995 (two surveys), and the earliest in 1978. The total areal coverage of these surveys comprises less than 50% of the proposed Study Area. More than 50%of the Study Area has 111 never been surveyed for cultural resources by qualified archeologists. Within the Study Area, none of the proposed Project's area of potential effects (APE) has been surveyed for cultural resources. The records research identified 11 archeological sites, as follows: CA-LAN-140- (Nelson, Undated)described as "shell and refuse." CA-LAN-141 - (Nelson, Undated) described as "refuse of abalone shells, whale and other bones." CA-LAN-303- (Hayden, 1995) described as"shell scatter and artifacts" CA-LAN-821 - (Hector and Rosen, 1975) described as"wide, light shell scatter..." CA-LAN-822- (Rosen, 1975) described as "shell scatter" CA-LAN-884- (Stickel, 1978) "shell midden" CA-LAN-1019- (Rosen, 1979) described as "...four areas of shell and flake scatters, each separated from each other by sterile soil." CA-LAN-1249- (McAuley 1985) "shell midden" 2-63 CA-LAN-1250- (McAuley 1985) "shell midden" CA-LAN-1351 - possible extension of LAN-1250 CA-LAN-2253- (Van Horn, 1992) described as "shell deposit with chipped stone tools" The records indicate that sites CA-LAN-884 and CA-LAN-2253 have undergone limited test excavations. CA-LAN-884 was tested by Stickel in 1978, and CA-LAN-2253 was tested by Van Horn in 1993. The remainder of sites have not been investigated. Therefore, the potential significance of the sites cannot be determined at this time. Only two of the archaeological sites within the Study Area have been evaluated (at least partially) for potential eligibility for the National Register of Historic Places. Historic Sites - Wayfarer's Chapel. This site is not listed on the National Register of Historic Places or as a California Historic Landmark but considered to be of local historic importance. It is located on Palos Verdes Drive South. Whaling Station Site. This site is California Inventory of Historic Resources Number 381. It is described as a California Historic Landmark which was established in 1864 and used to process whale oil. The actual site of the station has not been located. 1111 Villa Francesas. This building is on the northwest corner of Peppertree and Palos Verdes Drive South is on the National Register of Historic Places. Shipwreck Records.A study of shipwreck records was also performed. As shown in Table 2-18 these records indicate the potential presence of four submerged shipwrecks, and one World War II Japanese submarine within the underwater portion of the Study Area. Table 2-18 Shipwrecks Name of Ship Date Lost American Girl 1951 Avalon 1926 Bonnie K 1950 Melrose 1935 Sakura (Sub) 1941 2-64 1