Loading...
HomeMy WebLinkAboutH_5224_SREPORT ON FORCES AFFECTING SAND DISTRIBUTION AND IMPACT OF STORM DRAIN DISCHARGE IN THE VICINITY OF CARNATIO)l COVE Prepared for City of Newport Beach Prepared by Moffatt & Nichol, Engineers 250 W. Wardlow Road Long Beach, California 90807 August 1980 L-1911 I . Introduction Purpose and Scope CONTENTS Description of Existing Conditions Upland Drainage and Storm Drain Discharge Waterfront Property Bathymetry and Sediment Description Storms Wave Climate Analysis Storm Drain System Littoral Process Statement of Problem Meeting With Homeowners Corrective Measures Considered Construction Cost Estimates Discussion of Alternatives Summary of Findings Appendix 1 3 4 4 5 6 8 10 10 10 11 14 14 16 17 24 25 INTRODUCTION Carnation Cove is located in the south end of Newport Bay, near the Bay entrance channel and adjacent to a residential area known as Corona del Mar, all within the City of Newport Beach (figure 1), The Cove receives storm water discharge from a 60-inch diameter storm drain, which is the outlet for a drainage basin area of 490 acres (figures 2 and 7). During the past 40 to 50 years, the Cove has been developed for boat-docking facilities and beach-recreation activities by the adjacent property owners. Reports by the property owners around the Cove indicate that in the past 3 to 5 years the level of the sand in the Cove has lowered approximately 2 to 3 feet, sand and silt build-up under the boat docks has accelerated, and the storrn··water discharge at the 60-inch outlet appears to have increased. The property owners have sta-t:ed that the storm-water discharge seems to be the cause of the beach .erosion and the sand and silt build-up under the boat docks. A comprehensive report on the Jasime Creek Storm Drain, the storm-drain system which drains to the Cove, was prepared for the City in 1979 by Alderman, Swift and Lewis, Consulting Engineers. The report identified deficiencies in the existing drainage system and proposed construction of new reaches of storm drains to improve the efficiency of the drainage system in order that flooding problems and maintenance accessibility problems could be alleviated, The report also included discussion of and cost estimates for constructing desilting structures at the storm drain inlet and constructing a 72-inch Reinforced Concrete Pipe extension of the existing 60-inch R.C.P. outlet into the Newport Harbor Entrance Channel. l 'l::;------;----- Ut,/!THJ> 8T,11'HB ~ WH~T COAS'r CALil<'OllNIA NEWPORT BAY ,.r .... , .. ,~, .. ,, •• ............ ,.,,,.,,. SO~~<>l~'OS IN Yl<ET -, ""'" tow,n "'~ "'""" .. '" Ul'1>' The severe winter storms in January and February 1980 appeared to accelerate the beach~erosion problem, and the turbulent storm-water discharge at the 60-inch outlet caused additional concern to the adjacent property owners. The combination of the many complex forces affecting the movement of sand in an oceanfront harbor, with a cove, beach, bulkhead, storm drain outlet, and boat dock area involved, indicated that more definitive data were needed in order to find solutions to the problems .. The City of Newport Beach requested Moffatt and Nichol, Engineers, to prepare an engineering study which would define the beach erosion and storm-drain problems and describe several possible courses of action. 2 PURPOSE AND SCOPE The purpose of this study was to determine the forces affecting sand distribution and the impact of storm-drainage discharge in Carnation Cove. The report was to -include descriptions of several alternative structures which would reduce the storm-. drain-discharge noise, vibration, and erosion potential. Preliminary construction cost estimates were to be provided to help evaluate. the alternatives. Qualitative results were des.ired, with regard to sand movement and the performance of alternative storm-drain and erosion-control structures, relying primarily on data developed from existing sources. Sediment samples were taken to define sediment types .in the study area. 3 DESCRIPTION OF EXISTING CONDITIONS Upland Drainage and Storm-Drain Discharge The master planning and design of storm-drain facilities for this particular drainage basin followed procedures described int he 1973 Orange County Flood Control District Hydrology Manual. The "Jasmine Creek Storm Drain Design Report" provides a good description of the existing storm-drain system which collects and discharges storm water to Carnation Cove. The report also includes a complete hydrologic analysis. The report indicates that the existing 60-inch storm drain, from Bayside Drive to the outlet in the bulkhead at the edge of the Cove, is large enough to carry the design discharge from the drainage basin. Historic practice of the general principle of storm-water drainage has involved a philosophy of intercepting, collecting, and disposing of storm-water runoff as rapidly as possible. The cumulative effects of urban storm drainage have been a principal cause of increased frequency of downstrea.m flooding and have necessitated development of large··scale downstream engineering works to prevent flood damage. In the past 10 to 20 years, there has been increased attention to the desirability of storing rainfall close.to where it falls, which sometimes requires trade- offs with use of the land. This is the concept that hac.< been used on the Jasmine Creek drainage basin. In 1964, the Orange County Flood Control District constructed Harbor View Dam (figure 1) to create a storm-water retention basin, with approximately 4.0 percent of the total drainage area upstream of the dam. This Dam provides for storing the increased storm~water runoff which has resulted from urban development, without increasing the size of the existing downstream storm drains. 4 ) As drainage areas become completely developed with residential, commercial, and public improvements, the erosion of sand and silt decreases. In the Jasmine Creek drainage basin, an estimated 10 percent of the area remains undeveloped. Even though sand and silt erosion will be reduced, debris will still be a minor problem. The City has recently completed a new inlet structure and debris catch basin to alleviate this problem; the catch basin is at the inlet to the Jasmine Creek storm drain upstream of Fifth Avenue. Waterfront Prope_l_'.'t_y The area immediately adjacent to Carnation Cove is completely developed with single-family residences. Approximately two- thirds of the houses are constructed with a reinforced concrete bulkhead at the ocean side to protect the property from erosion by wave action. The houses around the northern side of the Cove are constructed above maximum tide level and are set farther back from the waterline than are the bulkhead-fronted houses. These houses depend on the sand beach for shore protection. City maps show that the private property ownership extends to the Line of Mean High 'ride established by Orange County Superior Court Case No, 40024 (figure 2). Within the water area of the Cove, there are 10 piers varying in length from approximately 130 feet to 300 feet. Boat docks at the ends of the piers have been constructed by the adjacent property owners. These piers were constructed to lengths required to reach depths of water adequate for docking boats. Even so, it is necessary to periodically dredge silt from under the docks to keep the boats from touching bottom at low tide (see Appendix for Photographs of Cove). 5 Bathymetry and Sediment Description On 11 July 1980, a general site inspection was conducted at Carnation Cove. Sediment samples and bathymetric measurements were taken by Moffatt and Nichol, Engineers, with assistance from the Newport Beach Harbor Department. Soundings were taken by lowering a weighted line into the water and later correcting the readings to the mean lower low water (MLLW) datum. Results of the measurements are presented in table 1. A thin. layer of surface sediment was obtained from each location shown on figure 3. ·Each sample was gathered by hand and placed in a plastic bag. Although no mechanical analysis was performed, a few samples were allowed to dry and a visual description is included in table 1. When wet, the samples taken from around the docks appeared to contain a large percentage of silts and clays, however, in a dry state these samples were classified as dark brown silty fine sand. In contrast, samples taken bayward of the docks not only appeared to contain silt and clay when wet, but were classified as such when allowed to dry. The sediment types along a typical profile line A-A (figure 3) within Carnation Cove are shown on figure 4, Near the bulkhead and extending bayward approximately 280 feet, the material is a brown medium sand with shell fragments. Farther bayward, the grain size of the sand decreases and the amount of silt increases. Beneath the docks, the sediment is a dark brown silty fine sand, as sample 10 indicates. Bayward of the docks, the amount of silt and clay increases substantially; the sediment is generally a dark brown silt and clay with some fine sand. Sediment samples were also obtained from the shoal along the entrance channel jetty. This material is a clean fine sand which would be suitable as a beach sand if pumped onshore. 6 Table 1. -Soundings And Sediment Sam12.les Soundings Corrected Sample Description Samele No, Soundinqs (ft.) for Tide (ft. MLLW) Dr 1 15 11 Dark brown silt and clay with some fine sand 2 16 12 Dark brown silt and clay with some fine sand 3 Brown medium sand with shell frag:- ments 4 16 12 Dark brown silt and clay with some fine sand 5 12 9 Dark brown silty fine sand 6 14 10 Dark brown sand with some, silt 7 13 9 Dark brown silt and clay with some fine sand 8 2 +l Brown medium sand with shell frag- ments 9 4 1 Brown medium sand with shell frag- ments .10 12 9 Dark brown silty fine sand 11 15 11 Dark brown silt and clay with . some fine sand 12 16 13 Dark brown silt and clay with some fine sand 7 '77 G) C ::0 fTl "' ,· ~ ~ @ / '· DATUM: MLLW ( FU Sediment somDle· designation so.undings and samples token on July 11, 1980 0 53 106 212 APPROXIMATE SCALE IN FEET '· .4. B. 11.0 ,2. -~ \ ' \ ,. ~ 5. '-' ··® \ \ \) V II. . ,,,,,,--STORM DRAIN 11/ l.Y IA • +I. @ +I. It. ! OUTLET ~ # I I/ # !/ II // 1/ ft! I! I/ ,, ®·~ ' I. ! I rlr~ LJ !17, 8, u ru(l v Q9l' •· L I I @ 9 (z)i . ' II, f 15, ®I ! 10. 17 © 12. l ~ A 12 ® 16. 19. SOUNDINGS AND SAMPLE LOCATIONS -,, C) C ;,:J rn -1> BROWN MEDllJM SAND WITH SHELL FRAGMENTS ! +10 ' I! +5 o l -5 -10 !l li !! if Ii 'i • h 11 ! !j I DARK BROWN , !SILTY FINE SAND' 'lli ![ I l! .. I, DARK BROWN SILT ~D CLAY , WITH SOME FINE"s~ BOAT DOCKS ----._ /v -15 '------+----+----+-------"-i-----+------l----t-------+--,/li'--~ 0 50 DATUM: MLLW Soundings and samples token on July II, 1980 100 150 200 250 TYPICAL PROFILE LINE A-A VERT. ·1" = 10' HOR. I"= 50' 300 350 400 500 Storms Rain storms in the 1977-78 and 1979-80 rain years have been noted for their severity in the Southern California Coastal Area. The storm periods o:E January and February 1980 were characterized by successive episodes of rain-bearing clouds driven from the Central Pacific Ocean by atmospheric jet-stream patterns lying more southerly than usual. 'rl:iis series of devastating rainstorms struck Southern California for the second time in 3 years and the third time in 12 years. The storms of February 13 to 21, 1980 were not as long-lasting as those of February and March 1978 or of January 1969. However, this 9-day period was among the wettest and most destructive short-storm periods ever recorded in the region. Eighteen deaths were directly attributed to the series of storms, and earl.y estimates of property damage totalled $270 million, Six main storm systems occurred during February 12 to 21. These.successive storms dumped more rain on already saturated ground, compounding previous storm damage, and causing new flooding and mud slides throughout Southern California. On February 18 and 19 Storm 5 struck the coast causing more flooding and mud slides. Orange and San Diego counties were particularly hard hit. Flooding of the San Luis Rey River, in the vicinity of Oceanside, caused fatalities and extensive property damage and disrupted transportation.· Storm 5 also generated large swells as it raced toward the coast. A long fetch of west-southwesterly winds preceded the storm. Maximum breakers of 10 to 15 feet pounded the coast on 8 the 19th and 20th. Erosion and damge to beach structures were widespread. Storm 6 arrived on the morning of the 20th, and by afternoon heavy rain was again disrupting the lives of Southern Californians. Heaviest rains were in the San Diego County mountains, where up to 5.5 inches fell during the passage of Storm 6. This was the most severe series of storms since the great storms of 1916 and 1927 in most southern coastal areas. The rainfall of January 1916 was almost double the rainfall of February 1980, and the rainfall of February 1927 is comparable to February 1980, During the 20-21 February storm, the property owners adjacent to the 60-inch storm drain outlet reported the impact of the storm-, .. water discharge with the high tide level resulted in loud noise, vibration, and a plume of water estimated to be 10 to 15 feet high. Storms which have a significant effect on the wave climate within Newport Bay are those with strong winds originating from the south. In both 1978 and 1980, major storms created problems for the Newport Bay area. Wind data obtained from the Newport Beach Harbor Department document the storm of the 9-10 February 1978, during which the wind direction varied from southeast to southwest. For a period of 43 hours, the average wind speed was 40 miles per hour, with a maximum reading of 90 miles per hour. According to the patrol watch commander's log, heavy seas were corning straight into the Harbor. Most of the damage· was conce.ntrated along the entrance channel; however, storm winds and heavy seas still had sufficient energy to destroy the guest docks fronting the Harbor Department building, which is about 1 mile from the mouth of the entrance channel. 9'' Wave Climate Carnation Cove is exposed to wind generated waves in the Bay from the west and ocean swell-generated waves from the southeast. Boat-generated waves are another source of relatively small waves that enter the Cove. WaveE; from the west are wind-generated over a relatively short fetch length of l mile and have wave heights are generally less than 1 foot. Figure 5 shows the approach direction of wind generated waves into Carnation Cove. A preliminary analysis of ocean wave refraction revealed that the entrance channel to Newport Bay has a relatively small exposure window. In order for any significant ocean wave.action to reach Carnation Cove, the storm must originate from southeast through south-southeast. During such a condition, ocean swells propagate down the entrance channel. and the wave fronts .. begin to refract or bend toward the shoreline. The shoaling depth near the shoreline alters the wave characteristics, causing a reduction in sp,,ed and a change in the direction of propagation. Figure 5 schematically shows how waves refract along the shoreline and enter Carnation Cove. The wave heights of the refracted waves are usually less than 1 foot, except during southeast and south- southeast storms. Storm waves with breaking hei9hts of approximately 3 feet have been observed on the beaches just south of Carnation Cove. Although the storm wave heights are reduced upon entering Carnation Cove, the waves have sufficient energy to set up a longshore littoral transport to the north. ANALYSIS Storm Drain System The design of the existing storm drain and the proposed storm drain additions are in conformance with commonly accepted· engineering practice. The storm-drain discharge point is located 10 FIGURE 5 in the approximate path of the original natural drainage course that existed prior to development of the area. In fact, the cove was assisted in its formation because the drainage course met the Ocean at this point. (See copy of 1875 U.S. Coast Survey Topography Map, Figure 6). The 1979 Alderman, Swift, and Lewis "Jasmine Creek Storm Drain Design Report," Appendix E, verified that there have been only very minor variances in the drainage watershed from previous studies. The City has not changed the drainage area. The Harbor View Dam created the storm-water retention basin, which reduces the peak flow in the storm drain, thereby compensating for the increased runoff factor due to urban development. (Jasmine Creek Drainage Basin, Figure 7) The existing 60-inch storm-drain discharge pipe has the capacity for the maximum design flow from this drainage basin. The design capacity was probably reached during the 1980 storms and there was no damage to adjacent property from storm water overflow which indicates the storm drain outlet is well designed. Littoral Processes Two distinctly different types of littoral processes affect sediment distribution within Carnation Cove. In one process, sediment in a limited area is transported offshore by the discharge from the storm drain. During periods of heavy rainfall, the discharge scours a trench in the beach, and the scoured beach sediments together with sediment carried in the discharge, is carried offshore (figure 8). As the discharge moves offshore into deeper water, its speed decreases and the flow fans out. 11 :':! C, C :,:, "' (l) ,•~ IA!,', ."f!~-'f'-71"•''"""..,. __ _ • -~ •.,..,_;§;~ : ~~,;';\,: • \ M -~--d,Jv _r-~f">>,:,"A-, ,)Ji,\_ \ \ ', J 1 !~' ;::,··~ ·-:-i ·::. ~<.J ~ !iw.J ..,,-..... :-. \"~,, f \ ' ',' J \ • -ip.-:;/ • ' , ..... " X , ' • ..--'} J \'/ '' ,· \ ../ J;;j,/, ~ ' y_';!i[,;J J;,-;:;y, / , -1'':--· • ,i:: ·,;.•'f/1t.',-~HY·~,.,~ .. . \ -~·:i;.,,~, ~~ 1 ,. ~1:-"~wi'j,1-~-'--.'---\:\ --\ I \·\\~,¼-. ~ "!!i,\_V-✓' '°'(,i' ~'·z,, ,-, / \_..- \ ( V ,:,Y/ 0 '. ''"',c-, • ' (U ,, "'~\' _.,---_...,,..-\ jjt,, 1·f~, ' -·-.. ,1 I .. -_,,,,,.,._ \. · \ . ~~ ~\~ ·J r ,>~'::}, , ,,, S _./ {;, , _ ,\ _ _,,., , ;><,, J-,,,_ ·<.,~*.1•/Di ... ,".,,. ,.-\' 11i) ',·,,\~J , ,: {~-..... :,,,-.,.,\ 1\ { ~, , 1,l • , , {. ..:\:,-., / ·, _,,, s~~• X. \ _/ . I \\\, ,·r_ ,i4 r ~ \> 21>-~ ~ ;' ' us C-0As"f SURVET t"'-,t Q;.J~ §~\''i:\ ~,~-~! /),,. ,_ C.....X.J't-..... __ ... ·' -\r, \'-_ TOPOCHAI'Jf't !NYlClNlTYOF _,,..-r ,,,:..--r \\ \ NE:Wl'OH'r llAY ,'\ • •~~~:, , l (U!,;'~ CAL!:\NI,:;..,..~ /_,, ' ·"G ; ,,. ·f-~ --.. _.,,,__,..""'~ .,:, ' ' ' ., ,-~,,,.,h n, ... ..,.,._no ,,,..-·, '. ·1:/ ~~ .. -;.:>-\:. •·1•i""'""~;;-:--\\ \ -~ •• : V r 1 • 1t1 / _...,,..-· \ ,.....-; / ' . ' \ "\ ?7 ~\\ ¾~,. \ ~""'"" ~·-' \ o,............ ~ ,l,r .,.->c--._ • • , -~'l------• ..,w,y \ I -' \ ·• · •II • ', (i'C:::--'::::,~~ ·, \ ~ .. , ,, .. --·' c::::::::-. '_.,. ,.-_ ~\ { \ ~ .; \ I "-M~"-'~\ • ~-~ • ... -. ' ) J .,} \: ~ ·-., , ~ -✓ \' • • • ·-¥,-.., y---,~ ~,-' ' ,. \ ' "-; . . . ,·,, . :),), ii :~ l •, .• ,/ \ \ ' • , , . \'-,~Cl-. '"' '·-.,J,: -,t:l•'_ ,. .... ,.) R'' ,/,;;~-(/ hydrogr,iphic sur,ey, ::.,, ___ ~]'1'/ J . , _, -~ , i~: ~-&,''fff,J :. ~----•,., , ,J ~ ~lif('( ~ _ show mg Newport Bay at ~ .. _ \ I/, . , _ , ~ ._ , ·.a" -✓ .. ,. , '1-i.. , . -----. 1tfl ~ 7 -/\ '°' "• """' ""'"' ~i\l i J'J,t;y v:; ••. ':/':' .,JI e_, ~3,~ I~ areas ,1re marshlands, ..: 10,._/ /r --< '1\k_•lt/;,-1,J! '1:,J!'f:,, ' -,.,,,___ ~A,_ . ~.;;-,!,.-~-~J!i/Pf-!ct+'"' "°' ' "'.,.. ~.. " :\\ . ,. 1 \ ,.-':;,,0 I Ii lightly sh,ided portions ~---,s~f,. ).r, -.-\'\1t::i\.i);•;ffg;'J?c!;'~J,,,:, ,,\ y ~J.i,~ ·,,_c:W1>:, • .;,~~::::tJ/;;; (,__~::::.'.'.-7\ ,,_ --~ /h~";f,: \ \ \ \' , ' r',,•--------~--\ -'.•,· tlY~ •. ,,,,.""',•~,-;;,_,~ <f'l:_·:.,;o -·, • • :·"ii:/ ~ if!J.i:1-.J~ c 0,, 'i,;__,,-'·"Ji,'' I~-are l!delands, and dots •,., f:lJ'./ -r---., _, ,-~:J '-<:J-1::.--=~ .. ~,t-,1~'3"',,~.-,-•. ,.. , ---~ • "/, '--\"( 1 't-'H/'1\~ v ';) "' I l!'<-"'""-"~~""-----.'-"/,\:,,.__-"""V. ' • , • '•• l ~ I , ", J along the peninsula , { 1 "1 --• .::---:;,:--~;,.,_ • • .-,~-.-·-~ ;::::_.,,,,,,,'M_y;1l!:, ,b:>::-~ ..... ',. ~-...... , , ,,;,,;;:,c::;:"'iiii. yi,,J = t' 1J;~1r. 1 " --.1£1 I~ ••• !'if!.,-·' • ~ •w•"'~".:I:" ,,,-~ '{;:;;:::z.:i...::. .... J -""'=-' I! \ represent large sand --W/·----..e-~:;,;,J_t.;:;=--";/:rr-. ,,j&.¥/1~r·•~'lj).1{b-;;,,~i:'r!:./?r!;}':t~'ij~ ;;:::;=::-c~ .~ ;. . .::·:. ·-.::--) •11r,J1 "-/1 I j \ \~ --~"-., :P"'>':;;""jj#-'io"-f;,~1'!:.._'/Jii~a~.,."""':.~;,~,"•"';1<.,. • --..,_.c:.,,-IJ .......__-, •... __ i, ~/I \ ~ dunes. 1 \ ·.,._":..,~ • 't'\ 'l'r,,. .._,,:,~, ~;-i_i:J;l;:odit"' ,. ~ •• • ,. ,. -~-~ .. -11~1 \ [(\\ \ '--..; \~ '-~-,.,;,, , i,2> • ~ ,.J. ',---· . --4-'"'f'~,.,,,;,__ • ,. JJ:\ ' \ \)\ ~ .... l.~~1.-1,, .• ', ~-\\• / i' \' ' JJ:-~ , ,. • . , r,. V ,, )' "\ \\ r··. -;,; 'f!!J1c~ m ,. , ·-'~\f.J( j , \\ .,.,.. \ ' • f?J5?.~3t......-":"' -;;,o,_'!ff!j= 1/ \~ ~ .... :~:...:.* :, ~·\~.,,.· ,I) . --~,';·-. ' -.Pt-•--..;:,-' /:_(,; ~ \ ~~~ ',· ,".( J,\ ~-ob ] .✓,. \\ -/4 , C , • ,4 ·,!;\\\~ \\ ,, !,; . . , ' ,.-. ,a ,-.~ \.\\.· C' -~ I .>?/_·.~ .. ---... '' .. ' .· -.. ·· ·.·• ... ·.·\··· .... ·'.-~ .. ----d-~ ---_./ •• N -\-. \\ .·• .\ /, • '\\·\ . . ~-, ~===--\_-_,-··· ,. \\ . ~ }.)._ 'fl/., / . . 1";Ji, • .. . . , .'.. W\ _,_ ·;,i ~ ,,.-).\ • • CARNATION COVE ..... -;-,, JASMINE CREEK 24- JASMINE CREEK DRAINAGE BASIN FIGURE 7 PLAN NO SCALE 5 ' ) _,/-8 UL I( HE A D~, _____ ,,., 8 --------sroRM DRAIN DISCHARGE PIPE 5___ __ _ ------'-r-..t~-_ ____ -------r,lr~-A VE ~9 T ION R E FI LL TR E N C.H • !ill//1/!ill/1 .' . ---~~. _ .,.... . .:,;'-::J ;,,, /1r'/ 1 ----tlj)T.1 ---~G.Q.VJL.L8.1;:..N.C.tl______ . SECTION A-A NO SCALE FIGURE 8 By the time the discharge flow has.reached the boat docks, the turbulence has lessened, and the sediments are allowed to settle. These sediments may form a shoal beneath nearby docks and create a problem for boat owners. Subsequently to the storm, the relatively small waves which enter Carnation Cove on a daily basis gradually push the adjacent beach sediments into the scoured trench (figure 8), Beach sediments fill the trench until its level is again equivalent to the surrounding beach. In the other type of littoral process, storm waves set up alongshore littoral transport which carries material downdrift. Longshore littoral transport within Carnation Cove is a result of storm waves propagating down the channel and refracting into the cove. Evidence of wave refraction is demonstrated on the cove beaches just south of Carnation Cove. Wave action has alined these beaches parallel with.the wave crests (figure 5). This alinement reduces the potential for longshore littora1 transport to almost zero, In contrast, when an unusual storm wave from the southeast enters Carnation Cove, the wave fronts are obligue relative to the bulkhead (station 1 figure 5). This configuration and .angle of wave attack produces a potential to transport longshore littoral drift from in front of the bulkhead to the downdrift beach. Once the littoral drift moves past station 2 during storm condtions, waves reflecting along the corrugated steel sheetpile bulkhead between station 2 and station 3 assist in rapid transport of littoral drift to the north, where sand is deposited on the beach next to station 3. The Harbor Department has constructed and extended a groin on· the beach at station 3 to retain sand. Sand has leaked over, 12 around, and through the groin and shoaled under the docks adjacent to station 3. 'rhe source of this sand is Carnation Cove. ·The predominant movement of sand from Carnation Cove is due to severe storm waves from the southeast transporting sand offshore and toward the Harbor Department Beach. The erosion has increased in the past few years due to the exceptional increase in rainfall and southerly storms. The shoaling problem is primarily a result of the above movement; and it is also related to the storm-water discharge, which transports beach sand and minor amounts of sediment into the Bay .. 13 STATEMEN'r OF PROBLEM Meeting with Homeowners On 2 July 1980, Dr. James Walker and Mr. George Johnson, engineers from Moffatt and Nichol, met with a committee of the Carnation Cove Protective Association to discuss the problems of the Cove as the homeowners perceive them. To prepare for the meeting the homeowners were requested to submit, in written form, the following information: 1. historical background of the problem; 2. a statement of the problem (as it exists at the present time) ; 3. a statement of what they think the solutions should be. The property owners responses, copies of which are included in the appendix, are summarized below. The homeowners believe the quantity and velocity of the st_orm-water discharge has increased over the past 3 to 4 years. 'I'hey associate this increase with new storm drains constructed in the upstream drainage area. When the tide is high and the storm drain is flowing full, the force of the water from the drain impacting the ocean water at the storm drain outlet causes a plume of spray and water to reach a height which is higher than that of the head of a person who is standing on the top of the adjacent bulkhead. The noise of the storm drain discharge is very loud, like the sound of water at the end of a penstock at a large dam. Their observations of the storm drain outlet during storms causes them to believe.sand and silt are brought into the Cove and are washed into the boat docking area, where it shoals. The storm flows also are believed to transport beach sand offshore. 14 The homeowners estimated that since 1977 there has been a loss of sand in the cove such that the level has dropped 2 to 3 feet overall and 4 to 5 feet in certain places next to the bulkhead. They point out that the wooden public stairway next to the storm drain outlet had an extension added to the bottom in October 1977 so it would reach the lowered sand level. They stated that the sandl.ine prior to 1977 filled up half the diameter of the 60 .inch storm drain pipe outlet. The sandl.ine is now at the bottom of the pipe. The existing level of the sand is the lowest they have ever observed. This lowered sand level presents a very unpleasant sight during the lower tide levels. Rocks and telephone and electrical underwater cables are exposed. During medium tide levels, the beach is no longer visible. The homeowners indicated that even though Carnation Cove is a public beach, people living upland no longer come down to Carnation Cove due to a lack of a sandy beach, the unsightly appearance, and the danger of tripping on submerged rocks. The homeowners at the meeting were asked to express their primary concerns and to propose solutions without consideration of who would finance the solutions or be responsible for financing the solution. Their verbal responses identified the following major items: 1. the sand beach needs to be restored; 2. the sand level under the boat docks needs to be dredged to provide adequate water depth at low tides; 3. storm-drain discharge needs to be changed or modified to eliminate or at least to reduce, noise, vibration, erosion, and sediment-carrying potential. 15 4. the lowering of the sand level has exposed some vertical joints without grout in the bulkhead and has allowed sand to wash out :Erom behind the bulkhead, thereby creating voids under homeowners' property. CORRECTIVE MEASURES CONSIDERED The following descriptions of possible alternative beach protection measures, or combinations thereof, are considered to be the most feasible and practical methods of preventing further beach erosion, reducing the storm drain discharge problem, and restoring the beach to a desirable configuration. The determination of which alternative is the best for the Cove most likely will depend on the source of funding and the funding limits; however, this determination is beyond the scope of this report. 16 Alternative 1 -350-Foot Extension of Storm Pipe. Figures 9 and 10 show the general plan for alternative 1. This alternative is a 350-foot extension of the storm drain. The pipe would be either supported with steel pilings or suspended from a pier. The discharge would be near the leads of the existing docks. An extension of the storm drain pipe would help solve three problems within Carnation Cove. First, the discharge plume which occurs during heavy rainfall would be eliminated or at least moved farther offshore. With the pipe outlet located 350 feet offshore, the noise at the discharge would be reduced as well. Second, shoaling under the boat docks may be reduced. Instead of settling under the docks, any sediment carried by the discharge should move bayward into the deeper waters. Third, the scour trench formed by the present discharge and movement of beach sediments offshore would be eliminated, resulting in less loss of beach material near the outlet. An extension, however, would not solve the problem created by wave action eroding the beach and undermining structural footings. Preliminary Cost Estimate Description 350-foot extension Subtotal Contingencies (20%) Subtotal Engineering & Design (10%) Supervision & Adm. (8%) TOTAL Quantity_ 350 17 Unit Unit Cost L.F. $ 700.00 Cost $245,000 $245,000 49,000 $294,000 29,400 23,500 $346,900 -.,,~ .. z ;; O'. 0 :,; I- Q'. '.'.; 0 I-I-:, <I) 0 :;,j ,·.~.;, ·,::--.._r.-J1<::I J s.:;~'1,, -,~o '· .._,'..(,S ·~ "o ~:::::-' SC:. -r.;, ~ '--'.,----·-~ --~-"·-!!" o N-.., --~'::-~ ~ ~ -=-OJ~ ~;=-~ ~ ::::c.~::c,:c=, :c=c-1:="--c:..;'"=~~=""'"·---__ -=:J '-" z ;:: <I) X w j :r: u w <l'. CL LIJ (L ro :ii 1--n: 0: 0 0 I- a.. U) 5' w u.. w ::'. 0 z I-<:( z w z :? > n: u, 0 w z u I-w ,.J 1-- z <:( X w 0 I- 1--0 <l'. 0 LL z 0: 0 <l'. 1/) u "" FIGURE 9 "Tl C, C ;;;:, rn _,, +10 1 0 + -5 + -10 -5 0 OATlJM ! MLLW 60 INCH RCP ( EXlSTlNG) j I' 11 ,I 'I t " 50 100 / 72 INCH RCP (PROPOSED) I! ),j' Ii ii i Ii '~1 t ii i1 li ii i I II ·1 !41··1 !! I, ' '1 jl ; • i! ii 11 '1 1! -t 'I IT h ' L " II 11 I !j ii I, ii 1 " "-..,._ 150 200 250 300 350 FOOT EXTENSION. OF STORM DRAIN .PIPE VERT. 1"=10' HOR. !"= 50' -ILJ 11 1 1.1 I I , I ' I !, 11 'I I' t _! 350 400 500 0 ~· ---------------------------------------------- Alternative 2 -Sand Replenishment and 350-Foot Extension of Storm Pipe This alternative, shown on figure 11, is alternative 1 with the addition of beach replenishment. Approximately 14,500 cubic yards of sand would be applied on the beach to elevate it and widen it. A section through the sandfill is shown on figure 12. The toe of the fill would extend approximately 160 feet to MLLW. Mean higher high water (MHHW) at Carnation Cove is roughly 5.4 feet above MLLW. This results in a dry beach width of about 50 feet. A beach would alleviate underminings of structural footings and would lessen piping losses of material from behind the bulkhead. Besides providing protection, the beach would be returned to a useable recreation area. The storm-drain extension would act as a jetty groin and divide the cove into two cells. This would tend to stabilize the beach on both sides of the pipe. Downdrift transport of sand to the north of the pipe would continue during southeast storms and an allowance for backpassing 2000 to 3000 cubic yards of sand should be included in the annual maintanence charges. The backpassing would be from the Harbor Department Beach adjacent to station 3 figure 5. Preliminary Cost Estimate Description 350-foot extension Sandfill Subtotal Contingencies (20%) Subtotal Eng. & Design (10%) Supervision & Adm. (8%) TOTAL QuantitY: 350 14,500 18 Unit L.F. CY Unit Cost $700.00 $ 9.00 Cost $245,000 130,'300 $375,500 75,100 $450,600 45,060 36,048 $531,700 ,, 0 C :,:, "' Ii II \\ \1 \ , ·-· -·-··--·-----·-,_......_, \\ ;, , I\ \ l1 I\ \\ ~ II . \\ . 11 •• \ _"'"'" "~~------1 '1 . I ii f . l1 I I I I rrJ li u CARNATION COVE, NEWPORT BEACH ALTERNATIVE 2 SAND REPLENISHMENT AND 350 FOOT .EXTENSION OF STORM PIPE .~ );t STORM DRAIN _ OUTLET ~ .,, 0 C ;:u rn N -60 INCH RCP (EXISTING) 72 INCH RCP ( PROPOSED) +10 T +9 MLLW (BULKHEAD HEIGHT) ,_+8 M·u:w If =~a;;,=====7r1 ==1===,====7:1F~ , I , -t-: ---1, -r-----,! ---11 -i ~ l 20 1 1 ll Ii 11· ! ! :::::::::7 I '. ij ll !: 1 SAND FILL--------1 ,, 11 II -~ ---------~--.c:.:: --,,-----1-, ---11 ; o 1! ~ I r H 11 160' -, , !' -5 -10 ------------BO AT ---,....--Jl. I ij I li " ½ Ii I! ji ii 11 ' I DOCKS -15 ~--~---+-------if-------+-------+-------+--------t-------t-------+~\----l 0 50 100 150 DATUM: MLLW . 2 SANO FILL QUANTITY: 560FT. =20.7GY/LF 200 250 BEACH NOURISHMENT VERT. 1": 10' HOR. 1"= so' 300 350 400 500 Alternative 3 -Two 175-Foot Timber J·etties Parallel jetties could be constructed as shown on figure 13 to channelize the storm-drain discharge. By confining the discharge for 175 feet, it then would not scour the sand from the beach. This would reduce beach-sand loss and decrease shoaling to a degree. The lighter, smaller-diameter storm-drain sediments would move into deeper water beyond the boat docks before settling. A scour trench would form between the· jetties; however, it would eventually stabilize. Several types of jetty construction could be employed. This estimate was based on timber planks inserted between two H-piles. The timber jetties would prevent adjacent beach sand from being carried into the scour trench and slightly decrease the shoaling under the docks. The problems of noise and the water plume during storms would remain. Preliminary Cost Estimate Description Quantity Steel H-piles installed (average length 18 ft.) 70 4 in. x 8 in. Timber Planks installed between H-piles 350 Subtotal Contingencies (20%) Subtotal Engineering & Design (10%) Supervision & Adm. (8%) TO'rAL 19 Unit ea. L.F. Unit Cost $1,000.00 $ 75.00 $70,000 26,250 $96,250 19,250 $115,500 11,550 9,240 $136,290 .,, C, cl Ri! I ~ ,. ~ \'. i1 \ i \ \ . t I:~ ii DRAIN OUTLET ~ ,' STORM \ /-11 II • I I ~ \ \ !I I ~ ~ rt ) CARNATION COVE, NEWPORT BEACH ALTERNATIVE 3 TWO 175-FOOT TIMBER GROINS ~ u ~ Alternative 4 -Sand Replenishment and Two 175-Foot Timber Jetties Alternative 4, shown on figure 14, combines the timber jetties of alternative 3 with the sand replenishment of alternative 2. As in alternative 3, the timber jetties should help reduce the shoaling problem under the boat docks by confining the storm-drain discharge for 175 feet. The sandfill would solve the problems of footings being undermined and loss of material from behind the bulkheads. The jetties would stabilize the beach. Sealed jetties would impound sand updrift of the southern jetty and provide a recreational beach. Some sand would drift around the head of the jetty to renourish the downdrift beach and some would be transported offshore to shoal under the dock. The downdrift beach would continue to erode, however at a much slower rate. The jetties would substantially reduce the annual maintenance charges for backpassing. Preliminary Cost Estimate Description Sandfill Quantity 14,500 Steel H piles installed 70 (average length 18 ft.) 4 in. x 8 in. Timber Planks 350 installed between H-piles Subtotal Contingencies (20%) Subtotal Engineering & Design (10%) Supervision & Adm. (8%) TOTAL 20 Unit Unit Cost cy $ 9.00 ea. $1,000.00 L.F. $75.00 Cost $130,500 70,000 26,250 $226,750 45,350 $272,100 272,210· 21,770 $321,080 ..,, C, C :,J rn -.):> ---~-------·---, -·------··-•. ,. ' I \ ----··----~·-- \ \ \1 I ii I I ---r,EXISTING BEACH'r\- ,. I) \ I \ 1\ \I Ii '\ lftt~ ' /1 /I I L-l . CARNATION COVE 1 NEWPORT BEACH ALTERNATIVE 4 SAND REPLENISHMENT ANO TWO 175-FOOT TIMBER GROINS ~ Ii',/ STORM DRAIN OUTLET \ I\ I "''"" ,,JI >- t= ! I I I ~----rr-~I I ' § I I 1-c 11 ;; --1-Ii .,, C) C ::0 CT\ _, {J1 . \ \ \ I lr)i I J...-,,1 i I i \) I] LJ CARNATION COVE, NEWPORT BEACH ALTERNATIVE 5 SAND REPLENISHMENT, TWO 175-FOOT AND ONE 75-FOOT TIMBER GROINS ~ '),i/ STORM DRAIN OUTLET l-~1 , I \/ Alternative 5 -Sand Replenishment, Two 175-Foot Jetties, and One 75-Foot Timber Jetty_ Alternative 5 has the same characteristics as alternative 4 with one additional benefit. A 75-foot.t.imber jetty located just north of the existing Harbor Department Beach would tend to stabilize the other cell of the bisected Cove, thereby reducing backpassing requirements. The projected future alinement of the proposed sandfill is shown on figure 15, Wave act.ion would gradually transport sand from the southern cell around the jetties to renourish the downdrift beach. The 75-foot jetty should allow the downdrift beach to build with only minor losses of sand around the head. All jetties should be effectively sealed to prevent sand transport through voids. Because of the rock bottom, it may be necessary to secure the timber bulkhead to steel pipe or II-pilings placed approximately every 8 feet. Preliminary Cost Estimate Description Steel II-piles installed (average length 18 ft.) 4 in, x 8 in. Timber Planks Quantity 85 installed Between H-Piles 425 Subtotal Contingencies (20%) Subtotal Engineering & Design (10%) Supervision & Adm. (8%) TOTAL 21 Unit ea. L.F. Unit Cost Cost $1,000.00 $85,000 $ 75.00 31,875 $247,375 49,475 $296,850 29,690 23,750 $350,290 Alternative 6 -Periodic Dredging and Beach Nourishment. Dredging under the docks and placing the sandy material on the beach would satisfy the shoaling and beach erosion needs. The material under the docks has a sand content. The silt and clays should wash out of the fill and go offshore, leaving a sand beach. Some of the sediments may not be suitable for beach fill and would have to be disposed of at sea. More sediment samples would have to be taken to develop this solution. Other sources of sand include the Harbor Department Beach and slip area and the entrance channel shoal. Littoral transport would continue to erode the Carnation Cove beach and cause accretion at the Harbor Department Beach. This is a matter of maintenance backpassing and replenishment, Shoaling would continue to occur under the docks and another dredging episode would be required. Preliminary Cost Estimate Description Sandfill Contingencies (20%) Subtotal Quantity Unit 14,500 CY Engineering & Design (10%) Supervision & Administration (8%) Total 22 Unit Cost $ 9.00 Cost $130,500 26,100 $156,600 15,660 12,530 $184,790 Other Plans Considered An energy-dissipating structure would reduce turbulence of the discharge flow and would spread the flow over a wider area. This structure was rejected for the following reasons: 1. it would require a rather large, reinforced concrete structure approximately 30 feet in width and length constructed on the ocean side of the bulkhead which would not be aesthetically pleasing; 2. there is no guarantee that the structure would reduce the noise level, and it could increase the noise; 3. the structure would increase maintenance cost because it would have to be cleaned out periodically; 4. the structure, being open to the oceanside, could become an attractive nuisance to children who might.seek to play or hide in it; and 5. the flow of water discharging over: the energy dissipator weir would still need to be channeled across the shallow beach area. It would appear the only benefit derived from this type of structure would be to hide from view the violent agitation o:E the storm water as it discharges from the 60-inch pipe outlet. 23 DISCUSSION OF ALTERNATIVES Alternative 6 provides the most expeditious way of restoring sand to the beach since it involves only dredging. However, it will not provide any form of beach stabilization. Alternative 3 by itself will permit a very slow, gradual accretion of sand against the timber bulkheads. However, alternative 4 adds beach sand replenishment to return the Cove to a beach shoreline. With the timber jetties, the storm--water discharge will be channelized across the beach and this would prevent sand on the beach from being drawn into a scour trench and moved offshore. Alternative 5 adds a 75-foot long timber groin to alternative 4, which would reduce maintenance backpassing and stabilize the beach. Alternatives 1 and 2 provide more complete. solutions to the stated problems and they are also the most costly. These two alternatives also create several new problems, such as: interference with two of the boat docks, possible hazard to boating and swimming at certain tidelevels, and possible obstacle to people using the beach. Environmental analysis reviews and approvals will be required as to the visual effect (acceptability) of the pipe, the silting effect elsewhere, etc. 24 SUMMARY OF FINDINGS O The existing storm drain system and the proposed storm drain additions are properly designed. O The existing 60-inch storm drain discharge pipe has capacity for the design flow from the Jasmine Creek drainage basin. O The predominant mover of sand from Carnation Cove is severe storm waves from the southeast. o Erosion of sand beaches has increased in the past 3 years due to exceptionally severe storms. o The shoaling problem is caused by movement of sand by storm caused wave action and it is also related to the force of the storm water discharge which transports the beach sand and minor amounts of sediment into the Bay. 25 REPORT ON CARNA'rION COVE APPENDIX 1. looking aaa! t.oward slorm drn!n ouH"! !n oonc:rnte b11!kha1HI from f!rl>! pier north ·ot storm drnio oull;>t. 4. looking norlh Imm deck of !!rst house south ol storm drnln"' 7. Closeup view of 60-hrnh storm drain ou11<,-,1. 9. t.ook!ng eou!hwes! from firsl pier soulh ol storm drnin ou!!el at the bulkhead .. 11. looking norlhwesl hom l!ral pler nor!h of storm drain out!al. 12. Lool<lng north from fire! pior norlh of storm drain outlel. \AJFDrVESDAY :;TUL '( ·. :2/}vl S U B J E C T:_ ·-· I 7f:2-_A c. 'r ;;l3 ~ 3 (p iP.. ei t-l A 's r-7:.-oliT 6A'f StDE- Ve-a.. /1'1l::J. fL AS YOU KNOW, HOPEFULLY, THE NE\.::'CF.T BEACH CITY COUNCIL APPROVED THE EXPENDITURE OF $7,500.00 TO IHVE AN INDEPENDE!!T ENGIKEERING. COMPANY MAKE A STUDY OF THE PECULIAR--TO-THE-C.4.RNATION COVE TIDAL ACTION, THE WAY TIE STOrt.l-: DP~UN EM?TIE S INTO TlB CO'lE AND THE GENERAL DRAINAGE PROBLEM THAT EXISTS. DURING HEAVY STORMS. MR. ,JOHNSON, AN ENGINEER WITH THE FIRH DOING THE STUDY., WOULD LIKE TO HAVE THE OPPORTU:-IITY T0'1,LK WITH AS HANY RESIDENTS Oi.i' '.J.HE COVE AS POSSIBLE. HE WILL lE HZRE AT THE ABOVE JJA'.l'E AND TIME? HE WOULQ_ JP PREClATE H,WING YOU SUBMIT \.ffiITTEN H.t.TERIA.L TO HIM AS FOLLOWS: (1.) HISTORICAL BACKGR01.rnD, AS YOU !'.!WW OF IT. (2.) THE PJtoBLEM AS IT EXISTS AT '.!.'HE PRESENT TIME • (3.) }HIN£ DO YOU 'i.'HINi'. THE SOLUTION S~!Otrr.n R,~? • 2323 Bay::;irle Drive Corona del Har (Carnation Cove) liISTOHICAL BACKGROln-IG: The sefl l-lall in Csrnation Covel-las began about September 1948, Our house at the.above address was built about 1950. Previous to the sea wall being built, I remember a very rocky stretch of beach along Bayside Drive l-lith the water corruning close to the road, The contractor who· installed the wall, Eldon Osborn, told me very recently that t,he sea wall was placed where it is because a market survey of demand for lots indicate-I that the public wanted small beach lots. After the wall was in place, dredg5.ng was done to· fill in behind the ·wall and to build up a beach on the bay side, that was a gently sloping, sandy beach; however, currents washed the sand out and :the :fill was again used to build up the beach •. It washed out again. Jn 1960, the Tracys bought their. present home at the above address. While the sand was higher than it is now, and the telephone and Edison company cables were covered. np, the ; beach was completely under water at a medium high tide. After the big apartment house was built in China Cove, the baa ch built itself back up . so that there was very little, if any, clearance between the sand and the bottom o:f the concrete planters on our porch .• When ever there was a rain storm, some sand was washed out into the_ Bay and u.~der the , piers; however, nothing as to compared to what happened after the new concrete storm drain was installed four or five years ago. After the storm drain was re--modeled, the greater volume of water and with its greater, nozzle-force intensity leaving the drain, the sand was quickly washed away from the. beach and out into the Bay. The tidal currents in Carnation cove have to been seen to be believed. Waves come silmu.'1taneously :from both ends of the cove and_converge in the middle of the cove opposite the drain. Sand is pushed/pulled by the tidal action into position in front o:f the drain. When there is water conuning down the drain.with much force1 the sand ls then washed out into the Bay. • Cat-walks leading to the piers have been errodc,d so that they have toppled over. · . The sea wall has be,~n exposed and the :force of the waves has pulled out the grou:ting and then the sand.is sucked out :from behind the sea wall. This leaves treirendous voids unter the houses, behind the sea wall. A.lf'f. DREDGING TH.AT PIER OWNERS DO ONLY !L~S A VERY TEHPORARY BENEFIT. PROBLEM AS SEEN BY TRACYS The sand is pushed from the beach because of a concononent action of tidal action and excessive drain discharge, especially during a storm period. The sand leval o:f the beach is at an all time low. This has created hazzards on. the beach because of rocks, de9ris and exposed cables, all of which are sometimes covered ;;ith water. Pilings for the riers are being erroded and are in danger of falling over .. Voids behind the sea walls and under houses are a menace and threat. SOLUTIOlJ: Extend the storm drain out into the bottom of the bay be;;ond the pier and float line- Build a sea wall out at property line to hold new extension of drain in place and then ~!}} 0 i~-; ~.'.;.h,~~:\ ;o .. :~:'.k:~~-1-f~~e: "~a~dy be"-:h• Owners would pay for sea wall in .from of them I I I ,_ I • . ... .. ' I -::z::. y ~ 9 Ct\ l • I • • • \ ' , ... . - • • ,. ' • I '- ' . ' -" .. ----~ • -:-:7.;.; :r- .~ .-, . ··•--·--...... ....:.....----·:· -~·,;:;_, :. -··-•---.•- • • , ~ ~ • ~/) /7-Y).) :)./',' 11 J / CJ 7 0 -)•(.l.~ / 9 7 / \..,~.,.{jc .. '2., • { __ J...<f:..,',,< c;_ .(...~ · ~ ..,,,..,A..e-~/.v ._cJ-t,.~ L/ 3 -2c:c ea. cL/..c·?Z .. -i--a-,.-;,;_./ · t M-· di' r ,e_, C I; .µ , V>d:-?zr j • , -:J,v77nJ J 17 :J. -·· 11.J -. ()--U/2,,-.s ,2, '/tc ,<L-clA.Lb,-1~c··. • . . . . ' •. ,. • .•. ' .' -,. . . :· 1.,,,v-r1,,a,.. ,,,,,4_~ ~·. ~--c-/4J ,,_~ J1v-L.,I met. .. ~ .··.•··•·•· • .. __:µL;aj. (. 8'. 7,~ cU}g_~Y _) • • 7/J-?YYL/ ; 1 7 c-: 7 8' :._ . ·w...e-~-La,,t.,;:i/ i--t-L d:2.,,1.:_t.,1 • • f' • , . • .:-~ ', '. ·: . . . . • V' • -•.. ' +J"'> ~~~-t6 ·~~Z)~ &;:tz: --cd-1ft--~C ,---.,._ ___ . i ->0r0n I 9 7 6 -. 7 J_, ~~ t-,/~u ,;-1-.. b--&1 1.--Cr ~/~ ceJ , • 1 • ·21J • f-·i: '-J°-~~ ~~ 0? JrGu ~b 17~.e../ i ~l,L; ...ci,Z: C!...Lt t_.£~; , . . . • ... . • . . .·~ .... · ·. . • . . lJ:e '-,--Ac:vt-<--" cJ,t,,Jo~p 1..--Aa~I cc L--{u~I'---' V/J.1.4Y/ ~ ..... :~j fl---/J.-.2--'v<__,,U '-✓-7 ~£~ '--f~JJ ~;_~ ,. ·_ . . . ~ . . -• ' . . _ Lu ~QlA: ~ Vlu.6-DG.JA.d ctv_d T l'Y\ouQ_d L~ 3Y2 L[<2Q,YS ~q o > I <?w 1 td~ woJ:, o... p\Q_C\. 6~t C.V!Qu..9--=, 1)u.:rL0.q tow .\--L<l1::.. iV\<:::xc::. wah o__ -pQ...,r\..cJ beo.~h 1 -~= ~ ~ ~~ stcu.<s 1Y1<2J -11-\e 60.lAc! o...uc\ -wi~ boa.I-:\ lJJQru.. hd-Cl..~Yau..u.cl , T '{\:i:: y-c, clc:5 +(\gJ -0. Ye-V<.0\.,'0 o.__,r pa..Yeu..(- hol \f w~ oc,.__;\--4-o -IP-ts '? d=.l-<'5 Ll.l<iXE.. (.Do1.__>e.v-~ , --r ne \')Ll~7 --tv?ia.\--hold u{l Q'.&.\._< ~ '(:>O-t<J::1 l\J(b{e.. \ri.'(\"(\~ r-kD.1J{'d llJ\.. ~ ~y<:suncl 0-.1.\.d ·\~ Q.G.0k:.a - <1.tru,~ ouJ b\"<.sm (Y\<1(1,( '\G~ Stu4S W!lrtQ -~~f- \:xixe.~ D 1·sG..1Dls, • . • ~ \u. \ t,al.LL d 4 l O \'" es • Q' 0Yl \'. QJ\JYl <id -Q. &rd --~~­ f'Qp1. cl QJJ..0 ra01clll ~hmt9QD ~aJ ~etu<e o~c..un.Qd \ \I\ ~ a '-\QOJl'.T a. ud o.. Lx:,uJ +~ <::, Wl,ui 6 <'{r. _ _ 11A0~0.f,w..~ t~Q a.\'\'\~uJ-~ u-D:Je< d1llc\'\o,'9Q~ \rmYl ~ k,,•(f5" 4to'OY) d(Qlji) I b ·\.,(:1:.Si-\.,U_) QC:t(J,11) f,S •.. -_. t-anQu. \c • '\6'rcrkc{--+Cu:_ \jQec0J/\ . -• . • ll5u-u__l -_1-c_h~ be1t~xd ,· • •• / I 7 ff=y ~ //4c-e:.. _ \ ,.,,..,. '\. ~,/~)f}· ··~· '. .-' . \ 'Bernard N. Pesenberg 22)1 Bayside Drive Corona del r•iar,, Calif. June 26, 1980 • -h. June 27, 1980 , MY OBSERVATIONS OF THE CA..'lNATION COVE SAND DISTRIBUTION Each property in Carnation Cove has a somewhat different perspective on sand distribution and the effects of current,, __ tide and storm waters.· Those of us who live to the west of the present sea. Wall are effected in a somewhat different way than other residential properties. The outlet at the bottom of any canyon or gully: in, Southern California will receive strong erosive ef'f"ects during rain storms. The area in question drains storm waters from several hundred acres ln Corona del • I can remember the storm watex· action be:fore the present sea, wall was constructed. Torrential waters were deposJ.ted. . at the botton of Carnation street and into the bay during storms. The w waters cut through the banks above the sand_, • ·' and made a gully down over the beach and to the bay. Storms were us\ually a:ccompanied _ by strong wind.s. The. winds_ i er7oded the beach and washed sa.YJ.d into the bay,. The storm waters seemed to keep the mouth o:f Carnation Cove cl.ea:i:- of large sand deposits. De:fore the present ~ewport Beqch br !aters were built I think in· 19.36, there was very 11 ttle si . ) 'Ch on the present slte of Carnation Cove. When the "Waters had been completed, the sandy beach was y filled in, However, I can remember be:fore the • I ' • .. De sen berg Carnation Cove Jur1e 26, 1980 2 sea wall was built and this may have been in the early 50's seeing small, keel sailboats sail into Carnation Cove at high tides . In fact I distinctly renember a 30 foot / deep keeled, Ta.hi ti Ketch saili:Jg up to within about . • 50 feet of the present storm drain outlet and hitting sand and being stuck there on its side as the tide went ·ut. It refloate<'l at the next high tide. I can also remember the :"outh of the present storm drain being filled with. sand, the sand was washed ·out_ during storms and filled up again in periods 1>1hen· there was little rain. . . It may be that.the number of piers cuts down the circulation of • waters tha't might w,,sh sand into the channel~ . . I feel that the gradu~l build up of roof tops and concrete streets and driveways from the a:rea which drains into Carnation Cove must effect the volume of water that empties into· the storm drain in Carnation .Cove by. increasing the flow substantially. There fore· I believe that the people. who live upstream have some financial responsibility in contributing to a safe disposal of storm waters. I am referring to the property owners who 11 ve il'l the highlands of Corona d,c:1 Mar from which the storm waters drain. There are a number of problems in Carnation Cove and one of them. is the· buiJ.d up of sand a:round the piers and slips making the use of them for safe boating very difficult. I don't know what has cqused this, however in the past, the Newport .rlarbor ~-was filled with sand bars. It took a great deal of dredging to make the harbor deep enough for boats to use the harbor. ' ' . ' Dese::1terg Carnation Cove June 26, 1980 J There is a particular problem at 2231 Bayside DRlve. The beach in front of the house has for the first time since I llved here starting in 1939, developed a cliff in the sand. Portions of my beach are now washed away ~reating a dangerous condition~ Someone could fall off the sand·during the dark because there is an abrupt drop of two or three feet. I sh.ould like to know if the porch at 2301 Bayside Drive, bull t beyond the sea ,:,all has caused my beach to wash away.. . A. series· of concrete structures has been built beyond .. this por::h to protect it from tidal action. After the last concrete wall was completed, my bee.ch began to wash away. I find some silting or sand buil,ding up at the end of my slip • where I keep a small deep draft sailboat. I would like to know the :::olutitin to this problem. '•