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HomeMy WebLinkAbout08-05-1986 - AgendaCITY OF NEWPORT BEACH • PARKS, BEACHES AND RECREATION COMMISSION REGULAR MEETING TO BE HELD TUESDAY, AUGUST 5, 1986 CITY HALL COUNCIL CHAMBERS 7:00 P.M. AGENDA I. PROCEDURAL MATTERS 1. Call to Order 2. Roll Call 3. Approval of Minutes - Meeting of July 1, 1986 4. Adoption of Agenda II. JOINT MEETING WITH FRIENDS OF OASIS (Agenda Attached) III. 5. Little Corona Study (Memo and Reports Attached) IV. • (Keview ano make Appointments) 6. Street Tree Committee - Chair Wolfe IBILIT I 7. Recreation Program Committee -Commissioners Brenner and Taft 8. Oceanfront and Beach Committee - Commissioners Springer and Taft 9. Capital Improvements Committee - Chai.r_Wolfe 10. Budget Committee - Ohair Wolfe 11. Friends of Oasis Liaison - Commissioner Springer 12. Friends of the Theatre Arts Center Liaison - Commissioner de Boom V. PUBLIC COMMENTS VI. DISCUSSION ITEMS 13. Commission Objectives 14. Review of Current Capital Proiects t ttac -he — _-15_ Veh_i_cu_lar-Access._Restrictton fo_r Bayside Drive (Memo —Attached) 1.6.._2arl- ancL_St. -eet Tree Division (Report Attached) 17. Recreation Division (Report Attached) VII. SPECIAL. UgQj_E_N_LORIAS_T_MINUTE ITEMS VIII. ADJOURNMENT Item No. 3 CITY OF NEWPORT BEACH is arks, Beaches & Recreation Commission July 1, 1986 City Council Chambers 7 D.M. INDEX Call to Order Roll Call Approval of Minutes Adoption of Agenda Seating of New Commissioner Ex- Officio Member Present: Ronald A. Whitley Staff Present: Jack Brooks, Park and Street Tree Superintenden Mark Deven, Recreation Supt. Dottie Flohr, Secretary I. PROCEDURAL MATTERS Item #1 The meeting of the Parks, Beaches and Recreation Commission was called to order at 7:05 P.M. Item #2 Roll call was taken. Commissioners Brenner, Konwiser, Springer, Taft and Wolfe were present. Commissioners de Boom and Hopkins were absent. Item #3 Commissioner Springer asked that the minutes show she voted nay on Item #9, Status of West Newport Park, and Chair Wolfe asked that the minutes show he voted nay on Item #16, Encroachment Request, under Commissioner Hopkins' motion. Motion was then made by Commissioner Konwiser and seconded by Taft to approve the minutes of the June 3, 1986 meeting as corrected. Unanimous. Item #4 The agenda was adopted as presented. Chair Wolfe requested an updated report on the status of all capital projects in progress at each meeting under Discussion Items. Such projects would include the Little Corona Study, Bonita Creek Park, Community Youth Center, Restrooms and the Bicycle Trail on the beach front and at Grand Howald Park. II. ACTION ITEMS Item #5 - Seating of New Commissioner - Virginia Herberts Chair Wolfe announced that Commissioner Hopkins, who served five years on this Commission and whose term expired, is being replaced by newly appointed Virginia Herberts. Chair 2 Wolfe introduced Commissioner Herberts who gave a brief background of herself and said she is pleased to be working with the Commission. INDEX Call to Order Roll Call Approval of Minutes Adoption of Agenda Seating of New Commissioner CITY OF NEWPORT BEACH arks, Beaches & Recreation Commission Page 2 Citv Council Chambers 7 n.m. INDEX- V. F. _ Item #6 - Election of Officers for 1986 -87 Election of Officers Motion x Chair Wolfe opened the meeting for nominations and Seconded x Commissioner Taft nominated Wolfe as Chair._ Seconded-by Ayes x x x x x x Konwiser. Commissioner Taft then motioned the nominations be closed. Seconded by Konwiser. Unanimous. ¢ Motion x Commissioner Taft nominated Commissioner Brenner for Vice Seconded x Chair. Seconded by Konwiser. Commissioner Taft moved Ayes x x K x x x the nominations for Vice Chair be closed. Seconded by Konwiser. Unanimous. Ron Whitley noted this was the first time in the history of the Commission that a Chair has had successive terms in that position. Mr. Whitley then presented a plaque to Chair'Wolfe on behalf of staff and the Commission for the fine job he did this past year. Chair Wolfe thanked the Commissioners and said they were a great group to work with Seating of the,Commissioners then took place. Item #7 - Request to Prohibit Sponsorship of Foot Races by Request to Prohibit Alcohol and /or Tobacco Companies Sponsorship Ron Whitley reported that„ although there is no written of Foot Races by policy, the City has never had an event sponsored by a Alcohol cigarette and /or alcohol company. The Special Event proces and /or approving all permits is through the Finance Department Tobacco rather than this Department. Companies Mr. Lars de Jounge, 208 Marigold Avenue, Corona del Mar, addressed the Commission. Mr. de Jounge expressed concern over beer being served to minors•at the Spring Tune Up Run, which was sponsored in part by Miller Brewing Company. Mr. de Jounge ran the race and said he had a hard time finding anything else to drink. It is Mr. de Jounge's opinion that it is not good to drink beer immediately after a race; and that since beer and tobacco are unhealthful, they should not be associated with sports events. Following questions and discussion, Mr. Whitley referred to Policy I -21, Bike and Foot Race Policy. A condition could be added that prohibits such events from having cigarette and alcohol sponsorships. Mr. Sam Johnson of Ford Aerospace Corporation, which sponsored the Spring Tune Up Run, addressed the Commission. He explained that the largest drinking area, which was for 3 beer, was at the suggestion of the Newport Beach Police Department. There was a water, station at the end of the finish line and soft beverages were also passed out. CITY OF NEWPORT BEACH arks, Beaches & Recreation Commission Page 3 City Council Chambers 7 p.m. INDEX Mr. Johnson answered questions and noted that out of the 1600 runners, only 50 were in the 16 -20 year age group. He explained how the beer was dispensed and controlled with the help of the Police Explorers and Police Department. Attendance was up by 250 this year and they have had no complaints in the past six years of running the race. He also mentioned that many runners like a cold beer when they have finished a race. Mr. Dick Power, Executive Director of the Harbor Area Boys Club which helped sponsor the race, addressed the Commission. He explained how beer was dispensed and, if there was any question as to age, the individual was turned down. He said he felt the race was.well run, precautions taken, and the roped area for beer properly guarded. Mr. Lou Yantorn, Resource Development Director of the Boys Club, addressed the Commission. He said he felt the Spring Tune Up Run is a first class race and not demeaning to the • youth of the community in any way. Mr. Yantorn reported he has never seen any kind of poor conduct in the past six years and feels the Ford people put on an event of which everyone can be proud. Mr. Carol Kamper, 1329 Santa Ana Drive and a member of the Board of Directors of the Orange County Board'of Cancer, addressed the Commission. Speaking on behalf of the Orange County American Cancer Society, Ms. Kamper recom- mended races not be sponsored by tobacco companies, however, she said that they would not be opposed to beer being provided if it is only served to adults. Upon the close of Public Testimony, discussion followed concerning such ideas as prohibiting dispensing but not sponsorship; not having sponsorship if minors are participa- ting; the philosophy of free enterprise, etc. Motion x Commissioner Springer motioned the City prohibit sponsor- ship of events by alochol and cigarette manufacturers. Motion fails for lack of a second. Motion x Commissioner Brenner motioned the City impose a ban on Seconded x dispensing alochol and cigarettes at events which include persons under 21 years old. Seconded by Herberts. Chair Wolfe then asked for comments from staff. Mark Deven reported the City conducts two runs per year which have never been sponsored by alcohol or cigarette companies. Mr. Whitley reported that the City's park policy is open to any kind of sponsorship, however, alcohol cannot be served in City parks. CITY OF NEWPORT BEACH arks, Beaches & Recreation Commission Page 4 City Council Chambers 7 p.m. INDEX S Motion x Commissioner Brenner moved to add an addendum to Policy I -21, Seconded x Bike and Foot Race Policy, that events which include Ayes x x x entrants under 21 years old ban dispensing alcohol and Nays x K x cigarettes at or after the event. Seconded by Herberts. Motion fails. Motion x Chair Wolfe mgtio.ned the Commission recommend City Policy Seconded x I -21 prohibit any alcohol or tobacco companies from Ayes x x x x sponsoring bike and foot races. Seconded by Springer. Nay y Motion passes. Abstain x Item #8 - Request to Remove'Parkway Tree at 220 Heliotrope Request to Remove Park - Motion x Ron Whitley reviewed H.K. Chaney's request for tree removal way Tree Seconded x and reported the Street Tree Subcommittee met and decided Ayes x x x x x x to retain the tree because of its value. Mr. Dick Burns, 236 Heliotrope, addressed the Commission. He feels that the tree should be saved since it is so • large and beautiful. In addition, it is his understanding all local residents are to be informed when a tree might be removed. Mr. Whitley clarified tree policy stating the local home- owner associations are notified when a tree removal is to take ,place. However, since Corona del Mar has no official homeowner association, Mr. and Mrs. Jim McDonald represent Corona del Mar on the Street Tree Subcommittee. Mr. Whitley also noted that the tree was recently root pruned on the sidewalk side (property owner's inland side) to appease them and still allow the tree to be retained. Commissioner Herberts added that she talked to residents in the area and they love the tree and want it saved. Commissioner Konwiser suggested the tree be pruned since it is worth a lot to the residents and they want to keep the tree. Jack Brooks replied that since they are mature trees, they will be trimmed lightly. Commissioner Brenner moved the parkway tree at 220 Helio- trope be retained but thinned out. Seconded by Konwiser. Unanimous. Item #9 - Encroachment Permit Request for 2727 Ocean Blvd. Encroachment Permit Mo h x Following a brief review of the request for an encroachment Request Seconded A permit from Gary Hamilton, 2727 Ocean Blvd., Chair Wolfe Ayes x x x x x x motioned the Commission approve the encroachment of the SSeconded'by sidewalk from the curb to the front door without the fence. Brenner. Chair Wolfe amended his motion to include the 4'sidewalk. Seconded by Brenner. Unanimous. CITY OF NEWPORT BEACH arks, Beaches & Recreation Commission Page 5 City Council Chambers 7 p.m. INDEX Item #10 - Designation of Bayside Drive Park Designation of Bayside Motion Following a brief background review by Ron Whitley, Mr. Ed Drive Park Seconded x Giffin, 307 Larkspur Avenue, addressed the Commission and Ayes x x x x K x read a letter from Ron Covington, President of the Corona del Mar Community Association. They are upset that Council approved a parcel of land at Jasmine Avenue and Bayside Drive to be used as•a parking lot rather than a park. They are now concerned and would like to assure that Bayside Drive Park developed on road right -of -way be guaranteed to remain as a park. Following questions and discussion, Commissioner Taft motioned the Commission request the City Council to adopt a Resolution prohibiting vehicular access, except for emergency and public utility vehicles, on the Bayside Drive right -of -way between Carnation Avenue and Jasmine Avenue. Seconded by Konwiser. Unanimous. • Item #11. - Ad Hoc Sign Committee Ad Hoc Sign Motion x Commissioner Konwiser, Chair of the Ad Hoc Sign Committee, Committee Seconded x reported Commissioners Springer and Taft and Director Ayes x x x x x x Whitley met both at the staff office and the sign department. Commissioner Konwiser presented pictures of the proposed signs and explained costs, design, colors, size, etc. The time schedule for placement is two years. Following questions, Commissioner Herberts motioned to accept the proposal of the Ad Hoc Sign Committee as presented. Seconded by Brenner. Unanimous. Item #12 - Review of General Plan Amendment for Newport Center Review of General Motion K Ron Whitley passed out a report from the Planning Department Plan Seconded x on General Plan Amendment 85 -1(B). Amendment Ayes x x x x K x Pat Temple, Environmental Coordinator of the City's Planning Department, addressed the Commission and handed out Exhibit 1 -4, Newport Center and Peripheral Sites E•IR. Ms. Temple explained that the General Plan Amendment has been in the Planning Department system for the past year and requests changes or increases in the original development. Specifically, Ms. Temple reviewed the Planning Commission's • actions and staff recommendations regarding three park issues, namely, Bayview Landing, Newport North and Westbay, 6 all of which require this Commission's consideration. Ms. Temple also explained the park process wherein whenever a tract map is filed, it is brought to the Parks, Beaches and Recreation Director to bring to the Commission's attention. CITY OF NEWPORT BEACH arks, Beaches & Recreation Commission Page 6 City Council Chambers 7 p.m. INDEX - Following questions and discussion, Commissioner Taft motioned the Commission support the recommendations of the Planning Commission on General Plan Amendment 85 -1(B) as they relate to parks and'open space of Bayview Landing, Newport North and Westbay. Seconded by Springer. Unanimous. III. PUBLIC COMMENTS None. IV. DISCUSSION ITEMS Item #13 - Recreation Division Recreation Division Mark Deven reported June has been a busy month for the Department since the summer program started the week of June 23. The Corona del Mar Scenic 5K held June 6 was a• huge success as far as the large number of participants is • concerned. Last year there were 1350 and this year there were over 1900. Staff, 'however, needs to work harder on solving the logistical problems, control over the runners, and the dispensing of water. Mr. Deven also thanked the Corona del Mar Chamber of Commerce whose volunteers helped and worked so diligently on' the race. Mr. Deven reported the Swim Team is increasingly popular and successful thanks to the parent support group and the swim coach. Mr. Deven announced the July 4th celebration at Mariners Park and invited the Commissioners to attend. The cooperative "Parklife" program with the YMCA starts this week and Mr. Deven will provide an update at the next Commission meeting on August 5. Concerning Oasis, the seniors took a trip to Expo '86 and grading has begun on senior housing. Mr. Deven will re- confirm that the joint meeting with Oasis will be at the Commission's August 5 meeting. Commissioner Springer said the Oasis people really appreciate that more Commissioners are attending their meetings. Students comprising the Youth Council have been appointed, however„ there is one vacancy left, i.e., the freshman from • Newport Harbor High. Officers will' be elected at their next meeting. Chair Wolfe asked for a monthly report on the Youth Council and thanked Mr. Deven for the excellent job he has done on coordinating it. E 0 • CITY OF NEWPORT BEACH 1 Parks, Beaches & Recreation Commission Page 7 ��� ,' • City Council Chambers 7 p.m. INDEX Park and Street Tree Division Item #14 - Park and Street Tree Division Jack Brooks announced a new roof was installed at the Mariners Park Multi- Purpose Building and, as a result, the Park forces installed new drain lines. The Park crews, also removed the black top and installed concrete in the driveway at the Mariners Park Library. They will also be relandscaping at this site. V. SPECIAL, URGENT OR LAST MINUTE ITEMS Mr. Deven explained the Recreation Facility Directory usage and Curt Herberts, 2290 Channel Road, suggested a container for the Directories be installed at the end of Channel Road for those who need the maps. Mr.,Whitley reported John Wolter from the Public Works Department will have a report on Bicycle Trails at the next Commission meeting. Mr. Whitley also reported $1.5 million is available for Bonita Creek Park at this time. Regarding the Community Youth Center, the working drawings are progress•ing,,smoothly. Mr. Deven will provide a time line at the next Commtsston meeting. Mr. Whitley reported he will provide a report on all capital improvement projects at the next Commission meeting which will be updated monthly. He also announced the Balboa Pier restrooms• are in operation but still need some more work. They will be closed from midnight to 6:00 A.M. Chair Wolfe asked that the subcommittee chairs keep their committees active and that updates be provided at the next Commission meeting. Commissioner Brenner recommended sending a congratulatory letter to Harbor View School since they were recently given national recognition as an exemplary elementary school. She also suggested including the cooperative effort of faculty, parents, etc., which encourage a child's develop - ment. Mr. Whitley will draft the letter. VI. ADJOURNMENT There being no further business, the Parks, Beaches and Recreation Commission adjourned at 9:50 P.M. Zer-C r Jlc Dottie o r, ecre arl y Park and Street Tree Division • Item II CITY OF NEWPORT BEACH Parks, Beaches and Recreation Department DATE: July 29, 1986 TO: Parks, Beaches and Recreation Commission FROM: Recreation Superintendent SUBJECT: Joint Commission /Friends of Oasis Meeting Agenda In preparation of the joint meeting between the Commission and the Friends of Oasis, staff has met with Friends' President, Dr. Charles McCann, and developed an agenda with background information. In the interest of time, the Friends have agreed to limit the agenda to three items which will be discussed in detail during the meeting of August 5, 1986. Therefore, the agenda items are: 1. Insurance 2. Capital Improvement Projects Oasis Facility Master Plan Insurance The Friends and City staff were notified in May by Alexander and Alexander, Insurance Brokers, that St. Paul Insurance Company would not renew General and Automotive Policies for the Friends. Currently, the City provides 50% of the premium which requires liability limits of $1;000,000 as determined by the Safety and Insurance Administrator. The requirement for insurance is specified under Council Policy I -17, Oasis Senior Center Operation and Relationship. A final determination regarding the insurance issue is not available at this time. The Friends are considering dropping their transit service, thereby deleting the automotive liability. A new policy must be reviewed and approved by the Safety and Insurance Administrator. Capital Improvement Projects The Friends wish to provide information to the Commission regarding Capital Improvement priorities for Fiscal Year 1987 -88. Specifically, the City's preliminary budget indicates the possibility of a Needs Assessment for Seniors budgeted at $20,000; the Friends Executive Board is reconsidering this request in view of other potential projects. Long Range Planning /Oasis Master Plan The Long Range Planning Committee has been a fund raising campaign and-considering a raising campaign will begin,with a social Oasis Multi- Purpose Room. The master plan • staff and will recommend the future use of dedicated behind the north wing. charged with the important tasks of developing master plan for the Oasis facility. The fund on Friday, October 3, from 4 -6 PM in the development will be coordinated with City 1+ acres of new park land recently 17" FA MA 517-7- WW11A MOM • July 25, 1986 TO: PARKS, BEACHES AN VRECREATION COMMISSION FROM: Public Works Department SUBJECT: LITTLE CORONA BEACH STUDY RECOMMENDATIONS: DISCUSSION: Review the subject study. Item No. 5 Schedule a hearing to receive public comment and to recommend plan of action to City Council, The 1958/86 budget provided funds for preparation of the subject study. ,,_-The firm of Moffat and Nichol Engineers has completed the study and the City Council has referred it to the Parks, Beaches and Recreation Commission for review, hearing, and recommendation for plan of action. Little Corona Beach has been a popular sunbathing and swimming beach • for many years. In the 1960's heavier than normal rainfall caused erosion of the beach and undermining of the adjacent bluffs. Several wooden structures were constructed to control the erosion which occurs during the winter and the stagnant ponds which formed behind the beach berm during the summer. Those structures were washed out and in 1970 the existing concrete bottom control structure was constructed. Since that time a 20 -foot notch was cut in the structure and large rock (one foot to two feet in diameter) has been added to the structure. City staff have been satisfied that the concrete bottom control structure has controlled the erosion and trapped sediment and growth behind the structure has eliminated the stagnant ponds. Because of concern with the loss of sand from the beach during the past several winters, Moffat and Nichol Engineers were hired to investigate Little Corona Beach. The investigation has five objectives: (1) to document changes that had occurred in the shoreline of the sandy beach in the recent past, (2) to establish the causes of the shoreline changes, (3) to provide con- ceptual solutions to the shore retreat problem, if one exists, (4) to determine the net effects, if any, the Buck Gully bottom control structure has on beach behavior, and (5) to provide alternatives or modifications to the bottom control structure while maintaining its design objective to control head cutting and toe erosion at the outlet of Buck Gully. Moffat and Nichol Engineers performed underwater surveys, beach sur- veys; walked and surveyed the Buck Gully watershed; studied soil samples from behind the bottom control structures, reviewed City ,plans, reviewed Los Angeles District Corps of Engineers' historic shoreline maps, reviewed historic aerial photographs of the area; and interviewed people from the community who have • 9 observed Little Corona Beach in the past. As a result, the study found that July 15, 1986 Subject: Little Corona Beach Study Page 2 "Little Corona Beach (LCB) has been a near - stable beach in the past 50 years and will likely remain so barring a large increase in storm wave occurrences. The beach sand resource can be managed at present without a beach replenishment project or the construction of "hard" structures to retain the sand. The Buck Gully control structure is meeting its design objectives and has not had a significant adverse effect on the sand resource of Little Corona Beach. Several things could be done to enhance the recreational aspects of Little Corona Beach: (1) remove cobbles near the shoreline, (2) reduce the active width of the spillway on the bottom control structure, and (3) reduce the area of rock exposed on the bottom control structure." It appears to City staff that these recommendations can be implemented by City forces. At present, sand has returned to the beach and the bottom control structure, and most of the large rock is buried. When comments have been received a plan of action will be formalized to provide recommended modifi- cations to the beach in the winter when the bottom control structure and rock are exposed. • A copy of the report < _ Yom. XZ Benjamin B. Nolan Public Works Director E 10 JW:jd Att. is attached for the Commissioners. INVESTIGATION OF SHORE CONDITIONS AT LITTLE CORONA BEACH FINAL REPORT PREPARED FOR City of Newport Beach • Moffatt & Nichol, Engineers 250 W. Wardlow Road Long Beach, CA 90807 (213). 426 -9551 is 2 EXECUTIVE SUMMARY Synopsis. Little Corona Beach (LCB) has been a near- eltable beach in the past 50 years and will likely remain so barring a large increase in storm wave occurrences. The beach sand resource can be managed at present without a beach replenishment.project or the construction of "hard" "structures to retain the sand'. The Buck Gully control structure is meeting its design objectives and has not had a significant adverse effect on the sand resourcelof LCB. Several things could be done to enhance the recreational aspects of LCB: (1) remove cobbles near the shoreline, (2) reduce the active width of the spillway on the bottom control structure, and (3) reduce the area of rock exposed on the bottom control structure. Objectives,. In November 1985 the City of Newport Beach initiated a contract With Moffatt & Nichol, Engineers of Long Beach to investigate LCB. The investigation had five objectives: (1) to document changes that had occurred in the shoreline of the sandy beach in the recent past, (2) to establish the causes of the shoreline changes, (3) to provide conceptual solutions to the shore retreat problem, if one exists, (4) to determine the net,effects, if any, the Buck Gully bottom control structure has on beach behavior, and (5) to provide alternatives or modifications to the bottom control structure while maintaining its design objectives to control headcutting and toe erosion at the outlet of Buck Gully. Shoreline Behavior and Coastal Processes. Little Corona Beach (LCB) is a 1200 -ft long, south - facing pocket beach located in Corona Del Mar, California. About one -half its length is sandy; the remainder is bedrock and cobbles. It is backed by erodable, 40 to 80 -ft high bluffs that are most resistant at the headlands. The sandy beach is widest at the outlet of Buck Gully., a high - gradient ephemeral stream with a 2 mi2 watershed. With one exception, the region offshore of LCB is rocky with mostly shore - normal topographic lineations having an average bedrock height above the, 'surrounding bottom of 4 to 6 ft. The notable exception • is a sloping 200 to '300 -ft wide flat - bottomed - depression that trends Q- 3 1 . south into deep water off the outlet of Buck Gully. This depression, which is filled with sand, plays a major role in the behavior of sand at LCB. Net (irreversable) changes in the position of the shoreline in the past 50 years were not discernable when three sources of information were analyzed. Shoreline change maps constructed by the National Ocean Service (NOAA) from historic charts dating from 1875 to 1982 showed long -term changes in beach width were within a ±40 -ft envelope. Vertical aerial photographs taken between 1937 and 1984 showed the position of the shoreline was remarkably unchanging in that period, even after severe wave storms, and after high flows in Buck Gully. Discussions with City staff, especially those in the Marine Department who have manned or supervised the life guard station at LCB, and with residents who have visited LCB over a long time period, also indicate LCB has been generally stable. The beach narrows during periods of high- energy south swell. This is also a time when rip currents are in • evidence in the sand chute. During period's of lower wave activity the beach widens. A near - constant sand volume is naturally contained and maintained above and below mean lower low water (MLLW) at LCB. The volume of sand that enters the system from Buck Gully and as a result of bluff erosion appears to be equal to the volume that leaves the system through the sand depression or chute. Sand does not appear to enter or leave LCB around either the Poppy Avenue or Arch Rock headlands. The balance of sand reaching the beach above MLLW, and the equal loss in a seaward direction, appears to be maintained as a result of a critical shore - normal sand slope from the beach at the outlet of Buck Gully down the sand chute to deep water (about -35 ft). An addition of sand at the landward end either widens or increases the elevation of the beach. A return to a slope in dynamic equilibrium with waves and currents requires the input,sand volume be released down the chute. • Need for Beach Replenishment. The LCB sand resource appears to be in good shape. Events external' to the LCB system, such as a reduction in J \y ., sand supply from Buck Gully, or further revetting of the bluffs, will likely not have a major impact on the LCB sand volume. Sand additions drive sand reductions by passage through the chute. Thus, a reduction in sand supply is not ,critical. Artificial beach stabilization is not warranted at this time. An addition of sand at present would not likely result in a long -term beach, width increase.. Should severe waves that approach from the south reduce the volume of sand above MLLW by transporting it seaward of -35 ft �(MLLW) an artificial placement of sand could be warrented. About 100 yd3 of appropriate -sized sand will produce a shore advance of 1 ft. Sand sources include the region behind the bottom control structure, land sources with transport to LCB by truck haul, or possibly an offshore source. The offshore source must be in a water depth below 35 ft and seaward of the active LCB sand system. A "hard" structural alternative, not recommended at this time, would be to construct an impermeable dam across the sand chute, perhaps in a water depth of 10 to 25 ft. This would pond or ";perch" sand and reduce the gradient of the upper chute • allowing the beach width to increase until an equilibrium slope is again attained. Sand would probably have to be artificially added to widen the beach. Bottom Control Structure. The bottom control structure was designed to reduce headcutting upstream of the outlet of Buck Gully, and to eliminate toe erosion of the bluffs at the outlet caused by streamflow. Both of these design objectives have been met. The control structure appears to have not had a long-term effect on the width or volume of sand on the beach. Since its construction around 1970, about 3,500 yd3 of sand has been deposited in the basin formed upstream of the structure. Perhaps an additional 1,500' yd3 of sand ,was deposited upstream of the basin• as a result of the increase in the base elevation of the basin. Prior to 1970 about 300 yd3 /yr• of sand -sized material was, on average, carried to LCB in Buck Gully. D'i,scharge varied greatly from year to year. Since the basin is now full, a simi'lar or possibly lesser amount will be 3 5 N carried to LCB in the future. The amount will probably be less because of deposition in the vegetation- chocked channel above the basin and below 5th Street. The vegetation is.nurtured by an ever - increasing volume of nutrient -rich nuisance water contributed by residences. With or without the bottom control structure,•a near permanent channel will exist, to drain Buck,Gu.11.y. Recommendat.ions. A number of things could be done to alleviate some of the problems at LCB. Cobbles have been more noticable since 1978, probably because of an. increased incidence'of wave storms. These cobbles, exposed when beach sand is moved offshore, could be removed. The volume of cobbles is relatively low compared to the volume of beach sand so no adverse effect,.on beach stability is anticipated. Flow is across, about a 60 ft width of the bottom control structure during high discharge events in Buck Gully. This exposes the 60 to 80 -ft long rock spillway (revetment)_. The,20 -ft wide notch cut in the structure in the late 1970's 'could be cleared of rock and the Buck Gully • channel directed 'toward the notch to channel flow in the reduced width. This would reduce the area of rock exposed and slightly reduce the width of the channel across the beach. 0 Rock exposed by stream flow on the seaward face of the bottom control structure could be covered with sand during the late spring to autumn dry season. This would ,reduce the visual impact of the bottom control structure. I< 4 6 , . .j CITY OF WEWPORT BEACH INVESTIGATION OF SHORE CONDITIONS AT LITTLE CORONA BEACH FINAL REPORT. 0, f PREPARED BY' 0 F MO'FFATT & NICHOL, ENGINEERS 0 CALIFORNIA - O,REGON - HAWAII - M.ILCIHIGAN May 19, 1986 Mr. Benjamin B. Nolan Director, Public Works City of Newport Beach 3300 Newport Blvd. P. 0. Box 1,168 Newport Beach, CA 92663 -3884 Dear Mr. Nolan: It was our pleasure to prepare this report on Little Corona Beach. The first part of the report addresses shoreline behavior and coastal processes, including sediment discharge in Buck Gully. Effects of the Buck Gully bottom control structure on the beach are discussed in the second part. Recommendations to improve conditions at Little Corona Beach are given at the end of the report. Our analysis indicates the shoreline of Little Corona Beach advanced and retreated on a seasonal basis, but has not experienced a significant long- term net position change in the last 100 years. A near — constant sand volume is appears to be naturally maintained in the system.. The sand volume that enters from Buck Gully and as a .result of seacliff erosion is equal to the sand volume that leaves the system beyond a 35 —foot depth in the bathymetric depression off the Buck Gully outlet. The slope of the depression appears to be the controlling parameter. An addition of sand at the landward end widens or increases the elevation of the beach thereby steepening the slope. A return to dynamic equilibrium appears to require a seaward release of the input sand. The bottom control structure was designed to reduce headcutting in Buck Gully, and to eliminate toe erosion of the seacl-iffs at its outlet. These design objectives have been met. To reduce the visual exposure of the structure two things could be done. The 20 —foot wide notch in the structure could be cleared of rock with the Back'Gully channel directed to the notch. This would reduce the width of the spillway section and its visual impact. The visual impact of the structure could be further reduced with sand placed on the rock during the low —flow spring and summer season. Sincerely, MOFFATT & NICHOL, ENGINEERING ., Craig H. Everts CHE /smy P. O. BOX 7707 • 250 WEST WARDLOW ROAD • LONG BEACH • CALIFORNIA • 90807 • (213) 426 -9551. 774 -5650 r, w INVESTIGATION OF SHORE CONDITIONS AT LITTLE CORONA BEACH FINAL REPORT PREPARED FOR City of Newport Beach 0 Moffatt & Nichol, Engineers 250 W. Wardlow Road Long Beach, CA 90807 (213) 426 -9551 • J TABLE OF CONTENTS Page ACKNOWLEDGEMENTS 5 INTRODUCTION 6 PART I. SHORELINE BEHAVIOR AND COASTAL PROCESSES AT LITTLE CORONA BEACH 7 A. HISTORIC SHORELINE AND BLUFF BEHAVIOR 7 1. Historic Shoreline Maps 7 2. Aerial Photograph Analyses 8 3. Beach Observers 12 B. CAUSES OF BEACH BEHAVIOR 16 1. Control Volume 16 2. Sediment Volume Change Rates 16 a. Longshore Sand:Transport 18 (1) Sand Transport Around Poppy Avenue Headland 18 - (2) Sand Transport Around Arch Rock Headland 26 b. Cross -shore Sand Transport 26 (1) Bluff contribution 26 (2) Buck Gully Contribution 28 _ i. Buck Gully Field Visit 28 ii. Sediment Yield 30 iii.. Sedimentation Upstream of LCB 34 iv. Sediment Discharge to LCB 36 (3) Sand Flux at Base of Shoreface 36 c. Effect of Relative Sea Level Fall 37 d. Beach Replenishment 38 e. Sand Volume on LCB 39 t d CONTENTS (Continued) Puce 3. Sediment Budget Results 40 PART II. EFFECT OF BOTTOM CONTROL STRUCTURE 42 1. Background 44 2. Field Investigation 44 CONCLUSIONS 53 1. 2. 3. 4. RECOMME 1. 2. 3. Beach Behavior in Past 53 Causes of Beach Changes 53 Beach Stabilization.Recommendation 53 Effects of Control Structure 54 NDATIONS 56 Remove Cobbles 56 Reduce Width of Spillway 56 Reduce Rock Exposure at Structure 56 REFERENCES 57 0 % a • EXECUTIVE SUMMARY Synopsis. Little Corona Beach (LCB) has been a near - stable beach in the past 50 years and will likely remain so barring a large increase in storm wave occurrences. The beach sand resource can be managed at present without a beach replenishment project or the construction of ",hard" structures to retain the sand. The Buck Gully control structure is meeting its design objectives and has not had a significant adverse effect on the sand resource of LCB. Several things could be done to enhance the recreational aspects of LCB: (1) remove cobbles near the shoreline, (2) reduce the active width of the spillway on the bottom control structure, and (3) reduce the area of rock exposed on the bottom control structure. Objectives. In November 1985 the City of Newport Beach initiated a contract with Moffatt & Nichol, Engineers of ,Long Beach to investigate LCB. The investigation had five objectives: (1) to document changes that had occurred in the shoreline of the sandy beach in the recent past, (2) to establish the causes of the shoreline changes, (3) to provide conceptual solutions to the shore retreat problem, if one exists,, (4) to determine the net effects, if any, the Buck Gully bottom control structure has on beach behavior, and (5) to provide alternatives or modifications to the bottom control structure while maintaining its design objectives to control headcutting and toe erosion at the outlet of Buck Gully. Shoreline Behavior and Coastal Processes. Little Corona Beach (LCB) is a 1200 -ft long, south- facing pocket beach located in Corona Del Mar, California. About one -half its length is sandy; the remainder is bedrock and cobbles. It is backed by erodable, 40 to 80 -ft high bluffs that are most resistant at the headlands. The sandy beach is widest at the outlet of Buck Gully, a high - gradient ephemeral stream with a 2 mil watershed. With one exception, the region offshore of LCB is rocky with mostly shore - normal topographic lineations having an average bedrock height above the surrounding bottom.of 4 to 6 ft. The notable exception is a sloping 200 to 300 -ft wide flat- bottomed depression that trends 1 x f south into deep water off the outlet of Buck Gully. This depression, • which is filled with sand, plays a major role in the behavior of sand at LCB. Net (irreversable) changes in the position of the shoreline in the past 50 years were not discernable when three sources of information were analyzed. Shoreline change maps constructed by the National Ocean Service (NOAA) from historic charts dating from 1875 to 1982 showed long -term changes in beach width were within a ±40 -ft envelope. Vertical aerial photographs taken between 1937 and 1984 showed the position of the shoreline was remarkably unchanging in, that period, even after severe wave storms, and after high flows in Buck Gully. Discussions with City staff, especially those in the Marine Department who have manned or supervised the life guard station at LCB, and with residents who have visited LCB over a long time period, also indicate LCB has been generally stable. The beach narrows during periods of high- energy south swell. This is also a time when rip currents are in evidence in the sand chute. During periods of lower wave activity the • beach widens. A near - constant sand volume is naturally contained and maintained above and below mean lower low water (MLLW) at LCB. The volume of sand that enters the system from Buck Gully and as a result of bluff erosion " appears to be equal to the volume that leaves the system through the sand depression or chute. Sand does not appear to enter or leave LCB around either the Poppy Avenue or Arch Rock headlands. The balance of sand reaching the beach above MLLW, and the equal loss in a seaward direction, appears to be maintained as a result of a critical shore - normal sand slope from the beach at the outlet of Buck Gully down the sand chute to deep water (about -35 ft). An addition of sand at the landward end either widens or increases the elevation of the beach. A return to a slope in dynamic equilibrium with waves and currents requires the input sand volume be released down the chute. Need for Beach Replenishment. The LCB sand resource appears to be in good shape. Events external to the LCB system, such as a reduction in 2 x sand supply from Buck Gully, or further revetting of the bluffs, will • likely not have a major impact on the LCB sand volume. Sand additions drive sand reductions by passage through the chute. Thus, a reduction in sand supply is not critical. Artificial beach stabilization is not warranted at this time. An addition of sand at present would not likely result in a long -term beach width increase. Should severe waves that approach from the south reduce the volume of sand above MLLW by transporting it seaward of -35 ft (MLLW) an artificial placement of sand could be warrented. About 100 yd3 of appropriate - sized sand will produce a shore advance of 1 ft. Sand sources include the region behind the bottom control structure, land sources with transport to LCB by truck haul, or possibly an offshore source. The offshore source must be in a water depth below 35 ft and seaward of the active LCB sand system. A "hard" structural alternative, not recommended at this time, would be to construct an impermeable dam across the sand chute, perhaps in a water depth of 10 to 25 ft. This would pond'or "perch" sand and reduce the gradient of the upper chute • allowing the beach width to increase until an equilibrium slope is again attained. Sand would probably have to be artificially added to widen the beach. Bottom Control Structure. The bottom control structure was designed to reduce headcutting upstream of the outlet of Buck Gully, and to eliminate toe erosion of the bluffs at the outlet caused by streamflow. Both of these design objectives have been met. The control structure appears to have not had a long -term effect on the width or volume of sand on the beach. Since its construction around 1970, about 3,500 yd3 of sand has been deposited in the basin formed upstream of the structure. Perhaps an additional 1,500 yd3 of sand was deposited upstream of the basin as a result of the increase in the base elevation of the basin. Prior to 1970 about 300 yd3 /yr of sand -sized material was, on average, carried to LCB in Buck Gully. Discharge varied greatly from year to year. Since the basin is now full, a similar or possibly lesser amount will be 3 l t carried to LCB in the future. The amount will probably be less because of deposition in the vegetation- chocked channel above the basin and below 5th Street. The vegetation is nurtured by an ever - increasing volume of nutrient -rich nuisance water contributed by residences. With or without the bottom control structure, a near permanent channel will exist to drain Buck Gully. Recommendations. A number of things could be done to alleviate some of the problems at LCB. Cobbles have been more noticable since 1978, probably because of an increased incidence of wave storms. These cobbles, exposed when beach sand is moved offshore, could be removed. The volume of cobbles is relatively low compared to the volume of beach sand so no adverse effect on beach stability is anticipated. Flow is across about a 60 ft width of the bottom control structure during high discharge events in Buck Gully. This exposes the 60 to 80 -ft long rock spillway (revetment). The 20 -ft wide notch cut in the • structure in the late 1970's could be cleared of rock and the Buck Gully channel directed toward the notch to channel flow in the reduced width. This would reduce the area of rock exposed and slightly reduce the width of the channel across the beach. 0 Rock exposed by stream flow on the seaward face of the bottom control structure could be covered with sand during the late spring to autumn dry season. This would reduce the visual impact of the bottom control structure. 4 i LJ i ACKNOWLEDGEMENTS , The findings of this investigation were enhanced as a result of assistance provided by many people and organizations. Special thanks are due the staff of'the City of Newport Beach, especially John Wolter, Cooperative Projects Engineer, who assisted in all field investigations; Ben Nolan, Public Works Director; Ronald Whitley, Director,,Parks, Beaches and Recreation; David Harshbarger, Director of the Marine Department; Don Webb, City Engineer; Eric Bauer, Marine Department. Tom Dolan of the Corps of Engineers, Los Angeles District, provided many of the aerial photograph sets used in the shoreline behavior analysis. 5 -• INTRODUCTION On 20 November 1985, the City of Newport Beach commissioned this investigation to: • quantify shoreline behavior at Little Corona Beach (LCB), and determine if a net retreat of the shore has occurred in recent years, • establish a sediment budget for Little Corona Beach, and establish -the causes of shore ,retreat if it exists, using a sediment budget analysis procedure, and • provide conceptual solutions to a shore retreat problem, if one exists, and provide sand management recommendations for Little Corona Beach. On 24 February 1986, the City of Newport Beach requested the study be expanded to: - • determine the impacts,of the bottom control structure at the mouth of Buck Gully on LCB, and • provide alternatives or modifications to the bottom control structure while providing a means to eliminate headcutting problems in Buck Gully as well as controlling stream migration that causes toe scour at the bluffs at the entrance of the gully (design objectives of structure). This report is divided into two parts. The first part addresses shoreline behavior and its causes at LCB. Emphasis of the second part Ts on the bottom control structure, 2 L S PART I. SHORELINE BEHAVIOR AND COASTAL PROCESSES AT LITTLE CORONA BEACH HISTORIC SHORELINE AND BLUFF BEHAVIOR This section addresses the behavior of the shoreline and the toe of the bluff at LCB since 1875. Bluff changes are irreversible. When a bluff retreats its consolidated toe (not talus) does not advance again. Shoreline changes, conversely, are both irreversible and reversible. Reversible changes come as a result of movements of sand from the exposed beach to temporary submerged depositional sites and back again. An example is storm- caused, seaward transport of beach sand with consequent beach loss, and post -storm onshore transport and beach gain. Such changes are often seasonal. The most common sequence in California is beach loss in the stormy autumn and winter season and beach building in the spring- summer season. During the latter period long - period swells and the absence of storms promotes the shoreward transport of sand. LCB faces south - southwest, the direction from which the beach - building swell propagates. Shorel'ine and bluff behavior is herein established using three types of evidence: (1) historic shoreline maps, (2) historic aerial photographs, and (3) qualitative observations based on discussions with city staff and local residents. 1. Historic Shoreline Maps. In 1985 the Los Angeles District of the Corps of Engineers and the National Ocean Service (NOS) published a set of shoreline change maps which cover the LCB reach and adjacent beaches (NOAA /NOS - COE /LAD COOPERATIVE SHORELINE MOVEMENT STUDY, Imperial Beach - San Pedro, CA). The five shorelines shown,for LCB are the Mean High Water (MHW) lines at the times NOS or its predecessor the Coast and Geodetic Survey made their surveys. These were in 1875., 1934, 1959., 1971 (land surveys), and March 1982 (aerial photographic survey). Because of changing survey procedures, changes in sea level datum before 1927, and other reasons, the maps probably represent sandy shorelines at ±20 ft of the actual locations when used for comparative purposes. • Seasonal (reversible) changes are greater than ±20 ft so the maps are 7 x , best used to establish long -term trends in net shoreline changes • (irreversible over the period selected). The results of the map analysis are: • Headlands bound LCB and much of the shore is rocky. Early surveyors had difficulties following the shoreline around such headlands, and consequently shoreline position tolerances for the 1875 -1934 period are probably 140 ft. The shoreline change maps indicate the MHW shoreline did not fluctuate more than 140 ft from its 1982 position at LCB. e In the 1959 -1982 period the shoreline change maps indicate fluctuations (for the surveys given) were not more than 120 ft of the MHW shoreline position in 1982. • No large losses or gains in beach occurred between LCB and Pelican Point between 1875 and 1982. 9 Big Corona Beach has been stable or slightly accreti_onal since it was • established against the south jetty at the Newport Bay Entrance sometime after 1926 (map data) and before 1934. Prior to then, Big Corona Beach did not exist in its present wide and stable configuration. Between 1959 and 1982 the shoreline of Big Corona Beach experienced little change in position. Twenty thousand cubic yards of sand were placed on the beach in 1981. The total volume of sand held on Big Corona Beach by the south jetty is between 7.5 and 9x105 yd3. 2. Aerial Photograph Analyses. Aerial photographs provide useful, generally two - dimensional, information on beach behavior. Changes in shoreline location; beach width and length; and, in areas where the water is usually clear, shallow water features., may be established when aerial photographs taken at different times are compared. Shoreline position is often the most useful of the parameters. However, it is also a parameter that is difficult to establish definitively because of tide effects. The results of this analysis are accurate to 120.ft. D A i Several sources of aerial photographs were analyzed in this Is investigation. The results, presented chronologically below, primarily address shoreline position at the time the photographs were taken. (1) August 1937: U.S. Navy photographs show East Little Corona Beach (ELCB) was nearly devoid of sand. West LCB (WLCB) was sand - covered with a dry width of 50 ft east of Buck Gully and 0 ft west of Buck Gully. The wetted width was about 20 ft east of Buck Gully and 40 ft west of Buck Gully. (2) 21 June 1938: This Corps of Engineers photograph shows ELCB contains little sand while WLCB is 700 -ft long and the dry width is 120 ft at the Buck Gully outlet. The wetted beach width was 70 ft. All pocket beaches in Corona Del Mar contained sand at this time. The submerged sand chute between rocky ledges offshore Buck Gully was 320 -ft wide. Buck Gully from PCH halfway to the coast was dry and the bed was _ sand or gravel /rocks or both. • (3) 4 March 1946: Corps of Engineers photographs show a 450 -ft long beach of triangular (plan view) shape on WLCB with a maximum dry .width in the center at the Buck Creek outlet of 110 ft. The wetted portion of the beach was of constant width of 100 ft. Very little sand is apparent on ELCB. Kelp was growing at the time of these photographs off all rocky beaches. A gap 200 to 500 -ft wide extending south from the Buck Gully outlet was devoid of kelp suggesting the rocky bottom was _ sediment covered and no holdfasts were available for the kelp. (4) 8 December 1954: Corps of Engineers photographs show very little to no sand on ELCB, and sand in a plan -view triangular pattern on WLCB. The apex of the triangle was at the Buck Creek outlet. Dry beach width there was 110 ft, tapering to zero 225 ft eastward. Wetted beach width was 180 ft and constant between rock ledges on both sides (this is a low tide photo, the beach gradient appears.to be about 1:30). The distance between the ledges at MLLW (or lower) was 210 ft. The is submerged opening extended normal to shore at the Buck Creek outlet. It 0 a 1 (5) 1960 -1972, Corps of Engineers Photos: These oblique ground photographs showed no sand on the rocky beach west of the Poppy Avenue headland at any time. Big Corona Beach appeared to be quite stable in sand volume and in the position and shape of the shoreline. (6) 2 September 1960: Beach width (dry) was about 120 ft and beach length was about 480 ft at the time this Corps of Engineers (Los Angeles District) photograph was taken. The beach just northwest of Arch Rock was 15 to 20 -ft wide. LCB at the outlet of Buck Gully was crescent - shaped and oriented parallel to a line between the Poppy Avenue and Arch'Rock headlands. The region just upstream of the present control structure in Buck Gully was sand - covered and about 120 ft x 120 ft (about 15,000 ft2). (7) 11 August 1961: This is a low- tide -stage vertical aerial • photograph in the Los Angeles District Corps of Engineers archives. Dry beach width was 80 ft on the main LCB and slightly less than 20 ft on the south portion of LCB. The offshore sand chute was 200 -ft wide. Sandy beach orientation was south of a line parallel to a line between the Poppy Avenue and Arch Rock headlands. (8) 10 May 1965: This Corps of Engineer photograph (Los Angeles _ District archives) shows an 80 -ft wide dry beach (maximum) and an 80 -ft wide wetted beach (interti'dal area). The slope of the wetted area was about 0.09. Sandy beach length was approximately 450 ft. The region behind the present control structure was open and sandy with an area of about 6,000 ft2 (120 ft x 50 ft). (9) 29 December 1966: This dry beach .was 80 -ft wide and 450 -ft long on a Corps of Engineers photograph (Los Angeles District). There was no sand on the southeastern portion of Little Corona Beach. The sandy shore was oriented parallel to a line between the Poppy Avenue and • Arch Rock headlands. 10 was bounded by rock for at least 200 ft. Some sand appeared to be held • in rocks toward Big Corona Beach. (5) 1960 -1972, Corps of Engineers Photos: These oblique ground photographs showed no sand on the rocky beach west of the Poppy Avenue headland at any time. Big Corona Beach appeared to be quite stable in sand volume and in the position and shape of the shoreline. (6) 2 September 1960: Beach width (dry) was about 120 ft and beach length was about 480 ft at the time this Corps of Engineers (Los Angeles District) photograph was taken. The beach just northwest of Arch Rock was 15 to 20 -ft wide. LCB at the outlet of Buck Gully was crescent - shaped and oriented parallel to a line between the Poppy Avenue and Arch'Rock headlands. The region just upstream of the present control structure in Buck Gully was sand - covered and about 120 ft x 120 ft (about 15,000 ft2). (7) 11 August 1961: This is a low- tide -stage vertical aerial • photograph in the Los Angeles District Corps of Engineers archives. Dry beach width was 80 ft on the main LCB and slightly less than 20 ft on the south portion of LCB. The offshore sand chute was 200 -ft wide. Sandy beach orientation was south of a line parallel to a line between the Poppy Avenue and Arch Rock headlands. (8) 10 May 1965: This Corps of Engineer photograph (Los Angeles _ District archives) shows an 80 -ft wide dry beach (maximum) and an 80 -ft wide wetted beach (interti'dal area). The slope of the wetted area was about 0.09. Sandy beach length was approximately 450 ft. The region behind the present control structure was open and sandy with an area of about 6,000 ft2 (120 ft x 50 ft). (9) 29 December 1966: This dry beach .was 80 -ft wide and 450 -ft long on a Corps of Engineers photograph (Los Angeles District). There was no sand on the southeastern portion of Little Corona Beach. The sandy shore was oriented parallel to a line between the Poppy Avenue and • Arch Rock headlands. 10 (10) 9 December 1969: This Corps of Engineers (Los Angeles • District) photograph was taken at.the time of a very low tide ( -0.4 ft MLLW). It shows a dry beach width of 70 ft, a length of about 500 ft and a minimum offshore sand chute width of 210 ft. (11) 14 June 1970: In this vertical aerial photograph in the Los Angeles District (Corps of Engineers) archives the dry beach width was _ 90 ft (about 10 ft on the south portion of LCB). Beach length was about 450 ft. All of Buck Gully was heavily vegetated except the area near the present control structure which appeared, at the time the photograph was taken, to be in the process of being graded. Shore orientation was parallel to a line between the Poppy Avenue and Arch Rock headlands. (12) 17 September 1979: This 1:480 scale aerial photograph obtained by contract by the City of Newport Beach shows a 350 -ft long beach at WLCB with an average width of 70 ft. The axis of the submerged gap was 120 -ft wide and offset slightly west of the outlet of Buck Creek. (13) July- August 1984: This is a 1:480 scale aerial photograph obtained under contract by the City of Newport Beach. ELCB'was, as usual, almost devoid of sand. The dry sand beach at WLCB was about 360 -ft long and 70 -ft wide. The sand was mostly in the east 60% of the WLCB compartment. It appeared the submerged gap between the rock ledges was 175 -ft wide, centered on the Buck Creek outlet and oriented parallel to Buck Gully. The shoreline reach west of the Poppy Avenue headland was gravel and boulder covered. The shoreline reach east of Arch Rock was sandy. This analysis of historic aerial photographs suggest the following behavior of Little Corona Beach: Since 1937 the position of the shoreline has fluctuated (reversible changes) but without a discernible advance or retreat (irreversible or net changes). 11 ! 1 • Beach width near the outlet of Buck Gully averages about 80 ft with • fluctuations from 70 to 120 ft. Beach length averages 450 -500 ft with fluctuations between 450 and 700 ft. • The 500 -ft long reach between Arch Rock and the minor rocky point just south of Buck Gully has historically contained little sand above mean sea level. Even when LCB north of the minor rocky point shifted toward the south, little sand was carried to the south (this suggests longshore sand transport rates are low at LCB). i • When the beach is wide the sand - filled portion of the chute -like trough off Buck Gully is depleted of sand (width of sand fill is small). - When the beach is narrow the sand fill is wide (this suggests a coupling; sand when it leaves the beach is carried offshore and is - stored in the chute, when the beach.is wide the sand has moved onshore from the chute). • The plan orientation of LCB varies slightly with wave approach • direction. However, because of protection afforded by the headlands the shift in orientation is small ( < 10 degrees) and not enough to drive sand to or around the bounding headlands. 3. Beach Observers. Observations by people who frequently visit the beach often provide useful information on beach behavior. This is the case at LCB where, in particular, local residents and the Marine Department staff made useful comments. A meeting was held on 11 December 1985 with the staff of the Marine ! Department, and on 14 December 1985 and 10 April 1986 with people who live near the beach, to discuss the study,. During other visits to LCB discussions with local people also yielded information. The conclusions from these discussions are: • In March 1978 the beach at LCB retreated to its minimum width of 20 to 40 ft. It subsequently recovered to its present width of 80 ft (dry • beach). 12 . • According to lifeguards who visit the beach during all seasons, there Sis usually more sand southeast of the Buck Gully outlet than northwest of it. The tidepools to the southeast (exposed rock area, Figure 1) have never been completely covered with sand. 0 Tfie °Marine Department staff feels that if there was a net loss of sand from LCB in the past 15 years the volume lost was small and not detectable. Large seasonal (reversible) changes mask net (irreversible) changes. Large, generally long - period swell from the south tends to move sand from above to below MSL. A scarp often forms. The most effective circumstances for offshore - directed transport occurs during storms from the south at the time of a spring or perigean spring tide. Periods of lower height swell tend to return sand to the beach. Westerly and northwesterly swell is not a problem at LCB because of its orientation and the sheltering effect of the Newport Bay Entrance jetties and the Poppy Avenue headland. • Some reversible winter sand losses from the upper part of the beach occur as a result of "gullying" as Buck Gully discharge passes over the top of the bottom control structure (Marine Dept. staff)'. • Local residents feel the bottom control structure is the main problem at LCB because it has put an inland boundary on the beach and thereby effectively narrowed it. Some believe gullying caused by the structure has been the irreversible cause of beach erosion. During periods of moderate to heavy swell, rip currents develop and flow to the south off the center of LCB (off the outlet of Buck Gully). According to Marine Department staff little longshore sand transport and no longshore transport around the Poppy Avenue headland or Arch Rock headland have been observed. 'No sand volume changes were observed on 13 H l • W IC 4 < °u Y • i Awe Hone, Y J O n shv Im m 0 W J O W A c� �y O y< x r s Y O O e x v 14' u .1 I hQ V � z a r c 0 a O O pp O V 4 v IL 4 W � m Z Q O 2 O h ¢ V O V O J W � J C7 a ]. 1 LCB after the 20,000 yd3 beachfill was placed on Big Corona Beach in • 1981. 9 When sand is lost in 2 to 3 -ft depths the bottom near MLLW has been observed to be rocky and covered with loose boulders and cobbles. Under this condition a bar has usually formed at a depth of about 10 ft. • According to lifeguards and local residents there was never enough sand to drive a jeep around the rocky area just southeast of the Buck _ Gully outlet. The shape of this rocky exposure has not changed in recent times. • • Silt and mud -sized material is carried to and beyond the beach in Buck Gully during periods of rainfall- • Bluff retreat is thought to be insignificant. • In 1875 (old chart in Newport Beach Public Works offices) there was much kelp offshore of LCB. This indicates the rocks found offshore today were also exposed (not sand covered) in 1875. • In the pre - development period around 1921 Buck Gully was sparsely vegetated. Much cactus grew in.and near the channel. The sand thickness at the life guard tower is believed to be about 6 ft. • Rocks and cobbles now observed at LCB are considered a new phenomenon by local residents. They were not there before the late 1970's (Note: this was also the start of the 1978 -1983 period of wave storms and abnormal shore retreat along the California coast). These rocks and cobbles were not observed in late 1985 and early 1986. Y5 F ; CAUSES OF BEACH BEHAVIOR • Two conditions are necessary to cause a shoreline to retreat. First, the sand at and near the shoreline must be mobilized. Next, a mechanism must exist to transport the mobilized sand away. A Sediment Budget Analysis (SBA) was used to address the movement of sand and other sediment. It is, simply, a technique in which all the sediment movements into and out•of a fixed coastal region (control volume) are summed. Shoreline position change is usually considered the dependent variable in an SBA. For a change in shoreline positi.on sediment must be added (accretion') or removed (erosion), or the position of the plane of water must change (sea level rise or fall) with respect to land. The approach used at LCB is that described by Everts (1980, 1985). 1. Control Volume. 'Losses or gains of sediment and changes in water surface elevation relative to lan6 must be quantified. within a finite, enclosed space, i.e., a control volume in a fixed reference time period, • when the SBA approach is used. An important criterion in defining control volume boundaries is that they be established so shoreline position changes can be directly related to sediment volume changes. The landward boundary of the control volume is defined as the location of the upper limit of wave uprush at the base of the bluffs and the seaward face of the Buck Gully control structure. The seaward boundary is that limiting depth and distance beyond which sediment changes do not affect the littoral sediment 'regime. It is here assumed to be at the base of the shoreface, i.e., the location where the near - coast, steep, concave -up profile meets the•planar, seaward dipping continental shelf profile (Everts, 1978). This boundary is at a depth of about 35 ft and oriented normal to shore in the sand chute. It also extends from off the Poppy Avenue headland to the Arch•Rock headland. 2. Sediment Volume Change Rates. The direction and rate of transport for sediment which enters or leaves the control volume must be quantified. The easiest way to establish the sediment volume change is . to address each transport mechanism separately. Table 1 summarizes possible transport mechanisms. Alongshore, onshore - offshore, and 16 1 J • TABLE 1. SEDIMENT BUDGET CONSIDERATIONS- LITTLE CORONA BEACH SAND SOURCE.OR SINK 1. Longshore Sand Transport a. Poppy Avenue Headland b. Arch Rock Headland 2. Cross- Shore'Sand Transport a. Bluff Contributions b. Buck Gully Contributions (pre - control structure) c. Sand Flux, Seaward End of Chute 3. Sea Level Change Effects NET VOLUME CHANGE, YD3 /YR 01 01 +60 yd3 /yr +300 yd3 /yr 7 02 - 4. Beach Replenishment 03 _ • 5. Natural Sand Production 04 NET SAND VOLUME CHANGE 0 to 360 yd3 /yr Ilittoral barrier 2recent sea level decline at LCB 3possible 1 -2 yd3 /yr ('average) in past 20 yr 4biological (shell) production is less than 2 yd3 /yr, offshore the beach 17 vertical sediment transport elements must be considered in summing changes through the boundaries of the control volume. Natural and artificial changes that occur within the control volume must also be considered. Except in areas where calcium carbonate sediment, including shells and shell fragments -, constitute an appreciable percentage of the shoreface sediment volume, natural production or loss within the control volume is usually small. This is the case at LCB. ,In all considerations of sediment transport into or out of the control volume, changes in sediment size must be addressed. Silt and mud -sized material transported in Buck Gully will not remain on the beach. Only sand -sized or larger sediment contributes to the volume of the beach. The SBA approach is not a panacea. To work it requires site - specific field data which are costly and time consuming to acquire. Research is still required before the SBA methodology is refined in sufficient detail to accurately quantify all its elements. An SBA is, therefore, an inexact and evolving ,tool. But, at present, it is one of the most • useful approaches to establish and quantify the causes of shore retreat or advance. The following sections address each of the terms in.Table 1. a. Longshore Sand Transport. Sand clearly moves at and near the beach in a shore - parallel direction in the LCB reach from east of the -" Poppy Avenue headland to the intertidal rocky protrusion 200 ft east of the Buck Gully outlet. Some sand moves from there to the Arch Rock Headland, but the volume is much lower. There the beach is very thin -and was never more than 20 -ft wide. Often it is absent. The main _- question concerning longshore sand transport at LCB' is whether sand moves around the headlands, and if it does -, what the net direction of transport and its magnitude is. (1) Sand Transport Around Poppy Avenue Headland: Big Corona Beach has been relatively stable since it was created east of the east jetty at the entrance to Newport Bay (see section on aerial photograph analysis). At only one time since it Was created has sand been artificially added to Big Corona Beach. That was in August 1981 when He f 1 20,000 yd3 was placed there (Corps of Engineers, Los Angeles District, • "Maintenance Dredging at Newport Harbor ", 1981). A total 82,000 yd3 was dredged from the east side of the channel and the remainder was placed on Balboa Beach. Quite possibly the material reached the channel from Big Corona Beach by movement through, over, and /or around the east jetty. The nean grain size of the beach sand was 0.24 mm while the mean grain size of the dredged sand was 0.18 mm. This is consistent with a Big Corona Beach source of material in the channel because the smaller size fraction of the beach deposit would more likely be carried into the channel. With the exception of this leakage ( < 2,000 yd3 /yr) Big Corona Beach appears: • to be contained in a longshore sand transport sense between the east jetty and the Poppy Avenue headland, and • to be neither gaining nor losing sand in a cross -shore direction. Results of an offshore survey also suggest the Poppy Avenue and Arch is Rock headlands are littoral barriers. On 18 December 1985 a bottom survey was made seaward of LCB to: • establish bottom topography and sediment characteristics, determine, semi - quantitatively, the volume of sand in the active LCB system, • gather field evidence for use in establishing the net longshore transport rate around the Poppy Avenue headland and the Arch Rock headland, and • gather field evidence to establish the net cross -shore transport rate and transport path at LCB. The field survey consisted of three dives culminating in measurements along the five transects shown im Figure 1. Vessel and diver support was provided by the Newport Beach Marine Department. 19 'Figures'2 to 4 (upper diagram) show the bottom contours parallel and • normal to shore at the three longest transects, and the verticaldistance rocks project above the bottom (Figs 2 and 3). The most outstanding feature, as previously mentioned, is a shore - normal sand chute that extends offshore of the outlet of Buck Gully,(Fig. 5). Rocks on either side of the chute generally project 2 to 10 ft above the bottom. They are irregular in plan and crest shape. Plan areas vary from 10 ft toe, 1,000 ft2 with plan shapes that could be bounded by a circle or square to very linear shapes. Linear rock exposures usually trend normal to shore. Rocky projections decrease in ,distance above the bottom with increasing depth. The percent of the bottom covered by sand is shown in the middle diagram of Figures 2 and 3. The bottom within the sand chute is almost wholly covered by sand. In scattered areas of the chute ( < 1 percent) loose rocks to 2 -ft diameter and fixed bedrock is exposed (upper diagram, Fig. 5). The percent of the remaining bottom away from the sand chute that is sand covered increases with increasing depth, and in water depths y 20 ft with distance away from the sand chute. Sand size estimates are shown in the lower diagram in Figures 2 and 3. As shown in Figure 4, sand size based on a laboratory analysis progressively decreases as depth increases in the sand chute. In all water depths sand size increases toward, and especially east, of the sand chute. Sand in the trough is generally finer than in depressions among adjacent submerged rocks at the same depth. In many areas, especially east of the sand chute, sand in these depressions is composed _ of shell hash of local origin. Sand in the sand chute and elsewhere is mostly rounded quartz. Most submerged rocks in shallow water are covered with a healthy growth of grass. In shallow and deep water kelp is using the rocky areas as holdfasts. Bottom characteristics of transect A -B off the Poppy Avenue headland and A' -B' off Arch Rock are not illustrated with diagrams. They are similar. Both are oriented sub - normal to the regional orientation of the shoreline. Along both (to depths of 26 ft) the bottom is rocky with 20 1 S 1 `I 0 O p C• W d• , O I G 0 V ! J c A A' DOTANCE. MI FEET FIGURE 2: BOTTOM TRANSECT A -A' '21 A Y i 0 DISTANCE IN FEET FIGURE 3: BO.T,TOM..TRANSECT 8 =6� 22 0 Inc • _ 0 r- W 10 R W W 20 O. 30 W 1 40Ii �; < 'too »z.: O pj 30 1 . 00 �0 0 1 IOOAREE � O - � Z ' C O ! VERY fmE 0 DISTANCE IN FEET FIGURE 3: BO.T,TOM..TRANSECT 8 =6� 22 0 v � O Z f0 < 0'. Q It W a rr i I I ii 101 LITTLE CORONA BEACH is tOfOIIUMY. 1666, 0 w Lu _10 I M NATNTM6WM AN E6TMATt SAMD W GN.0mm Vxm "amo06 0) -20 a IVWXK 6Kl06Nm i7 -30 _ ,00 K10 200 300 400 500 600 700 600 _ HORIZONTAL DIBTANOE IN FEET FIGLM 4:. MEAN, SAND SIZE_N SUBMERGED CHUTE.AT LITTLE' CORONA BEACH, PROFILE SHOWN ON BOTTOM DRAWNOISIZE.DATA.EROM SIEVE ANALYSM.r 23 1 +l 1 J • 0 s �1 R �J s w W a v e Q z dc u n e s Awo Hops J w O W w 24 u 1, N c W � W C2 W . U . r" 2 N O 2 V - O H m . D . f9 fr w m h W cc . Vr Y aj V O �w'i dc o'er O 0 ■AhHo OHVe 07omm"Ing ax e� it zoo w 24 u 1, N c W � W C2 W . U . r" 2 N O 2 V - O H m . D . f9 fr w m h W cc . Vr aj •Moor mbsfnsns tip' �w'i o'er 0 ■AhHo OHVe 07omm"Ing ax e� it zoo w 24 u 1, N c W � W C2 W . U . r" 2 N O 2 V - O H m . D . f9 fr w m h W cc . Vr aj •Moor mbsfnsns 24 u 1, N c W � W C2 W . U . r" 2 N O 2 V - O H m . D . f9 fr w m h W cc . Vr i projections averaging 6 ft above the bottom. Sand cover is low ( < 20 percent) compared to rock exposure coverage. Sand within the depressions amongst the bedrock projections is quite coarse compared to other locations. Much is of local origin; some may be relic of lower stages of sea level; some, but probably a small portion, may have been transported in recent time during very energetic flow events. In all cases the sand thickness in depressions between rock projection is low (< 1 ft). Poppy Avenue and Arch Rock headlands are littoral barriers. Evidence includes: * lineations in rocky bottom topography are oriented, on average, about 210 degrees, or in a near shore - normal, direction, thus making it difficult for sand to move parallel to shore, * rock projections, which inhibit longshore sand transport, are 2 to • 10 -ft high away from the chute, and the greatest heights of the projections are near the headlands (Figs. 2 and 3), 9 rocky projections above the bottom extend out to beyond the estimated seaward limit of significant sand'transport, meaning the projections impede or halt longshore sand transport in all: of the active littoral zone, • the chute is oriented•to the south near its seaward end and only slightly south - southwest near the shore; wave refraction from the dominant southern direction will be small and channeled up the chute so the breaking wave angle will approximate that of the shoreline. The chute opens to the south which tends to "funnel" wave energy up the chute. This is the condition for almost nd. net longshore transport, • sand size generally increases away from the chute at depth (Figs. 2 and 3) suggesting the bottom material away from the channel and toward the headlands is Less mobile, and 25 S x 0 sand away from the channel contains more shell "hash" of local, not • beach, origin suggesting it forms and stays mostly in place. (2) Sand Transport Around Arch Rock Headland. The same arguments made against sand moving in an alongshore direction around the Poppy Avenue headland pertain, as well, for the Arch Rock headland. It appears LCB is a closed longshore transport system contained between these headlands. b. Cross -Shore Sand Transport. Bluff retreat and flow in Buck Gully contribute sediment to LCB at its upper boundary. Sand apparently moves in a net seaward direction at the seaward boundary of the control volume. (1) Bluff Contributions: The bluffs backing LCB are a source of sand. To quantify that source three things must be known, the average (long -term) shore retreat rate, the bluff elevation, and the portion of • sand in the total sediment volume that is liberated as the bluffs retreat. 'Figure 6 shows bluff sand percentage and bluff elevation. Both are estimates made in the field. Bluff retreat rates are difficult to estimate because historic survey data are unavailable and the rates have been small, and no doubt, episodic. Historic map and aerial photograph analyses indicate the bluff retreat has been low (.,. 20 ft) and in the past 100 years. Bluffs west of the Buck Gully outlet stand vertically and appear to be quite resistant with the exception of a slump at the location shown in Figure 6. East of Buck Gully the bluff slope averages about 50 degrees and the bluffs appear less resistant to weathering and mass movements. The base of these sloping bluffs is not scarped to a significant degree and the slopes are well vegetated. Some riprap has been placed at the toe indicating retreat since the region was developed. A narrow walkway about halfway between the Gully outlet and Arch Rock has been cut near the beach indicating toe retreat of less than 0.5 ft /yr (average) in the • past 30 years. The slope above the toe cut has probably not moved a great deal. 26 t � • W r 0 W, i u to _ °• FW— co • e••,'' fsy w o .1: W iu 7,•, � k +� W o .. �5.: f,•,r, m • • i LYE.•. Q O O W iiii:� is W W i •.,• • O O ► i:••iY•• t CS O = t ' i•Y• iii= V dc r,Yx C.. lk zu Ai'Ino NOM c •,;l1;,'d o O •AYIf10 mono . rn o CO) IL !' U. NAY E.i J O ;11NOdNO /1MNrN1 'AA N'NOIIVAN'13 uj w QNVN•'1NNOYN� 193Yo 'i111iN - • 27 u For the purposes of the SBA the bluff retreat west of Buck Gully outlet • is assumed to be 0.1 ft /yr (long -term average) and 0.2 ft /yr (long -term average) east of the outlet. Sand contributions are, thus, 25 yd3 /yr west of the outlet and 35 yd3 /yr east of the outlet for a total long -term average bluff contribution of sand of 60 yd3 /yr. (2) Buck Gully Sediment Contribution: Buck Gully extends from Signal Peak about 4 mi to its ocean outlet (Fig. 7) at LCB. Its catchment basin consists of approximately 800 acres of rugged, generally undeveloped Irvine Company land. About 400 acres in Corona Del Mar and Newport Beach is developed as medium- density residential property. A number of questions concerning Buck Gul'ly have direct relevance to conditions at LCB: • Prior to residential development of portions of the Buck Gully watershed of Newport Beach (approximately 1965) and Corona•Del Mar (approximately pre -1930) what volume of sand was carried, on average, yearly to LCB from Buck Gully? 9 How did the sand discharge rate change with development? 9 How much sand has been trapped behind the bottom control structure since it was constructed in 1970? How much sand is now reaching LCB after passing the bottom control structure? • Will the bottom control structure impede the movement of sand to LCB in the future? These questions were addressed in a field trip over parts of the Buck Gully watershed (Fig. 7), a sampling program in the depositional area behind the bottom control structure, and various office analyses. I. Buck Gully Field Visit. Some slope areas and most of the channel of • Buck Gully were visited on foot on 11 December 1985. The 15 sites at 1 y • • • 29 A 10 �F :v 0 J' :3 _._ N W G H 2 cc G W m rc 7 W . N M m � C { G 0 0 f. V V J } J ID /SJ J J co n Y ' 00 z V m LL Q .m 0 is W INC LL = O 4 010 00 a which specific notes were taken are shown in Figure 7. Abbreviated remarks from the field notes for each of those sites are given in Table 2. The following conclusions may be drawn from this field visit: • Vegetation on the approximately 800 acres of Irvine Company property is of the-non-irrigated, and land type typical of undeveloped foothill regions of coastal southern California. Major gullying is not -- evident except at and near unimproved roads on slopes. • Vegetation adjacent to the developed 400 acres of the watershed is lush, probably as a result of increased soil moisture from lawn watering on upslope developed areas and increased nutrients in the form of dissolved fertilizer from the same sources. • The Buck Gully channel is erosional and contains sand in its upper reaches; it contains mostly mud and silt on the surface in the lower 1.5 -mi reach. _ • Sediment has been trapped at and above a few road crossings of Buck Gully above the developed area. The total volume trapped is probably less than 5,000 yd3 with an unknown sediment size distribution. * Recent sediment deposition in a low gradient, concrete -lined part of the channel about 1.5 mi above LCB was silt and mud (Site 14, Table 2). The deposit was completely covered with vegetation indicating -• little or no sand had passed that section recently,(since 1983 floods, anyway). • The effects of the 1980 and 1983 high - precipitation years was not evident except in what was not seen. Quite possibly a year of major discharge such as 1983 would have flushed sediment that had collected in the channel and carried it to and possibly past LCB. ii. Sediment Yield. Field evidence indicates little sediment that reaches the channel of Buck Gully northeast of 5th Avenue remains for long in the channel, i.e., delivery at 5th Avenue is nearly the same as 30 TABLE 2. Conditions at Sites on Buck Gully, December 19851 • SITE REMARKS 1 upper tributary; 1 -ft wide, i -ft deep, v- shaped channel in eroding sandstone; loose, medium -sized sand in dry pools; channel gradient about 1:5 2 upper main channel; 3 -ft wide, 2 -ft deep, v- shaped channel in eroding shale; coarse sand in channel bed; channel gradient about 1:9 3 upland slope at divide between Buck Gully and Los Trancos Canyon; sandy surface with abundant sandstone outcrops 4 channel region of tributary; medium to coarse sand 5 main channel; medium sand bed; mud cover on sand; u- shaped, 6 -ft wide by 4 to 8 -ft deep channel; side slopes 1:2 • 6 main channel; boulders, cobbles and gravel; no sand' -in channel; abundant silt and mud 7 main channel; boulders with silt and mud matrix; sand is less than 5 percent of total sediment volume 8 main channel with mostly silt and mud fill; some pea - gravel sized material; no sand 9 main channel with silt and mud fill covered by 4 -in thick deposit of leaves; 'u- shaped channel 20 -ft wide with 4 to 8 -ft high, near - vertical banks 10 main channel; medium sand bottom; u- shaped, 12 -ft wide with 10 -ft high banks • 1see Figure 8 for site locations 31 s y 11 main channel with gravel- medium sand fill; 16-ft wide with 1:3 • (slope) banks 12 main channel with•vertical banks of compacted silt and mud; bottom deposit is composed of shale chips in-gravel-size range with some medium sand; shale outcrop•about 0.5 mi upstream 13 weed - choked main channel about 1 mi upstream of LCB; mud bottom, no sand'in channel'; u- shaped channel 20 to 40 -ft wide with 1 to 3 -ft high banks; road crossings with culverts create upstream reservoirs 14 main channel contains ,a 1504t long,•u- shaped concrete section ,about 20 -ft wide at a lower gradient than stream gradient; concrete reach is filled with s•i'lt and mud deposit with increasing thickness in downstream direction; no sand has passed this site recently 15 tributary (small); some shal•ey gravel and sand enters here; main channel choked with grass, weeds and brush;.no sand visible; large (to 1 -ft dia) boulders cover some of channel bed 32 a y the total sediment moved into the channel upstream in the watershed. Recent deposition in the channel and floodplain does not appear to be significant except at two road crossings. This suggests that most of the volume of sediment carried from the slopes of the watershed to the channel is further carried to downstream of 5th Avenue. Sediment yield in nearby areas can provide an order of magnitude -- approximation (or better) of the yield in Buck Gully when engineering judgement is used. Sediment yield estimates in nearby watersheds are given in the following sections: • San Diego Creek. Mustafa (1978) estimated sediment production in undeveloped areas of this watershed to be about 175 yd3 /yr -mi2. • San Diego Creek. Boyle Engineering Corporation (1982) in a comprehensive analysis of sedimentation in this watershed estimated the sediment yield of the Santiago Hills (foothill, open space area similar to Buck Gully, but in a wetter, more inland location) to be 1800 T /yr -mi2 or about 1500 yd3 /yr -mi2. Thirty -two percent of the sediment was estimated to be sand -sized (or. about 500 y'd3 /yr -mi2). The sediment yield (sand- sizes) for developed urban foothill areas was estimated to be about 60 yd3 /yr -mi2. Sand yield in foothill areas where construction was in progress was estimated at 2500 yd3 /yr -mi2. • Sand Canyon Reservoir,. Boyle Engineering Corporation (1982) -- estimated sediment yield in this foothill, (6.4 mi2) watershed at 1200 yd3 /yr -mi2 based on reservoir infilling rates. Assuming a sand fraction equal to 32 percent, the sand yield would be about 400 yd3 /yr -mi2. San Diego Creek. During the very wet year of 1983 about 110,000 yd3 of sand -sized material (0.125 -0.3 mm) were deposited in two basins of San Diego Creek upstream of Upper Newport Bay. (U.S. Geological Survey, letter to John Wolter, City of Newport Beach, 4 Nov 1983). In Upper Newport Bay 28 percent of about 150,000 yd of material deposited was sand -sized (J'. Wolter, pers comm. 17 Jan 86). The remainder was silt and mud - sized. Total sand carried to downstream reaches in San 33 Diego Creek was thus about 150,000 yd3 or 1250 yd3 /mil. This discharge probably represents 5 to possibly greater than 10 years discharge so that the average yield is 100 -200 yd3 /yr -mi2 in the San Diego Creek watershed. This watershed is less topographically rugged, but is undergoing more change and development than the Buck Gully watershed. • Wintersberg -East Garden Grove Channel. This watershed (about 30 _ mi2) in northern Orange County is a low gradient region that is mostly developed. In 1979, 6,000 yd3 of sand was removed from a basin at its downstream end; in 1983 an additional 11,000 yd3 of sand was removed. (Tim Kashuba, pers. comm., 16 Jan 1986). These volumes represent the sand -sized sediment transport in the channels for five (plus) wet years. The average sediment yield is about 100 (or less) yd3 /yr -mi2 using the assumption that depositional volume equals yield. The above sand yield values.at nearby, undeveloped areas located in the Santa Ana foothills range from 100 to 500 yd3 /yr -mi2 (average = 300 yd3 /yr -mi2). Extrapolated to the undeveloped Irvine Ranch portion of the Buck Gully watershed (800 acres) this would be 375 yd3 /yr. Sand yields from developed foothill areas similar to the 400 acres of residential property in the Buck Gully watershed is 60 yd3 /yr -mi2, or about 40 yd3 /yr in Buck Gully. Total sand yield from Buck Gully, based on these extrapolations, would be about 400 yd3 /yr. Climate is a major factor in sediment yield with more intense rainfall at the Santa Ana Mountains than the Buck Gully watershed. Hence sediment yields in Buck Gully are likely less. Assuming that Buck Gully carries the same percent of sand as San Diego Creek, and rainfall intensity is such that its yield is three - fourths that of San Diego Creek, the sand yield of Buck Gully would average about 300 yd3 /yr. Variations from the average are the norm, varying from almost no yield in extremely dry years to perhaps ten times the average in extremely wet years. iii. Sedimentation Upstream of LCB. On 23 January 1986 sediment samples were obtained within and upstream of a depositional basin formed behind the bottom control structure that was constructed about 1970. 34 The purpose of the sampling was to establish, semi - quantitatively, the volume and size distribution of sediment's that have been deposited in the basin since 1970. Eleven holes about 3 -ft deep were dug using a post hole digger. The holes were along four transects normal to the channel and about 100 ft apart. Sediment removed was checked in the field for sand content. Penetration was monitored to establish, if possible, depth of relatively loose fill above the more compact, pre- control - structure grade. Results of this sampling program are: • The impoundment basin was full im January 1986. Between 80 and 90 percent of the sediment deposited above the bottom that existed before _ the control structure was constructed is sand. The remainder is mud and silt- sized. Sand deposition between 1970 and 1985 averaged 230 yd3 /yr. There is no evidence to indicate the basin did not reach capacity prior to 1985. It could have been earlier. • • In the impoundment basin sand size increases: a) upstream from the control structure, b) with depth, and 3) toward the channel which is on - the west side of the valley. e The volume of sediment deposited upstream of the bottom control structure is about 4,000 yd3 of which about 3,500 yd3 is sand. • The impoundment basin extends upstream about 340 ft from the bottom control structure to a recognizable change in gradient (upstream gradient = 1:15 with pools and riffles; downstream gradient = 1:40 in a vegetation chocked channel). • Upstream of the impoundment basin and downstream of the Pacific Coast Highway the v- shaped channel of Buck Gully has been filled, to some extent, probably as a result of the increase in elevation at the outlet. Hence the grade- change location. At the upstream end of the impoundment • basin the valley is about 80 -ft wide. The volume contained in this reach appears to be between 1,000 and 2,000 yd3. 35 S I • The impoundment basin and the Buck Gully reach downstream of the Pacific Coast Highway is chocked with grass, weeds, rushes., bushes and small trees. Drag on flow in this reach would be such that only large flows could carry sand to LCB. Quite likely since the last, pre -1970 extreme discharge (in 1969) very little sand has reached LCB from Buck Gully. iv. Sediment Discharge to LCB. The sediment yield in the Buck Gully watershed probably averages about 300 yd3 /yr although it.is highly variable. Since the control structure was constructed in 1970 about 330 yd3 /yr has been deposited upstream of it. Because of the thick - vegetation holding the sandy deposit upstream of the control structure and its affect on flow, only extreme water discharges are likely to scour it and carry it to LCB. At present it appears 300± yd3 /yr (average) are trapped between the control structure and Pacific Coast Highway. • Removal of the control structure would reduce the base elevation of Buck Gully and increase its grade below Pacific Coast Highway. This would probably •resul-t in the natural scour and transport to LCB of some of the -- sand now retained in the impoundment basin. It is unlikely it would greatly increase the sand delivery from upstream sources because of the entrapping capacity of the vegetation in the lower reaches of the stream. (3) Cross =Shore Sand Transport at the Base of the Shoreface. Beach sand primarily moves to an offshore depositional site from the beach, and returns to the beach, along the approximately 300 -ft wide, low gradient depression or chute that trend's directly seaward of the outlet of Buck Gulley (Fig. 5). Indirect evidence, including the shore - normal profile shape, orientation of the chute, and sand size _ within the chute, suggests that the net movement of sand in the chute has not recently been great in either an offshore or onshore direction at the 35 -ft deep (estimated) base of the shoreface. E 91 The longitudinal profile of the chute, shown in figure 4, was concave -up above a depth of 25 -30 ft on 18 December 1985 and concave -down below that depth. At a depth of 25 ft bedrock was exposed across the chute. Sand above a depth of 25 ft was contained in a mild delta -like deposit. The implication is the seaward limit at the time of the survey was at a depth of 25 -30 ft. This would not be the case if sand was moving through the chute in either a net onshore or net offshore direction. During a period of intense swell from the south, rip currents might carry sand further seaward, but visual observations suggest that rip currents rarely extend seaward past the 20 ft contour. The bedrock exposure at the cross - sectional shape juncture also suggests transport toward the 25 -ft depth from both directions. On the most recent chart (.hydrography in 3964 and 1966; NOS Chart Nos. 5108, 5142, respectively) the bottom profile above the 1841: depth contour was also extended seaward out from the Buck,Gully outlet. On 18 December 1985 large quantities of sea grass in rolls or tubes were • found at a depth of,about 30 ft. These grass mats were moving with bottom surge (swell from the south). Thirty feet was the cross -shore nodal point for grass on the day of the bottom survey. The nodal depth for fine - grained sand was Tess. Sand sizes decrease with increasing depth which also indicates the bottom is near a state of dynamic equilibrium. Although sediment size criteria are inconclusive, they indicate no great movement of sand either onshore or offshore occurred recently. All ev- idence indicates that net ,onshore or offshore transport at a depth of 35 ft was recently small. c. Changes in Relative Sea Level. A change in water surface elevation relative to the shoreface profile may have a significant effect on the _ shoreline. A relative water surface rise will result in a disequilib- rium of the shoreface profile. To reestablish the equilibrium the profile must move vertically a distance equal to the rise in sea level. Without a large influx of sediment from outside the system, the entire 37 a a profile will be forced landward as well as upward to acquire the sand necessary to achieve the upward profile shift. A long -term change in the position of sea level relative to land should be thought of as a site - specific phenomenon. The change may occur because of local sediment compaction, regional tectonic subsidence or uplift, long =term climatic changes, isostatic rebound, or as a world wide response (eustatic) to a changing volume of water in the oceans. The latter is predominately based on the amount of water tied up in glaciers and the water temperature of surface ocean waters. Tectonic activities can also alter the volume of the ocean basins. TABLE 3. VERTICAL CONTROL SITES NEAR LITTLE CORONA BEACH Site Station 1970 Elevation (ft)1 1976 Elevation (ft)1 South end of Poppy Avenue NB4 -26 -71 85.668 85.679 • South end of Milford Drive NB7 -5 -70 30.942 30.957 ino recent levelings The County of Orange as shown in Table 3. period between level (about 0.002 ft /yr). the stability of LCB future. has established vertical control stations near LCB At both locations during the recent six -year surveys there was a relative decline in sea level The present effect of relative sea level change on is negligible and should remain so in.the near d. Beach Replenishment. City of Newport Beach records show LCB has never been artificially restored or nourished with large volumes of sand. Several truck loads of sand were dumped on LCB about the time the _ Newport Bay Entrance was dredged. The volume of beachfilt placed would • be 20 yd3 /yr or less, an insignificant quantity for sand budget purposes. 38 4 A • e. Sand Volume on LCB. Knowledge of the total sand volume on the beach and shoreface of LCB is required to establish a relationship between sand volume change and shoreline change. It is also a quantity of use when interpreting the range of values that are probable for each term in the sediment budget. Above MLLW the beach averages about 80 -ft wide and 450 -ft long. These values come from the aerial photograph analysis. Sand thickness is less easily discerned. Beach sand level changes as viewed by local observers with respect to the underlying bedrock suggest an average beach sand thickness of six feet or less is reasonable. This is supported qualitatively by an extension of exposed bedrock under the sand deposit. No borings were made. Total beach volume above MLLW is 8,000 yd3 or less. Sand volume offshore of LCB is almost all in the sand chute seaward of the Buck Gully outlet. As shown in plan view in Figure 5, the chute • averages about 300 -ft wide to its seaward - limiting depth of 35 ft at 600 ft from the MLLW shoreline. Sand thickness is not easy to establish without borings. However, observations made during the offshore survey suggest it is a thin layer. Gradients on the rock substrate at either side of the chute are 0 to 2 degrees and the chute geometry appears to be that of a shallow depression. The average depth at the center of the depression of a slope of one degree were projected out from each side would be about 3 ft. The average shore - normal bottom slope is about 3 degrees. Near the 25 -ft depth region rocks crop out within the central one -third of the chute (Fig. 5). Assuming an average 2 -ft depth, the - chute contains about 13,500 yd3 of sand. Sand volumes in the region adjacent to the chute are negligible. A combination of average beach and chute volume estimates indicates the active littoral sand volume on and seaward of LCB is 20,000 to 25,000 yd3. Sand moves between the shoreface and beach in both shore - normal directions. A loss of about 100 yd3 of sand from above MLLW results in - an average MLLW shoreline retreat equal to about 1 ft (calculated to be 39 � J • equal to the average length of the beach (450 ft) times the average thickness of beach sand above bedrock (6 ft). 3. Sediment Budget Results, Table 1 provides estimates of net yearly losses and gains of sand at the boundaries of the LCB control volume. Losses or gains by longshore transport around the bounding headlands are assumed to be zero. Sea level effects, artificial beach replenishment and sand production as a result of biological processes have had little effect on the volume of sand in the LCB control volume in recent times. Cross -shore transport is assumed to be the only significant factor in the net volume of sand reaching or leaving the control volume. Sand reaches LCB as a result of bluff erosion and discharge from Buck Gully. Sand is lost from LCB by passing seaward and into deepwater in the sand chute. The volume passing out the sand chute is, as shown on Table 1, unknown, but can be estimated where all other loss -gain elements of the sediment budget are established. • The balance suggest losses down the chute equal gains from the bluffs and Buck Gully. Coupled with past shoreline stability evidence at LCB, -- this provides an interesting, and to this author's knowledge, not previously described, cause for that stability. Evidence indicates LCB has had a consistently stable, but dynamic shoreline position. Although the shoreline has shifted reversibly in location, the oscillations have been centered on a consistent location. This means the volume of sand on and probably offshore of LCB has remained dynamically constant. The interesting factor in this is that Buck Gully sand discharges have varied greatly while sand volume in the control volume has remained constant.. The reason can most rationally be attributed to a loss of sand out the chute equal to that which enters at its head. Thus, LCB is like a tilted bucket that is filled to capacity with water. If any more water is put in it, an equal volume of water overflows and leaves the bucket. An explanation (unproven) is that the beach is the upper limit of an equilibrium chute slope (Fig. 4). If the beach elevation increases, or the beach builds seaward, the upper end of the chute becomes oversteepened and 'sand is carried seaward until' the slope of the CI, J. _• 0 chute regains its dynamic equilibrium value. The slope is that imposed upon it by wave and current forces; it is not the angle of repose of sand. An understanding of this sand transport mechanism has strong implications to the management of sand on'LCB. 41 C R 0 PART II. EFFECT OF BOTTOM CONTROL STRUCTURE The bottom control structure at the outlet of -Buck Gully (Fig. 8) was designed to alleviate two problems. The first was headcutting, which lowered the grade of the stream in the lower reach of Buck Gully. Channel meandering was the other problem. It caused toe erosion of the bluffs, especially on the southeast side of the outlet. Both design objectives have been attained by the bottom control structure. In this section, impacts of the bottom control structure on the beach are defined, and possible alternate designs or modifications to the bottom control structure are provided. Criteria used to determine whether the bottom control structure has affected the beach are: Criterion 1. Establish the mean active sand volume on LCB for the . period before and for the period after the bottom control structure was constructed. "Active" in this context means the volume that is moved by wave or stream activity over the period'of.a year or so. Criterion 2. Establish the mean active width and length of LCB for the period before and the period after the bottom control structure was constructed. Criterion 3. Establish the before and after - construction rate at which the beach above MSL recovers after storm erosion. Does the bottom control structure reduce the rate at which beach sand returns after it is carried offshore in winter storms? Criterion 4. "Establ,ish: changes in the area of inactive, unvegetated', sand before and after construction. 'The inactive area is not routinely affected by wave action and not eroded during storms. It is the area upstream of the bottom control structure. 42 k a • • �� SCALE: 1•a*C' SEC. A —A NAIL IN CONC.-- EL. 11.14 M.G.L.' c 1• SEC. 0 -0 Y DENSE -^16� FIGURE 8: BOTTOM CONTROL STRUCTURE, BUCK GULLY 43 • This evaluation considers technical questions relating to beach behavior. Other questions such as the aesthetics of the bottom control structure and land cover in the region now behind the bottom control structure are not addressed. 1. Background. In the 1950's and 1960's erosion in two forms at Buck Gully had become a problem. Stream headcu.tting during rain storms was forcing a scour ,problem to move progressively upstream. In addition, stream meandering during high flow events was eroding the toe of the southeast bluff at the outlet. Stagnant water ponded upstream of the natural beach berm was also considered a nuisance. In the mid- 1960's a small wooden bottom control structure was constructed to alleviate the erosion problems. It was severely damaged during high flow events in 1965 and again in February of 1969 (Figs 9 and 10). In late 1969 the more substantial present bottom control structure was constructed (Fig. 8). It is 91 -ft long at the Gully outlet and about 4 -ft high at the upstream edge with ,a 6 -ft wide apron extending to a low lip at the downstream end. In - 1972 -1973 rocks were placed upstream of the structure, on the 6 -ft wide apron and against the downstream end, thereby acting as an energy- - dissipator and spillway (Fig. 11). These rocks were also apparently placed to prevent wave scour beneath the structure. In 1978 a 20 -ft long notch was cut in the upstream wall of the structure to reduce the head. Rocks comprising the riprap downstream of the structure are sometimes dislodged as a result of high Buck Gully flows across the riprap, and /or wave activity (Fig. 12). Since construction, a thick growth of reeds and bushes has established in the impoundment basin upstream of the structure. This vegetation clearly can withstand high discharges without significant deterioration. Because of its height and density the vegetation acts to reduce flow velocities at the structure. Peak flow (50 year recurrance interval may be about 300 cfs with upstream velocities of 10 ft /sec. 2. Field Investigation. ,. Difficulty arises when pre- structure conditions at Buck Gully are compared to present condition's with the bottom control structure. Data 44 ft ,. r 1 n • 1 sZ r �w ,:•Ihtr r�rr..tt �:rlt t •FY,y ! k J'Y r � ✓r �:rlt t •FY,y ! k J'Y r � a � y r Y t�i I ¢ U �1 99h ff f Jr '' v l 4 ;q ^ r 4 a � � a •L.r ! " S2� 0'. q. I R A i(I T 1 i rV SI w. r (t Ao t • i� 'ti•! ' ' .µ si { 4 � � i r •4 ,a 6 •�) � '. rot 4'; -a �ii: 1 y i p yti r •. 1 4 /� ;a 1ik 1 j � � ` (((( t t• Y,' i 4 ir. f r 7." a � y r Y t�i I ¢ U �1 99h ff f Jr '' v l 4 ;q ^ r 4 a � � a •L.r ! " S2� 0'. q. I R A i(I T 1 i rV SI w. r (t Ao t • i� 'ti•! ' ' .µ si { 4 � � i r •4 ,a 6 •�) � '. rot 4'; -a �ii: 1 y i p yti r •. 1 4 /� ;a 1ik 1 j � � ` (((( t t• Y,' i 4 ir. f 0 V 7>., I" r 1 �' � 11 %� ■e1 /l .�z � •�,�_�'�,/ �. � °' {kq�tl V �c Q 0.K, t , Y ' j / t , A �• t 1' i' IAty •'I, 0.1e N 4' [ f (F�'C• 4: �l R i 'SIT y, - t t��' �J �'•,` '��, 1VIV W� fl 1 Y t �' O 'F �• 1 C 4m �."� N C r n. • ,A� . Y '~' O w I ej l �` ia�]Q%� ��'` � LL '.. +v' . ayN ((° � yam• w .F,) �n ")) � •tit• V�i• ``'�{� ri 4 U Aa 46 A 0 Figure 11. Bottom control structure, February 1975. tx '11 IK ` ��- .ail►., .' a' . •!�'• e; �4k .. , • Figure 12. Bottom control structure, March 1986. 47 4 • were found to be less numerous and,, generally, less reliable with increasing time into the past. Physical conditions have also changed greatly. Development has brought increasing quantities of nuisance water and nutrients to Buck Gully. Lawn watering is the main culpret. Water and sediment discharge in the Buck Gully watershed is not the same as it was 40 years.ago, or even 15 years ago when the bottom control structure was constructed. On 13 March 1986, after a series of rain storms produced moderate water discharges in local streams, natural and structured stream outlets were visited between LCB, and Abalone Point. The purpose of the visit was to determine whether water discharge effects on the natural outlets draining mostly undeveloped watersheds of the Irvine Coast differed greatly from effects found at structured- outlets. Natural outlets draining catchment basins of the magnitude•of Buck Gully included Los Trancos, Muddy Canyon and Morro- Canyon. Smaller natural canyons were similar in catchment area to the bottom - controlled watershed that .drains • across Third Beach at Corona Del Mar (Fig. 13). Figure 14 shows the outlet at LCB on the same day from a similar perspective. The bottom control structure at Third Beach was about 2:5 ft above the sand level -_ at that time, and 20 -ft wide and constructed of timber sheets covered with grouted rock. Its design objective .was to prevent headcutting. Several of the smaller streams had natural control structures; that is, ,they .discharged over a hanging_ valley.• in rock to the beach (Fig. 15). In one case the vertical fall at the beach was about 20'ft. In others., flow was down,a ravine to the beach (Fig. 16). Figure 17 shows the ,outlet of uncontrolled'.Los Trancos Canyon'. Results of the field visit are: • The scour elevation of all streams was dependent on the sea surface elevation at the time of the discharge event. Natural streams with and•without•a drop at the beach, and streams at LCB and Third Beach with bottom control structures, cut only to about -1 ft (MSL) during the previous rain event. Discharge magnitude did not appear to be a • significant factor. Discharge's probably varied from 10 cfs to 100 cfs or more between streams. M _• • • c fJ SS" , SIP ^^' 'r.'J -r- •.� -r ^Ifs .ir • aye 1 .' AJ'f'- i_+�. -._ - i•� c;, Figure 13. Third Beach after March 1986 rainfall. " -, . Amm s - �. AR `�i� -- Figure 14. Little Corona Beach after March 1986 rainfall. 49 t i \J • Figure 15. Natural bottom control structure, Irvine Coast, March 3986. - s r 0 Figure 16. Outlet of ravine at Crystal Cove State Beach, March 1986 50 • •- • • . . - aims Figure 17. Outlet of Los Trancos Canyon at Crystal Cove Village, March 1986. 51 . , • • The width of the channel cut through the beach varied by no more than a factor of two between the streams with the largest and smallest discharge. This width at LCB was 40 ft; at Third Beach it was 20 ft; at Los Trancos it was 25 ft, at Muddy Canyon it was 30 ft,, at Morro Canyon it was 35 ft, and at smaller Irvine Coast streams it varied from 15 ft to 30 ft. The slightly greater width at LCB could be partially a result of the bottom control structure. • L • Bluffs adjacent to some natural outlets were cut by stream action. The toe of the (usually southeast) bluffs on a few small, and one large, Irvine Coast streams were cut by the recent stream flows. LCB and Third Beach bluffs were not eroded by stream action. The bottom control structures tend to channel the flow nearer the middle of the outlets. • Bottom control structures prevent headcutting. Natural channels exhibited much evidence of active headcutting. 52' • CONCLUSIONS 1. Beach Behavior in Past. All evidence indicates the shoreline at LCB has been dynamically stable within plus or minus'20 ft in the past 50 years. The sand volume did not vary by more than 2,000 yd3, or about 10 percent of the total volume in the LCB system. During this period at least 10,000 yd3 of sand was discharged down Buck Gully. The discharge rate has significantly declined in recent years because of the great increase in vegetation in the lower reaches of Buck Gully and as a result of impoundment upstream of the bottom control structure. 2. Causes of Beach Changes. Indirect evidence indicates LCB, above and below MLLW, holds a dynamically -fixed active sand volume. An equal volume of sand made available to the beach system as a result of bluff erosion (minor volume) and Buck Gully discharge (major volume) appears to be removed down the sand chute that extends off the outlet of Buck Gully. Beach and shoreface gradients in,a shore - normal, direction seem • to be the controlling factor. Thus, a year of abnormally high sand discharge in Buck Gully will not greatly expand the beach because the profile becomes oversteep and the sand is lost seaward. Likewise, a year in which sand discharge in the stream is low will not be a year in which the beach is especially narrow because onshore - directed transport maintains the equilibrium slope thereby reducing permanent losses to deepwater. Cobbles have been reported as more abundant on LCB (and possibly Third Beach) since 1978. Cobbles are exposed in greater quantities on southern California beaches after periods of abnormal wave storms. Such was the case between 1978 and 1'983 where shore retreat was greater than at any period of similar length since 1940. 3. Beach Stabilization Recommendation. Little Corona Beach does not appear to need artificial stabilization. I't has been remarkably stable during the past 50 year period when sand reaching the beach has varied is greatly from year -to -year. Sand losses equal gains with the gains driving the 'losses. If gains are reduced, losses are also apparently 53 reduced as well. Sand artificially added as beachfill would likely be • lost over a period of a few years as the beach trended toward its stable sand volume and profile. Should shore retreat problems occur and persist over a period of several years, beach replenishment would be the best treatment. Sand sources include: (1) land source with transport by truck, (2) retention basin source if environmentally acceptable, and (3) offshore source beyond the base of the shoreface. The retention basin source is an argument for keeping the bottom control structure. The volume of sand required to replenish the beach will be about 100 yd3 per foot of beach width increase desired. A sand size analysis should be made using data presented in Figure 4. Total volume and costs required will be low (1,000 yd3 would cost $2,000 to about $10,000 delivered to the beach). A "hard" structure, such as an impermeable rock sill across the sand chute could be used to hold sand on the beach by decreasing the cross -shore bathymetric slope. This solution would be costly and is not • recommended. 4. Effects of Bottom Control Structure. While the shoreline (seaward boundary of the beach) at LCB has remained dynamically stable, the landward boundary of the beach (at least at certain times) has been moved seaward. The net result is a reduction in exposed sandy area. Prior to the construction of the bottom control structure, a flat and nearly horizontal area averaging perhaps 100 ft x 100 ft (1/4 acre) at the outlet of Buck Gully was intermittantly available for volleyball games, picnics, sunbathing etc: When the beach elevation (berm) naturally built above the elevation of that sandy area, nuisance water collected there and rendered the area unusable. After the control structure was constructed, water plus sediment ponded there. Rapid growth of vegetation upstream of the bottom control strucure was enhanced by an increasing volume of nutrient -laden (fertilizer -rich) nuisance water (lawn water) contributed by newly - developed residential • areas in the Buck Gully watershed. With or without the bottom control 54 y • • structure, vegetation would likely be a problem at the outlet today because of the increased volume of nuisance water. The bottom control (perhaps 3500 yd3) does not appear to the beach. If the it (or an equal vo of the sand chute. structure has resulted in the entrapment of sand that would heretofore have reached the beach. This be a serious problem with respect to the health of sand was not contained behind the control structure lume) would likely have been lost seaward at the base During and,subsequent to discharge events in Buck Gully (especially autumn and winter season) a gully is formed below the bottom control structure. The gully is probably wider than it was when Buck Gully discharged naturally across and through the beach. 55. i . i, RECOMMENDATIONS. A number of things can be done to alleviate some of • the problems at LCB: 1. Remove Cobbles. Cobbles could be removed'by hand or possibly with an end loader and hauled away in a dump truck. Piling them against the bluffs as a form of protection is not recommended. Baseball to bowling - ball sized stones act as projectiles when acted upon by high waves. The mixing action of the stones could rapidly erode the toe of the LCB bluffs. The best time to remove the stones would be in early spring after the maximum volume of beach sand has been moved offshore (generally February - April). 2. Reduce Width of Spillway. At present, flow during high Buck Gully discharge events passes over most of the length of the spillway (Fig. 12). In the late 1970's a 20 -ft wide notch was cut in the structure. If rock was removed from that notch and the apron seaward of it, and if the Buck Gully channel in the impoundment basin was directed toward the notch, the width of the channel cut across the rock spillway and across • the beach could probably be reduced to 30 ft or so. 3. Reduce Rock Exposure at Structure. The rock revetment on the seaward side of the bottom control structure serves two functions. It protects the base of the structure from being undermined by wave action and it acts as an energy dissipator for flow in Buck Gully. It also detracts from the natural aesthetics of LCB. Sand scraped from the beach berm could be used to cover the rocks and thereby reduce this visual problem. The solution would be temporary and have to be repeated after each rainy season. The volume of sand requiring placement would be reduced if Recommendation 2 is implemented. 56 4A * 0 REFERENCES Boyle Engineering Corporation, "Newport Bay Watershed, San Diego Creek Comprehensive Stormwater Sedimentation Control Plan" unpublished report for the Cities of Irvine and Newport Beach and the Southern California Association of Governments, January, 1982. Everts, Craig H., "Geometry of Profiles Across Inner Continental Shelves of the Atlantic and -Gulf Coasts of the United States ", TP 78 -4, U.S. Army Coastal Engineering Research Center, Fort Belvoir, VA 22060, 1978, p. 92. Everts, Craig H., "Human Influence on the Sediment Budget of a Barrier Island ", ASCE, Proceedings, Coastal Zone '80, Hollywood, FL, Nov 1980, p. 863 -880. Everts, Craig H., "Sea Level Rise,Effects on Shoreline Position ", ASCE, • Journal of Waterway, Port, Coastal and Ocean Engineering,'Vol. III, 12.6, Nov 1985, p. 985 -999, • Mostafa, M. Gamal, "Sedimentation in Upper Newport Bay, California" unpublished report for The Irvine Company, by Williamson and Schmid, Civil Engineers, October 1978. 57 Item No. 7 • CITY OF NEWPORT;BEACH Parks, Beaches and Recreation Department DATE: July 29, 1986 TO: Parks, Beaches and Recreation Commission FROM: Recreation Superintendent SUBJECT: Recreation Programs Subcommittee Meeting On Thursday, July 24, Vice Chair Clyda Brenner and Commissioner A.Z. Taft met with Recreation Division staff, Mark Deven and Nancy Beard, to review the upcoming fall seasonal brochure and a selected program. The following report summarizes the meeting: Nancy Beard reviewed the fall brochure and highlighted new classes and activities, including youth programs, sports instruction, culinary arts and holiday crafts. Ms. Beard explained the Department's orientation in the fall toward expansion_of indoor activities in preparation for the holidays. Two new special events, the Yellow Brick Road Show and • Halloween Program, are planned for the fall at the Newport Harbor Art Museum and Lido Village, respectively. • fv Mark Deven reviewed senior programs development following Ms. Beard's report. Vice Chair Brenner and Commissioner Taft reviewed the attached summary Which details the operation of Oasis and efficient use of volunteers. Mr. Deven indicated that senior programming elements will be analyzed for possible expansion to other City facilities in addition to Oasis. � GF5 n LJ SENIOR PROGRAM DEVELOPMENT The City of Newport Beach provides services and programs to senior residents through the Oasis Senior Center in Corona del Mar. All elements of the Center's operation, including programming, administration and financial planning, are achieved through a partnership between City staff and the Friends of Oasis, a non - profit organization with 2,800 members. The Center was developed on the former Carden School site and dedicated on August 27, 1977. A new multi- purpose building was constructed on the east side of the Center in 1979. In the near future 1* acre of park land will be dedicated to the City extending the site's northern perimeter. In cooperation with the Friends of Oasis, the City will be considering future uses of the site .while developing the Oasis Master Plan. Recognizing both the potential for effective volunteer service and the anticipated significant annual expenditures for staffing and acquisition of equipment, the City Council adopted Council Policy I47 which formalized the Senior Center "s operational relationships in January, 1980. The policy requires a close, coopera- tive relationship between the City and the Friends of Oasis and specifically sets forth priorities for facility use, programming and administration, financial consideration and insurance conditions. Today the Oasis Senior Center provides services• to over 67,000 participant. units 'annually and supervises 19,000 volunteer.hours. The program elements encompass cultural and recreation programs, health and human services, special interests and special events. The unique cooperative relationship and program development has been . cited by neighboring cities as a model for cost effective service delivery to senior residents. The following brief descriptions of program elements are examples of the services offered at Oasis: Recreation and Cultural Programs The daily schedule of activities-at Oasis reveals recreation and cultural programs ranging from physical fitness, including dance and walking, to music and art, including ukulele instruction and landscape painting. Popular activities include table tennis, pool, shuffleboard, cribbage, and bridge. Staff administered Drograms, including the "Walkers not Rockers" class, are provided under strict safety require- ments by staff trained in Cardiopulmonary resuscitation and first aid. Other programs, including game room tournaments and shuffleboard, are conducted on -site but without staff supervision. Health /Human Services Through the generous donation of their,professional services, doctors, lawyers and dentists provide specialized programs to seniors in the areas of health and human services. Health screening and testing in vision, hearing, dental, podiatry and blood pressure provide a chance for detection of problems which are referred to the patient's regular doctor. Counseling, performed by specialists or through "peer groups ", address various psychological needs, such as dealing with the loss of a loved one or acceptance of change. A daily highlight of the Oasis schedule is the congregate meals served during the lunch hour. Not only does the meal serve the nutrition needs of the seniors, but it also provides an • environment which meets many social needs. Additional "human needs" services include Medicare forms assistance, shared housing, Outreach visits to the home- bound, wills /estate planning and information referral. • Special Events • �q _'Z During the past year, the Center promoted various Special Events celebrating Older Americans Week, the Founding of Oasis and special Holidays. In all cases the promotion and production of the events are made possible by the Friends of Oasis. The twice monthly Pancake Breakfasts are a regular favorite which draw participants to the Center on Saturdays. The festive nature of these events not only proves to be colorful and creative, but also draws the entire senior community together. Summary The Oasis Senior Center is comprised of dynamic program elements developed within a unique operational structure. Thi's structure, formulated through City Council policy, insures the participation of seniors in meaningful and critical ways. Although the City can look with pride at the accomplishments of the partnership of City staff and senior participants, new objectives will be addressed in the future. These objectives will attempt to continue the tradition of defining and ultimately meeting the needs of our City's senior residents. Item No. 14 CITY OF NEWPORT BEACH • Parks, Beaches and Recreation Department DATE: July 29, 1986 TO: Parks, Beaches and Recreation Commission FROM: Parks, Beaches and Recreation Director SUBJECT: STATUS OF CURRENT CAPITAL PROJECTS Bonita Creek Park Construction documents have been submitted to Public Works for- plan check. Should be approved for public bid purposes by September. Construction should begin by December with a completed park by next summer. Community Youth Center Construction documents scheduled to be submitted August 31. Bid package to be completed by end of September. Construction to begin in early January with a construction period of 6 months. • Park Facility Improvement Fund r 1 U An on going source for a variety of projects. Examples of use are land- scaping at new Balboa Pier restroom, landscaping at 1714 W. Balboa Blvd., railing at Corona del Mar Main Beach. West Newport Park Still pursuing a Coastal Commission permit for this project. 38th Street Park Park reconstruction to be done in conjunction with the Balboa Blvd. road widening project. Park will be part of the overall general contract. Cliff Drive Park Still working with the Newport Heights Community Association to develop a preliminary plan acceptable to local residents. Should complete this project by next June. Irvine Terrace Park Basically completed except for the planting of slope areas. Iq �gy - Kona10 A. Whitley • 2 Item No. 15 CITY OF NEWPORT BEACH Parks, Beaches and Recreation Department July 14, 1986 CITY COUNCIL AGENDA ITEM NO. E- Z �dj TO: Mayor and City Council FROM: Parks, Beaches and Recreation Director SUBJECT: Vehicular Access Restriction for Bayside'Drive Right -of -Way Between Carnation Avenue and Jasmine Avenue Recommendation: Adopt Resolution No. prohibiting vehicular access, except for emergency and public utility vehicles, on the Bayside Drive right -of -way between Carnation Avenue and Jasmine Avenue. Discussion: As indicated in the attached letter from Mr. Ed Giffen, a number of Corona del Mar residents would like to assure that Bayside Drive Park developed on road right -of -way be guaranteed to remain as a park. In 1904 the original Corona del Mar Subdivision Maps identify this roadway as Electric Way at a width of 120'. A resubdivision map recorded in 1922 shows a similar alignment identifying the area as Street right -of -way and not dedicated for Park purposes. In reviewing this matter with the City Attorney, it was his opinion that the City does not have the authority to designate the land or dedicate the land as a park. If the land is not used for road purposes, it could be subject to reverting to the original owner or a portion of the adjacent residential lots as appropriate. As an alternative to protect the area it is recommended that the City Council find the Bayside Drive right -of -way between Carnation and Jasmine Avenue is • no longer needed for vehicular traffic purposes and that a Resolution be adopted to that effect as provided for under Section 21101(a).of the California Vehicle• Code. LJ The Parks, Beaches and Recreation Commission at their meeting of July 1, 1986 unanimously supported the action as presented. Zd Ronald A. Whitley • • • June 19, 1986 Ron Whitley, Director & Commissioners Parks & Recreation Department City of Newport Beach 3300 West Newport Blvd. Newport Beach, CA 92663 Director and Commissioners: Over the objections of a number of residents in the area the City Council on June 9, approved a plan to make a parking area out of a parcel of land now used as a park at Jasmine Avenue and Bayside Drive. We would not want the existing six -block greenbelt area to meet the same fate. Therefore we recommend that the existing greenbelt area along Bayside Drive from Carnation Avenue to Jasmine Avenue be zoned as a park and placed under the jurisdiction of the Parks and Recrea- tion Department. Thank you. Ed Giff n 307 Larkspur Avenue Corona del Mar, CA 92625 21 • It • • 21 RESOLUTION NO. A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF NEWPORT BEACH AUTHORIZING THE CLOSURE OF BAYSIDE DRIVE RIGHT -OF- WAY BETWEEN CARNATION AVENUE AND JASMINE AVENUE TO VEHICULAR TRAFFIC AND DIRECTING THE CITY CLERK TO RECORD SAME WITH THE ORANGE COUNTY RECORDER. WHEREAS, Vehicle Code Section 21101 authorizes the closing of any highway (street) to vehicular traffic when the legislative body determines that it is no longer needed for such traffic; and WHEREAS, the City Council of Newport Beach has determined that subject to certain rules and regulations, said highway is no longer needed for vehicular traffic; and WHEREAS, this subject finding is predicated on the satisfaction of various conditions as set forth herein. NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Newport Beach, resolves as follows: 1. The excess right -of -way on Bayside Drive between Carnation Avenue and Jasmine Avenue, subject to satisfaction of the conditions set forth herein, is no longer needed for vehicular traffic; and 2. Upon satisfaction of the conditions set forth below, subject highway shall be closed for vehicular traffic consistent with the rules and regulations provided in this Resolution; and 3. The following rules and regulations are hereby set forth as conditions to the closure of subject street: (a) Emergency and utility vehicles shall be allowed access as needed for emergencies and repairs; and (b) That bicycles are allowed to continue to operate on llayside Drive right -of -way between Carnation Avenue and Jasmine Avenue. (c) The City Council is not precluded from repealing this Resolution and returning said street to its vehicular status at any time. • r y • • t • 40 13 BE IT FURTHER RESOLVED that the City Clerk be and hereby is directed to file this Resolution with the Recorder in and for the County of Orange. ADOPTED this _ day of ATTEST: City Clerk Mayor 1986. Item No.16 • PARK AND STREET TREE DIVISION JULY, 1986 PROGRESS REPORT Our Park Crews performed, the following tasks in addition to normal maintenance during the month of July: Hauled debris, cleaned area, installed'irrigation and landscaped at Nautical Museum. Cleaned unsafe cracks and filled with tar at bowling greens at San Joaquin Hills Park. Moved tables, chairs, barricades, etc., and returned them for July 4th celebration at Mariners Park. Picked up and disposed of brush cuttings at City Trailer Park. Landscaped new restrooms at Balboa Pier. Installed 9 benches in front of business in Corona del Mar. • Graded slope at Irvine Terrace Park. • ILA Our Street Tree Division performed the following: Trimmed 232 trees. Planted 17 trees. Removed 4 trees. Root pruned 14 trees. Completed 8 work requests. Areas being trimmed this month are the Orange County Airport and Westcliff. Item No. 17 RECREATION DIVISION JULY, 1986 PROGRESS REPORT Special Interest Activities As of July 25, over 3,300 participants have enrolled in Special Interest Classes ranging from Tennis to Dance Fitness. Multiple session registration will continue to increase enrollment through mid - August when most summer programs wind down. In addition to summer program activities, staff has also been busy preparing for the fall program. Over 30,000 brochures are scheduled to.be mailed August 15. Mail -in registration will begin August 29 and continue through the first week of classes, September 22. Youth Activities Youth programs seemed to dominate the July schedule, beginning with the July 4th weekend. The Mariners Park Independence Day celebration attracted 1,500 partici- pants for a bicycle parade, entertainment, cookout and picnic activities. The Newport Summer Games Swim Meet followed with a two day competition at Newport Harbor High School on July 5 -6.- Both events benefitted, from outstanding volunteer organization and assistance from the Mariners Independence Day Organizing Committee and Aquatics Parent Support Group. Youth sports, including girls softball, swim team and high school sports camps, will continue through the middle of August. Youth activities being offered at the Community Youth Center and Mariners Park are building in attendance. Sports and Aquatics Adult sports competition is winding down for 3,345 adult sports participants. By mid - August league play will be complete for 207 softball and 30 basketball teams. The annual Summer Softball Tournament is scheduled the week of August 16 -17. The Department's sailing program is experiencing a rebirth in popularity as a result of some new instructional philosophies requiring a structured approach. Over 500 students enrolled in week long sessions scheduled June 23 -July 28. Seniors Continuing programs and activities offered at Oasis tend to slow down during the summer as many participants take vacations. However, the Friends of Oasis are busy planning activities involving their membership, Board and Advisory Board. The Friends have recently asked Department staff to review policies and procedures regarding facility use and composition of the Newsletter which will help to facilitate cooperation and coordination. Other issues important to the Friends are addressed in the report concerning the Joint Commission /Friends of Oasis meeting. Attached is the August schedule of events at Oasis. Youth - Council • At their meeting of July 1-5, the Youth Council elected the following officers for the 1986 -87 term: Jeff Glueck, Chairman; Dana Johnston, Vice Chairman; and Jessica Jones, Secretary. The Youth Council also reviewed a staff report on the 1986 -87 Work Program and discussed the proposed Battle of the Bands event tentatively scheduled either August 16 or August 23. A summary of the July 15 meeting is attached. C4'J O ri q , Y' � r` � (n • N N•.^ d ate^ N �A�rr J J F Nrry �l ^ N .O .N-rvN < V7 N lit C* .r A 1,��1 r• N ro s. F`. GLI °o c c rn O O O r N N N hi N CJ A ro k. a) 1 •F) •r e�� n 0 y wL c0 M C"" N •— U N H N N ., F Q A � �--� r 4J r LM E o rt .E o,ro •- �W�jj J J V) Jam.' U d U d W w O U. E Q) b t..) co C tU ro N M X Nr+� b�ro W X, N N N M I Ol W Old, Ol W Old' N �•,. ' 1v y w ' r- W N N Ch N N FF' O� • � � �' N N m ^[m•IH C i O v D] � 0 1a t• N m m 1 N 3 �nN .. d b r~ Chj cm N co N C4'J O ri q , Y' � r` � (n • N N•.^ d ate^ N �A�rr C4'J O ri q , Y' � r` � (n • N N•.^ W ate^ N J J F Nrry �l ^ N .O .N-rvN C4'J O ri q , Y' � r` � (n • CITY OF NEWPORT BEACH • YOUTH COUNCIL JULY 15, 1986 CITY COUNCIL CHAMBERS - 6:00 P.M. Staff Liaison Present: Mark Deven I. PROCEDURAL-MATTERS Item #1 The meeting was called to order by Mark Deven at 6:05 P.M. Item #2 Roll call was taken. Councilmembers Antebi, Ford, Glueck, Hanson, Huffman, Johnston, Jones, Phillipe and Roberts were present. Pete Bryan, Battle of the Bands Coordinator, was also present. Item #3 The Agenda was adopted as presented with the addition of the July 30 Ad Hoc • Committee Meeting and Appointments for the Newport Youth Association. II., ACTION ITEMS Item #4 - Election of Officers Mark Deven announced that this meeting was the last meeting where he would act as Chairman. Mr. Deven explained the process for nominating officers and described the responsibilities of the Chairman, Vice Chairman and Secretary. Mr. Deven then asked for nominations. Jessica Jones nominated Jeff Glueck as Chairman of the Youth Council. Ann Phillipe seconded. Hearing no additional nominations, Dana Johnston moved that the nominations be closed. Amy Roberts seconded. Unanimous. Jessica Jones nominated Dana Johnston as Vice Chairman of the Youth Council. Carla Huffman seconded. Hearing no further nominations, Eric Antebi moved that nominations be closed. Carla Huffman seconded. Unanimous. Vice Chair Johnston nominated Jessica Jones as Secretary of the Youth Council. Amy Roberts seconded. Hearing no further nominations, Lisa Ford moved that nominations be closed. Ann Phill'ipe seconded. Unanimous. Item #5 - 1986 -87 Work Program • Mark Deven presented'a verbal report based on his memorandum to the Youth Council outlining the proposed 7986 -87 work program. The program is based on a six month schedule which may be reviewed in December. Many of the items listed for action by the Youth Council are based on Goals and Objectives which were developed from �� the responsibilities of the Youth Council indicated via Resolution 86 -2. -2- Chairman Glueck suggested that the Councilmembers review the report and take • action at the next meeting. Secretary Jones requested the addition of a December Dance which would be provided for both high schools. Chairman Glueck asked for that item to be added and then asked for a consensus of the Youth Council on deferring action until the next meeting. 'All Councilmembers agreed. Item #6 - Summer Meeting Schedule — Chairman Glueck proposed the meeting schedule for the rest of the summer: July 31, August 14 and August-28. All Councilmembers agreed by consensus. III. DISCUSSION ITEMS Item #7 - Battle of the Bands Chairman Glueck reviewed-the recent correspondence with Newport Dunes. Mark Deven reported that the Dunes seemed to be receptive but has not received their conditions for final approval. Mr. Deven then reviewed the City's Special Event process which he will initiate and the potential problems associated with amplified sound at the Dunes. In order to offset the anticipated costs, Mr. Deven indicated that the Department wiTl explore sponsorship contacts in the business community. Chairman Glueck suggested that the Youth Council form an Ad Hoc Committee to deal with the responsibilities of producing the event. After discussion between Councilmembers revealed an agreement;by consensus, Chairman Glueck moved that Pete Bryan be appointed to Chair the Ad Hoc Committee. Jenny Harrison seconded. Unanimous. Chairman dlueck asked for volunteers to be 6ppointed to the committee. Jenny Harrison, • Eric Antebi and Dana Johnston all volunteered and were appointed by consensus. Pete Bryan reviewed bands which have been contacted. The bands included Shattered Images, the Critoms and the Tories,. Pete Bryan appointed Dana Johnston in charge of publicity. Item #8 - Review of City Council Action Mark Deven reported on formal City Councilapproval of the Youth Council appointments. Mr. Deven also reviewed the City Council consideration of the General Plan Amendment with respect to Bayview Landing. IV. SPECIAL, URGENT OR LAST MINUTE ITEMS Item #9 - July 30 Ad Hoc Committee Meeting Mark Deven reported that all Youth Councilmembers are invited and encouraged to attend the last-Youth Ad Hoc Committee meeting on Wednesday, July 30, at 5 -7 PM on the Cannery Boat. Item #10 - Appointment to Newport Youth Association Mark Deven reported "that the Newport Youth Association Bylaws require two youth representatives. Mr. Deven asked Chairman Glueck if he would like to appoint two Councilmembers to the Board. Chairman Glueck asked the Councilmembers to consider this request and will take action at the next meeting. -3- V. ADJOURNMENT • There being no further business, the Youth Council adjourned at 7:31 P.M. M 'k Deven Jessica Jones 71 — ecreation Superintendent Secretary • • �)-9 -1.1 ,_