FINAL REPORT FOR 2009 ON THE CONDITION OF THE MUNICIPAL OCEANFRONT BEACHES IN THE BOROUGH OF AVALON, CAPE MAY COUNTY, NEW JERSEY

Transcription

1 FINAL REPORT FOR 2009 ON THE CONDITION OF THE MUNICIPAL OCEANFRONT BEACHES IN THE BOROUGH OF AVALON, CAPE MAY COUNTY, NEW JERSEY Storm waves pound the inlet revetment September 10, 2009 as the series of northeast storms began in the fall of The significant storms occurred in September, October, November, December 2009, and February and March of PREPARED FOR: PREPARED BY: THE BOROUGH OF AVALON 3100 DUNE DRIVE AVALON, NJ THE RICHARD STOCKTON COASTAL RESEARCH CENTER 30 WILSON AVENUE PORT REPUBLIC, NEW JERSEY MARCH 18, 2010

2 Table of Contents Introduction 1 Oceanfront Beach Surveys 2 Table 1: Oceanfront Beach Profiles Volume Changes, Individual Oceanfront Site Reviews 2 Photographs 1a, b, c to 10a, b, c for Each of 10 Oceanfront Profile Sites 3-40 Figures 1 to 20: Cross Sections of each of 10 Oceanfront Profile Sites 5-41 and Trend Graphs for Shoreline Change 6-42 Table 2: Summary of Beach Volume & Shoreline Changes 12/08 to 12/09 42 Summary of Avalon s Oceanfront Beaches 43 Table 3; Summary of Shoreline Changes from 2002 to Review of the Engineered Beach Sand Volume Changes 6-Months Post-fill 44 Typical Beach Profile 47 Glossary of Coastal Terms 48

3 INTRODUCTION: ANNUAL REPORT FOR 2009 TO THE BOROUGH OF AVALON ON THE CONDITION OF THE MUNICIPAL BEACHES 2009 was a year that continued the relative calm seen during That situation ended abruptly with a northeast storm September 2, The stage was set for a series of events that included a significant event October 14 15, 2009, which eliminated the deposits on the berm that accumulated during the summer. Between the 11 th and 15 th of November a more serious storm chewed its way through the berm and into the dunes in the more vulnerable places and resulted in a Presidential Disaster Declaration December 22, Two snow storm northeasters followed in December and January. Another event cut into the dunes along the northern shoreline February 12, The most recent event was a three day storm March 11 14, 2009 that excavated an additional 15,100 cubic yards from the 4-block section between 17 th and 21 st Streets. The general impact of this series of storms was seen all along the Avalon shoreline. All 10 sites lost sand volume, although south of 28 th Street the loss was only seen offshore. No dune damage occurred south of 23 rd Street where the foredune was lost that accumulated since 2002 seaward of the primary dune reinforced during the Federal beach restoration project. Sand volume definitely moved further seaward than at any time since the 1992 northeaster. A deep and wide trough now exists just beyond the -2.0 NAVD 88 elevation offshore. The bar further seaward is also much larger and extends beyond the 1,500- foot survey distance normally achieved by the survey team s swimmers. The inlet shoreline remains sand-starved, but unchanged by the storm events. The new revetment has successfully stopped large volumes of water coming over into the Borough streets and properties during the past winter. However, the lack of sand, once in front of the rock wall protecting the approach road to the Townsend s Inlet bridge allows northeast waves to crash onto the pavement and flood that area plus make driving up to the bridge challenging during a storm. Damage was extensive to the northern shoreline between 10 th and 23 rd Streets: 1. Total loss of the beach at the rocks between 10 th and 17 th Streets. Water is at the rocks during low tide. 2. Treacherous access to the beach in that same section because the rocks are difficult for most to navigate. 3. Significant loss to dune sand volume landward of the bulkhead line along the rocks as waves scoured it away during the height of each storm. About 40 feet of retreat landward of the bulkhead resulted. 4. Erosion at 17 th Street half way back to the developed properties from the position of the end of the rock revetment at 17 th Street. This cove was last present in the spring of 1987 just prior to the initial beach replenishment. 5. Greater than 50% loss of the dunes protecting the development landward between 17 th and 21 st Streets and the remaining dune is only half as high as the dune that has been lost to date. 6. Significant treat to the storm water outfall pumping station at 22 nd Street as the dune has nearly disappeared at that location. 7. Damage to dunes rapidly dissipates south of 21 st Street to the point of zero loss by 28 th Street. The CRC monitored the 10 oceanfront cross sections four times in These surveying activities continue a monitoring program dating back to The US Army Corps of Engineers restored the ocean beaches in 2002, and additional sand has been hydraulically pumped onto the beach in 2006 and 2008, with a contract to truck in quarry sand used in 2007 and 2009 to restore recreational access between 10 th and 17 th Streets. The following is a list of quarterly studies included in this report and the dates they were surveyed: Survey 103 December 17 & 23, 2008 Survey 104 March 16 & 19,

4 Survey 105 June 22 & 23, 2009 Survey 106 September 14 & 21, 2009 Survey 107 December 21 & 23, 2009 OCEANFRONT BEACH SURVEYS: Surveying the 10 oceanfront sites was resumed in 2006 when it was decided not to continue surveying the shoreline along Townsend s Inlet following completion of the new revetment wall. Oceanfront beaches were surveyed quarterly to depict both seasonal and annual changes. The observed changes show trends in both shoreline and volume changes that occurred in Table 1, below, shows the quarterly trend in sand volume change during Note that the beach replenishment was undertaken prior to the second quarter survey and appears as positive unit volume additions to the cross section at 12 th through 17 th Streets. Losses accelerated during the remainder of the year, peaking in the 4th quarter. Table Oceanfront Beach Profiles Volume Changes Profile Winter Spring Summer Fall Number 12/07-3/09 3/09 6/09 6/09-9/09 9/09 12/09 (yds 3 /ft) (yds 3 /ft) (yds 3 /ft) (yds 3 /ft) AV AV AV AV AV AV AV AV AV AV Quarterly Volume Change= 19,368 yds 3 114,717 yds 3-148,234 yds 3-412,401 yds 3 Review of the data collected during the interval that sand was trucked to the erosional zone documented the placement of 177,455 cubic yards. The sum of the four seasonal changes yielded a loss of -426,550 cubic yards to the municipal shoreline as shown by the results from the 10 sites. The direct comparison between December 2008 and December 2009 was -428,388 cubic yards. The difference is due to the variable distances surveyed each quarter on the seaward end combined with the deposition of sand far out to sea on large offshore bar systems. Either number points to a major impact by this winter s events on the sand quantity available on the Avalon oceanfront beaches. INDIVIDUAL SITE REVIEW: Since the advent of El Nino storm activity has caused a large measure of erosion and difficulty, the pattern of the past several years in reporting was continued to show the entire past 8 years as a trend of project s retreat and new sand supplies being provided to the beach. Each location is shown with pictures from the 2

5 spring survey compared to one from December to show the annual beach/dune changes produced in Avalon. The profile cross section follows the pictures and has the December 2008 to December 2009 cross sections shown in heavier lines compared to the other three quarterly profile lines. The trend starting with the 4 th quarter survey data in 2002 is continued into 2009 on the graphs at the end of each site s information package. AV Ninth Street Sand remains trapped in the cove made by the 8 th Street jetty and the Avalon shoreline that protects the beach south of the jetty to 10 th Street from northeast storm waves reducing the impact and diminishing erosion in this region. There is a substantial reserve of sand in the dune system as the dune toe curves in toward the inlet north of 10 th street to the jetty making an even deeper pocket of sand held in place by the jetty. Since the jetty is 400 feet longer than it was a decade ago, the beach has become about 300 feet wider at this profile location. The situation continued unchanged into By September the storm activity began so that by December 22, 2009 s 4 th Quarter survey, the beach had suffered retreat that grew steadily worse to the south. The shoreline actually advanced 32 feet while the sand volume grew by yds 3 /ft. 3

6 1a. March 16, b. September 21, 2009 Photographs 1a to 1c. 9 th STREET Photograph 1a shows the beach prior to the 2009 El Nino season that began Sept. 2 nd. Note that the revetment is exposed on the beach below low tide by the first quarter survey date. View 1b looking to the south along the toe of the dunes toward 12 th Street following the truck placement of 163,950 cubic yards of sand on the erosional hot spot. The sand provided a season of easy access and safe bathing for citizens. View 1c shows the beach December 22 nd following four moderate northeast events. The November 11-15, 2009 storm received a Federal Disaster Declaration. The erosion has moved the shoreline back to the revetment once again in the area between 11 th and 17 th Streets with the dune above the rocks stripped back about 12 feet. 1c. December 21,

7 Avalon, New Jersey - Quarterly Comparison 30 AV-9: Ninth Street (NJBPN #216) Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 1 - th The 9 Street profile site has been sheltered from northeast th storms since the 8 Street jetty was extended. This has meant that the berm and dune remain relatively untouched by this season s storms, but sand was deposited offshore extensively 3 since the fall survey. The net change was a yds /ft. sand volume gain with a 32-foot shoreline advance Distance, Feet 5

8 Feet from Reference Position Shoreline Trends at 9 th Street, Avalon, NJ *also NJBPN Site #216 The ACOE project was completed by early 2002 creating shoreline advances of between 250 and 325 feet Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Year Over twice as much sand was added in 2008 Loss rates slowed down by 2005 and sand was placed just south of the site in early 2007 Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Site is Sheltered from Storms by the Jetty Q Q Figure 2. The shoreline trend at 9 th Street retreated about 100 feet per year between 2002 and 2006 until sand placement in 2006 and The loss rate since the Federal project has declined due to frequent additions of sand by the Borough and the fact that the extended jetty acts to shelter the beach/dune part of the cross section. Sand did appear offshore at this site indicating some by-passing from the inlet. 6

9 AV Twelfth Street Twelfth Street has been a perennial problem since 1981 when beachfront erosion started its lengthy saga of impact along this segment of shoreline. The configuration of the rock revetment built following the disastrous 1962 northeast storm forms an apex seaward at 12 th Street making it about 50 to 75 feet further seaward than any other part of the protected section of beach between the jetty and 17 th Street where the revetment ends. Therefore, retreat to the rocks occurs first near 12 th Street and the rest of the shoreline rapidly peels away north and south from the apex as wave turbulence impacts the rocks and strips the sand away far more readily. The shoreline recession has actually gone negative by the 4 th quarter of The fall 2009 storms removed all remaining sand from the toe of the rocks leaving the site wet at low tide. The sand volume declined by yds 3 /ft. on the beach while sand appeared offshore as a bar deposit of yds 3 /ft. making the net change only yds 3 /ft. This sand s source may be the inlet shoals as the northeast waves propel it south in front of the oceanfront shoreline. The shoreline retreated 73 feet.. 7

10 2a. March 16, b. September 21, 2009 Photographs 2a to 2c. 12 th STREET Photograph 2a shows the beach south of the profile line with the rocks almost exposed prior to the placement of the 2009 trucked-in sand. View 2b followed the completion of the 163,950 cubic yard sand placement effort in June. The beach looked to be in good shape for the relatively small sand volume supplied. View 2c shows the beach December 22 nd following four significant northeast events. The rocks were completely exposed with dune retreat landward of the bulkhead. This has become three times worse by mid-march The low tide line is at the toe of the rocks leaving no wet beach along this segment. 2c. December 21,

11 Avalon, New Jersey - Quarterly Comparison 30 AV-12: Twelfth Street Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec 09 th Figure 3 - The 12 Street site was severely impacted by events in spite of adding trucked in sand by the June survey date. The material survived the -20 summer (21 Sept. survey) but was stripped to the rocks by a series of northeast events in the Fall of A huge wedge of sand was deposited offshore, derived from the inlet shoals since the loss from the beach is 3 unlikely the sole source. There was a loss of yds /ft. from the 3 beach, but just yds /ft. net loss. The shoreline retreated 73 feet Distance, Feet 9

12 Feet from Reference Position Q Q Shoreline Trends at 12 th Street, Avalon, NJ (AV 12) The rate of loss increased dramatically in 2005 as the shoreline pulled back toward the rocks Q Q Q Q Q Q Q Q Q Q Q Q Q Q Year The addition of quarry sand to the northern Direct Placement shoreline in 2007 produced Improved things the only net seasonal gain in 2008 in 8 quarters Truck-in then Severe Loss in 2009 Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 4. The shoreline trend at 12 th Street retreated about 150 feet per year between 2002 and 2009 to a point 52 feet behind the reference position. Sand was deposited on the shoreline in 2005 and again in The 2008 dredge fill was followed by more trucked-in material in 2009, all of which reversed the trend for about 6 months each.

13 AV Seventeenth Street This site has been almost at the southern end of beach nourishment for a decade because the loss rate rapidly declines south of here. The revetment ends a few feet north of the profile line, but did lie buried below the dunes, not seen since the 1987 fill was completed. The November 11 15, 2009 caused the rocks to be exposed once again, and by the end of the year the entire end of the revetment was once again visible. Continued storms in January, February, and March has made this situation significantly worse as the dune between 17 th and 21 st Streets retreated an additional 55 feet. The net change is a significant shoreline retreat (-49 feet) and sand volume loss ( yds 3 /ft.). 11

14 3a. March 16, b. September 21, 2009 Photographs 3a to 3c. 17 th STREET Photograph 3a shows the beach looking south toward 21 st Street. Note the fence on the beach and the width of the light brown beach grass on the foredune. View 3b followed the completion of the trucked-in sand placement effort in June. The grass is now green and the beach was stable until September. View 3c shows the beach December 22 nd following multiple northeast storms. The foredune was nearly gone and by the writing of this report the retreat is well landward into the darker vegetation (bayberry trees). 3c. December 22,

15 Avalon, New Jersey - Quarterly Comparison 30 AV-17: Seventeenth Street Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 5 - th 17 Street saw similar impacts from the storms where the summer trucked-in material survived until the Sept 21 survey, but then vanished to the rocks by late December. There was no offshore bar as at 12th Street, adding credence to an inlet source for that bar sand. 3 The beach lost yds /ft. for the year with little material stored offshore. The shoreline retreated 49 feet Distance, Feet 13

16 Feet from Reference Position Post-fill loss commenced immediately, but followed a linear trend to 2007 Q Q Shoreline Trends at 17 th Street, Avalon, NJ (AV 17) Q Q Q Q Q Q Q Q Q Q Q Q Q Q Year 2007 gain was produced by adding mainland quarry sand Sand was added by dredge in 2008 Sand Added was Taken in 2009 Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 6. The shoreline trend at 17 th Street retreated in a linear fashion over a six year period. The impact of sand deposition in 2005, 2007, 2008 and 2009 shows in the quarterly surveys and changes in the shoreline position, but did not change the trend direction or dramatically slow the rate of retreat. The zero elevation position on the beach moved from 650 feet to 90 feet in 7 years, a 560-foot landward retreat.

17 AV Twenty Third Street Located seaward of the Avalon boardwalk, this site begins to exhibit some shoreline and sand volume stability. The Federal project produced a sand volume increase including a wider dune added by the project. The beach filled in the fore dune slope around the fencing to create a beach with a stable cross section. The trend line flattens out in 2006 because the Borough commenced annual beach nourishment efforts in 2005, 2006, 2007, 2008 and This appears to have produced a balance in sand supply keeping the shoreline position relatively constant when compared to the shoreline immediately to the north. The net change was a 49-foot shoreline retreat and a yds 3 /ft. sand volume loss during 2009 (largely confined to the fourth quarter of the year). 15

18 4a. March 16, b. September 21, 2009 Photographs 4a to 4c. 23 rd STREET Photograph 4a shows the beach south toward the fishing pier. The dune can be reached during mild storms, but the foredune in the picture was developed seaward of the Federal project dune. View 4b followed the completion of the nourishment project to the north. The beach shows the beneficial effects of the summer s accumulation of sand from offshore. View 4c shows the beach December 22 nd following the series of fall storms. The low foredune in pictures 4a and 4b above has vanished as the older 2002 Federal dune how is back at the base of the beach. 4c. December 22,

19 30 Avalon, New Jersey -Quarterly Comparison AV-23: Twenty-third Street (NJBPN #116) Elevation, Feet (NAVD 88) Boardwalk Line Survey Date Dec Mar Jun Sep Dec Figure 7-23rd Street has been spared serious erosion, but all the added dune sand since 2002 was lost by December The ACOE dune remains in place and the beach is about as wide, just closer to the dunes. The 3 net change was a loss of yds /ft. with a 49-foot shoreline retreat Distance, Feet 17

20 Feet from Reference Position Q Q Shoreline Trends at 23 rd Street, Avalon, NJ (AV 23) *also NJBPN Site #116 Q Q Q Q Q Twenty-third Street sits at the transition point between serious erosion and beach stability Q Q Q Q Q Q Q Q Q Year The addition of sand to the northern beaches halted the retreat in the shoreline position 2009 Storms Renewed Retreat Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 8. The shoreline trend at 23 rd Street suffered a 156-foot retreat between December 2002 and September The trend became relatively flat following the 2005 beach nourishment and showed stability following the 2007 project. The recent history has been one of slow retreat as the storms had their impact this fall.

21 AV Twenty Eighth Street As one moves south from 23 rd Street the shoreline curves slightly to the west altering the angle at which the northeast waves strike the beach resulting in a lower impact from the erosion plaguing the beach north of 23 rd Street. The Federal sand addition to 28 th Street is essentially still present with a total shoreline retreat of 120 feet since 2002 (50 feet of which occurred in the fall of 2009). There was a second dune ridge resulting from sand accumulation around the post-project snow fencing erected following the sand placement. Storms carried sand into the space between the foredune line and that dune built by the Federal project in Most of the retreat occurred on the berm, not in dune erosion. The annual changes were a loss of yds 3 /ft. as the offshore trough developed and a 47-foot shoreline retreat. 19

22 5a. March 16, b. September 21, 2009 Photographs 5a to 5c. 28 th STREET Photograph 5a shows the beach after the 2008 winter with a double dune ridge that grew up following the Federal project in The beach is wider here and sufficient to prevent routine annual dune scarping. View 5b shows the foredune developed seaward of the Federal project dune built in The beach is wide and protects the landward development. View 5c shows the partial removal of the foredune as sand was pushed into the area between the Federal project dune and the foredune. The beach became narrower due to erosion of the shoreline 5c. December 22,

23 Avalon, New Jersey - Quarterly Comparison 30 AV-28: Twenty-eighth Street Elevation, Feet (NAVD 88) Boardwalk Line Survey Date Dec Mar Jun Sep Dec Figure 9 - th At 28 Street there was a landward transfer of sand to the foredune of yds /ft., but an overall net loss of yds /ft. on the profile as the beach retreated 47 feet and a deeper trough formed just offshore Distance, Feet 21

24 Feet from Reference Position Q Q Shoreline Trends at 28 th Street, Avalon, NJ (AV 28) 28th Street is within the accretional zone on the Avalon shoreline, but still received direct fill during Q Q Q Q Q Q Q Q Q Q Q Q Q Q Year This site has had a long history of slow shoreline advance seaward since 1981 Storm Losses in 2009 Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 10. The shoreline trend at 28 th Street illustrates the transition between an erosional shoreline and a relatively stable one. The Dec position reflects the Federal project sand volume. After an initial period of retreat in the project s shoreline position erosion had slowed by the second quarter of 2005 with just minor fluctuations in beach width since. Minor shoreline advances followed the recent project activity, but 2009 proved that loss would affect 28 th Street too ( yds 3 /ft. and a 47-foot shoreline retreat). Q4 2009

25 AV Thirty Fifth Street This was the southernmost site of the initial survey locations established in 1981 to document the onset of severe erosion between 9 th and 23 rd Streets. Sand lost from those beaches moved south adding to the shoreline everywhere south of 28 th Streets. The dunes at this site have advanced over 250 feet onto the beach as accretion continued over the past 21 years. Sand forms a ridge offshore and waves move the material as a bar onto the beach (where it is called a ridge and runnel). These features are frequently in evidence during the summer especially, but can occur any time the sea is quiet for 4 to 6 weeks. During 2009 the beach continued to grow until the fall when the storms commenced. The net change was a 7.32 yds 3 /ft. sand volume gain in the dunes followed by a yds 3 /ft. loss on the beach, but sand accumulated offshore to the limit of the survey distance of 1,589 feet ( yds 3 /ft.). Adding the numbers gives yds 3 /ft. with a 69-foot shoreline retreat. These offshore bars present at this time are far bigger than at any time in the recent past (since 1992). 23

26 6a. March 19, b. September 14, 2009 Photographs 6a to 6c. 35 th STREET Photograph 6a is a view to the north toward the fishing pier showing the spring berm from the foredune and access pathway. View 6b followed the summer accumulation and shows a wide berm and a ridge of new sand in the act of accumulating on the beachface slope. The wet streak is the runnel trough that forms landward of the ridge as it grows. View 6c shows the same view of the beach as 6b (above right). The beach retreated in the storms, but material was pushed up to the toe of the dunes. 6c. December 22,

27 Avalon, New Jersey - Quarterly Comparison 30 AV-35: Thirty-fifth Street (NJBPN #115) Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 11 - th At 35 Street the berm was also augmented by storm transport of 3 sand to the dune toe (+7.32 yds /ft.), but the beach retreated 69 feet and a deep trough formed just offshore. The net change was a loss 3 of yds /ft Distance, Feet 25

28 Feet from Reference Position Shoreline Trends at 35 th Street, Avalon, NJ (AV 35) *also NJBPN Site #115 Sand flowed to this site immediately following the ACOE fill, then tapered off Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q The situation became very quiet between 2005 and 2007, then resumed an advance, perhaps due to beach fills in '06 & '08 Q Year Fall 2009 Storm Loss Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 12. The shoreline trend at 35 th Street showed a rapid advance in the shoreline position following the US Army Corps of Engineers (ACOE) beach fill in This trend peaked in the summer of 2004 and the trend became nearly horizontal in the three subsequent years. Shoreline advance resumed in Q2 of 2007, likely due to sand arriving from recent fill activity. The trend remained positive until the 4 th quarter of 2009 when the largest beach loss since 2002 occurred.

29 AV Forty Fourth Street The site is a model of natural processes in action along the NJ coastline. The dune complex extends over a thousand feet landward to Dune Drive. The epitome of dune width and height exists along this segment of beachfront. The highest dunes exceed 50 feet in elevation and support a climax vegetation maritime forest growth of trees and ground cover plants. A series of newer dunes succeed each other toward the current dune used as the instrument station for the coastal surveys. Wind transport aids the building of dunes and the process has produced a long-term shoreline advance. A majority of the sand lost between 8 th and 20 th Streets is ultimately distributed between 28 th and 70 th Streets as a wider beach, and eventually a wider dune system. In ,000 cubic yards of the accumulated sand was harvested and hauled back to 20 th Street and spread along 600 feet of shoreline to add to the sand volume returned to the zone of erosion. The harvesting extended south to 60 th Street with a six-block area left alone as required by the bird biologists in the NJDEP. This zone was centered on 44 th Street. Storm activity acted to add sand to the dune toe, beach berm and beachface in minor quantities, but generated a huge offshore trough ( yds 3 /ft. between 769 and 1,252 feet from the reference) before the new offshore bar produced added material way out to sea (1,501 feet). The net annual change was a loss of 6.39 yds 3 /ft. and a 14-foot shoreline retreat, the least of any site except 9 th Street. 27

30 7a. March 19, b. September 14, 2009 Photographs 7a to 7c. 44 th STREET Photograph 7a shows the dune crest south across the expanse of relatively new dunes. The deposition of sand derived from the northern shoreline has expanded this region by almost 50% since The homes in the right distance sit on the 50-foot elevations in this 100-acre tract in Avalon. View 7b is a view to the south looking down the various ridges of dunes built over the last 3 decades. This is truly a magnificent shoreline. View 7c shows the beach December 23 rd following the November disaster storm and a subsequent multi-inch snow storm. The beach gained sand, but a huge trough offshore negated any net increase for now. 7c. December 22,

31 Avalon, New Jersey - Quarterly Comparison 30 AV-44: Forty-fourth Street Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 13 - th The 44 Street comparison shows sand added to the foredune toe with a smaller annual shoreline retreat (-14 feet) and a smaller total loss due to the deeper offshore 3 trough following the storms in 2009 (-6.39 yds /ft.) Distance, Feet 29

32 Shoreline Trends at 44 th Street, Avalon, NJ (AV 44) Feet from Reference Position No fill sand has ever been placed this far south on the island. Dunes grow wider as the shoreline advances Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q The trend line shows an advance of about 75 feet by 2008 Q Year 2009 Losses Cut the Seaward Advance of the Shoreline Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 14. The shoreline trend at 44 th Street demonstrates that sand has been moved to this site over this past 7 years of time by natural processes. No effort was expended in nourishment activity between 32 nd and 70 th Streets in Avalon, but sand volume lost in the project areas moved south and has been spread along this reach of the Borough shoreline. The trend continued positive in spite of the 4 th quarter 2009 retreat in the shoreline.

33 AV Fifty Eighth Street This site lies at the southern margin of what is called the high dune area. Development south of 58 th Street extended east of Dune Drive along numbered streets toward the beach, whereas no numbered streets extend east of Dune Drive between 58 th and 43 rd Streets and between 43 rd and 40 th the development only extends partially into the high dunes. The 4 th quarter un-did the prior three quarters of accumulation in The net loss was a yds 3 /ft. The deep offshore trough claimed yds 3 /ft. of that volume. The beach gained about 5 cubic yards of sand per foot of dune and upper beach. These center-island losses all consist of deep, linear trough systems parallel to the beach that go much deeper and wider than any since 1992 and push the bar further seaward to the point where the survey team swimmers cannot safely reach the closure with the unaffected sea floor. The net change for the year to just below the zero elevation datum was a 1.93 yds 3 /ft. sand volume loss. The shoreline, however advanced seaward by 78 feet. 31

34 8a. March 19, b. September 14, 2009 Photographs 8a to 8c. 58 th STREET Photograph 8a shows the beach and dune to the south at 58 th Street. The dunes are building across the upper dry beach as more sand is added to the shoreline. View 8b is a view south along another of the ridge and runnel systems to migrate onto the shoreline during the summer months. This is the cross shore transport process by which the beach gains sand. View 8c shows the beach December 22 nd under a winter sky. The dune is protected by a wide, dry beach on which a ridge is already forming in the winter following the earlier northeast storms to impact the beach. Thus far, no significant damage has occurred anywhere south of 23 rd Street. 8c. December 22,

35 Avalon, New Jersey - Quarterly Comparison 30 AV-58: Fifty-eighth Street Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 15 - th At 58 Street, the berm was cut down in the fall by storm activity, sand was blown or washed over the small foredune raising its elevation 3 (+5.22 yds /ft.), while the shoreline actually advanced 78 feet. A wide, deep trough formed offshore creating a negative net sand volume 3 change ( yds /ft.) and producing a bar further seaward than previously seen Distance, Feet 33

36 Feet from Reference Position Shoreline accretion shows a positive impact from the ACOE project as well as previous local projects since 1987 Q Q Shoreline Trends at 58 th Street, Avalon, NJ (AV 58) Q Q Q Q Q Q Q Q Q Q Q Q Q The 2006 retreat is unrelated to storm activity. Offshore bars approach the shoreline and produce a false retreat in the beach just prior to bar attachment 34 Q Year 2009 was Positive at This Site Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 16. The shoreline trend at 58 th Street was positive with a gradual decline in the rate of increase over the 7-year interval. The 100- foot advance between 2002 and 2005 may be related to northerly transport from the 2003 portion of the Federal project that commenced at 70 th Street and worked south restoring the Stone Harbor beaches that spring. Storm events have done little to slow the advance in this shoreline from 717 to 900 feet from the reference position in the dunes. Most of New Jersey s coast could benefit from a 183-foot seaward advance in the zero elevation position on the beach.

37 AV Seventieth Street This part of Avalon was not surveyed until the dunes were cut into steep vertical scarps by the December 1992 northeast storm. Earlier storms had missed this area and resulted in no dune erosion over the previous 15 years. The Borough undertook a post-storm repair and pushed sand up to the scarp to restore the dune s sand volume. The existing dune is about twice the width and three times the volume of that present in This beach is just north of the northern limit of the Federal beach nourishment project that extended south from here into Stone Harbor to the 122 nd Street groin in the spring of Shoreline advance and dune growth dominated this site since The beach did get narrower since the Federal project was completed, but the sand volume increased on the dunes and beach by yds 3 /ft. This year the site lost yds 3 /ft. while the shoreline retreated 40 feet. 35

38 9a. March 19, b. September 14, 2009 Photographs 9a to 9c. 70 th STREET Photograph 9a is a view to the south along the toe of the dunes. The beach is wide and provides both protection and a sand source for the dunes. Wind transport is building these features all along the Avalon shoreline south of 23 rd Street. View 9b is a view south, parallel to the toe of the dunes. The wrack-line shows where the first of the El Nino series of storms carried wave energy on this beach. View 9c shows the beach December 23 rd showing the extent of storm deposition of sand among the wrack debris moved onto the toe area in front of the dunes. About 3 cubic yards of sand were added during the 4 th quarter of c. December 23,

39 Avalon, New Jersey - Quarterly Comparison 30 AV-70: Seventieth Street (NJBPN #114) Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure 17 - th At 70 Street the offshore trough became 4-5 feet deeper and the bar increased in size as well. Sand was moved to the 3 dune toe (+1.69 yds /ft.), the shoreline retreated 40 feet and 3 the entire cross section lost yds /ft Distance, Feet 37

40 Feet from Reference Position Shoreline Trends at 70 th Street, Avalon, NJ (AV 70) *also NJBPN Site #114 Sand was placed on the southernmost Avalon beach in 2002, so shoreline advance appeared in 2003 Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q The trend produced an advance toward the end of the time period in 2008 Q Year 2009 Losses Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 18. The shoreline trend at 70 th Street shows direct influence by the Federal project in 2003 with a 123-foot shoreline advance. The shoreline trend remained mildly positive for the remainder of the time. The 61-foot shoreline retreat in the 4 th quarter of 2009 has flattened out the trend of shoreline advance.

41 AV-78 Seventy Eighth Street Positioned just two blocks from the boundary with Stone Harbor, this dune also suffered substantial erosion during the 1992 northeast storm. The volume of sand added to the dune is about a third greater than that present prior to the storm 17 years ago. The beach was enhanced by the ACOE project in the spring of That sand redistributed itself in both directions yielding an 80-foot retreat by By the end of the fourth quarter of 2009 the shoreline suffered retreat to a position This section of the Borough shoreline is dedicated to hotel/motel accommodations and is heavily utilized by those patrons during the summer and fall seasons. The beach continues into Stone Harbor where groins are spaced at street ends with the first one at 82 nd Street, four blocks south of this profile site. The same shoreline position measured during the Q4 survey in 2008 represents the beach s shoreline as it was following the Federal beach nourishment following the Q4 survey in The 78 th Street area received sand in 2002 and the effort continued in 2003 south into Stone Harbor using the Hereford Inlet borrow zone. 39

42 10a. March 19, b. September 14, 2009 Photographs 10a to 10c. 78 th STREET Photograph 10a is a view to the south along the seaward crest of the dunes. The beach was at the same width it had been at in View 10b is a view of the recreational beach in mid- September showing the beach width and the extent of the wet-dry area onto the berm. View 10c shows the beach December 23 rd with sand moving back onto the beachface at 78 th Street. The a second bar appears above the passive sea on the right side of the picture proving that it is the wave climate over time that determines the beach condition, not the season of the year. The storms brought the wrack to the dune toe, where later winds covered most of it with new dune sand. 10c. December 23,

43 Avalon, New Jersey - Quarterly Comparison 30 AV-78: Seventy-eighth Street Elevation, Feet (NAVD 88) Line Survey Date Dec Mar Jun Sep Dec Figure th At 78 Street a nearshore trough and bar have formed, pushing the existing offshore trough and bar seaward. The beach was reduced in 3 elevation to the toe of the dunes ( yds /ft.), the shoreline retreated 75 feet and the offshore trough itself produced a loss of yds /ft., but yds /ft. was deposited further seaward. The 3 net change was a loss of yds /ft Distance, Feet 41

44 Feet from Reference Position The Winter of Produced Substantial Retreat as the ACOE project adjusted Q Q Shoreline Trends at 78 th Street, Avalon, NJ (AV 78) Q Q Q Q Q Q Q Q Q Q Q Q Q The shoreline trend turned around in 2005 and continued until late 2007 when it went flat into 2008 Q Year 2009 Losses Q Q Q Q Q Q Q Q Q Q Q Q Q Annual Shoreline Position Shoreline Position Trend Poly. (Shoreline Position Trend) Figure 20. The shoreline trend at 78 th Street shows an influence from the ACOE project that commenced here in the spring of The shoreline retreated over the next 6-8 quarters as the fill profile adjusted to wave conditions then advanced seaward about 70 feet in spite of a 65-foot retreat during the 4 th quarter of The site saw two quarters of shoreline retreat during The beach and dune at the site were yds 3 /ft. ahead of the 2002 sand volume, but offshore losses generated the only down-beach negative sand budget.

45 In the table below, the annual comparison of shoreline changes and beach sand volume differences shows the December 2008 positions directly compared to those seen in December The plots emphasize these two surveys with bolder lines to allow a more direct visual comparison on the graphs for each site. Table Annual Oceanfront Shoreline and Volume Changes December 2008 to December 2009 Profile Shoreline Volume Avg Volume Distance Net Volume Cumulative Number Change Change Change Between Change Vol. Chg. (feet) (yds 3 /ft) (yds 3 /ft) (feet) (yds 3 ) (yds 3 ) Eighth Street Jetty ,400 15,400 AV ,571 25,971 AV ,328-8,357 AV ,888-79,244 AV , ,430 AV , ,256 AV , ,266 AV , ,245 AV , ,470 AV , ,046 AV , , Annual Oceanfront Total Volume Change 2009 = -428,388 cy This annual comparison data is highly impacted by the effects of the fall 2009 northeast storms. A halfmillion cubic yard sand loss is pretty significant especially when it is distributed along the entire Borough shoreline. The beach and dunes south of 23 rd Street WERE NOT HARMED and, in fact, gained sand volume. The big loss comes in the trough excavated by the storms at the base of the beachface taking that sand far offshore to build a huge offshore bar. The swimmers covered some of this feature, but were not able to extend the survey far enough to complete closure with the original sea floor. No prior surveys went that far seaward either, since those distances are usually reserved for the boat and depth sounding equipment. SUMMARY OF AVALON S OCEANFRONT BEACHES: This report now takes a look back to see where the sand has gone since the Federal project was completed in The December 2002 quarterly survey found that the ACOE placed 1,451,413 cubic yards of sand on the beach between the jetty at 8 th Street and a point between 28 th and 31 st Streets. The loss rate since amounted to hundreds of cubic yards of sand at 12 th and 17 th Streets which declined somewhat at 23 rd Street, then dropped to double digits at 28 th before becoming positive at the 35 th Street site. The review did not count the offshore trough and bar system that generated huge losses at most sites in December 2009 simply because the sand volume in the bar system cancels out between the excavation loss at the trough and the deposition gain at the ridge or bar. Also, the survey team is not able to reach much beyond 1,500 feet from the reference point on each profile due to safety issues swimming so far out into the ocean. They cannot reach to the point of closure in sand movement on these super large bars. 43

46 The table also does not count the 928,706 cubic yards placed between 9 th and 23 rd Streets by the Borough since Adding both additions of sand together, the CRC can track about a third of the sand put on Borough beaches since We know that very little returned to the Townsend s Inlet ebb-tidal shoal system due to the extended 8 th Street jetty and limited littoral transport to the north along the shoreline. Some undoubtedly moved south into Stone Harbor s northern shoreline because work for that community shows that the 82 nd, 90 th, and 95 th Street profiles show much lower loss rates than do the southern group of sites being surveyed. This quantity is not huge, but is not quantifiable either. The remaining site for sand deposition is further offshore than the quarterly surveys reach using swimmers. A 1-foot thick layer across a single acre of seafloor offshore would contain 1,611 cubic yards of sand from the Avalon beaches. There are far more than 1000 acres along the entire Borough oceanfront so each 1000 acres contains 1,611,000 cubic yards, less if the layer is thinner. Table 3 Summary of 2002 to 2009 Annual Oceanfront Shoreline and Volume Changes December 2002 to December 2009 Profile Shoreline Volume Avg.Volume Cell Net Volume Cumulative Number Change Change Change Distance Change Volume (feet) (yds 3 /ft) (yds 3 /ft) (feet) (yds 3 ) (yds 3 ) 8th Street Jetty ,540-51,540 AV , ,490 AV , ,460 AV , ,891 AV ,031-1,041,922 AV ,837-1,066,759 AV , ,722 AV , ,269 AV , ,733 AV , ,823 AV , ,171 Volume Change for Beaches Between the Jetty & 78th St. = -504,171 cy winter was a strong wake-up call that erosion is never a far away problem and that storm frequency can more than make up for one storm s intensity. The sum of loss at the critical erosional areas has been severe and will require a major hydraulic effort to put back so that the beach resembles that left by the ACOE in The CRC also suggests that the Borough might consider setting up a program of annually extending the profile lines seaward to at least 20 feet of water offshore to be able to answer the perpetual disappearance of so much sand. 44

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