FROM THE EDITOR’S DESK: WHERE DO YOU FIND SAND? Lesley Ewing
LITTORAL PROCESSES ALONG THE PACIFIC AND BAY SHORES OF SAN FRANCISCO, CALIFORNIA, USA Bob Battalio
Sand transport at the mouth of the Golden Gate entrance to San Francisco Bay is characterized based on prior studies and recent work by the author and associates (see acknowledgements). Littoral processes are driven by waves and tidal currents with high power and large changes in shore position have been observed, resulting in progressive damage risk to infrastructure. Sand transport rates are large over short periods but the net transport rates are relatively modest when averaged over one or more years. Two of the large sandy shores are considered in this paper: Ocean Beach and Crissy Field (Figure 2). This paper concludes that sand is transported from Ocean Beach through the Golden Gate and to Crissy Field by waves and currents. The sand transport path, rates, processes, and time scales are characterized using work accomplished since this linkage was identified by the author in the 1990s (Battalio and Trivedi 1996). From a scientific and engineering perspective, this paper provides insight into littoral processes in the study area. The intent is to complement other related studies, for use in coastal zone engineering and management. From a coastal zone management perspective, this paper implies that the problems we face are larger than sand transport and erosion. Rather, we are dealing with the legacy of development that has encroached on the shore and fundamentally conflicts with the shore’s dynamic nature. Therefore, this paper also aspires to raise questions about how we adapt to coastal hazards in the future, by considering the implications of past actions within the context of rising sea level and societal values. Key contributions are: • A synthesis of project reports not otherwise published in journals is linked to prior published work, providing a contemporary, integrated description of littoral processes. • The net rates of shore position changes from the mid 1850s to 2010 are characterized, and linked to prior human intervention including approximate time lags. • Sand transport rates are estimated, and linked to human intervention. This paper complements numerous other journal papers with a perspective that is focused on informing shore management.
WAIKIKI BEACH GETS A FACELIFT Scott Sullivan and David Smith
Waikiki Beach is the premier tourist destination in Hawaii, and one of the most heavily utilized water and beach areas in the world. The beach has been a workin- progress since the late 1800s, and this extensively modified shoreline requires periodic maintenance in order to ensure its continued existence. The largest nourishment and maintenance effort in 40 years was completed in May 2012 by the state of Hawaii, Department of Land and Natural Resources (owner), Sea Engineering Inc. (designer), and Healy Tibbitts Builders Inc. (contractor). The project involved the recovery of approximately 27,000 cubic yards of carbonate sand from shallow nearshore waters using a barge-mounted Toyo submersible pump, pumping the sand to shore through a 2,200-foot-long pipeline, dewatering on the beach, and moving the sand up to 2,500 feet along the shore for placement. The work was conducted safely in a very crowded area, while minimizing impacts to the visitors and businesses that depend on the beach. The project was successfully completed within budget, and stakeholders were happy with the enlarged beach. The project was a 2012 ASCE (Hawaii Section) award winner.
DOWNDRIFT BEACH EROSION ADJACENT TO THE INDIAN RIVER INLET, DELAWARE, USA Mohammad Keshtpoor, Jack A. Puleo, and Fengyan Shi
Indian River Inlet (IRI) is located at roughly the midpoint of the Atlantic coast of Delaware and is the major waterway that connects the Atlantic Ocean to two Delaware inland bays. Twin jetties constructed in late 1930s to keep the inlet from filling also interrupt the alongshore sediment transport. Since then, the updrift beach has accreted and downdrift beach suffered from erosion. In 1990, the U.S. Army Corps of Engineers constructed a sand bypassing system to mitigate the downdrift beach erosion by transferring sand slurry from the updrift to downdrift side of the inlet. In an effort to investigate the impact of the bypassing system on downdrift beach, Empirical Orthogonal Function (EOF) analysis is applied on beach profile data collected from 1985 until 2008 to address two questions. First, did the bypassing system fulfill the beach nourishment goals? If so, how much material is enough to be bypassed to protect the downdrift beach? EOF results show high correlation between the third temporal eigenfunction at the downdrift beach and time series of bypassed volumes from 1994 until 2000. The combination of the spatial and temporal eigenfunctions indicates that the mean value of bypassed volumes from 1991 until 2000 was likely sufficient to mitigate downdrift beach erosion. The downdrift beach has been eroded severely since 2009, even though the bypassed volumes have exceeded the optimum value for previous years. Increased erosion is likely related to extra-tropical storm impact, (i.e. Hurricane Felix 1995; Hurricane Irene in 2011; and Hurricane Sandy in 2012). Numerical simulation of hydrodynamics and sediment transport of inlet-adjacent areas is one of the most efficient ways to study the behavior of the downdrift beach to varying forcing boundary conditions. Here, we used a numerical model including sediment transport coupled with a wave model and a nearshore circulation model to meet the goals of this study. The major goal is to estimate the sediment transport rate variability under the effect of dominant and different directional waves to determine the important processes for downdrift beach erosion. Finally, we included the characteristics of Hurricane Felix (1995) within the model to obtain the results for a severe condition.
COASTAL FORUM: REGIONALITY: THE PATH TO A MORE SUSTAINABLE WATER RESOURCE FUTURE Howard Marlowe and Daniel Greene
This article highlights the significant benefits of budgeting, planning, and implementing U.S. Army Corps of Engineers’ (Corps) water resources projects on a regional (rather than a project-by-project) basis. The change is required because of two crucial developments. First, the Corps’ civil works budget has declined more than 16% in real terms since 2006. As a result of shrinking Corps budgets, critical water resources are precluded from receiving essential maintenance and crucial new projects are prevented from being constructed. Concurrently, the federal government’s approach to budgeting, planning and maintaining each individual water resource project needlessly drives up project costs and fails to properly manage our nation’s water resource needs. A regional approach to the Corps’ projects will extend the Corps’ constrained funding by cutting dredge mobilization costs, economically utilizing dredged material throughout regions, and coordinating administrative procedures and regulations across water resource agencies. In doing so, the Corps will be able to meet the nation’s water resource needs more effectively and efficiently.
COASTAL OBSERVATIONS: EVERETT HARBOR AND JETTY ISLAND, PUGET SOUND, WASHINGTON Andrew Morang and Ashley E. Frey
O’BRIEN AWARD WINNERS: AN INTERVIEW WITH RICHARD “SKIP” DAVIS Michael J. Starek
ASBPA 2014 NATIONAL COASTAL CONFERENCE CALL FOR ABSTRACTS
THE ASBPA’S SEVENTH ANNUAL PHOTOGRAPHY CONTEST
THE 2013 ASBPA PHOTO CONTEST WINNERS