Introduction

Methods

Sand and Beach Morphology Sediment Students and faculty at CSUCI explored the relationship between wave

energy, beach morphology, and sediment variability over three weeks in early summer of 2013. Beach morphology was directly correlated with wave energy. Wave energy itself is derived from wind, wave height, wave period, wave direction, wave type and tide, all of which fluctuates throughout the day. This study is the first step towards helping us understand how beach morphology (shape and structure) will respond to future energy fluctuations and disturbance. We measured 15 profiles and collected, sieved and analyzed 80 sediment samples from 5th Street, Ormond Beach, Water Canyon (Santa Rosa Island), Becher’s Bay (Santa Rosa Island), Paradise Cove, and Deer Creek East Beach. Our long term goal is to observe the effects of sea level rise, overgrazing by livestock, erosion, sedimentation, beach grooming, and human disturbances. We hypothesize that the removal of herbivores from Santa Rosa Island will increase vegetation extent and structure, leading to a decrease in erosion and reduced sediment supply to the beach.

Key Questions:

Does sediment variability play a role in beach slope?

How does energy affect beach slope?

How does energy affect sediment distribution?

1. Energy Monitoring •  Wave Height (ft) •  Wave Period (s) •  Wave Direction (˚) •  Wave Type (plunge, spilling, collapsing, etc.)

2. Survey Beach Profiles •  Establish Benchmark •  Backsight (BS) •  Height of Instrument (HI) [BS + Elevation] •  Foresight (FS) •  Elevation [HI – FS] •  Plot beach profiles

3. Collect and Analyze Sediment

Mean Grain Size: The beach is a changing accumulation of sediments and the beach profile results from prevailing wave conditions and sediment supply. The mean size of the sediments at any given time may be used to decipher how much energy there is in waves or currents and the conditions under which they have been deposited. Sorting: Sorting refers to the uniformity of grain size in a sediment. Particles become sorted on the basis of density because of the energy of the transporting medium. High energy currents tend to carry larger fragments. As the energy decreases, heavier particles are deposited and lighter fragments continue to be transported. This is why beach sands tend to be well-sorted. The energy of the waves or wind is usually relatively constant leading to finer grained sediments carried by wave or wind to the beach. As energy increases sediment sorting decreases.

Monitoring Sandy Beaches: Geomorphology & Sedimentation Claira Castillo, Laura Weber, Jasmin Guerrero, Daniel Hernandez, Danielle Johnson, Ariana Ornelas, Chelsey Ballot, James Wright

Dr. Linda O’Hirok, Dr. Sean Anderson, Dr. Donald Rodriguez Project Acceso 2013 Summer Reh Institute searc

email: linda.ohirok@csuci.edu

Literature Cited Dugan, J. E., Hubbard D. M., and Davis G. E. 1990. Sand Beach and Coastal Lagoon Monitoring Handbook. Channel Islands National Park, California. National Park Service, Channel Islands National Park, Ventura, California. December, 1990. Dugan, J. E., Hubbard D. M., Engle J. M., Martin D. L., Lafferty K. D., Ambrose R. F., Richards D. M., and Davis G. E. 2000. Macrofauna Communities of Exposed Sandy Beaches on the Southern California Mainland and Channel Islands. Proceedings of the 5th California Islands Symposium. OCS Study, MMS 99-0038: 339-346. Dugan, J.E. 2006. Utilization of Sandy Beaches by Shorebirds: Relationships to Population Characteristics of Macrofauna Prey Species and Beach Morphodynamics. Final Report. Minerals Management Service, U.C. Coastal Marine Institute. Prepared under MMS Cooperative Agreement No.14-35-0001-30758 Folk, R. L. 1974. Petrology of Sedimentary Rocks. Austin, TX: Hemphill Publishing Company. Komar, P. D. 1976. Beach Processes and Sedimentation. Englewood Cliffs, NJ: Prentice- Hall, Inc.

Acknowledgements Funding for this monitoring effort was provided by an HSI STEM Grant from the U.S. Department of Education (via Project ACCESO Title V). Additional support came from our CSUCI Santa Rosa Island Field Station and the National Park Service. This work could not have been completed without the efforts of James Wright and Chelsey Ballot.

5th Street 3-Dimensional Beach Profile Model

Upper Beach

Berm

Lower Beach

Ocean

Model depicts three transect lines 20

meters apart and ~ 65 meters in length

This model illustrates a small

beach cusp consisting of an

embayment surrounded by two

higher elevation horns

• weak positive trend between slope & energy

•  as wave energy increases, the beach steepens

• Paradise Cove anomaly possibly driven by storm swell prior to our survey

•  distinct energy & slope difference between the island & mainland beaches

•  positive trend for the mainland beaches

•  neutral trend for the island beaches

•  both island beaches

are located on a river mouth, leading to higher variation in sediment sizes

• positive trend in particle size on island

• positive energy trend on the mainland

•  lower energy on island beaches, may be driven by aspect and beach location

• positive energy trend among mainland beaches with relation to particle size

• more beaches now need to be visited

Energy and Beach Morphology