Beaches and shorelines, guidelines for monitoring ...

BEACHES AND SHORELINES GUIDELINES FOR MONITORING, DATA COLLECTION & EVALUATION SKILLS FOR DEVELOPMENT

5-9 February 2001 University of the South Pacific (USP) Lower Campus/Marine Studies Programme (MSP), Laucala Bay Suva, Fiji Islands

Russell J. Maharaj Commonwealth Secretariat/CFTC Expert SOPAC Secretariat Suva, Fiji Islands

SOPAC Training Report 91

2

Capacity Building and Technical Training: Beaches - Monitoring and Evaluation

TABLE OF CONTENTS Page Number

ABSTRACT

3

ACKNOWLEDGEMENTS

4

1.0

INTRODUCTION 1.1 General Comments 1.2 Background

5 5 9

2.0

SCOPE OF TRAINING 2.1 Introduction 2.2 Programme Outline 2.3 Resource Material 2.4 Follow-up Training and Advice

10 10 15 19 20

3.0

SOURCES OF INFORMATION

21

4.0

BIBLIOGRAPHY

22

APPENDIX I: SOPAC Task Profile APPENDIX II: Nearshore Processes APPENDIX III: Various Publications

SOPAC Training Report 91, 2001: Russell J. Maharaj

28 29 67


3

ABSTRACT The following is a transcript and a report of a Capacity Building and Coastal Technology Transfer initiative conducted by the South Pacific Applied Geoscience Commission (SOPAC Secretariat) for the Government of the Fiji Islands. The technology-transfer exercise was conducted via a technical training programme organized for eight (8) Fiji Islands Government departments, in the field of Coastal Management and Engineering. The training was focused on Beaches and Shorelines: Guidelines for Monitoring, Data Collection and Evaluation (SOPAC Task 2001.001). The project was formulated after a request was made by the Department of Environment (DOE), Government of the Fiji Islands, for structured training in the said area. The author, through SOPAC, has consulted for the Department of Environment on several previous occasions, advising on land reclamation, coastal protection, coastal developments and the environmental impacts of foreshore development in the Fiji Islands. During these consultations, the Department of Environment expressed the need for further technical resources and guidelines, which would enable them to evaluate proposals for coastal foreshore development. This capacity building initiative was subsequently formulated to meet the requirements of the DOE. A SOPAC project was formulated and after consultations with DOE, the training scope and level was agreed upon. It was suggested by the author, and further agreed, to include other Fiji Government ministries and departments, which work and have responsibilities for various aspects of the coastal environment, land reclamation, coastal construction and infrastructure, planning and national project development. To that end, a total of eight (8) Fiji Government departments were invited, and actively participated in the training program. These departments were:

1. 2. 3. 4. 5. 6. 7. 8.

Land & Water Resources Management Division Department of Lands & Survey Mineral Resources Department Fisheries Division Department of Town & Country Planning Public Works Deptartment Fiji Islands Maritime Administration Department of Environment

The DOE coordinated the selection and nomination of Government department representatives to attend the training. The individuals who attended the workshop were nominated by the respective Government departments. These lectures were delivered between 5-8 February 2001, at the University of the South Pacific (USP), Lower Campus, Laucala Bay, Suva. Fiji Islands. The lectures discussed the need for understanding beaches, beach dynamics and neashore processes within the framework of coastal hazards and risks. Erosion and erosion processes were discussed, as well as hydrodynamic aspects of nearshore environments. Engineering in the coastal zone was presented, within the framework of the coastal project cycle. Examples of coastal engineering projects were discussed. In addition, coastal protection structures were examined in the field and issues related to the appropriateness of these were highlighted. Construction material used along the shorefront was discussed, in particular, concrete and rip-rap and their performance in coastal environments. Issues related to optimum coastal management and engineering



4

were also discussed. A full list of up-to-date and state-of-the-art references on the subject is also given and is included in this report. Each participant was given the following copies of technical resource material for their use and reference:

1.

Maharaj, R. J. 2000. Guidelines for monitoring and evaluating beach erosion and shoreline dynamics. SOPAC Training Report 84. SOPAC Secretariat, Fiji. 190 pp/9.512 MB, CD-ROM Version. The manual was supplied as an Adobe Acrobat file on CD-ROM, together with Adobe Acrobat Reader Version 4.0, in addition to a printed, paper copy. This publication, also by the author, is not included in this report, as it is available separately from the SOPAC Secretariat Library or via the internet at: www.sopac.org.fj/Data/virlib/index.html

2.

Ed Thornton, Tony Dalrymple, Tom Drake, Edie Gallagher, Bob Guza, Alex Hay, Rob Holman, Jim Kaihatu, Tom Lippmann, Tuba Ozkan-Haller, 2000. State of Nearshore Processes Research: II. Technical Report NPS-OC-00-001, Naval Postgraduate School. Monterey, California, USA. This publication provides a good assessment of nearshore processes, with ample references for further reading and supplements the previous publication, SOPAC Training Report 84. This publication is included in this report as Appendix II, with full authorship and bibliographic referencing included.

3.

In addition, several other key papers were provided that cover the subject areas of the workshop. These are all appended in a single section, Appendix III, though not in digital format. Several of these papers are complete in themselves, and serve as good references for coastal management and engineering application.

Following the training workshop, Fiji was impacted by tropical cyclone Paula. In the aftermath of the cyclone, which caused erosion, damage to coastal property, infrastructure and villages, the author organised a field trip on 7 March 2001 for the same course participants, and informed the Fiji Islands national representative to SOPAC of the same (SOPAC Reference: TECHSEC: 209/COU/2.4). Sites along the Coral Coast, Viti Levu, were chosen, as they were easily accessible and were severely impacted. SOPAC Secretariat provided transport to and from the field. In addition, these impacted areas were the chosen sites for the field training and demonstration exercises and therefore, a post-cyclone evaluation provided good indication of the possible impacts that can result from constructing along the shorefront. During the training, a storm wave (as was experienced during cyclone Paula) was simulated for the same areas (based on atmospheric pressure of cyclones which have affected Viti Levu over the past 50 years), and the impacts on coastal protection and infrastructure highlighted. It is significant to note that, the predicted damage and failures were the same as that which occurred during cyclone Paula, especially for the Sigatoka road by-pass (next to the Outrigger Hotel). This, in addition to the problems of coastal construction, coastal protection failures, beach erosion and the risk associated with coastal development were highlighted during the follow-up, post-Paula field trip. Following the post-Paula field trip, the author also prepared a bound volume of technical guidelines and information on coastal management, engineering and standards for environmental monitoring, testing, and compliance, including ISO 9000 and ISO 14000 series. These were sent to the DOE (SOPAC Reference TECHSEC: 212/COU/2.4).



5

ACKNOWLEDGEMENTS The participation and delivery of this training was facilitated by the Commonwealth Secretariat (COMSEC) and South Pacific Applied Geoscience Commission (SOPAC) Secretariat. This project was funded and supported by the Commonwealth Secretariat (COMSEC) the Commonwealth Fund for Technical Co-operation (CFTC) and the Department for International Development (DFID), Government of the United Kingdom. This project was executed under SOPAC Project FJ 2001.001. Ms. Premila Kumar, and Mr. Mohammed Famaz Khan of the Department of Environment (DOE), Government of the Fiji Islands, coordinated the training/lectures. Their assistance is gratefully acknowledged.



6

1.0 INTRODUCTION 1.1 General Comments and Background The following is a report of in-country capacity building and technical training delivered at the University of the South Pacific, Lower Campus, Marine Studies Department, Suva, for the Government of the Fiji Islands. The training was on Coastal Processes and is SOPAC Task 2001.001 (Appendix 1) and was focused on Beaches and Shorelines: Guidelines for Monitoring, Data Collection and Evaluation. The project was formulated after a request was made by the Department of Environment (DOE), Government of the Fiji Islands, for structured training in the said area. The author, through SOPAC, has consulted for the Department of Environment on several previous occasions, advising on land reclamation, coastal protection, coastal developments and the environmental impacts of foreshore development in the Fiji Islands. During these consultations, the Department of Environment expressed the need for further technical resources and guidelines, which would enable them to evaluate proposals for coastal foreshore development. This capacity building initiative was subsequently formulated to meet the requirements of the DOE. A SOPAC project was formulated and after consultations with DOE, the training scope and level was agreed upon. It was suggested by the author, and further agreed, to include other Fiji Government ministries and departments, which work and have responsibilities for various aspects of the coastal environment, land reclamation, coastal construction and infrastructure, planning and national project development. To that end, a total of eight (8) Fiji Government departments were invited, and actively participated in the training program. These departments were: ü ü ü

ü ü ü ü ü

Land & Water Resources Management Division Department of Lands & Survey Mineral Resources Department Fisheries Division Department of Town & Country Planning Public Works Deptartment Fiji Islands Maritime Administration Department of Environment

The DOE coordinated the selection and nomination of Government department representatives to attend the training. The individuals who



7

attended the workshop were nominated by the respective Government departments. These lectures were delivered between 5-8 February 2001, at the University of the South Pacific (USP), Lower Campus, Laucala Bay, Suva, Fiji Islands. There were twelve (12) participants at this course:

E

Mr Jone Feresi Senior Agriculture Officer Land & Water Resources Management Division Ministry of Agriculture, Fisheries and Forests Robinson Complex Grantham Rd Raiwaqa PO Box 1292 SUVA. Fax: 383 546

Mr Mesake T. Senibulu Senior Surveyor Department of Lands & Survey PO Box 2222 Govt. Bldgs. SUVA. Fax: 301 720

Mr Isei Rayawa Technical Officer II Mineral Resources Department Private Mail Bag GPO SUVA. Fax: 370 039



Mr Iliapi Tuwai Senior Research Officer Acting, Fisheries Division PO Box 3165 Lami Fax: 361 184

Mr Muni Ratnam Goundar Acting Principal Marine Officer Fiji Islands Maritime Administration Box 326 Walu Bay SUVA. Fax: 303 251

Mr Aisake Raratabu Technical Officer 1 Department of Town & Country Planning PO Box 2350 Govt. Bldgs SUVA. Fax: 303 515

Mr Tevita Batiwale Senior Road Engineers Public Works Deptartment Private Mail Bag Samabula Fax:: 386 759

Mr Altaf Ali Senior Road Engineers Public Works Deptartment Private Mail Bag Samabula Fax: 386 759


8


9

Capt. Felix R. Maharaj Chief Hydrographer Fiji Islands Maritime Administration GPO Box 326 SUVA. Fax: 303 251

Mrs Eleni Tokaduadua Environment Awareness Officer Department of Environment PO Box 2131 Govt. Bldgs SUVA. Fax: 312 879

Mrs Premilla Kumar Senior Environmental Officer Department of Environment PO Box 2131 Govt. Bldgs SUVA. Fax: 312 879

Mr Mohammed Famaz Khan Project Officer Department of Environment PO Box 2131 Govt. Bldgs. SUVA. Fax: 312 879

1.2 Background – Skills for Development The Pacific Ocean is dotted with thousands of coral atoll islands, many of which are inhabited along coastal strips and foreshore areas and used for various socio-economic activities, ranging from nearshore fishing to aggregate extraction. In the region which is serviced by the South Pacific Applied Geoscience Commission (SOPAC), there are sixteen (16) small island developing



10

states (SIDS), occupying a total land area of about 560,000 km2, in 26 Million km2 of the Pacific Ocean (Table 1). These SIDS are the Cook Islands, the Federated States of Micronesia, Republic of the Fiji Islands, French Polynesia, Guam, Kiribati, Republic of the Marshall Islands, Nauru, New Caledonia, Niue, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu and Vanuatu. Many of these SIDS consist of coral atoll islands and are geologically young (Table 2), have low elevations above mean sea level and are generally flat. Elevation ranges from 1-5 m above mean water level and it is possible to see from one side of the island to the other. This makes these islands entirely coastal, in terms of their influence by the sea, their geographical disposition and their relative relief. As a result of their small land area, which can be between 0.0028 to 14.81% of their surrounding maritime area, many Pacific SIDS are exposed to large-scale regional oceanographic and weather phenomena. Frequent and annual events include cyclones and storms. These wreck havoc along the coastal and inland areas of many of these coral atoll islands, usually resulting in damage and destruction of coastal property, agricultural land and coastal engineering facilities. These also cause coastal flooding, coastal erosion/land loss and in some cases, loss of life. For many SIDS, the loss of lives can erode the skills base of the country and can prove to be a hindrance to economic development, causing persistent and undue poverty. The scale of many natural hazards in PICs, are in many cases, several orders of magnitude larger than the size of individual islands and consequently, are capable of engulfing entire island states. Typical examples are cyclones, which caused considerable damage to infrastructure and property (Table 3). On account of their small size and geographic location within a large ocean space, Pacific SIDS are continually affected by large ocean waves. These cause continuous erosion of coastlines, even under normal wave climate. In addition, the frequency of oceanographic hazards, modification of coastlines for human habitation and the mining of aggregate along the shore make many of these islands and communities vulnerable to coastal erosion. Oceanographic hazards and the possible threat of global warming and associated sea-level rise, in these low, small island countries, can also exacerbate the erosion hazard. Consequently, population and communities along the coastal fringes of these island states are vulnerable and face a possible threat to their very existence. These natural events and human occupation of fragile coastal areas can cause loss of scarce land, a culturally important and invaluable resource in many on these non-


11


market oriented developing economies. With Pacific SIDS having an average poverty rate of 15 %; GNP/capita between US $2,210 to ≤ $760; GNP from less than US $96 to $1,748 Million and external debt (as a % of GNP) as high as 56 %, any loss of land and damage to infrastructure and facility can seriously impair national and regional economic development (Table 1).

Table 1. Some demographic and economic indicators for Pacific SIDS (Maharaj, 2001d). SIDS

Fiji Islands New Caledonia Papua New Guinea Solomon Islands Vanuatu FSM Guam Kiribati Marshall Islands Nauru Cook Islands French Polynesia Niue Samoa Tonga Tuvalu

Land Area km²

EEZ, Million km²

Population, Thousands (1998-1999)

Population Growth, %/yr (1990-2000)

Population Density, Nos./km²

GNP, $ US Millions (1999)

GNP/Capita, $ US (1998-1999)

18,333

1.29

790

1

43

1,748

2,210

International Tourism, $ US Millions (1998) 266

18,576

1.74

207

3

11

NA

High Income

110

462,243

3.12

4,603

2.6

10

4,104

890

75

28,370

1.34

416

3.7

15

315

750

13

12,190 701 541 811 181

0.68 2.978 0.218 3.55 2.131

183 113 149 86 62

3.1 2.4 1.5 2.5 4.2

15 161 275 106 342

231 204 NA 101 96

1,170 1,810 High Income 910 1,560

45 NA 1,378 NA 3

21 237

0.32 1.83

9,919 19,103

1.8 -0.5

472 81

NA NA

NA NA

NA NA

3,521

5.03

227

2

64

NA

High Income

354

259 2,935 649 26

0.39 0.12 0.7 0.9

2.088 169 99 9,043

-3.1 0.8 0.4 0.9

8 58 153 348

NA 181 173 NA

NA 1,060 1,720 NA

NA 39 12 NA

Table 2. Pacific Island types and numbers (Maharaj, 2001d) SIDS

Island Type/s

Number of Islands

Fiji Islands New Caledonia Papua New Guinea Solomon Islands Vanuatu FSM Guam Kiribati Marshall Islands Nauru Cook Islands French Polynesia Niue Samoa Tonga Tuvalu

High island with many atolls Elevated coral with reefs High island with few atolls High island with few atolls High islands Atolls and few high islands Elevated coral, atolls with reefs Many atolls and elevated coral Many atolls Elevated coral and reefs High island and many atolls High islands and reefs Elevated coral and atolls High islands and atolls Many atolls High islands and many atolls

320 islands, with less than 12 high islands 12 islands Over 600 islands 992, with 6 large islands and many small low-lying ones 80 high islands 607 low-lying atoll islands, with four volcanic ones 1 emergent island 33 low-lying atolls 34 low-lying atoll islands and 870 reefs 1 emergent coral island 20 islands in 2 main groups, several are low-lying atolls 118 islands in 5 main groups 1 emergent island 2 main islands and 6 smaller ones 171, in 4 major island groups 9 low-lying atolls

Table 3. Some cyclones affecting the south Pacific (Maharaj, 2001d) DECADE 1939-1979 1990-1999 TOTAL

Oct/Nov 15 7 22

Dec 42 7 49

Jan 77 13 90


Feb 86 10 96

Mar 67 20 87

Apr-Jun 36 5 41

TOTAL 285 62 347


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In it’s 1997 flagship publication, A Future for Small States: Overcoming Vulnerability, the Commonwealth Secretariat, highlighted the fragility and susceptibility of many of these SIDS to natural disasters, including coastal hazards like sea-level rise and their associated effects, in particular, coastal erosion and coastal land loss. In turn, problems like coastal hazards, affect economic and social development in developing SIDS economies and make them economically vulnerable. This point was also highlighted and discussed in an Interim Report of a Joint World Bank/Commonwealth Secretariat Task Force on Small States: Meeting the Challenge in the Gobal Economy, 1999 and at the Commonwealth Heads of Government Meeting (CHOGM) 1999, Durban, South Africa. The fragility and vulnerability of the PICs to coastal and sea level rise hazards (Maharaj, 1999g and h) have also been the subject of key thematic sessions at the recent Conference of Parties Meetings, Bonn, Germany (COP-5), November 1999 and The Hague (COP-6), November 2000 respectively. At the 10th Subsidiary Bodies on Scientific and Technological Advice (SBSTA), Bonn, Germany, June 1999, the United Nations Framework Convention on Climate Change (UNFCCC) Secretariat also highlighted that coastal adaptation measures to sea-level rise (Maharaj, 1999k, 2000a, b and g) are key issues which needs to be addressed, especially in the context of Small Island Developing States (SIDS). This sentiment was also echoed at the Alliance of Small Island States (AOSIS), July 1999 Meeting in Majuro, Republic of the Marshall Islands and the World Science Congress, Budapest, 1999 and by the UNFCCC Secretariat, Bonn, Germany. To address current and future erosion problems and the possibly deleterious effects of sea-level rise in Pacific SIDS, requires assessment of site specific, local and regional environmental conditions. This also facilitates a rational approach to management of island resources. It is also necessary to understand the factors, which influence erosion susceptibility on these islands through time and space. This can be achieved only through a systematic and integrated approach, with sound data collection, analysis and management exercises. Only then, can optimum environmental and sustainable development strategies be formulated. This approach also facilitates the development of appropriate coastal adaptation technologies for anticipated sea-level rise and climate change. SOPAC, since it’s inception in 1972, has worked in the coastal and marine environment in the South and Central Pacific region. This includes work on coastal erosion and management, coastal natural hazards, bathymetry and hydrography and physical oceanography.



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In the fulfilment of its mandate, to provide technical expertise and advice to Pacific Island Countries (PICs) on these and related issues, SOPAC has completed many projects in these technical areas, to address development initiatives of PICs and fill data gaps. This is exemplified in the range of projects, which are included in its fiscal year’s work programme. These include projects on the assessment of the vulnerability to sea level rise, assessment of shoreline change, assessment of coastal adaptation strategies for anticipated sea-level rise and evaluation of aggregate potential. For many SOPAC member countries, in-country technical skills are generally unavailable, while technical guidelines and codes of professional practice are lacking. This lack of information and resources can seriously impair effective and timely management of island resources and development within PICs. In addition, the lack of a sound skills base also handicaps social and economic reforms and national development, which can contribute to persistent poverty. Capacity building and technology transfer are two key areas, which can effectively build national capacity. Providing timely and technically sound advice, and imparting appropriate technology to national counterparts contribute to the development of the growing skills base within countries and the Pacific region. These pave the way for optimum management of island resources and for opportune management of development projects in Pacific SIDS; in turn contributing to the social-economic development of the region. The technical training presented during this workshop and subsequently described in later sections, provides a sound base for the development and transfer of coastal monitoring technology to island nationals.

2.0 SCOPE OF THE TRAINING 2.1 Introduction To address the coastal erosion concerns and management needs of the Fiji Islands, it is first necessary to evaluate the existing nature of the coastal environment (Maharaj, 2001a). As mentioned earlier, for many Pacific SIDS and SOPAC member countries, technical know-how is generally unavailable, while technical guidelines and codes of professional practice are lacking. In many cases, where these information do exist, they are sometime too technical for the generally user, with responsibility for various aspects of the coastal environment, while in some cases, information may be over simplified.



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Empowerment of technical skills is one means of effectively addressing national environmental problems and development issues in country. To address this skill deficiency, a project was formulated by SOPAC Secretariat, with funding from the Commonwealth Secretariat (COMSEC) under the Commonwealth Fund for Technical Co-operation (CFTC) and the Government of the United Kingdom (UK) to prepare and present technical guidelines for the collection, analysis and management of data on beaches and shorelines, with emphasis on the effective management of island (= coastal) resources. This manual is one of the outputs from this project. The target audience is the group of Government professionals, working in the various marine resources, natural resource, environmental, engineering, planning, surveying and geological departments and environmental protection agencies in the Fiji Islands with responsibility for the coastal and marine environments. The content of the training programme is technical, but not complex nor over-simplified. It caters for the technician and non-specialised and/or beginning professional. It presents technical information in a logical and simplified format, with a focus on simple and important technologies and principles, which can be easily assimilated by the target audience. Simple, but practical, and technically sound methodologies are also presented and discussed, to address the needs of personnel who may not have access to specific or complex, expensive and in-accessible monitoring equipment. The lectures discussed the need for understanding beaches, beach dynamics and nearshore processes within the framework of coastal hazards and risks and shoreline management. Erosion and erosion processes were discussed, as well as coastal hydrodynamics. Engineering in the coastal zone was presented, within the framework of the coastal project cycle. In addition, case studies of coastal engineering were discussed, using examples of the recently constructed Sigatoka road bypass on the Coral Coast, Viti Levu. Examples of wave run-up and erosion, scouring, rip-rap stability and embankment stability under normal and storm (cyclone) wave attack was presented and discussed. This was done using ACES and CRESS coastal engineering software. In addition, sea walls, gabion baskets, concrete structures and bioengineering coastal protection were discussed and presented. Issues related to optimum coastal management and engineering were also discussed. A full list of up-to-date and state-of-the-art references on the subject was also given and is included at the end this report, Section 4.0.



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More specialised technical evaluation methodologies, design criteria or risk evaluation methodologies, on any of the subjects described in the subsequent text, is available by contacting the author at SOPAC Secretariat, Fiji at, www.sopac.org.fj or [email protected] This capacity building initiative was delivered and executed under SOPAC Project FJ 2001.001.

2.2 Programme Outline and Structure The following is an outline of the training activity.

Slide 1

BEACHES WORKSHOP MONITORING & EVALUATION

SOPAC PROJECT TASK FJ 2001.001

Russell J. Maharaj Commonwealth Secretariat/CFTC Expert SOPAC SECRETARIAT Suva Fij Islands

Contact SOPAC www. sopac.org.fj

5-9 February 2001 USP, Suva, Fiji



Slide 2

WORKSHOP DETAILS Day 1 - Monday Morning 0900-1045 hours o What is coastal engineering & managementscope? Coastal morphology and processes. 1045-1200 hours o Why monitor the coast and beach - hazards and risks?

4/18/01 10:09:15 AM

Russell J. Maharaj

Slide 3

WORKSHOP DETAILS Day 1 - Monday Afternoon 1300-1345 hours o What is coastal erosion and what to do about it? Erosion assessment. 1400-1500 hours o Introduction to water levels, waves, tides & longshore currents - hydrodynamics. 4/18/01 10:09:16 AM

Russell J. Maharaj


16


Slide 4

WORKSHOP DETAILS Day 2 - Tuesday Morning: 0900-1030 hours o Beach monitoring programs and data collection detailed examination of programme setup. Afternoon: 1300-1400 hours o Coastal/littoral data collection & o Data analysis and query. 4/18/01 10:09:18 AM

Russell J. Maharaj

Slide 5

WORKSHOP DETAILS Day 3 - Wednesday Morning: 0900-1030 hours o Coastal construction & shoreline protection: discussion of structural measures - rip rap, seawalls, groynes, pitched slopes; Afternoon: 1300-1500 hours o Material in coastal protection (testing & evaluation); design guidelines and maintenance of structures. 4/18/01 10:09:20 AM

Russell J. Maharaj


17


Slide 6

WORKSHOP DETAILS Day 4 & 5 - Thursday & Friday Thursday Field Trip: o Coastal erosion construction & shoreline protection: Suva peninsula. Friday Field Trip: o Coastal erosion construction & shoreline protection: Coral Coast. 4/18/01 10:09:21 AM

Russell J. Maharaj

Slide 7

RESOURCE MATERIAL Handouts to Be Distributed o Beaches guidelines/manual; o Examples of needs for monitoring beaches: sealevel rise and coastal risks and hazards (two papers); o Beach profile data examples; o Surf-zone hydrodynamics chart; o Grain-size classification of sediments/soils Table; 5/17/01 8:51:53 AM

Russell J. Maharaj


18


19

Slide 8

RESOURCE MATERIAL Handouts… o Saffir/Simpson hurricane scale, coastal terminology, swash zone morphology, beach water table and water flow, data collection program, hydraulic boundary conditions, EIA’s and beach projects, impact of beach structures, mitigation measures, groyne construction material, guidelines for application of beach control works, impact of seawalls, reasons for failure of vertical seawalls, concerns related to armoring, impact of seawalls, groyne terminology, problems with groynes and beach structures, engineering options and their problems. 4/18/01 10:09:25 AM

Russell J. Maharaj

2.3 Resource Material Each participant was given the following copies of technical resource material for their use and reference:

E Maharaj, R. J. 2000. Guidelines for monitoring and evaluating beach erosion and shoreline dynamics. SOPAC Training Report 84. SOPAC Secretariat, Fiji. 190 pp/9.512 MB, CD-ROM Version. The manual was supplied as an Adobe Acrobat file on CD-ROM, together with Adobe Acrobat Reader Version 4.0, in addition to a printed, paper copy. This publication, also by the author, is not included in this report, as it is available separately from the SOPAC Secretariat Library or via the internet at: www.sopac.org.fj/Data/virlib/index.html



20

E Ed Thornton, Tony Dalrymple, Tom Drake, Edie Gallagher, Bob Guza, Alex Hay, Rob Holman, Jim Kaihatu, Tom Lippmann, Tuba OzkanHaller, 2000. State of Nearshore Processes Research: II. Technical Report NPS-OC-00-001, Naval Postgraduate School. Monterey, California, USA. This publication provides a good assessment of nearshore processes, with ample references for further reading and supplements the previous publication, SOPAC Training Report 84. This publication is included in this report as Appendix II, with full authorship and bibliographic referencing included. The abstract of this publication has been shortened and the format of the paper modified, for consistency, to suit the style of this report.

E In

addition, several other key papers were provided and cover the subject areas of the workshop. These are all included in a single section, Appendix III, though not in digital format.

Several of these papers are complete, and serve as good references for coastal management and engineering application.

2.4 Follo-Up Training and Advice Following the training workshop, Fiji was impacted by tropical cyclone Paula. In the aftermath of the cyclone, which caused erosion, damage to coastal property, infrastructure and villages, the author organised a field trip on 7 March 2001 for the same course participants, and informed the Fiji Islands national representative to SOPAC of the same (SOPAC Reference: TECHSEC 209/COU/2.4). Sites along the Coral Coast, Viti Levu, were chosen, as they were easily accessible and were severely impacted. SOPAC Secretariat provided transport to and from the field. In addition, these impacted areas were the chosen sites for the field training and demonstration exercises and therefore, a post-cyclone evaluation provided good indication of the possible impacts that can result from constructing along the shorefront.



21

During the training, a storm wave (as was experienced during cyclone Paula) was simulated for the same areas (based on atmospheric pressure of cyclones which have affected Viti Levu over the past 50 years), and the impacts on coastal protection and infrastructure highlighted. It is significant to note that, the predicted damage and failures were the same as that which occurred during cyclone Paula, especially for the Sigatoka road bypass (next to the Outrigger Hotel). This, in addition to the problems of coastal construction, coastal protection failures, beach erosion and the risk associated with coastal development were highlighted during the follow-up, post-Paula field trip. Following the post-Paula field trip, the author also prepared a bound volume of technical guidelines and information on coastal management, engineering and standards for environmental monitoring, testing, and compliance, including ISO 9000 and ISO 14000 series. These were sent to the DOE (SOPAC Reference TECHSEC:212/COU/2.4).

3.0 SOURCES OF INFORMATION The ideas and rationale for the beach monitoring guidelines are based on the author’s experience in the Pacific and in other parts of the world. This also stems from numerous discussions between the author and Governmental agencies throughout the SOPAC Member Countries. Discussions were valuable with Government Departments in the Federated States of Micronesia, including the States of Yap, Pohnpei, Chuuk and Kosrae and island residents in more than twenty-five atoll islands in the FSM territorial waters. In addition, valuable discussions were held between SOPAC and other Government representatives of Republics of Kiribati and Fiji and the Cook Islands, on the need for these types of technical guidelines. The technical material presented is based on the author’s professional experience and consultation with state-of-the-art professional material available in published literature. These literature, are cited at the end of the text, and for the keen and enthusiastic reader, should provide ample and valuable further reference on this and related subjects. It was not the intention of the author to provide an exhaustive list of methodologies in these guidelines, but to provide representative and appropriate examples, which are valuable and useful within the framework of project development in Kiribati.



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4.0 BIBLIOGRAPHY ASTM, 1999. Annual Book of ASTM Standards. Soil, Rock, Building Stones and Geotextiles. ASTM, Philadelphia. Barrett, P. J. 1988. Report on Phosphate, other Minerals and Groundwater Resources and on Aspects of Rehabilitation Planning and methodology, Nauru, Pacific Ocean. Commission of Inquiry into the Rehabilitation of the Worked-Out Phosphate lands of Nauru, 9, D946-D999. Bowders, J. J., Scranton, H. B. and Brodreick, G. P. 1998. Geosynthetic in Foundation Reinforcement and Erosion Control Systems. ACSE Geotechnical Special Publication No. 766. ASCE Press, Virginia. CIRIA, 1991. Manual of the Use of Rock in Coastal and Shoreline Engineering. CIRIA Special Publication 83 & CUR Report 154. A. A. Balkema, Rotterdam. CIRIA, 1996. Beach Management Manual. CIRIA Special Publication 153. CIRIA, London. Geological Society of London (GSL), 1999. Stone: Building Stone, Rock, Fill and Armourstone in Construction. Geological Society of London Engineering Geology Special Publication, 16. Hamnett, M. P. 1992. Natural Disater Mitigation in Pacific Island Countries. South Pacific Disaster Reduction Programme Report RAS/92/360, UNDP/UNDHA. Herbich, J. B. 1991. Handbook of Coastal and Ocean Engineering. Volumes 1 & 2. Gulf Publishing, New York. Hudson, R. N. 1958. Design of quarry stone cover layers for rubble mound breakwaters. U. S. Corps of Engineers, Waterways Experiments Station Research Report 2-2. Ignold, T. S. 1994. Geotextiles and Geomembranes Manual. Elsevier Advanced Technology, Oxford. IHE-Delft, 1999. CRESS: Coastal and River Engineering Support System, Version 7.00. IHE, Delft. ISRM, 1981. Rock Characterization Testing and Monitoring. Pergamon, Oxford. Jacobson, G. and Hill, P. J. 1993. Groundwater and the rehabilitation of Nauru. In: G. Mcnally, M. J. Knight and R. Smith (eds.), Collected Case



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Studies in Engineering Geology, Hydrogeology and Environmental Geology. Geological Society of Australia/ Butterfly Books, Sydney. Pp. 13-119. Lamberti, A. (ed.), 1992. Design and Reliability of Coastal Structures. TECHWARE, Technoprint, Bologna, Italy. Latham, J.P. (ed.) 1998. Advances in Aggregate and Armourstone Evaluation. Geological Society, London, Engineering Geology Special Publication, 13. Maharaj, R. J. 1998. Assessment of Coastal Erosion Problems in the Outer Atoll Islands of Pohnpei, Chuuk and Yap States, Federated States of Micronesia. SOPAC Technical Report 268. Maharaj, R. J. 1999a. Coastal erosion in Pacific Small Island Developing States (SIDS) – the need for an approach to integrated coastal management (ICM). CoGeoenvironment News, IUGS Commission on the Environment, June 1999, 15- 19. Maharaj, R. J. 1999b. Coastal Erosion and Shoreline Protection: Needs for an Approach to Sustainable Development and Integrated Coastal Zone Management (ICZM) in Pacific Small Island Developing States (SIDS). Proc. 42nd Annual Mtg. Assoc. Eng. Geol., Salt Lake City, Utah, USA, September 26-29, 1999: 77-78. Maharaj, R. J. 1999c. Coastal Erosion and Management in the Federated States of Micronesia (FSM). SOPAC Miscellaneous Report 347. SOPAC Technical Secretariat, Fiji. Maharaj, R. J. 1999d. Risk assessment in coastal engineering and management in Pacific SIDS. In: K. Crook and P. Rodda (eds). SOPAC 28th STAR Annual Meeting, Abstract Volume. SOPAC Miscellaneous Report 355. Maharaj, R. J. 1999e. Assessment of onshore aggregate resources, Pohnpei, Federated States of Micronesia (FSM). SOPAC Preliminary Report 111. Maharaj, R. J. 1999f. Engineering geological assessment of onshore aggregate resources, Pohnpei, Federated States of Micronesia (FSM). SOPAC Technical Report 301. Maharaj, R. J. 1999g. Report of Presentation of a United Nations Framework Convention on Climate Change (UNFCCC) Technical Paper on Coastal Adaptation Technologies (FCCC/TP/1999/1). SOPAC Miscellaneous Report 332.



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Maharaj, R. J. 1999h. Report of a United Nations Framework Convention on Climate Change (UNFCCC) Experts Meeting on Coastal Adaptation Technologies. SOPAC Miscellaneous Report 322. Maharaj, R. J. 1999i. Coral reef mining and coastal risks in Pacific Small Island Developing States (SIDS). Paper accepted for the 31st International Geological Congress (31-IGC), Rio de Janeiro, Brazil, 6th – 17th August 2000. Maharaj, R. J. 1999j. Appraisal and management of risk in coastal engineering and management. Lecture delivered for the Integrated Coastal Management Course, MS-302, Marine Studies Programme, University of the South Pacific, Laucala Bay, Fiji, 30th August, 1999. 53 MB. Maharaj, R. J. 1999k. Coastal adaptation technologies: response to sea level changes. SOPAC Training Report 79. Maharaj, R. J. 2000a. Coastal adaptation technologies: Pacific Island countries needs and concerns. Paper presented at the Pacific Islands Conference on Climate Change, Climate Variability and Sea-Level Rise. Rarotonga, Cook Islands, 3rd - 7th April 2000. Maharaj, R. J. 2000b. Assessment of Pacific Island Countries (PICs) in relation to climate change and sea-level rise. SOPAC Miscellaneous Report 371. Maharaj, R. J. 2000d. Coral reef mining in Pacific atoll environment. Abstract published in: The ICRI Regional Symposium on Coral Reefs in the Pacific: Status and Monitoring; Resources and Management, 22-24 May 2000. Noumea, New Caledonia. Maharaj, R. J. 2000e. Impact of dredging on reefs in Micronesia. Abstract published in: The ICRI Regional Symposium on Coral Reefs in the Pacific: Status and Monitoring; Resources and Management, 22-24 May 2000. Noumea, New Caledonia. Maharaj, R. J. 2000f. Geology and sustainable development. SOPAC Miscellaneous Report 398. SOPAC Secretariat, Fiji. Maharaj, R. J. 2000g. Guidelines for preparation of an environmental assessment of a diesel power generating plant, Pohnpei, Federated States of Micronesia. SOPAC Technical Report 308. SOPAC Secretariat, Fiji.



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Maharaj, R. J. 2000h. Lectures on coastal hydrodynamics processes and risk in coastal engineering and management. SOPAC Training Report 85. SOPAC Secretariat, Fiji. Maharaj, R. J. 2000i. Guidelines for monitoring and evaluating beach erosion and shoreline dynamics. SOPAC Training Report 84. SOPAC Secretariat, Fiji. Maharaj, R. J. 2001a. Pacific Islands at risk. SOPAC Miscellaneous Report 399. SOPAC Secretariat, Fiji. Maharaj, R. J. 2001b. Coastal engineering design of a rip-rap revetment for shoreline protection, Yaren District, Nauru. SOPAC Preliminary Report 124. SOPAC Secretariat, Fiji. Maharaj, R. J. 2001c. Monitoring and control of coral reef dredging in Pacific Small Island developing States: environmental and engineering implications. In: J. Dobson (ed), Dredging for Prosperity. WODCON/EADA, Kuala Lumpur, Malaysia. CD-ROM, Version 1.0. Maharaj, R. J. 2001d. Pacific Islands at risk: foreshore development and its implications for vulnerability and development of adaptation strategies to climate change. In: N. Mimura (ed), Proceedings of the APN/SURVAS/LOICZ Conference on Coastal Impacts of Climate Change in the Asia Pacific Region, 14-17 November 2000, Kobe, Japan. EAJ and APN, Japan. Maharaj, R. J. 2001e. Assessment of volcanic rock for construction in the Federated States of Micronesia. In: Uusinoka et al (eds.), Aggregates 2001: Environment and Economy. IAEG and Finnish National Group of the IAEG, Tampere. CD-ROM, Vol. 1.0. Maharaj, R. J. 2001f. Assessment of coral rubble for construction in the Federated States of Micronesia. In: Uusinoka et al (eds.), Aggregates 2001: Environment and Economy. IAEG and Finnish National Group of the IAEG, Tampere. CD-ROM, Vol. 1.0. Maharaj, R. J. 2001. Assessment of coastal engineering and environmental impact of a boat harbour facility, Anibare Bay, Nauru. SOPAC Preliminary Report 127. SOPAC Secretariat, Fiji. Minster, J. B. and Jordan, T. H. 1978. Present-date plate motions. Journal of Geophysical Research, 83, 5331-5354. Okal, E. 1991. Aspects of Pacific Seismicity. Pure and Applied Geophysics, 135, No.2.



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Peake, S., Maharaj, R. J. and Verhagen, H. J. 1999. UNFCCC Technical Paper on Coastal Adaptation Technologies - FCCC/TP/1999/1. Paper presented at a Special Session of the 10th Meeting, Subsidiary Body on Science and Technology (SBSTA), Bonn, Germany, 9th June, 1999. Pilsarczyk, K. W. 1996. Offshore Breakwaters and Shore Evolution Control. A. A. Balkema, Rotterdam. Smith, M. R. and Collins, L. 1993. Aggregates. Geological Society, London, Engineering Geology Special Publication, 9. Speight, J. G. 1996. Environmental Technology Handbook. Taylor and Francis, New York. Soulsby, R. 1998. Dynamics of Marine Sands. Thomas Telford, London. Thorne, C. R., Abt, S. R., Barends, F. B. J., Maynord, S. T. and Pilarczyk, K. Y. 1995. River, Coastal and Shoreline Protection. Erosion Control Using Riprap and Armourstone. John Wiley, New York. Thornton, E., Dalrymple, T., Drake, T., Gallagher, E., Guza, B., Hay, A., Holman, R., Kaihatu, J., Lippmann, T., Ozkan-Haller, T. 2000. State of Nearshore Processes Research: II. Technical Report NPS-OC-00-001. Naval Postgraduate School. Monterey, California, USA. U. S. Navy, 1996. Global Tropical/Extratropical Cyclone Climatic Atlas. CD-ROM, Version 2.0, September 1996. U. S. Fleet Numerical Meteorology and Oceanography Detachment, National Climatic Data Centre, NOAA & U. S. Naval Meteorology and Oceanography Command. U. S. Army Corps Of Engineers, 1984. Shore Protection Manual, Vols. 1 and 2, 4th Edition. U. S. Government Printing Office, Washington. UNEP, 1997. The Environmental Management of Industrial Estates. UNEP IE Technical Report No. 39. UNEP, France. USEPA, 1990. Subsurface Contamination Reference Guide. Report No. EPA/540/2-90/011. USEPA, Washington, D.C. Van de Meer, J. W. 1987. Stability of breakwater armour layers. Coastal Engineering, 11, 219-239. Van de Meer, J. W. 1998. A code for dike height design and examination. Proc. ICE Conf. Coastlines, Structures and Breakwaters. Thomas Telford, London.



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Van Loon, H. 1984. Climates of the Oceans, Volume 15. Elsevier, Amsterdam. Van Rijn, L. 1990. Handbook of Sediment Transport by Currents and Waves, H 461. Delft Hydraulics, Delft, The Netherlands. Van Rijn, L. 1998. Principle of Coastal Morphology. Aqua Publications, The Netherlands. Wood, C. 1995. Environmental Impact Assessment. Longman Scientific and Technical, England.



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SOPAC TASK PROFILE BEACHES MONITORING AND EVALUATION FIJI ISLANDS CAPACITY BUILDING AND TECHNICAL TRAINING Task: FJ 2001.001

Proposed: January 2001

SOPAC Unit: Coastal

Work Program: 2001

Started: February 2001

Completed: February 2001

Objectives:Prepare technical guidelines for the assessment of beach erosion and dynamics, to assist in the sustainable use and management of the coastal zone in the Fiji Islands. Proposed: SOPAC Technical Reports and in-country presentations detailing the achieved objectives. Background:Coastal erosion and shoreline management continues to be a chronic problem for many SOPAC SIDS. While this silent natural hazard has plagued the region for years, technical information to evaluate various aspects of erosion and management of coastlines are unavailable at the local level. Where information is available, it is sometimes too technical and complex or may be even be over-simplified. The objective of this task is to prepare and present technical guidelines which can be used for the monitoring, evaluation of beach and shoreline change in the Fiji Islands. The guidelines will discuss the various aspects of coastal dynamics and erosion, how to identify and characterise erosion, what data should be collected, how to collect, process and manage data and how to utilise the data sets for coastal management, environmental impact assessment and coastal engineering. In addition, practical aspects of erosion and beach monitoring will be presented, which are feasible for the Fiji Islands. Equipment Needs: Laptop computing resources, multi-media projector, ACES and  CRESS coastal engineering software. Work Plan:

1. Review coastal problems in SOPAC SIDS. 2. Review existing technical guidelines and manuals. 3. Prepare appropriate guidelines and draft report. 4. Publish report. 5. Present and distribute to member countries.

Information:

N/A

Clients:

Fiji Government.

SOPAC Personnel:

Russell J. Maharaj.

Report:

SOPAC Training Report and written technical guidelines.



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APPENDIX II

Nearshore Processes

Report Based on the Nearshore Research Workshop St. Petersburg, Florida September 14-16, 1998

1 March 2000

Technical Report NPS-OC-00-001 Naval Postgraduate School, Monterey, California 93943 NEARSHORE PROCESSES RESEARCH Report Based on the Nearshore Research Workshop St. Petersburg, Florida, U.S.A. September 14-16, 1998 Ed Thornton, Tony Dalrymple, Tom Drake, Edie Gallagher, Bob Guza, Alex Hay, Rob Holman, Jim Kaihatu, Tom Lippmann, Tuba OzkanHaller



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EXECUTIVE SUMMARY Understanding nearshore processes is increasingly important because the majority of the world's coastlines are eroding. The increased threat of global warming and the resulting rise in sea level may accelerate erosion problems. Beaches are a primary recreational area, are essential to commerce, and are important to nation defence, especially since the end of the cold war. Increasing our knowledge of nearshore process is crucial both economically and militarily.

Priority Science Issues:

E E

Fluid and sediment processes in the swash zone Breaking waves, bottom boundary layers, and associated turbulence

E

Wave and breaking-wave induced currents

E

Nearshore sediment transport

E

Morphology

Research Strategies:

E E E

Community models should be developed and tested to synthesize scientific progress. Observations spanning a range of scales should be conducted on different beach types. Improvements to the community infrastructure to fulfil these research strategies. Establish a nearshore data bank to archive and exploit existing data.

E

Establish additional long-term measurement programs.

E

Improve instrumentation for measurements in the nearshore.

E

Develop a community bathymetric measurement capability.



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1.0 INTRODUCTION The nearshore ocean, extending from the beach to water depths of about 10 meters, is of significant societal importance. More than half the U.S. population lives within 50 miles of the shoreline. Beaches are the primary recreational destination for domestic and foreign tourists.

Figure 1. Space-time scales of morphology in the nearshore



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In California, beaches generate more visitor attendance days than all other major attractions (Yosemite, state parks, theme parks including Disneyland) combined, equating to $14 billion annual direct spending. More than twice as many tourists visit Miami Beach than visit Grand Canyon, Yosemite, and Yellowstone National Parks combined. The foreign exchange benefit to the US from tourist spending now exceeds that from the export of manufactured goods (62). However about 85 percent of the sandy shorelines of the United States are eroding from a combination of damming of rivers, inlet improvements, sea level rise, and large storms. Accurate prediction of nearshore processes can improve coastal management and lead to substantial benefit for coastal communities. This report concerns basic scientific and engineering research in the nearshore ocean. A long-term goal of nearshore research is to understand and model the transformation of surface gravity waves propagating across the continental shelf to the beach, the corresponding wave-driven circulation in the surf zone, and the resulting evolution of surf zone and beach face morphology. Progress toward this goal since the last Nearshore Research Workshop (59) a decade ago is reviewed below. The review is divided into small-, intermediate- and large-scale processes based on the space and time scales of nearshore fluid motions (Fig. 1). Understanding nearshore processes well enough to develop a realistic coupled waves-currents-morphologic evolution model is a challenging goal. Significant progress has been made during the past decade, and the prospects for major advances in the next 10 years are exciting.

2.0 REVIEW During the last decade, field experiments and numerical models have shown that nearshore wave transformation, circulation, and bathymetric change involve coupled processes at many spatial and temporal scales (Figure 2). The properties of waves incident from deep water and the beach profile (large-scale properties) determine the overall characteristics (e.g., surf zone width) of nearshore waves and flows (intermediate-scale properties). However, small-scale processes control the turbulent dissipation of breaking waves, bottom boundary layer and bedform processes that determine the local sediment flux. Cross- and alongshore variations in waves, currents, and bottom slope cause spatial gradients in sediment fluxes resulting in large-scale, planform evolution (e.g., erosion or accretion). As the surf zone bathymetry evolves, so do nearshore waves and currents that depend strongly on this bathymetry.



Figure 2. Coupling of the small-, intermediate-, and large-scale processes


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34


2.1 REVIEW OF SMALL-SCALE PROCESSES [0.1

MM

-10

M;

0.1

S

-1

DAY]

Introduction Ten years ago progress in understanding small-scale sediment dynamics was limited by lack of measurements of both sediment and fluid motions. Models of the wave-current bottom boundary layer were mainly 1?D and bedform models were mainly 2?D. Over the past decade, however, new measurement technologies have provided insight into the complexity of the fluid-sediment interaction over a wide range of conditions. In addition, 3?D small-scale process models are beginning to produce results at a level of detail surpassing measurements.

Bed State New high-resolution measurements using acoustic altimeters and side scan sonars now quantify the 3-D character of bedforms at high temporal and spatial resolution. Spatial variability of bedforms has been documented using CRAB-mounted sonars; for example, 10 to 40 cm high lunate and straight-crested mega ripples are often seen on the seaward flanks of bars, in the nearshore trough, and in rip channels, but their origin and spatial variability are not understood (122). Temporal evolution of bedforms at fixed location has been observed during a storm (48). Transition between bedform types occurs on time-scales comparable to time-scales of changes in fluid forcing, but is also linked to bedform scale and forcing history. Under large waves, significant changes in small-scale bedforms can occur within a single wave cycle (44). In contrast, largescale bedforms can exhibit significant hysteresis in their temporal evolution (124). These complexities in bedform development are not included in models for sediment transport or fluid motion. Variation in sediment size may contribute to the high variability of bedforms in the nearshore. Cores through a storm-deposited bar at Duck revealed grain size variations from millimetres thick cross-bedded laminae of grains having diameters two to three times the mean grain size, to several cm thick horizontal strata of coarse sand and fine gravel (22, 105). The temporal and spatial variability of grain size is greatest in the swash zone, where sediment varies from fine sand to gravel and cm-long shell fragments over distances of tens of centimetres and over times order of individual swash excursions. Models of bedform development are not able to reproduce the full range of patterns observed, but promising results have been obtained using two different approaches. The existence of both longitudinal and transverse instabilities of the coupled fluid-sediment system has been demonstrated, suggesting a mechanism for the formation of at least one 3?D ripple type



35

(128). However, these models depend on parameterisations of the poorly known near bed turbulence and sediment flux. Bedforms have been also simulated as the result of self-organization of mobile bed sediment (76,133). Self-organization models depend on codification of complex granular-fluid physical phenomena into simple rules designed to represent the details of the sediment transport. However, there is no accepted basis for selecting the appropriate rules. The hypothesis that for directionally variable flows, bedforms become aligned in a direction such that the gross transport normal to the crest is maximized (103) was confirmed in field experiments (34). This direction may differ substantially from the direction of the net bottom stress.

Fluid Forcing The wave bottom boundary layer (WBBL) is only a few cm thick over a flat bed and changes rapidly. Owing to the difficulty of resolving the spacetime structure in the field, tests of WBBL models have relied upon laboratory measurements (68). New techniques using a traversing laserDoppler velocimeter (125), vertical stacks of hot film anemometers (31), and acoustic Doppler techniques (117) have been used to profile the WBBL in the field. Bottom boundary layers associated with mean flows are typically 1 m thick and can be measured with standard velocity sensors. The vertical structure of mean on-offshore currents (undertow) observed in the field has been modelled using a cross-shore variable eddy viscosity (40). The log profile was found to describe well the vertical profiles of strong (> 1 m/s) longshore currents. Measurement of the cross-shore variation in the vertical structure of the mean alongshore current revealed an order of magnitude variation in the bottom shear stress coefficient across the surf zone owing to variations in the physical roughness of the bed (35). Existing models, precluding predictions of Cf, cannot predict roughness caused by bedforms. Turbulence is generated at the surface under breaking waves and in the bottom boundary layer. The details of breaker-induced turbulence and energy dissipation have been studied in the laboratory, and both obliquely descending vortices and horizontal vortices have been observed (89, 120). Breaking waves have been modelled theoretically (81). In the field, the vertical structure of turbulence under breakers and bores was investigated using hot films. Turbulence intensities were found to be 1% of the wave orbital energy, and to decay slowly with increasing depth, indicating strong vertical mixing (35). Depth-averaged turbulence levels were consistent with a bore dissipation model (123). The turbulence intensities in the WBBL were elevated under wave crests, and dissipation rates were larger than in the overlying fluid by at least a factor of 2 (30).



36

Models for the vertical structure of the wave-current bottom boundary layer have been under development for some time (39, 109). However, there is no accepted theory for turbulent flow over the rough and erodible bottom typical of coastal environments. Most models are 1-D and depend on either an analytical (e.g., eddy viscosity) or a numerical (e.g., k-epsilon) turbulent closure scheme. An important issue is the degree of no linearity in the superposition of the wave and current contributions to the total stress. Comparisons between constant eddy viscosity and k-epsilon models have revealed systematic differences in the predicted no linearity (113). Better agreement was found between time-varying eddy viscosity models and k-epsilon models of non-linearity in the mean stress (86). Fully 3?D models, using direct numerical simulation techniques (111), are producing realistic pictures of instability development and the onset of turbulence in the WBBL, but are limited to low Reynold's numbers owing to computational constraints.

Sediment Transport Sediment transport models for combined wave-current flows usually are formulated either in terms of flow energetics or bottom shear stress. In these models, sediment transport is separated into suspended load and bedload. Suspended load is understood better than bedload owing to the difficulty of obtaining non-intrusive measurements of the motion of particles in the thin bedload layer. An important question is whether either transport modes dominates in different nearshore environments. Models of sediment suspension build upon the fluid boundary layer models by adding a sediment conservation equation and boundary conditions on the sediment flux. Important questions relate to the mechanisms and parameterisations both for sediment entrainment from the bed, and for upward mixing of sediment into the water column. Sediment entrainment is represented either as a diffusive or convective process (90). Boundary conditions for either process remain understood poorly. Post-entrainment mixing is represented either as pure diffusion, or as a combination of turbulent diffusion and a vertical convective flux associated with large eddies. These different representations may reflect shifts in the dominant physical processes as a function of bed state and forcing energetics. In most stress-based bedload models, the transport rate is proportional to the excess bed shear stress raised to a power between 1.5 to 2.5. No method for direct measurement of bedload transport suitable for nearshore field conditions has been developed. Indirect estimates of bedload transport rates made from bedform migration measurements support the use of stress-based models for current dominated cases (46).



37

Vertical profiles of suspended sediment concentration and size can now be measured acoustically in the field. However, comparison of such observations with theoretical predictions yields mixed results. Direct measures of sediment flux profiles, obtained using a coherent acoustic Doppler profiler, showed sediment flux in-phase with wave velocity (and wave stress) within 2 cm of the bed, but with increasing phase variation above this level (115). Neither purely diffusive models nor convective models find general application to the usual range of small-scale bed states (78). Field observations consistently document the strong modulation of the suspension concentration profile at infragravity wave frequencies, and especially the association between suspension events and wave groups (42). These events have been described as near bottom "stirring" during the first few waves in the group, followed by "pumping up" to progressively greater heights during later waves, illustrating the dependence of the instantaneous suspended sediment concentration on the prior wave history (43, 45). Models describing sediment transport under wave groups, with and without bound long waves, find the transport direction is dependent on grain size and transport intensity. Bound long waves result in an offshore contribution to the sediment transport because the offshore motion in the long waves occurs simultaneous with the high waves and high sediment concentration (20). At time scales shorter than a wave period, suspension is highly intermittent. Phase averaging of temporal variations in suspended sediment concentration over a flat bed (21) reveals pronounced asymmetry with respect to time during the wave cycle, in contrast to the more symmetric behaviour over rippled beds (93). Characteristic phaserelated differences in the spatially coherent structure of the suspension layer have been identified using video observations of flat and transition rippled beds (14). Modelling and observational techniques for 2- and 3-D studies of suspension are evolving. Sediment suspension over a bed of fixed ripples is described by a discrete vortex model, which exhibits the development of sediment clouds several ripple heights high with a horizontal separation equal to the ripple wavelength (2, 95). Computed instantaneous concentration profiles exhibit pronounced inversions similar to those reported in laboratory experiments (108). Newly developed compact underwater laser-video systems (15) provide 2-D images of suspension and bed elevation profiles, which facilitate comparison of field and laboratory observations with 2-D models. At sufficiently high bottom stress, bedload occurs as sheet flow in a horizontal layer of thin vertical extent that may lack a significant suspension component. There are numerous laboratory measurements of sheet flow in unidirectional and oscillatory flows (118, 100). Reasonable agreement with experiments was obtained for the sediment flux, velocity profile, and thickness of the sheet in unidirectional flow by applying a two-


38


phase theory that incorporated particle collisions (67). Discrete-particle models based on molecular dynamics for dry granular flow (23) are being developed for nearshore bedload transport. These models calculate the forces on an assemblage of individual grains at small time steps, and have been extended to incorporate fluid forces including flow accelerations (9). Results from simulations compare favourably with available laboratory experiments (73). 2.2 REVIEW OF INTERMEDIATE-SCALE PROCESSES [1M -10 1 YEAR]

KM,

1

SEC-

Introduction On coasts exposed to the open ocean, the primary energy source for the small-scale processes discussed above is wind-generated waves (swell and sea) propagating from deep water toward the shoreline. The transformation of directionally spread; shoaling waves approaching the surf zone can be modelled quantitatively, at least on simple bathymetry. Heuristic extensions to the models to describe breaking waves allow accurate prediction of wave propagation across the surf zone. Inside the surf zone, models and observations demonstrate that nearshore circulation is complex, even on beaches with relatively simple bathymetry that does not vary substantially in the alongshore direction. Rather than a stable mean flow, driven only by breaking waves (as in analytic models of the 1980's), nearshore circulation has been shown in the last decade to include turbulent shear flows and eddies, instabilities, and both wave and wind forcing. In addition, the importance of coupling between nearshore waves, currents, and the changing bathymetry is recognized, resulting in the hypothesis that variations in the nearshore bathymetry result from feedback between the driving forces and morphologic change.

Surface waves During the last decade, there has been considerable progress toward modeling quantitatively the shoaling wave transformation. Models based on the Boussinesq equations predict accurately the shoaling of nonbreaking near-normally incident swell and sea observed in shallow water on natural beaches (32, 24, 25). Recently, the Boussinesq equations have been extended to deeper water and to stronger non-linearity (129), and stochastic evolution equations appropriate for directionally spread, random waves have been developed (49) and validated by comparison with field observations (91). These models do not contain adjustable parameters and predict accurately the asymmetrical wave shapes and orbital velocities that are believed important to wave induced nearshore sediment transport.



39

Analysis of breaking waves across the surf zone indicates that the observed decay of wave spectra is primarily the result of non-linear transfers from the spectral peak to higher frequencies, and that dissipation occurs in the high- frequency tail of the spectrum where energy levels are relatively low (54). Observations also indicate that breaking results in an increase in the directional spread of wave energy, in contrast to the directional narrowing with decreasing depth predicted by refraction theory (53). The effect of breaking on the transformation of waves propagating across the surf zone has been modelled by including heuristic dissipation terms in both time- (104) and frequency-domain (70) Boussinesq models. With suitably tuned parameters that control the dissipation rate, Boussinesq-type models predict accurately the wave height decay and shape changes of near-normally incident waves propagating across the surf zone (12, 71), and 2-D waves breaking around circular shoals (10). Numerical models that solve the unsteady Navier-Stokes are being used to simulate spilling and plunging waves over a sloping bed using volume of fluid technique to track the discontinuous free surface (81). Models that incorporate the effect of the wave roller, the turbulent wedge of white water on the bore face that is advected shoreward at the wave phase speed (19), also describe accurately surf zone wave propagation. Ongoing work is directed toward integrating small-scale breaking wave dynamics (see Small-Scale section) into Boussinesq and roller models that predict the evolution of wave height and shape across the surf zone. Unlike sea and swell waves (periods 5-20 s), lower frequency infragravity waves (periods 30-300 s) are not strongly dissipated by wave breaking in the surf zone. Infragravity waves are believed to be generated nonlinearly by groups of incoming wind waves (83). The non-linear forcing is strong during storms, and infragravity waves can dominate inner surf zone velocity and sea-surface fluctuations, with heights exceeding 1 m (63). Field observations suggest that infragravity waves can be reflected at the shoreline and may consist largely of edge waves refractively trapped between the shoreline and deeper offshore waters. Observations from a range of coastal settings suggest that infragravity energy levels on the continental shelf depend not only on conditions in nearby surf zones, but also on the general geographic surroundings. For example, more infragravity energy is trapped on a steep narrow shelf than on a gently sloping wide shelf (50,51). The role of bar trapped edge waves in sediment transport and bar movement is unknown, but possibly is significant. Wave number-frequency spectra of run-up at a barred beach found, in addition to the expected edge and leaky mode infragravity waves, significant non-dispersive wave energy was outside the gravity wave region and not associated with shear instabilities. These unexpected observations imply a strong decorrelation can occur between trough and shoreline fluid motions (55). Thus, contrary to previous assumptions, shoreline energy levels are not necessarily a good indication of the overall infragravity wave field. The existence of energetic bartrapped edge waves (8) suggests that trapping also may occur at other



40

depth perturbations such as submarine canyons and offshore shoals. The swash zone is the region where the beach face is intermittently covered and uncovered by wave run up. A numerical model based on the 1-D depth-averaged non-linear shallow water equations with bore-like dissipation (75) predicts accurately runup oscillations measured on a finegrained beach (98, 99). Boussinesq models recently have been extended to include swash motions, and model predictions agree well with theories for 1-D runup (81, 85) and with measurements of 2-D runup on an impermeable laboratory beach (10, 74). Although wave runup on fine grained and impermeable beaches is modelled well, accurate prediction of runup on coarse-grained beaches may require a model that includes percolation effects. Additionally, prediction of fluid velocities in the runup may require inclusion of a turbulent bottom boundary layer.

Nearshore circulation Sea and swell waves incident on a beach can drive strong (e.g., 1.5 m/s) quasi-steady currents in the surf zone. Models based on a balance between gradients in the wave radiation stress and the drag of the mean flow on the seabed predict accurately the observed cross-shore distribution of alongshore currents on near-planar beaches. However, on barred beaches, observed alongshore currents are often maximum in the bar trough, rather than on the bar crest as predicted (13). The predictions may be inaccurate because the models do not include surface rollers (that cause spatial lags between initial wave breaking and the transfer of momentum to steady currents), mixing by vertically sheared mean horizontal flows (119), alongshore variability in the waves and bathymetry, of shear waves. Observations (102) and models (7) suggest that breakingwave driven alongshore currents often are unstable. The growing instabilities, called shear waves, have periods of 1-10 minutes and maximum rms velocities of 40 cm/s. Results from fully non-linear models suggest that shear instabilities might both alter significantly the crossshore structure of the mean alongshore current and produce energetic eddies (110, 94). Gradients in wave radiation stress caused by breaking waves also drive set-up, the super-elevation of the mean water level. The set-up forces an offshore-directed mean flow (undertow) and alongshore gradients of set-up can drive rip currents. However, set-up is difficult to measure, as are the breaking processes. Therefore the driving mechanism for undertow (a primary cause of beach erosion during storms) is understood poorly. In addition, it has been shown numerically and in the laboratory that instabilities of the undertow result in a train of vortices that rotate about an axis parallel to the shoreline, and migrate slowly offshore (80). Substantial alongshore topographic variations over spatial scales of 1 km are often observed (82) (see Large-scale section). Models suggest that such alongshore-bathymetric variability can cause alongshore variations in the wave set-up that significantly influence the nearshore circulation (97).



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Momentum balances based on observations collected at Duck, NC suggest that the dominant forcing of mean alongshore flows was associated with the oblique propagation direction of the incident waves, rather than topographically induced alongshore gradients in wave set-up (29). However, laboratory (41) and numerical model (11) studies suggest that gaps in otherwise alongshore uniform bars may cause offshore directed rip currents that are fed by strong flows in the bar trough. Rip currents are shown to occur theoretically as the result of instabilities of an alongshore-perturbed setup/setdown when wave refraction or topographic evolution is taken into account (28). Detailed field observations of strongly bathymetrically controlled nearshore circulation are lacking. The transition of alongshore currents from the continental shelf to the surf zone has been investigated (79). Observations suggest that density and wind-driven along shelf currents sometimes are strong immediately seaward of the surf zone, and in some cases oppose wave-driven alongshore flows within the surf zone. Both shoaling waves (through wave set down) and wind-driven alongshore currents (through geostrophy) contribute significantly to crossshore tilts of the mean sea surface seaward of the surf zone. These processes (as well as tidal currents) are not generally included in existing models for nearshore circulation.

Surf Zone Bathymetry During the past decade the coupling between waves, circulation, and changes in nearshore bathymetry has begun to be observed and modelled. On many beaches, changes in the position and height of sand bars are the primary source of cross-shore bathymetric variability, and these bars may be linear, alongshore periodic, or alongshore irregular (58, 82). Hypotheses for sand bar formation include the break point and infragravity wave mechanisms, both of which may be important (58). In these models, the spatial scales of sand bars are determined ("forced") by the spatial pattern of waves and currents. During storms, wave-breaking induced undertow dominates energetic-based modelled sediment transport (33, 121). Undertow is strongest near the bar crest where wave breaking is intensified (40) and the resulting gradients in modelled crossshore transport lead to predicted seaward bar migration, as observed. As the sand bar moves offshore, the location of intense wave breaking and maximum undertow also migrates seaward. Thus, the coupling and feedback between waves, currents, and bathymetry results in continuous offshore sand bar migration during storms. Existing models do not predict the slower, onshore migration of the sand bar observed in the surf zone during periods of low waves. Field observations suggest net onshore sediment transport and sand bar migration is associated with cross-shore gradients in asymmetrical fluid accelerations owing to pitched-forward non-linear waves, although the constitutive relationship between fluid acceleration and sediment motion is not known (26).



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Numerical models have been developed for coupled fluid-sediment instabilities of longshore currents on initially alongshore-uniform platforms (27). Alongshore-periodic bar features are predicted to develop owing to strong, positive feedback between the mean alongshore current and the evolving bathymetry. The length scales of morphologic features are determined by the unstable ("free") modes of the coupled fluid-morphology system. Similar interactions between incident wave runup and beach face topography are predicted to lead to the formation of beach cusps, alongshore-periodic variations in the shoreline location (130). The relative importance of free and forced mechanisms in forming natural morphologies is unknown, and is an objective of current research.

2.3 REVIEW OF LARGE-SCALE PROCESSES [1 - 100 DECADES]

KM, MONTHS-

Introduction Driven by societal needs to make long-term predictions, large-scale models to predict topographic response have been developed by integrating short time-scale processes, including wave transformation, fluid motion, and sediment transport (77, 112). This approach is sometimes referred to as "bottom-up" modelling or the aggregation of small- to largerscale processes. Typically, a spatial pattern of the waves and currents is imposed on a starting morphology, and a new morphology is predicted using a sediment transport formula (6, 57, 58, 64). A morphology that can be predicted successfully using this approach exhibits what is known as "forced" behaviour. These models have some skill for short-time scales of weeks, but their model skill is uncertain over large-time and space scales. The uncertainty of long-term predictability has led researchers to suggest that the nearshore response is sensitive to initial perturbations in the beach profile and that morphological feedback to the wave and current field is strong (114). Under these assumptions, the evolution of topography does not depend solely on the instantaneous small-scale processes, but incorporates some degree of time history in profile configuration and may be driven by instabilities of the coupled fluid-morphology system (16, 27, 28). Such a system is thought to exhibit "free" behaviour, in which the predictability time scales are limited by the strength of the non-linear feedback, or growth rate of instability. These system traits are elements of non-linear pattern formation (1, 61, 101) and self-organized behaviour (130), and suggest different approaches to modelling that depend on aspects of the feedback. Thus, at long time scales, these systems may be modelled in terms of a simpler, carefully chosen set of equations derived from empirical study of the system in an approach called "top-down" modelling.



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The general topic of dynamics of the nearshore system at long-time (months to decades) and length scales (kilometres and longer) is known as Large Scale Coastal Behaviour (LSCB), which lies between the shorter scales of traditional nearshore processes (represented here in terms of intermediate and short scale processes) and the much longer scales of Coastal Marine Geology. LSCB was not considered in the first St. Petersburg meeting, but formulation of a research framework (including links to shorter scale processes) was an important aspect of this workshop.

Measures of Large Scale System Response Models for nearshore processes are based around laws for the conservation of mass, momentum, and energy. At intermediate and small scales, understanding the nearshore implies understanding the dynamics of both its fluid and sediment components. At the longer time scales of LSCB, emergent variables based on a hierarchy of time scales may dominate nearshore processes, i.e. small-scale processes become slaves to large-scale bathymetry at longer time scales. As bathymetry is the main variable of interest at the long-time scales of LSCB, the primary tool is conservation of sediment mass. At the still longer scales of marine geology, grain size partitioning within conservation of mass becomes important. A description of bathymetric state might requires specification of independent points in the cross-shore (say every 1-2 m) measured at perhaps 102 points in the alongshore, a total of 104 independent variables for a single realization. Development of evolution equations for such a large number of variables is daunting, and thus reduction of dimensionality is desirable. Some success can be achieved by representing cross-shore profiles in terms of a small number of EOF or power law functions (3, 18). For area descriptors (both horizontal dimensions), progress has been made by using sets of morphological "state" descriptors, defined primarily by a mix of subjective sand bar/trough characteristics (84, 134). The most common measure of beach state used by coastal zone managers and coastal engineers is the location the shoreline (a measure which also is obtained easily from survey or remote sensing). To develop a predictive understanding of variability of the shoreline then requires an understanding of how the shoreline is related to, and represents, overall profile variability. Consider the simplified case of a beach whose behaviour can be viewed as the superposition of a deterministic annual signal and an underlying trend (Figure 3a). In this case, the prediction of long-term behaviour would be specified by the trend (averaging over annual signals), with a confidence limit associated with the variance of the annual signal about that trend.



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Nearshore variability occurs over all space and time scales, with significant energy at the longest scales. Prediction of LSCB are made beyond a particular time (or space) scale, T', with shorter period (or length) fluctuations considered to be variance about the prediction (Figure 3b). As an example, annual cycles in sand bar location may have no LSCB impact (only providing variance), whereas net alongshore transport gradients, dune overtopping, or offshore losses can lead to important LSCB signals. In other words, if mass conservation is implemented via a box model, the fluxes within the box may be irrelevant, whereas fluxes across box boundaries may determine long-term behaviour.

Sources of LSCB Energy Forcing of large-scale nearshore variability can arise from several possible sources, including external factors (wave climate, currents and winds), non-linear interactions within these external factors, and internal (to the system) factors. Directly forced response results from forcing energy at the same frequency. For example, a beach may erode slowly owing to a slow increase in the wave climate energy. Thus, the signature of the forcing in space and time provides a template for the nearshore response. Resonance may result in large nearshore response for relatively low forcing.



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Figure 3a. Variations of a synthetic coastal signal showing the superposition of an annual cycle and a long-term trend. 3b. Spectrum of a more realistic case of coastal variability with variance at all scales. LSCB is the low frequency portion of the spectrum, whereas the high frequency energy is simply variance about LSCB.

Non-linear interactions may transfer energy of the forcing spectrum from high frequencies (perhaps annual cycles) to LSCB. For example, increased suspended loads under winter storm waves might tend to be carried preferentially offshore by bottom return flows from upwellingfavorable winter winds. The corresponding summer conditions might drive only a weak onshore transport, thus produce a net sediment loss (erosion).



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Spontaneous generation of LSCB variance (often called free behaviour) is caused by instabilities and feedback within the nearshore system. A wellknown example of such free behaviour is the generation of bed forms on an initially smooth river bed (72). The bedforms are not caused by a preexisting pattern in the river flow, but by an instability and feedback between a perturbation in bottom roughness that causes a disturbance to the flow and sediment transport that reinforces the perturbation. The presence of fluid motion does not introduce any scales, but acts as a catalyst to the process. In the nearshore, a number of possible feedback mechanisms exist. Sand bars may be generated by, and may induce the onset of wave breaking. Similarly, rip channels through a sand bar may be generated by, and may induce alongshore gradients in wave height.

Other Influences When consideration of nearshore behaviour is extended to larger scale, many new processes or influences must be considered (Figure 4). The focus of the 1989 St. Petersburg report was on the interaction of fluid (including wind) processes with evolving morphology. However, at larger scales the response of the nearshore is also a function of climate, sea level, regional sediment fluxes, and anthropogenic effects. Many of these external influences do not involve strong feedbacks. Thus, there may be a greater potential for developing simplified forcing functions in the absence of significant free behaviour, consistent with suggestions that behaviour may become more predictable at long time scales.



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Figure 4. Processes that influence LSCB. Note that only one arm describes the traditional fluid-topography dynamics that have been the focus of much recent field experimentation. At longer scales, many other processes also contribute.

Data The application of any modelling approach relies on accurate field measurements of nearshore topography. Few data sets of appropriate magnitude exist, thus attempts to verify long-term, large-scale models have been limited. Large-scale, long-term bathymetric or morphological observations include: (1) the Dutch JARKUS profile data (131), which span 4 decades and hundreds of km of coastline, but have sparse alongshore resolution and are sampled annually, (2) the Duck CRAB profile data (5, 96), which span 2 decades, have dense alongshore resolution, and are sampled on a monthly basis, but only extend alongshore about 1 km, and (3) the ARGUS video data (60, 82), which have dense alongshore resolution and



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are sampled daily at numerous locations about the world, but are limited to inferences of sand bar position and shape within the surf zone that extend alongshore about 1-2 km. Each of these data sets has revealed valuable insight into long-term large-scale nearshore response, but have limitations for testing of LSCB.

2.4 REVIEW OF NEW TECHNOLOGIES IN THE NEARSHORE Although new technologies have led to advances in the understanding of nearshore processes, there are gaps in measurement capability. Some of the new technologies have been the result of efforts by nearshore scientists and engineers. Additionally, off-the-shelf availability of DGPS advances in electronics and microprocessors, the application of simple video techniques, and the use of on-line data have revolutionized methods of measuring and disseminating data. DPGS allows rapid and accurate survey of large areas while driving or flying. Microprocessors have made innovative data acquisition and new measurement systems possible. Online, time-lapse video stations located around the globe have revealed the complexity of macro-scale morphology at time and space scales not previously recognized. In the following, technology is divided into remote sensing and in situ measurement techniques.

Remote Sensing Remote sensing can be further divided into techniques from moving platforms, such as airplanes or satellites, and stationary locations. Remote sensing from moving aircraft has undergone significant technological development during the past ten years. These systems are able to discern fine scale details of nearshore wave and surface current fields. Scanning sensors such as the scanning radar altimeter (SRA, horizontal resolution of 10 m, 0.2 m vertical accuracy) and the airborne topographic mapper (ATM, a lidar system, horizontal resolution 1.5 m, 0.08 m vertical accuracy) use a direct ranging technique to measure the free surface topography including foreshore regions. Both systems use the time of flight of the return signal from the air-water interface to derive the topography at sub-meter resolutions and can be deployed repeatedly to detect topographic change. Other lidar systems (using different primary wavelengths) can measure bathymetry (66) using the same principle. SRA and ATM were used to measure the wave field during the Duck94 experiment (65). The SRA shows promise in determining swell wave dissipation and scattering. Conventional synthetic aperture radar (SAR) has been used in imaging large-scale currents and other phenomena with fairly large space and time scales from both space borne and airborne platforms. Ocean waves,



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however, are difficult to study with this technique because they undergo substantial spatial and temporal variability over the course of the integration time of the imaging. Modulation transfer functions are required to translate between the image and the actual free surface processes. This allows SAR to discern wave kinematics, but provides little information on dynamics. A modification of SAR that incorporates the phase information inherent in the imagery (38), called interferometric SAR (INSAR), potentially is capable of measuring the spatial distribution of surface currents in the surf zone (87, 88, 107, 127). This technique offers 10 m resolution imaging of the surface currents over a large domain. Stationary platforms offer the advantage of long-term measurements, but with limited coverage. Optical and radar systems are being used from stationary platforms. A successful application is the ARGUS video stations (60), which provide on-line time-lapse images from around the world linked to the Internet. Electro-optical and infrared remote sensing techniques have been used successfully (56, 132), and are presently being transitioned to moving aircraft for the measurement of bathymetry, wave spectra, and surface currents. HF-radar is used routinely to map nearshore currents with O (100 m) resolution. Imaging Doppler radar offers the possibility of mapping surface currents at 10 m resolution (88).

In-situ Measurements The preceding review identified a number of gaps in measurement capability, such as fluid velocities and particle flux profiles in the bottom boundary layer and in the surface boundary layer under breaking waves, and velocity and sediment concentration measurements in the swash. Sensors to obtain some of the needed measurements are in an advanced state of development. Suspended sediment concentration measurements in the swash and surf zone are measured with fibre optic backscatter probes (FOBS) (4) and gated acoustic backscatter measurements (47, 106, 126). Three-component velocities are measured using acoustic Doppler velocimeters, in both single-point (107) and vertical profiling configurations for simultaneous co-located particle velocity and particle concentration, and therefore sediment flux measurements at subcentimetre scale (116, 117). Sector scanning Doppler sonars are used to resolve horizontal velocities of waves on scales of O (400 m) (112). Drifters with DPGS are being developed for use in the surf zone in conjunction with fixed flow meters to yield improved maps of nearshore currents. Conductivity sensors have been developed to measure sheetflow near the bed for 2-D flow in a laboratory channel (100), but measuring fluid and sediment dynamics near the bed in the field remains daunting. Small-scale morphology is measured with acoustic altimeters mounted on moving platforms (122) and at fixed locations (33, 105), and with rotating side-scan sonars (48). These new sensors were deployed successfully



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during recent field experiments, and ongoing research is directed toward comparing the results with model predictions. Lasers offer the advantage of higher spatial resolution systems to measure morphology, sediments, and fluid velocity. Laser Doppler Velocimetry (LDV) has been used in the laboratory to obtain detailed kinematics of shoaling and breaking waves (120), and initial attempts have been made to measure turbulence under waves in the field (125). Particle imaging velocimetry (PIV) is being used in the laboratory to measure turbulence and is being transitioned to the field. A focused development program for autonomous underwater vehicles (AUV) has resulted in the capability of surveying with in situ instruments for hours over distances of 10's of km at high speed (3 knots). Small (1m) vehicles such as REMUS are being used for fine scale bathymetry surveys and wave measurements, but their area of operation is limited to outside the surf zone. Bottom crawling AUV's show promise for deploying instruments and making measurements across the surf zone and the inner shelf. These new technologies allow improvements for examining nearshore processes by extending the measurements to both larger and smaller space-time scales with increased resolution and accuracy. The challenge is to assimilate the data into improved models to provide accurate predictions of nearshore processes.

3.0 RECOMMENDATIONS FOR FUTURE RESEARCH A broad spectrum of nearshore science questions was discussed and priority areas of research identified. Although the priority science issues of swash, breaking waves, and sediment transport from a decade ago remain on the list, new acoustic and optical tools should result in significant progress in the next decade. There was general agreement that a research strategy of combining field experiments and numerical models will lead to the most rapid progress. Observations are needed to test model predictions, and can reveal new and unexpected phenomena. Improvements to the community infrastructure are recommended to fulfil these research strategies.

3.1. PRIORITY SCIENCE ISSUES 1. Fluid and sediment processes in the swash zone should be studied concurrently within the observational and modelling efforts described below. Observations suggest that during onshore flow, processes of suspension and transport of sediment in the swash zone may be dominated by turbulence at the bore front. In contrast, during offshore



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flow, transport may be driven by the bed shear stress associated with a growing bottom boundary layer. A long-term goal is to develop and validate models of wave run up velocities that could provide spatially dense predictions of swash zone flows to drive sediment transport models and to estimate morphological change. Such models need to account for the effects of bore turbulence, the bottom boundary layer, infiltration into and out of the permeable beach, and longshore currents to predict velocities in the swash zone. Field observations of run up velocities, infiltration, and sediment transport will be necessary to test the models and to determine the importance of these processes on natural beaches. Areas of particular interest include: •

sensitivity of swash zone sediment transport and wave run up to seepage of water into and out of the permeable bed, including unsaturated flow processes,

•

effect of mean longshore currents and shear waves on swash zone sediment transport.

2. Breaking waves, bottom boundary layers, and associated turbulence are important to wave energy dissipation and sediment transport, but are not understood well. The breaking of waves in the nearshore results in changes of the wave-induced momentum that drive nearshore currents and pressure gradients. Breaking wave processes are only qualitatively understood and models are crude. Turbulent wave boundary layers are just starting to be measured in the field using instrumentation with improved spatial and temporal resolution. Prototype-scale laboratory experiments can facilitate these efforts. Observations of these small-scale processes are needed to improve parameterisations used in large-scale models. Research issues include: •

horizontal and vertical structure of turbulence and vorticity under breaking waves,

•

dissipation of the wave energy due to bubble entrainment during breaking,

•

horizontal and vertical distribution of mass flux of breaking waves,

•

effects of wind on breaking,

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effects of reflection, infragravity waves, and currents on wave breaking,

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intensity of wave breaking as function of wave and bathymetry conditions.



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3. Wave and breaking-wave induced currents drive nearshore sediment transport; so understanding these flows is a prerequisite to predicting morphological change. Although wave breaking on simple bathymetry can be parameterised crudely, important processes such as the modification of incident wave directions and shapes by wave breaking are not understood well. Recently developed models suggest that the mean, breaking-wave driven nearshore circulation has a complicated three-dimensional structure even on relatively simple bathymetry. Observed currents contain substantial fluctuations at infragravity periods (approximately 1 minute) that appear to result from a combination of gravity (e.g. edge) waves and vorticity (e.g. shear) waves, but the generation mechanisms and overall significance of these low frequency motions are largely unknown. Thus, even on simple bathymetry, only the gross characteristics of surf zone waves and wave-driven circulation are predicted accurately. Models suggest additional processes occur on complex bathymetry, such as topographically controlled rip currents, but these models contain considerable empiricism (e.g. in modelling the effect of complex bathymetry on wave breaking) and are untested with field observations. To predict nearshore flows for given wind, incident wave fields, and arbitrary nearshore bathymetry, the following issues must be addressed with both observations and models: •

effect of breaking on the frequency-directional distribution and shapes of incident waves,

•

role of mixing mechanisms (e.g. shear waves, shear dispersion, wave generated turbulence) in nearshore circulation,

•

feedback between the time varying circulation (including edge and shear waves) and incident waves,

•

effect of complex bathymetry (including bedforms) on nearshore waves and circulation,

•

transition from tidally and wind-driven shelf flows to wave-driven surf zone flows,

•

three-dimensional structure of mean currents.

4. Nearshore sediment transport is a non-linear function of the fluid velocity, and thus highly sensitive to asymmetries in the fluid motion. A feature distinguishing sediment transport in the nearshore from other environments (e.g. rivers) is the wide variety of mechanisms for producing flow-field asymmetry, including shoaling and breaking waves, wave groups, mean currents, and shear instabilities of the longshore current. These asymmetry-generating mechanisms have more or less well understood origins in the non-linear interactions between the different



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frequency components of the fluid forcing, and between the flow field and the bathymetry. By comparison, our understanding of the corresponding sediment transport asymmetries is limited, with no generally accepted mathematical formalism or solid empirical basis upon which to develop predictive models. The results of recent observational research are beginning to provide diagnostic examples of the linkages between asymmetry in the sediment response and asymmetry in the flow. Some of this work suggests that sediment transport models developed for rivers can be adapted for use in the surf zone, but do not always perform well. This may be owing to a poorly parameterised bottom boundary layer, the importance of acceleration (which is not accounted for), or bed forms (e.g. ripples and mega-ripples), which affect the suspension of sediments and whose migration may be responsible for unaccounted mass transport of sediment. Research issues include: •

predicting bed load and suspended sediment transport under combined wave and current forcing,

•

turbulent wave/current boundary layers over 3-D small-scale morphology,

•

effects of moving sediment on boundary layer,

•

contribution to sediment transport by bed form migration,

•

effects of grain size distribution on sediment transport.

5. Morphology (and its variability) is an important end product that the models will predict. However, because sediment transport is not understood well, prediction of morphological change is inadequate for most purposes of interest. For example at smaller scales, ripples and mega ripples are observed to be ubiquitous, but have not been incorporated into models even though their effect on the flow field (as roughness elements) and sediment transport may be significant. Complex patterns in long-term, large-scale morphology have also been observed. However, models for morphology change have predictive skill only for short-term changes, whereas long-term, large-scale predictions are not yet possible. Research issues include: •

predicting morphology across the spectrum of length scales,

•

free vs. forced large-scale morphology models,

•

understanding feedback between morphology and the flow field,

•

coupling between length scales.



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3.2 RESEARCH STRATEGIES Community models should be developed and tested. • Sufficient understanding of waves, wave-induced circulation, and sediment transport exists to warrant concentrated efforts to produce a fully coupled model of wave-driven hydrodynamics and bathymetric evolution. In the past, segments of the nearshore modelling community have proceeded, in near isolation, to develop models of nearshore wave processes and wave-induced circulation that have been tested with laboratory data only. Field observations and numerical modelling efforts should be better integrated to improve existing numerical models and synthesize the knowledge of nearshore processes. •

Further development of existing model components is critical. For example, swash zone processes are not included in any model of circulation, wave dissipation, or morphology change. Breaking wave, bottom boundary layer, and turbulence parameterisations need to be improved. Existing sediment transport relationships fail under many common conditions. Better understanding of all of these processes will improve morphology predictions. •

Increased emphasis on the development of a real-time predictive capability for nearshore circulation and morphology using data assimilation techniques, and on the use of forecasts from such models to guide field experiments. Data assimilation has become an important method for improving model predictions in other fields, but has not become commonplace in the nearshore community. Testing the predictive skill of such models will require the continued development of measurement technologies for remote and mobile adaptive sampling of the predicted property fields. As a direct response to the workshop, an ad hoc committee on Community Modelling was formed during the workshop to develop plans to fulfil the recommendations above. A five-year nearshore wave, current and morphology modelling and data assimilation program was proposed to the National Ocean Partnership Program (NOPP), and was subsequently funded for years 1999-2005.

Observations spanning a range of scales should be conducted for different beach types. Many of the field observations of waves and currents have been acquired at the U.S. Army Field Research Facility (FRF) at Duck, N.C. because of logistical support (e.g., the CRAB, an amphibious survey and work platform). Although the moderately sloped beach at Duck is the most intensively studied beach in the world, the generality of these intermediate-length and time scale observations is unknown. It is



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important to study a range of beach environments, especially different grain size and beach slopes across the spectrum of length and time scales. Therefore, it is recommended to: •

use new technologies to make detailed observations of small-scale fluid and sediment processes. Such observations will help to improve parameterisations of breaking wave and boundary layer processes including associated turbulence and shed light on the physics of sediment transport. •

make simultaneous observations of small, intermediate, and large-scale processes. Fluid and sediment processes are coupled across all scales, and thus models of circulation and bathymetric evolution depend on realistic parameterisations of small-scale processes, as well as an understanding of the larger-scale context (e.g., sediment sources and sinks (perhaps km away or offshore), shelf-scale wind and density driven circulation, alongshore variations in continental shelf bathymetry, and the incident wave field. •

conduct experiments on both steep and flat beaches. Sediment size and permeability in the swash zone are expected to increase with increasing beach slope. Wave transformation (skewness and asymmetry, wave energy dissipation, and wave-driven circulation) is significantly different on steep and flat beaches. Thus, the cross-shore distribution of breaking, boundary layer processes, and turbulence intensity and their effects on sediment transport are expected to be different in the different environments. Together these processes produce different morphological features. •

conduct experiments on 3-D beaches. In contrast to Duck, where nearshore processes are controlled largely by the height and approach direction of the waves, processes on a pocket beach or near a headland, jetty, or submarine canyon are expected to depend strongly on the local bathymetry. Such complicated geometries have not been studied in the requisite detail to make morphologic predictions.

3.3 INFRASTRUCTURE NEEDS Establish a nearshore data bank to archive and exploit existing data. Standard data sets to test and calibrate models are needed. A number of extensive data sets exist, but are not archived adequately, and are thus relatively inaccessible to the community. Common data formats and efficient means of data dissemination via WWW are needed.



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Establish additional long-term measurement programs Long-term measurement programs of waves and morphology (e.g., Duck, NC) have proven invaluable in identifying processes important to largescale coastal behaviour and provide a setting for shorter-term studies. Such programs are usually well beyond the means of individual laboratories. A new long-term observational field program on at least one site having a beach type different than Duck is a national priority.

Improve instrumentation for measurements in the nearshore Long-term funding for instrument development is necessary to bring new techniques to fruition. Development requirements include:

•

higher temporal and spatial resolving velocity and sediment measurement instruments using both acoustic and optical techniques, •

rapid measurement techniques of sediment grain size distribution,

•

surf zone drifters to complement arrays of fixed flowmeters.

Develop a community bathymetric measurement capability. Bathymetry is a primary boundary condition for all nearshore processes, and accurate measurements are needed for all field and modelling studies.

4.0 ACKNOWLEDGEMENTS We thank the National Science Foundation, the National Oceanographic Atmospheric Agency, the Office of Naval Research, the U.S. Army Corps of Engineers, and the U.S. Geological Survey for supporting this workshop. We thank the Coastal Geology Branch of the U.S. Geological Survey for hosting the meeting and Sandy for doing much of the work.

5.0 REFERENCES 1. Aarninkhof, S. and R.A. Holman, 1999, Monitoring the nearshore with video, Backscatter, 10(2), 8-11.



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2. Asp Hansen, E., J. Fredsoe, and R. Deigaard, 1994, Distribution of Suspended Sediment Over Wave-Generated Ripples, J. Waterway, Port, Coastal and Ocean Engng., 120, 37-55. 3. Aubrey, D.G., 1979, Seasonal patterns of onshore/offshore sediment movement, Journal of Geophysical research, 84, 6347-6354. 4. Beach, R. A., R. W. Sternberg, and R. Johnson, (1992). A fiber optic sensor for monitoring suspended sediment. Mar. Geol. 103: 513-520. 5. Birkemeier, W. A., 1984, Time scales of nearshore profile change, Proc. 19th Intern. Conf. Coastal Eng., ASCE, New York, 1507-1521. 6. Boczar-Karakiewicz, B., D. L. Forbes, and G. Drapeau, 1995, Nearshore bar development in southern Gulf of St. Lawrence, J. Waterw. Port Coastal and Ocean Eng., 121, 49-60. 7. Bowen A. J. and R. A. Holman, 1989, Shear instabilities of the mean longshore current. 1. Theory, J. Geophys. Res., 94, 18023-18030. 8. Bryan, K. R., P. A. Howd, and A. J. Bowen, 1998, Field observations of bar-trapped edge waves. J. Geophys. Res., 103, 1285-1305. 9. Calantoni, J. and T. G. Drake, 1998, Discrete-particle model for nearshore bedload transport: EOS Trans. AGU, 79 (17), Spring Meeting Suppl., S122. 10. Chen, Q, J. T. Kirby, R. A. Dalrymple, A. B. Kennedy, and Arun Chawla, 1999, Boussinesq modeling of wave transformation, breaking, and runup. II: 2D, J. Waterway, Port, Coastal and Ocean Engineering, 126 (1), 48-56. 11. Chen, Q, R. A. Dalrymple, J. T. Kirby, A. B. Kennedy, and M. C. Haller, 1999, Boussinesq modeling of a rip current system, J. Geophys. Res. 104 (C9), 20,617-20,637. 12. Chen, Y., R. T. Guza, and S. Elgar, 1997, Modeling spectra of breaking surface waves in shallow water, J. Geophys. Res., 102, 25,035-25,046. 13. Church, J. C. and E. B. Thornton, 1993, Effects of Breaking Wave Induced Turbulence Within a Longshore Current Model. Coastal Eng. 20, 1-28. 14. Conley, D.C., and D. L. Inman, 1992, Field Observations of the FluidGranular Boundary Layer Under Near-Breaking Waves, Journal of Geophysical Research-Oceans, 97 (C6), 9631-9643. 15. Crawford, A. M., and A. E. Hay, 1998, A simple system for laserilluminated video imaging of sediment suspension and bed topography, IEEE Journal of Oceanic Engineering, 23 (1), 12-19.



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16. Damgaard Christensen, E., R. Deigaard, and J. Fredsoe, 1994, Sea bed stability on a long straight coast, Proc. 24th Intern. Conf. Coastal Eng., ASCE, New York, 1865-1879. 17. De Vriend, H. J., 1991, Mathematical modeling and large-scale coastal behavior, Part 1: Physical processes, J. Hydraulic Res., 29, 727-740. 18. Dean, R. G., 1991, Equilibrium beach profiles: characteristics and applications, J. Coastal research, 7, 53-84. 19. Deigaard, R., 1993. A note on the three-dimensional stress distribution in a surf zone, Coastal Engin., 20, 157-171. 20. Deigaard, R., J. B. Jakobsen, and J. Fredsoe, 1999, Net sediment transport under wave groups and bound long waves, J. Geophys. Res., 104 (c6), 13,559-13,575. 21. Dick, J. E., M. R. Erdman, and D. M. Hanes, 1994, Suspended Sand Concentration Events due to Shoaled Waves Over a Flat Bed, Mar. Geol. 119, 67-73. 22. Drake, T. G., 1997, Final Report of Field Studies of Nearshore Sedimentary Structures, US Army Corps of Engineers, Waterways Experiment Station, CR-CHL-97-3, 157pp. 23. Drake, T. G., and Walton, O. R., 1995, Comparison of experimental and simulated grain flows: Journal of Applied Mechanics, 62, 131135. 24. Elgar, S., M. H. Freilich, and R. T. Guza, 1990, Model-Data comparisons of moments of non-breaking shoaling surface gravity waves, J. Geophys. Res., 95, 16,055-16,063. 25. Elgar, Steve, R. T. Guza, and M. H. Freilich, 1993, Observations of Nonlinear Interactions in Directionally Spread Shoaling Surface Gravity Waves, J. Geophysical Research, 98, 20299--20305. 26. Elgar, S., E. L. Gallagher, and R. T. Guza, 2000, Nearshore sand bar migration, Nature, sub judice. 27. Falques, A., A. Montoto and V. Iranzo, 1996, Bed-flow instability of the longshore current, Continental Shelf Res., 16. 28. Falques, A., A. Montoto, and D. Vila, 1999, A note on hydrodynamic instabilities and horizontal circulation in the surf zone, J. Geophys. Res., 104 (C9), 20,605-20,615. 29. Feddersen, F., R. T. Guza, S. Elgar, T. H. C. Herbers, 1998, Alongshore momentum balances in the nearshore, J. Geophys Res., 103, 15,667-15,676.



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30. Foster, D. L., 1996, Dynamics of the Wave Bottom Boundary Layer, Ph.D. Thesis, Oregon State University, 114pp. 31. Foster, D. L., R. A. Beach and R. A. Holman, 1999, Field Observations of the Wave Bottom Boundary Layer, J. Geophys. Res., in press. 32. Freilich, M. H., R. T. Guza, and Steve Elgar, 1990, Observations of nonlinear effects in directional spectra of shoaling surface gravity waves, J. Geophysical Research, 95, 9645--9656. 33. Gallagher, E. L., S. Elgar, and R. T. Guza, 1998, Observations of Sand Bar Evolution on a Natural Beach, J. Geophysical Res. 103, 3203-3215. 34. Gallagher, E. L., S. Elgar and E. B. Thornton, 1998, Observations and predictions of megaripple migration in a natural surf zone, Nature, 394, 165-168. 35. Garcez Faria, A. F., E. B. Thornton, T. P. Stanton, C.V. Soares, and T. C. Lippmann, 1998, Vertical Profiles of Longshore Currents and Related Bed Shear Stress and Bottom Roughness, J. Geophys. Res. 103, 3217-3232. 36. George, R., R. E. Flick, and R. T. Guza, 1994, Observations of Turbulence in the Surf Zone, J. Geophys. Res. 99, 801-810. 37. Gleik, J, Chaos, 1998, Making the new science, 354pp, Penguin Books, New York. 38. Goldstein, R. M., and H. A. Zebker, 1987, Interferometric radar measurements of ocean surface currents, Nature, 328, 707-709. 39. Grant, W. D. and O. S. Madsen, 1986, The continental shelf boundary layer, Annual Rev. Fluid Mech., 18, 265-305. 40. Haines, J. W. and A. H. Sallenger, 1994, Vertical Structure of Mean Cross-Shore Currents Across a Barred Surf Zone, J. Geophysical Res. 99, 14223-14242. 41. Haller, M. C., R. A. Dalrymple, and I. A. Svendsen, 1998, Rip channels and nearshore circulation, Coastal Dynamics >97, 594-603. 42. Hanes, D. M., 1991, Suspension of sand due to wave groups, J. Geophysical Research, 96 (C5), 8911-8915. 43. Hanes, D. M., and D. A. Huntley, 1986, Continuous measurements of suspended sand concentration in a wave dominated nearshore environment, Continental Shelf Research, 6 (4), 585-596.



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APPENDIX III VARIOUS PUBLICATIONS ON COASTAL PROCESSES, MANAGEMENT AND ENGINEERING


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88..00 R RE EFFE ER RE EN NC CE ES SA AN ND DR RE EA AD DIIN NG G LLIIS STT The following is the reference and reading list recommended for this course. All books were provided free of charge to students throughout the programme.

Allsop, N.W.H., (ed.). 1998: Coastline Structures and Breakwaters. Pub: Thomas Telford Ltd, London. American Society of Civil Engineers., 1995 Hydrographic Surveying. No.25. Pub: ASCE, U.S.A. Bacon, P.R., Deane, C.A., and Putney, A.D., 1988: A Workbook of Practical Exercises in Coastal Zone Management for Tropical Islands. Pub: Commonwealth Secretariat, London. Badgley, P.C., 1959: Harper’s Geoscience Series: Structural Methods for the Exploration Geologist. Pub: Harper & Brothers, New York. Berkman, D.A., 1989: (comp.) Field Geologist’s Manual. (3rd ed.) Pub: The Australian Institute of Mining and Metallurgy. Butler, B.C.N., and Bell, J.D.,1988: Interpretation of Geological Maps. Pub: John Wiley & Sons, Inc., New York. Cambers, G., 1998: Coping with Beach Erosion. Coastal Management Source Books. Pub: UNESCO, France. Cheng, F.Y., and Sheu, M.S., (ed.). 1995: Urban Disaster Mitigation. Pub: Elsevier, Great Britain. CIRIA Special Publication., 1991: Manual on the use of rock in coastal and shoreline engineering. CUR Report 154. Pub: A. A. Balkema Publishers, Netherlands. Clark, J.R., 1995: Coastal Zone Management Handbook. Pub: CRC Lewis Publishers, New York/London/Tokyo. Crandell, D.R., Booth, B., Kusumadinata, K., Shimozuru, D., Walker, G.P.L., and Westercamp, D., 1984: Source-book for volcanic-hazards zonation. Natural Hazards 4. Pub: UNESCO, France. Dennison, J.M., 1968: Analysis of Geological Structures. Pub: W.W. Norton & Company, Inc., U.S.A. Driscoll, F.G., 1986: Groundwater and wells. Pub: Johnson Division, St Paul, Minnesota 55112.

Economic and Social Commission for Asia and the Pacific.,1991 Manual and Guidelines for Comprehensive Flood Loss Prevention and Management. Pub: UNDP. Fairbairn, T.J., 1997: The Economic Impact of Natural Disasters in the South Pacific. With special reference to Fiji, Western Samoa, Niue and Papua New Guinea. Pub: Quality Print LTD, Suva, Fiji. Fetter, C.W., 1994: Applied Hydrogeology (3rd ed.). Pub: Prentice Hall Inc. U.S.A. Garcia, L., 1997: Developing Effective Education and Awareness Programmes. An information guide for national disaster management officials. (No Publisher detail). ISBN: 982-364-002-5. Georgiou, S., Whittington, D., Pearce, D., and Moran, D. 1997: Economic Values and the Environment in the Developing World. Pub: Edward Elgar Publishing Ltd, UK. Hailwood, E.A., and Kidd, R.B., (ed.)., 1990: Marine Geological Surveying and Sampling. Pub: Kluwer Academic Publishers, Boston/London. Hamnett, M.P., 1996: Natural Disaster Mitigation in Pacific Island Countries. A policy guide for planners and decision makers. Pub: Pacific Printery Ltd. Hamnett, M.P., 1996: Natural Disaster Mitigation in Pacific Island Countries. A policy guide for planners and decision makers. Briefing Manual. Pub: Pacific Printery Ltd. Irvine, W., 1995: Surveying for Construction. (4th ed.) Pub: McGraw-Hill Companies, London. Ishihara, K., 1996: Soil Behaviour in Earthquake Geotechnics. Pub: Clarendon Press, Oxford. Kearey, P., and Brooks, M., 1991: An Introduction to Geophysical Exploration. (2nd ed.). Pub: Blackwell Scientific Publications, Oxford. Kreimer, A., and Munasinghe. (ed.)., 1991: Managing Natural Disasters and the Environment. Pub: Environmental Policy and Research Division/The World Bank, Washington DC. Latter, J.H., Lloyd, E.F., Smith., I.E.M., and Nathan, S., 1992: Volcanic Hazards in the Kermadec Islands, and at Submarine Volcanoes between Southern Tonga and NewZealand (Vol 17). Pub: Department of Geology, Auckland. Lislie, R.J., 1995: Geological Structures and Maps: A Practical Guide. (2nd ed.) Pub: Butterworth-Heinemann Ltd, Oxford. McConnell, K., 1998: Revetment systems against wave attack – A design manual. Pub: Thomas Telford Ltd, London. McGregor, A.M., and McGregor, I.K.L., 1999: Disasters and Agriculture in the Pacific Islands. Pub: UNDP-South Pacific Office.

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