FOREWORD

"Let me just lay out for you four (4) or five (5) of the questions that are facing us which are indicative of the difficult problems we face in managing this area. First, should the State allow new construction or rebuilding along beaches that are subject to storm waves and repeated damages? If the answer to the question is 'No', how are we going to protect the rights of private property owners along the shorefront? Second, it is physically and economically feasible to protect shoreline property? Third, what responsibility, if any, do state taxpayers have to protect private beachfront property? Fourth, should those who locate hazard areas bear the risk and the financial burden for that decision? Fifth, if the state undertakes protective measures that benefit flood prone property owners, should the state recoup some or all of those costs from those property owners? If the answer is no, we must ask why not? If the answer is yes, we might ask how are we going to do it? Finally, is the present state authority adequate to deal with these problems; and if not, what kind of statutory action should be taken in our General Assembly to give the state the necessary power to do the job? The answers to those questions are difficult; in fact, some of them make you uncomfortable just thinking about them, but that's the nature of the beast."*

*Governor Pierre S. du Pont, IV, Introductory Remarks, Governor's workshop on the Management of Shoreline Erosion and Flood Prone Areas, March 6, 1978.

The geologic trends and processes which have formed the Delaware coastline into its present configuration began approximately 14,000 years ago, when the continental ice sheet began to recede. The resulting sea level rise has continued right up to the present time and can be expected to continue into the foreseeable future. The change in shoreline position during this period of sea level rise has been dramatic, as the shore responds to the pressure of the encroaching sea. About 14,000 years ago sea level was about 440 feet below its present elevation and the coast of Delaware was positioned approximately 100 miles eastward of its present location, at the edge of the continental shelf. Since that time, sea level has risen to its present position and has flooded across the continental shelf pushing back the sandy coast to where we find it today. Most indications are that the trend in sea level rise will continue.

Prior to the last "ice age" the shoreline position in Delaware was near the edge of the Piedmont, meaning that most of what is now the State of Delaware was under the sea. Sea level rise is returning the coast to a previously held position. If the present rate of sea level rise continues over the next 5,000 to 10,000 years, the shore of the Delmarva Peninsula will approximate the plus 50 foot contour and the Peninsula will become a series of isolated islands.

The present sea level rise rate, relative to land features, is approximately 1/2 foot per century. This vertical rise in sea level will result in a variety of erosion rates along the ocean and bay coasts depending upon storm frequency and intensity, and the topographic and geologic nature of the various beach segments. Continuity of the individual geomorphic units is carried out by influence of wind, waves, and currents reworking the sediment contained in the beach unit. Sediment is supplied to Delaware beaches from eroding Pleistocene headlands and neighboring beaches via littoral transport. The sedimentary unit extends underwater, and this underwater area is as important to the beach as is the visible portion of the beach. The marine transgressive barrier beaches of Delaware are created, maintained, and moved by ocean waters. Conservation of their natural size and proportion is maintained throughout this migration process, and understanding the marine transgression means accepting the long term scenario of encroachment of the sea into areas of present day uplands. Beach stabilization projects must be undertaken with the knowledge that their implementation will only serve to slow the natural processes for a relatively short period of time. It is also imperative to consider the entire sedimentary system and the effect on updrift and downdrift beaches when planning a shore protection system.

"A very large amount of work has been done on coastal erosion in the Delaware area by the U. S. Army Corps of Engineers. Some detailed statements as to rates of erosion, sediment sizes of beach sands, and recommendations for protection of the coastal zone against further erosion have been made. Much of the work of the U. S. Army Corps of Engineers has been analysis of the economics required of a system to protect the beach. In view of this, recommendations are sometimes made to build jetties or groins to interrupt the flow of sediment in the nearshore zone. Other recommendations have been to pump sand onto the beach to restore the beach to its former profile. As recognize by the U. S. Army Corps of Engineers, any such protection measures for the coastal zone, particularly the type of coastal zone that occurs in Delaware, are temporary in nature and must of necessity be considered procedures which need to be renewed. Over the short-term period (a decade or less), it is obvious to the geologist that change is the most pervasive element. This factor has long since been recognized by the U. S. Army Corps of Engineers and by other researchers. On the other hand, it is difficult for the public to recognize and accept this. Accordingly, there has existed considerable amounts of friction between agencies attempting to protect the shoreline position of the Delaware coastal zone and the public who 'call for the protection'. Concerned citizens often do not realize that the value of the land being protected may frequently be less than the cost of protection."**

**Dr. John C. Kraft and Dr. Chacko J. John, Introduction, the Geological Structure of the Shorelines of Delaware, Delaware Sea Grant Technical Report, #DEL-SG-14-76.

Shoreline change is most extreme during high energy storms periods. A beach which has appeared to be static over a relatively long period of time can experience rapid change in its configuration. The following account of storm activity illustrates this point.

Storm Damage Data

Storms. Two types of storms can produce serious damage to the Delaware Coast. These are defined in terms of their zone of origin; either tropical or extra-tropical. Those storms of tropical origin in which the wind velocity is greater than 74 miles per hour are considered to be hurricanes. Storms of extra-tropical origin, though they may follow any of several paths in affecting the area, are typically characterized by strong easterly or northeasterly winds and are commonly designed "northeasters". Tropical storms reach these latitudes with hurricane force predominately in late summer and fall. Northeasters, though not excluded completely from the warm season, are far more prevalent during the colder portion of the year.

Tropical hurricanes are potentially the most intense storms reaching the Atlantic Coast in these latitudes. These disturbances usually lose their intensity before reaching the Delaware Coast, but in the unusual cases where their strength is retained, they can be very destructive. The centers of tropical storms have passed both inland and seaward of the Delaware Coast, but no hurricane intensity storm center in historic time has passed directly over the Delaware Coast area. The potentiality of such an experience is very real and the physical effects to be expected therefrom have been taken into account in determining the average value of annual damage. Tide and wind data associated with the significant storms of record are presented on Table 1.

Hurricane damage along the Delaware Coast has been relatively light because few hurricanes, if any, have made direct landfall in the recorded past. Early observation and recording of storm activity was incomplete, but major storms in the Delmarva Peninsula area were observed and recorded as early as 1667 when a major storm swept through the area. A major storm reached Delaware in 1821, wreaking considerable destruction in Lewes. The absence of coastal resorts during this time period prevented coastal damage from being newsworthy. Undoubtedly severe erosion, overwash, and inlet cutting occurred, but with little effect or consequence to man.

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