the foreshore zone retreats parallel to itself with rising water level. 

 (Author) . 



081 DUBOIS, R. W. 1976. "Nearshore Evidence in Support of the Bruun Rule 

 on Shore Erosion," Journal of Geology . Vol 84, pp 485-491. 



The Bruun Rule on shore erosion states that for a beach and nearshore 

 profile at equilibrium, as water level rises, sediments are eroded from the 

 beach and deposited in the nearshore zone; in turn, the nearshore bottom is 

 elevated in direct proportion to the rise in water level. The Rule was tested 

 under field conditions. At Terry Andrae State Park, Wisconsin, nearshore pro- 

 files in Lake Michigan were surveyed once a week from April through July as 

 lake water level seasonally rose. The nearshore zone consists of two long- 

 shore bars which parallel the shore. The Bruun Rule is applicable in the zone 

 of the first longshore bar system. As lake water level rose, the bars ad- 

 vanced landward, and from the base of the foreshore to the crest of the first 

 bar, the elevation of the nearshore bottom increased. On the lakeward slope 

 of the first bar crest, no deposition or erosion occurred. The elevation of 

 the second bar crest remained constant as water level rose. (Author). 



082 DUBOIS, R. N. 1980. "Hypothetical Shore Profiles in Response to Rising 

 Water Level," Proceedings of the Per Bruun Symposium . Newport, Rhode Island, 

 International Geographical Union Commission on the Coastal Environment, Bureau 

 for Facility Research, Western Washington University, Bellingham, Washington, 

 pp 13-31. 



The purpose of this paper is to present some of my thoughts on how shore 

 profiles should respond to rising water levels. The first part of this paper 

 will focus on the behavior of an equilibrium shore profile in response to a 

 rise in water level; the state of equilibrium will be with respect to wave 

 action and sediment supply. The second part of this paper will deal with the 

 behavior of disequilibrium shore profiles in response to rising water levels; 

 the state of disequilibrium will be with respect to sediment supply and wave 

 action, respectively. Throughout this paper, it is assumed that the physical 

 properties of sediments in each segment of a shore profile remain reasonably 

 constant as the magnitude of coastal processes varies. 



The behavior of a shore profile can be conceptualized to range from a 

 state of complete equilibrium to a state of complete disequilibrium with 

 respect to coastal processes. A shore profile adjusts to wave dimensions, 

 sediment supply, and water levels. If the magnitude of each of these primary 

 variables remains constant, then the profile can be viewed as being in a state 

 of complete equilibrium. On the other hand, if the magnitude of all process 

 variables continues to change with the passage of time, then the profile can 

 be viewed as being in a state of complete disequilibrium. A shore profile may 

 also exist in a state between complete equilibrium and complete disequilib- 

 rium; for example, a profile may be in equilibrium with one or two of the 

 process variables and in disequilibrium with the rest of the variables. 



When a shore profile is in complete equilibrium, the position of the 

 total profile relative to a fixed point on land and the shape of the profile 



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