The Corps of Engineers, Los Angeles District (SPL), has also begun studies 

 on Bolsa Chica known, as the "Feasibility Study", and it is important to 

 establish the relationship between the WES studies and SPL's efforts. SPL's 

 Feasibility Study will examine more alternatives than the two being examined 

 by the WES studies, and SPL will consider more than just the technical issues 

 being examined by WES. 



Scope . The studies of the Bolsa Chica area conducted by WES are grouped 

 into the following five general categories, three of which pertain to 

 modeling: 



a. Numerical modeling of long-term shoreline response as influenced 

 by placement of entrance channel stabilization structures, 

 including sand management concepts . 



b. Numerical modeling of tidal circulation, including transport and 

 dispersion of conservative tracers, in the Bolsa Bay, Huntington 

 Harbour, and Anaheim Bay complex. 



c. Physical modeling of the proposed entrance channel, interior 

 channels, and marina with regard to wave penetration, harbor 

 oscillation, qualitative sediment movement paths, and storm water 

 runoff . 



d. Assessment of the potential of the proposed non-navigable ocean 

 entrance to maintain itself as a tidal inlet in an open 

 configuration. 



e. Assessment of potential impacts to surfing that might arise from 

 construction of a project at Bolsa Chica. 



Details of these five tasks are provided in the following five sections . 



SHORELINE RESPONSE NUMERICAL MODELING 



Purpose . The purpose of the shoreline response modeling effort was to 

 utilize a proven numerical shoreline simulation model to assess and quantify 

 the potential long-term impacts of the proposed ocean entrance system at Bolsa 

 Chica due to the longshore movement of beach sand, and to evaluate the poten- 

 tial for mitigation of any adverse effects induced by the entrance. 



Tasks . The shoreline response modeling involved three major tasks: 

 preliminary shoreline response modeling, 20-year wave hindcast of the Bolsa 

 Chica region, and comprehensive shoreline response modeling. The preliminary 

 modeling task utilized existing shoreline change data and existing wave data 

 to develop, calibrate, and verify a shoreline change numerical model for the 



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