maintenance costs which can be justified for the navigation project and 

 experience with maintenance requirements on that project to that time, 

 provided, however, that the Federal shares shall not exceed 42 percent of 

 the costs of those increments. 



The Chief of Engineers concurred in the views and recommendations 

 of the Beach Erosion Board. 



WAIMEA BEACH AND HANAPEPE BAY, KAUAI. T. H . 



Waimea Beach and Hanapepe Bay are located about 7 miles apart on the 

 south shore of Kauai, an island about 27 miles in diameter in the 

 Hawaiian group. Agriculture is the basic economic activity on the island. 

 The populations of the villages of Waimea and Hanapepe are respectively 

 about 5,900 and 1,500. At Waimea, the problem area is about 1,240 feet 

 long, of which 624 feet of shore is publicly owned. At Hanapepe Bay, 

 the problem area is about 1,525 feet long, of which about 1,225 feet of 

 shore is publicly owned. Kauai is an island of volcanic origin with 

 rugged terrain. The steep streams bring large quantities of debris to 

 the shore during periods of storm runoff. The problem beaches, located 

 respectively west of Waimea and Hanapepe Rivers, are composed almost 

 entirely of these materials. Beaches east and west of the problem areas 

 are composed principally of coral and shell derived from marine sources. 

 The prevailing winds in the Hawaiian Islands are the northeast trade 

 winds. Waves generated by these winds are refracted before reaching 

 the south shore of Kauai and approach the problem areas from the southeast. 

 Waves from the south are higher but are less frequent. 



At Waimea Beach there appears to be a general westward predominance 

 of littoral drift as a result of the wave action from t he southeast and 

 southerly swells, however, there has been accretion at the wall at the 

 mouth of Waimea River. Apparently, the problem area about 1,240 feet 

 long, beginning 500 feet west of the river mouth, is a nodal zone from 

 which material is lost in both directions. At Hanapepe the breakwater 

 on the east side of the bay shelters the bay head beach from waves from 

 the southeast. Diffracted waves and southerly swell cause eastward 

 movement of beach material and progressive erosion on the western half 

 of the shore at the head of the bay. 



The Division and District Engineers and the Beach Erosion Board 

 concluded that the plan of protecting the publicly owned shores of Waimea 

 Beach and Hanapepe Bay by constructing rubble-mound seawalls is the 

 most practicable of all the methods studied because of its low initial 

 and annual costs. They further concluded that the work is economically 

 justified and that the Federal Government should participate in the 

 improvements of the publicly owned shores by bearing one-third of the 

 initial costs of construction. They recommended adoption of a project 

 for construction of rubble-mound seawalls for the protection of the 

 shore areas at Waimea Beach and Hanapepe Bay, the United States to 

 reimburse local interests to the extent of one-third of the first cost 

 of protection of the publicly owned shores, subject to certain conditions. 



The Chief of Engineers concurred in the views and recommendations 

 of the Beach Erosion Board. 



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