not penetrate the area, although the site may appear to be well protected from those 

 directions. Before selecting a harbor in a roadstead location, the vulnerable approach 

 directions must be carefully analyzed by thorough examination of historical wind and wave 

 records and by wave refraction study techniques. A special case of roadstead siting is a 

 harbor on the lee side of an offshore island, where the island acts as a breakwater against the 

 prevailing waves. 



6. Open Shorelines. Some factors controlUng harbor location dictate that a site be selected 

 along an open shoreline. In this case, protection against wave action must be achieved by 

 breakwater-type structures (Fig. 6). Two steps that will provide guidance on site selection 

 are: (a) to make a statistical study of the historical wave chmate coupled with wave 

 refraction analysis to pinpoint areas of frequent wave convergence; and (b) to make 

 subsurface probes to detect bedrock levels that can be used to ascertain the possibihty of 

 keeping the harbor close to shore by dredging into the shallow nearshore bottom to obtain 

 navigable depth. Both steps require the assistance of specialists. The resulting information 

 will be useful in the detail design of the harbor complex after the site has been selected. 



7. Riverside Sites. Rivers often provide excellent water courses for smaU-craft cruising. 

 Harbor sites may be found along or just behind a river bank, the choice usually depending 

 on good road access to the site and places where the current near the bank is minimal. 

 Floating docks may be anchored to dolphins or boomed out from the shore on the open 

 river, where they are not in violation of navigation-encroachment regulations and flood 

 control or other restrictions (Fig. 7). Some protection from floating debris and ice may be 

 required, depending on the physical environment and characteristics of the river. Also, 

 provision must be made for adjustment of the floating system to fluctuations in the water 

 level of the river. 



In some instances, channels and basins may be excavated into and behind the river bank 

 to provide safe small-craft harbors. The navigation entrance to the basin should be at a point 

 along the river bank where the current is minimal and preferably connect with the 

 downstream end of the basin. The site must be located in an area where it can cope with 

 extreme high and low river levels both with respect to slip anchorage and access from the 

 land. Many off-river basins have entrance shoaling, as suspended sediment carried by the 

 river is deposited on the bottom in the quiet entrance waters. Only experience will 

 determine the severity of this problem along a river and may dictate whether an off -river 

 basin or a complex of riverbank slips is best. 



IV. ENVIRONMENTAL SITING CONSIDERATIONS 

 1. Local Weather Factors. 



a. Precipitation. Normal rainfall or light snowfall present no serious problem in 

 small-craft harbor design, provided an adequate surface-drainage plan is adopted. Such a 

 plan must provide for a facihty capable of draining the waters from a maximum probable 

 rainfall without eroding the perimeter land; and also for the diversion of any possible 



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