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<br />Jetty Stream Sank '~:osion Conttol <br /> <br />Jetties are an effective method of controlling stre~m bank erosion an slli~e <br />to moderately meandering curve" Jetties ty~icaLly are not feasiole ac. s:,ar? <br />curves, Jetties f\1l1ction by deflecting the flaw from ehe stream al<ay from :oe <br />stream bank. Jetties can be cOnstructed completely from rock or they can ~awe <br />a di~t, sand or gravel core with rock on the surface for erosion protection. <br />Rack must be large enough to withstand the farce of the I<ater without belni <br />displaced, T~e si.e and spaci., of the jetties dopends an the physicaL c~ar- <br />actaristics of the strea~; for example, the channel width and the 3harpness of <br />the c.urve. A jett)r should not extend into the stream frorQ the bank mOl~e t:"'1.an <br />20 percent of the channel width, The design of jetties requires an ev.lua.lan <br />of the downstream c~hannel and bank conditions to d\void causing erosion a':1.d <br />ather prab leu. <br /> <br />Jetties <br />tices . <br />reaches <br /> <br />can be used to protect a stream bank without using any other t'rac- <br />However, il: is generally recommended to shape and seed the bank <br />between jei:tiu, <br /> <br />~aintenance requirements for this practice include replaclng or reposielanini <br />any rack which has been displaced. Over a period of a few years, sediment <br />bars may develop n....r the downstream end of the joetty. These "ravel bare <br />should be removed 1;0 keep the Jetty system functioning properly, A malnten- <br />ance lnspecdon Shl>11ld include a look at the downstream bank to check far <br />erosion which could have been caused as a result of the jetties, <br /> <br />36 <br />