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the Animas River basin. This report also determines the average velocity of the 100 year peak <br />flow event to be 8 feet/second. In designing the size of the boulders used in the rock jetty, it <br />was assumed that the uppermost tier of boulders (1 or 2 boulders) would be the weakest since <br />they do not have the weight of any boulders above them. The size of the boulders were ana- <br />lyzedusing the CSU procedure, which sums the moments around a pivot point and calculates <br />the turning forces in a given condition to determine a safety factor. A safety factor is calcu- <br />lated for a boulder in a normal bed and on a sideslope. The calculations aze presented below: <br />Project Name: THOMAS PIT JETTY <br />Date: 01/19/02 By:" GL <br />Description: JETTY OF 5' DURABLE ROCK FOR 100 YR EVENT <br />ASSUME FLOW IS 6.5 FEET HIGH OR 1.5 FEET <br />ABOVE UPPERMOST BOULDER <br />TEST 1 RIPRAP STREAMBED LINING CSU PROCEDURE <br />INPUT D= 6.5 Depth of flow feet <br />INPUT Y= 62.4 Density of water Ib/cu.ft. <br />INPUT S= 0.00734 slope of channel %/100 <br /> T= Tractive force Ib/cu.ft. <br /> T= 2.877104 =(D'Y*S) <br />N= Stability = 21T no units <br /> Parameter Y(SG-1)Dso forturbulentflow <br />INPUT Dso• 4.5 Average diameter of riprep in feet <br /> SG= 2.65 Speafic Gravity of the rock used <br />from above N= 0.134937 <br />INPUT 0= 70 Angle of repose of riprap Degrees <br />INPUT 2= 0.41997 Bedstope angle Degrees <br />SF(BOTTOM)= 7.266972 cos( *tan O SAFEfY FACTOR <br />sm +N*tan(O) <br />BOTTOM RIPRAP IS STABLE <br />TEST 2 RIPRAP BANK LINING <br />INPUT A= 0.41997 Angle of streamline (bed) assuming uniform Row <br /> (same as bedslope angle Z) DEGREES <br />INPUT SS= 63.43 sideslope angle <br />B= 11.69162 tan'' (cos(A)/(2*sin(A)/N*tan(O)+sin(A)) <br /> 0.206938 <br />N'= 0.081625 fJ* f1+SIN(A+B)/2) BANK STABILITY PARAMETER <br />SF(BANK)= 2.456051 cos(A)*iari(~ 2.747404 <br /> N'*tan(O) + sin(SS)*cos(B) 1.118627 <br /> BANK RIPRAP IS STABLE <br />Thomas Pit 2/02 15 <br />