Open Channel Calculator
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<table width=”100%” border=”0″ cellspacing=”0″ cellpadding=”5″>
<tr> <td valign=”top”> <SCRIPT src=”opencalc.js”>
…
</SCRIPT> <FORM method=post> <TABLE border=1 cellSpacing=5 class=”size12pt”><TBODY> <TR> <TH>Required Information</TH> <TR> <TD>Enter the Slope:</TD><TD><INPUT onchange=SetSlope(this) size=4 name=FSlope></TD><TD>Enter the <B>Channel</B> Top Width (feet):</TD><TD><INPUT onchange=SetTw(this) size=4 name=FTw></TD> </TR> <TR> <TD>Enter the <B>Channel</B> Bottom Width (feet):</TD><TD><INPUT onchange=SetBw(this) size=4 name=FBw></TD><TD>Enter the <B>Channel</B> Height (feet):</TD><TD><INPUT onchange=SetHeight(this) size=4 name=FHeight></TD> </TR> <TR> <TD>Enter the <B>Flow</B> Depth (feet):</TD><TD><INPUT onchange=SetDepth(this) size=4 name=FDepth></TD><TD>Enter the n value:</TD><TD><INPUT onchange=Setnval(this) size=4 name=Fnval></TD> </TR></TBODY> </TABLE> <P> <TABLE cellSpacing=5 border=1><TBODY> <TR> <TD colSpan=2><INPUT name=”button” type=button onclick=Opencalc(this.form) value=Calculate!></TD><TD colSpan=2><INPUT type=reset value=Reset name=Reset></TD> </TR></TBODY> </TABLE> <table width=”100%” border=”0″ cellspacing=”0″ cellpadding=”5″><tr> <td valign=”top”><TABLE border=1 cellSpacing=5 class=”size12pt”> <TBODY><TR> <TH colSpan=3>Results</TH><TR> <TD colSpan=3>The wetted perimeter is <INPUT size=3 name=FPer>Feet. <P></P></TD></TR><TR> <TD colSpan=3>The <B>flow</B> area is <INPUT size=3 name=Farea>Square Feet. <P></P></TD></TR><TR> <TD colSpan=3>The hydraulic radius is <INPUT size=3 name=FRh>Feet. <P></P></TD></TR><TR> <TD colSpan=3>The C value is <INPUT size=4 name=FCval> <P></P></TD></TR><TR> <TD colSpan=3>The <B>flow</B> is <INPUT size=4 name=Fcfs>CFS. <P></P></TD></TR><TR> <TD colSpan=3>The <B>flow</B> is <INPUT size=6 name=Fgpm>GPM. <P></P></TD></TR><TR> <TD colSpan=3>The velocity is <INPUT size=4 name=Fvel>FPS. <P></P></TD></TR> </TBODY></TABLE></td> <td width=”50%” valign=”top”><span class=”size12pt”><strong>Design Use Values of Manning’s <i>n</i> </strong></span> <TABLE BORDER CELLSPACING=5 class=”size10pt”> <TR> <TD><b>Channel Material</b></TD><TD><i><b>n</b></i></TD> </TR> <TR> <TD>clean, uncoated cast iron</TD><TD>0.013-0.015</TD> </TR> <TR> <TD>clean, coated cast iron</TD><TD>0.012-0.014</TD> </TR> <TR> <TD>dirty, tuberculed cast iron</TD><TD>0.015-0.035</TD> </TR> <TR> <TD>riveted steel</TD><TD>0.015-0.017</TD> </TR> <TR> <TD>lock-bar and welded</TD><TD>0.012-0.013</TD> </TR> <TR> <TD>galvanized iron</TD><TD>0.015-0.017</TD> </TR> <TR> <TD>brass and glass</TD><TD>0.009-0.013</TD> </TR> <TR> <TD><b>wood stave</b></TD> </TR> <TR> <TD><LI>small diameter</TD><TD>0.011-0.012</TD> </TR> <TR> <TD><LI>large diameter</TD><TD>0.012-0.013</TD> </TR> <TR> <TD><b>concrete</b></TD> </TR> <TR> <TD><LI>with rough joints</TD><TD>0.016-0.017</TD> </TR> <TR> <TD><LI>dry mix, rough forms</TD><TD>0.015-0.016</TD> </TR> <TR> <TD><LI>wet mix, steel forms</TD><TD>0.012-0.014</TD> </TR> <TR> <TD><LI>very smooth, finished</TD><TD>0.011-0.012</TD> </TR> <TR> <TD>vitrified sewer</TD><TD>0.013-0.015</TD> </TR> <TR> <TD>common-clay drainage tile</TD><TD>0.012-0.014</TD> </TR> <TR> <TD>asbestos</TD><TD>0.011</TD> </TR> <TR> <TD>planed timber</TD><TD>0.011</TD> </TR> <TR> <TD>canvas</TD><TD>0.012</TD> </TR> <TR> <TD>unplaned timber</TD><TD>0.014</TD> </TR> <TR> <TD>brick</TD><TD>0.016</TD> </TR> <TR> <TD>rubble masonry</TD><TD>0.017</TD> </TR> <TR> <TD>smooth earth</TD><TD>0.018</TD> </TR> <TR> <TD>firm gravel</TD><TD>0.023</TD> </TR> <TR> <TD>corrugated metal pipe</TD><TD>0.022</TD> </TR> <TR> <TD>natural channels, good condition</TD><TD>0.025</TD> </TR> <TR> <TD>natural channels with stones and weeds</TD><TD>0.035</TD> </TR> <TR> <TD>very poor natural channels</TD><TD>0.060</TD> </TR></TABLE></td></tr> </table></FORM><div align=”right”><span class=”size10pt”>Copyright 1998 Donald R.Milam, PE </span> </div></td></tr><tr> <td> <div align=”center” class=”size10pt”></div></td></tr> </table>
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