Yuba-Feather supplemental flood control project

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" rowspan="2" width=185 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <A HREF="index.htm" TARGET="_top" TITLE="David Ford Consulting Engineers"><U><B><IMG SRC="0d058960.png" border=0 width="88" height="150" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></U></A></div> <bR> <div>    <FONT SIZE="1" COLOR="#000000" FACE="Verdana" > </FONT></div> <div> <B> <TABLE BORDER="0" CELLPADDING="4" CELLSPACING="1" WIDTH="156" BORDERCOLORLIGHT="#FFFFFF" BORDERCOLORDARK="#FFFFFF" FRAME="VOID" RULES="NONE" HSPACE="0" VSPACE="0" > <tR> <tD VALIGN=TOP HEIGHT= 27 WIDTH="146"><div> David Ford Consulting Engineers, Inc.</div> </tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 27 ><NOBR><div> 2015 J Street, Suite 200</div> <div> Sacramento, CA 95811</div> </NOBR></tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 27 WIDTH="146"><div> tel: 916.447.8779</div> <div> fax: 916.447.8780</div> </tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 27 WIDTH="146"><div> <A HREF="mailto:support@ford-consulting.com" TARGET="_top" TITLE="mailto:support@ford-consulting.com"><U>support@ford-consulting.com</U></A></div> </tD> </tR> </TABLE></B></div> <div>    </div> <bR> <div> <A HREF="index.htm" TARGET="_top" TITLE="David Ford Consulting Engineers"><U>Home</U></A></div> <div> <A HREF="id461.htm" TARGET="_top" TITLE="About us"><U>About us</U></A></div> <div> <A HREF="news.htm" TARGET="_top" TITLE="News"><U>News</U></A></div> <div> <A HREF="hydrologic_engineering.htm" TARGET="_top" TITLE="Hydrologic engineering"><U>Hydrologic engineering</U></A></div> <div> <A HREF="water_resource_planning.htm" TARGET="_top" TITLE="Water resource planning"><U>Water resource planning</U></A></div> <div> <A HREF="flood_economic_and_risk_analyses.htm" TARGET="_top" TITLE="Flood economic and risk analyses"><U>Flood economic/risk analyses</U></A></div> <div> <A HREF="flood_warning.htm" TARGET="_top" TITLE="Flood warning"><U>Flood warning</U></A></div> <div> <A HREF="decision_support_system_development.htm" TARGET="_top" TITLE="Decision support system development"><U>Decision support systems</U></A></div> <bR> </td> <td valign="top" colspan=2 height=40 BGCOLOR="#3366CC" TEXT="#080000" bgproperties="fixed" background="14400980ezthpx.png"> <div> <B>Yuba-Feather supplemental flood control project</B></div> <div> </div> </td> </tr><tr> <td valign="top" height=440 colspan=2 BGCOLOR="#FFFFFF" TEXT="#080000" bgproperties="fixed" background="06c00962egerdp.png"> <div> <TABLE BORDER="0" CELLPADDING="2" CELLSPACING="1" WIDTH="547" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="ALL" HSPACE="0" VSPACE="0" > <tR> <tD VALIGN=TOP COLSPAN=3 BGCOLOR=#CC0000 HEIGHT= 16 WIDTH="537"><div> <B>Situation</B></div> </tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=3 HEIGHT= 205 WIDTH="537"><div> In the past half-century, levees on the Yuba and Feather Rivers in Northern California have failed five times. These levee breaks have resulted in the loss of 41 lives and caused significant property damage in the areas adjacent to the confluence of the two rivers. The Three Rivers Levee Improvement Authority (TRLIA), a joint powers agency between Reclamation District 784 and Yuba County, has taken a proactive role in investigating alternative means of providing supplemental flood control in the region. TRLIA has already constructed levee fixes and setbacks along the Yuba River, Bear River, and lower Feather River. Now, TRLIA is evaluating alternatives for enhancing the upper Feather River levee south of Marysville. This evaluation is Phase IV of the overall Yuba-Feather Supplemental Flood Control Project.</div> <bR> </tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=3 BGCOLOR=#339933 HEIGHT= 16 WIDTH="537"><div> <B>Action</B></div> </tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=3 HEIGHT= 573 WIDTH="537"><div> YCWA asked us to evaluate the damage reduction benefits of the proposed alternatives, using procedures that would be acceptable to the Corps of Engineers and to the California Department of Water Resources. Our assignment called for us to compute economic benefits for sixteen proposed inundation-reduction alternatives and to prepare a technical document describing our methods and summarizing our findings.</div> <div> We assembled an economic analysis model that considered potential flood damages in seven impact areas (IA) adjacent to the confluence of the Yuba and Feather Rivers, shown in the figure. We applied Corps uncertainty analysis methods to compute expected annual damage (EAD) for the without-project condition and each of sixteen proposed alternatives.  We also computed the present value of expected project benefits based on a 50-year project life.</div> <div> <IMG SRC="218564f0.jpg" border=0 width="342" height="335" ALIGN="RIGHT" HSPACE="6" VSPACE="6">The possibility of multiple locations of inflow to the impact areas provided an additional technical challenge for this work. To account for this, we developed an innovative scheme that computed system-wide EAD based on levee-failure risk along the various damage reaches in the study area.</div> <div> EAD and other measures of risk and project performance were computed and reported. These, along with environmental assessments by others, provide indices for comparing alternatives and for selecting a plan for construction.</div> <bR> </tD> </tR> </TABLE></div> <bR> <bR> <bR> <bR> </td> </tr></table></body>