Hydraulic modeling of Stewart Tract, Sacramento-San Joaquin Delta

<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>Hydraulic modeling of Stewart Tract, Sacramento-San Joaquin Delta</B></div> <div> </div> </td> </tr><tr> <td valign="top" height=440 colspan=2 BGCOLOR="#FFFFFF" TEXT="#080000" bgproperties="fixed" background="06c00962egerdp.png"> <div> <B> <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= 82 WIDTH="537"><div> Our client planned a development on a tract in the San Joaquin River (California) delta. The tract is surrounded on all sides by levees. The client wished to reconstruct the levees to provide additional protection, and originally asked us to define the hydrologic boundary conditions (upstream flow and downstream stage) for computation of design stages at the tract. </div> </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= 443 WIDTH="537"><div> We developed a strategy for determining the proper combination of upstream and downstream boundary conditions for this complex hydraulic system, using an integrated hydrologic / hydraulic / statistical model. We first developed appropriate upstream and downstream boundary conditions for defining the design event. Through research, we discovered upstream discharge-frequency and downstream stage-frequency functions that were developed by the Sacramento District of the Corps. Next, we developed a UNET model of the system, using topographic and bathymetric data gathered from the Corps, from the State of California Department of Water Resources, and from surveys commissioned for this study. We calibrated UNET with historical stage data, which we retrieved from USGS and State of California Web sites. Then we identified design event boundary conditions by analyzing combinations of upstream and downstream boundary conditions, seeking the combination that yielded a design event elevation that matched well the elevation developed with statistical analysis of data at a gage adjacent to the tract.</div> <div> In subsequent work, we used UNET to evaluate the impact of various levee breaches on the tract and on the surrounding area to rate hydraulic structures and to quantify the hydraulic impacts of various configurations of the levee system.</div> <div> In January 1997 a major flood caused significant flooding in the region. The damage included more than 14 levee breaches and relief cuts and the flooding of our client's tract. Our client asked us what the outcome would have been if the proposed project had been in place during the flood. To answer the question, we exercised the capabilities of UNET (such as levee breaches, timed gate openings, and routing between storage areas) to model the complex flooding that was observed. We were able to accurately reproduce much of the event and provide our client with the answers they required.</div> </tD> </tR> </TABLE></B></div> <bR> </td> </tr></table></body>