Runoff computations: Los Angeles County

<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>Runoff computations: Los Angeles County</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> The 600-sq mi Santa Clara River basin in Los Angeles County, California, is the site of significant proposed development, and our client, the Los Angeles County Department of Public Works, is responsible for floodplain management and drainage in that basin. Accordingly, the Department initiated a review of runoff computation methods in the basin, and contracted with us to assist.</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= 377 WIDTH="537"><div> We reviewed current standards for estimating design storm runoff and suggested improvements to these procedures. We developed an extensive historical hydrometeorological database for the basin, using HEC-DSS. We developed for the watershed a geographic information system (GIS), with relevant data on soil types, land use, elevation, and so on. Then, we combined these databases to calibrate HEC-1 models for 801 subcatchments in the basin. Finally, we used the calibrated models to compute runoff hydrographs throughout the system for the LA County design storm. These hydrographs are stored in an HEC-DSS database. </div> <div> We developed and provided a specialized visualization tool, which we designated<FONT SIZE="2" COLOR="#111111" FACE="Verdana" > the Santa Clara Viewer, as a component of this work. The Viewer is illustrated on this page. It queries and retrieves, from an HEC-DSS database, design storm hydrographs throughout the Santa Clara River watershed. The database queries are formed within the Viewer, based upon where on the map a user clicks. To provide the retrieving and plotting capability, we developed the Viewer in Visual Basic. It integrates our own HEC-DSS database manipulation library, ESRI's MapObjects GIS tool, and a third-party graphing tool.</FONT></div> <div> The Santa Clara Viewer illustrates how we bring together our skills and knowledge of hydrologic engineering and decision support systems. Using GIS analytical capabilities, we developed rainfall-runoff models of the watershed. Model parameters were estimated from spatial relationships of land use and soil type data, subcatchment boundaries were delineated with a digital elevation model, and so on. The hydrographs computed with the models were stored in the HEC-DSS database. </div> </tD> </tR> </TABLE></B></div> <div> <B><IMG SRC="17913710.png" border=0 width="531" height="369" ALT="Bitmap Image" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <bR> <bR> <div>  </div> </td> </tr></table></body>