Private Water Crossings: Considerations Before You Build

14 | PRIVATE WATER CROSSINGSA box culvert is a crossing design that is usedmore frequently in areas where habitat protectionis important. A single or series of box culverts areembedded with continuous streambed materialthrough the structure. These structures perform likea bridge by matching the channel width.It is important that any washout of streambedmaterial during high water flow is refilled naturallywith sediment as flow recedes.ROAD SURFACEBANKFULL WIDTHNATURAL CHANNELPROFILEANTI-SCOURDOWNSTREAMCUTOFF WALL(TYPICALLY 3’ - 5’DEEP)Figure 3.3-3. Embedded box culvertsEmbedded box culverts maintain a continuousstreambed through the structure. If site conditionspermit, an open-bottom box with a natural streamEMBEDDED BOXCULVERTS SETBELOW CHANNELLEVEL 12”-24” TOFORM A “NATURAL”STREAM BOTTOMchannel bottom is preferable in sustaining channelfunction.Figure 3.3-4. Concrete vented ford - The number of box openings depends upon the width and flow of the channel. A continuousstreambed maintains channel function.