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• rock vein construction will be placed along the toe of the embankments as shown in Drawing 2 to <br />further reinforce bank stabilization at kev locations. <br />The rock veins will be constructed starting at the upstream location shown on Drawing 2 and <br />proceeding sequentially downstream. After construction of a rock vein, next vein location downstream <br />will be determined by the field engineer based on observations of the flow conditions downstream of the <br />constructed rock vein. This field adjustment of spacing will also consider estimated routing at higher <br />flows and available rock volume. <br />During construction, the rock vein will be keyed into the outside bank and into the bed at a depth of <br />about 1.5 feet as shown in Figure 2-I. Even though design procedures have not been developed for <br />determining appropriate rock size in rock veins, experience dictates that a medium rock diameter Dso of <br />36 inches or larger should be used with a minimum rock size of about 24 inches (Wittier 1999). A Dso <br />of 42 inches specified for this design. Also, each rock vein should contain an anchor rock located neaz <br />the bank which has a diameter of 70 to 80 inches. <br />The minimum width of the rock vein is 3.~ feet at the toe with the width increasing to about 6.5 feet at <br />the channel bank. Gravel, cobbles, and sediments excavated during installation of the rock vein are <br />replaced among the rocks in the rock vein and along the bank immediately upstream and downstream of <br />the rock vein. <br />2.4. Design Drawings <br />The design plan for rock vein length and spacing is provided in Drawing 2. Atypical rock vein section <br />is included in Figure 2-1. <br />2.5. Design Volumes <br />Based on the rock vein design in Figure 2-L and the estimated AVL of 18 feet (plus and additional 3 <br />Feet for keying into channel bank), approximately 20 cubic yards of rock will be needed for each rock <br />vein. To stabilize [he 660 foot length of channel with rock veins as shown in Drawing 2, up to 440 <br />• <br />P.}1A Filename 6mprtcUcsip~doc I l <br />07/30/99 <br />