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<br />~ <br />r, <br />~ <br />~( <br />~ <br />J <br /> <br />290+00, would be used for levee embankment. The location of five <br />tentative borrow areas is ShO,lIl on plates 1, 2 and 3. Results of <br />investigation of three of the tentative borrow areas are discussed <br />in SECTION VIII - GEOLOGY, SOILS AND CONSTRUCTION ~~TERIALS. It is <br />intended that the borrow areas in the existing river channel would be <br />worked in a manner that would obtain the best material and at the <br />same time improve the configuration of the existing river channel to <br />pass flood flows. <br /> <br /> <br />9-05. Erosion Control. Since bank velocities up to 8.3 feet per <br />second would occur along the river, protective measures against scour <br />would be required for the riverside levee slope. A double row of <br />flexible-type steel jetties would be placed at the toe of levees at <br />critical locations to retard bank velocities. The reduction in <br />velocity allows partial deposition of suspended sediment upon which <br />vegetal growth further retards flows and stabilizes deposited material. <br />Details of the bank protection jetties are. shown on plate 26. <br />Locations of jetty fields are shown on plates 2 through 13. Riprap, <br />to prevent scour, would be placed at the outlet end of the Consolidated <br />Irrigation Ditch intake structure and at the outlet end of all drainage <br />structures except those at the relocated county road corssings. Rip- <br />rap would also be required at the outlet end of pipes at the Sewage <br />Pumping Plant. <br /> <br />9-06. Interior drainage. Interior drainage facilities would consist <br />of excavated drainage ditches on the landside of the levee, gravity <br />outlets, and associated ponding areas. The drainage ditches would <br />collect trapped storm runoff from the lands ide and transfer it to one <br />of the drainage outlet structures where it would discharge into the <br />river. All drainage structures that discharge into the river would <br />be provided with slide gates for manual control and flap gates which <br />would automatically prevent flow toward the lands ide of the levee <br />during periods of high flow in the river. A general plan of the <br />interior drainage system is shown on plates 1, 2 and 3. TIle hydraulic <br />elements are discussed in SECTION VII - HYDROLOGY AND HYDRAULIC DESIGN. <br /> <br />9-07. Sewage Lagoons. The three existing open sewage lagoons shown <br />on plate 11 discharge into the Arkansas River in an open ditch that <br />would be cut off by construction of the right bank levee. A l2-inch <br />gravity drain line would be provided that would extend from the <br />northeast lagoon through the levee to the river. The drain would be <br />equiped with a flap and emergency slide gate located on the riverside <br />of tne levee. <br /> <br />9-08. Based)n the standard project hydrograph, the maximum time that <br />effluent from the sewage lagoons would be blocked is about five days. <br />A 4-inch surcharge in the existing lagoons would provide storage for <br />the required five-day effluent volume. Therefore, the lagoons would <br /> <br />I <br />~ <br /> <br />28 <br /> <br />Revised 6-26-69 <br />