Laserfiche WebLink
• Cut-to-Fill Sloes <br />Generally, a major problem azea is created when grading operations begin. The <br />problem azea starts at the cut to fill transition and extends along the tce of the embankment <br />slope. Figure A-11 (page A-24) shows this azea and suggests some possible temporary <br />consols that should be installed. Controls in this area should be provided at an eazly stage <br />of grading and maintained throughout excavation embankment operations and until permanent <br />controls are installed. <br />Newly excavated ditches may be highly susceptible to erosion and often contribute to <br />the siltation of waterways. Although desirable, it is not always practical to provide necessary <br />ditch lining immediately after excavation. Consequently, timely installation of temporary <br />erosion and siltation control measures is important <br />Figure A-12 (page A-25) shows a typical situation involving side and median ditches <br />or swales. Dumped stone, jute mesh, or sod can be used to effectively minimize erosion of <br />ditch bottoms and sides. Hay bales can be used as temporary check dams w assist in <br />controlling erosion and minimizing siltation. In providing the protection shown in this figure, <br />the width of the lining of dam should extend far enough up the ditch slope to effectively <br />• contain the runoff and prevent erosion and washout at the edges. <br />Figure A-13 (page A-2~ illustrates the use of temporary dams for use in wider ditches <br />or small streams. These types of dams are generally used where flow must be maintained by <br />providing a spillway opening. As a word of caution, careful consideration should be given <br />to temporary dams constructed of graded stone to assure that the size of the stone selected is <br />large enough to withstand the force of the flowing watts. A number of temporary stone dams <br />have been constructed utiliring two inch stone, while they have been quite effective during <br />the periods of low flow, they have failed during periods of heavy rain. As a rule of thumb, <br />about 50°k of the stone should be 6 inches or larger for dams in small streams. <br />Most highway construction projects aoss some form of a waterway--a stream, river, <br />pond, etc. These are highly critical areas that must be protected from siltation. <br />For s~ttaller streams, where temporary. dams can be used without causing upstream <br />damage, a log and hay erosion check dam can be used. Figures A-14A and B (pages A-27 <br />and A-28) show the general plan details of this type of dam. These dams can be constructed <br />from readily available native material and should be placed on the downstream side of the <br />construction area. <br /> <br />A-7 <br />