Laserfiche WebLink
Pro~~r1 Frlr <br />FrGruary ~. 1999 <br />Pu3r _' <br />The two toe drains were installed on the eastern half of the slump azea in the vicinity of PZ-4. <br />The maximum depth of the toe drains was approximately 8 feet bgs at their southern ends to zero <br />at their northern ends. Both toe drains were approximately 50 feet in length. They were <br />constructed in the same fashion as the French drains. <br />A surface drainage ditch was excavated immediately upslope of the slump head scarp. The ditch <br />was constructed as a v-ditch 1.5 feet deep with 2H:1 V sideslopes. As shown on Figure 1, the <br />drainage ditch extends approximately 20 feet beyond the eastern margin of the slump and <br />discharges to undisturbed ground beyond the western margin. The ditch will collect any surface <br />runoff from upslope azeas and divert the runoff around and away from the slump. <br />In addition to the installation of the drains and diversion ditch, the head scarp was backfilled and <br />re-graded at a minimum slope of 2 percent to promote positive drainage. The positive grade was <br />verified in the field by the field engineer using ahand-level and engineers tape. <br />The portion of the slump area disturbed by the construction activities was re-seeded in October <br />1998 with the seed mixture described in Table E-I.l, which is found in Exhibit 1 of the 1998 <br />Annual Reclamation Report. <br />u <br />• <br />