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f%s` <br />Siltation si'~c ;;~„ ~ Natural rock outcrops ~ <br />-. <br />~ ~. <br />vy r <br />~ rC3_I <br />Perm,. ~, ~.; ,~~~~~ ._.,1 slope ~I~ ~ nr~; ., ~ ~,r~all t~ naiiv~ ,~in~) <br />The inspection then proceeded to culvert #3 that conveys surface runoff from the east area <br />to the north under the permanent road- Riprap channels are located at the inlet and outlet of <br />this culvert The operator had recently constructed arock-lined channel to safely convey <br />flows down to sediment control ditch 096. Following removal of ditch D96, after the site has <br />been revegetated and demonstrated to be stable, flows from this culvert would enter a <br />natural arroyo. Additional small riprap is necessary in the ditch both above and below culvert <br />#3 to prevent piping around and under the larger rock. <br />The inspection then proceeded to Fill 8, the lone valley fill located on the north side of the <br />disturbed area. The fill appears to have held up extremely well due following the latest <br />precipitation and runoff. Fill outslopes are in accordance with the design plan Final <br />placement of rock on the lower portion of the side downdrains remains to be completed. <br />Also, the east downdrain where it intersects with ditch D96 requires reshaping and final <br />placement of riprap. Minor reshaping of the terrace bench intersections with the west <br />downdrain is also necessary to ensure proper function. <br />Culvert #4 is located within 150 feet of the top of the east downdrain to Fill 8. This culvert <br />carries flow under the permanent road. The outlet side of this culvert will likely need to be <br />checked for adequate grade to carry flow to the top of the downdrain. It may also regwre a <br />riprap or other protective lining to ensure long-term function. The road surface above this <br />culvert was very wet and muddy, indicating poor drainage of the road surface. Grading and <br />shaping of the road over a significant distance of the roadway may be necessary. Improving <br />the road sub-base material may also be necessary to improve drainage. <br />The upper drainage ditch on the steep north side that directs flow to the east was traversed. <br />Due to erosion and siltation in this ditch, flows have exited this ditch early and resulted in <br />excessive rills and gullies on the hillside below Material eroded from these rills and gullies <br />has added to siltation of the permanent road ditch. Maintenance and improved shaping of <br />this upper ditch is necessary to ensure adequate function. The same is true of the road that <br />leads to the center core of the ridge. While this feature was constructed to allow vehicle <br />access to the top of the ridge, its geomorphic function is diversion of flow off upper slopes to <br />the broad, rolling area above Fill 8. Siltation has also resulted in flow leaving this ditch early. <br />Maintenance is again required. <br />