Attachment-003-DesignCriteria.pdf

Design Criteria Site 1, 2 and 3

• Should any prehistoric or historic materials be observed, operations should cease at the work site until the Forest archaeologist can assess significance and determine best course of action.

• Road construction and maintenance shall be to Forest Service specifications. Install appropriate drainage control structures (e.g., water bars) on all non-paved roads constructed or utilized when the project is completed. Water bars shall be constructed to meet standards indicated in the guide Water Bar Placement and Construction Guide for Siuslaw Forest Roads (will be provided to Contractor during the pre-work meeting). In addition, any brush removed should be placed on top of disturbed soil adjacent to the roadbed, and at the outfall of the water bars to disperse water energy and flow.

• Vegetation and soil disturbance needs to be kept to a minimum to reduce the opportunity for erosion and concentrated overland flow.

• Void areas in the soil profile resulting from structure removal need to be backfilled with material that closely matches the hydrologic characteristic of the soil.

• After project completion of each site, local vegetation debris needs to be placed over all exposed mineral soil.

• Use minimum passes on project routes to minimize soil compaction.

• Access sites near meadows along meadow edges.

Site 3 only

• In stream work will be conducted at low flow conditions during Oregon Department of Fish and Wildlife’s in-water work period (July 1-August 31). If in stream work must be done at another time a waiver from ODFW must be attained.

• Consultation will occur with a fish biologist to determine any appropriate dewatering or worksite isolation prior to in stream work.

• No stream crossings with heavy equipment will be used to accomplish project work. If stream crossings are deemed necessary, consultation will occur with a fish biologist to determine the appropriate location and methods to minimize impacts to aquatic and riparian habitats.

• All foreign materials excavated from the dam, wooden pump house, and concrete tank will be transported from the site with the fewest possible trips in order to minimize impacts to existing riparian soils and vegetation.

AG-04R4-S-10-0033

Mary's Peak Water System Siuslaw National Forest

• Equipment will be refueled and serviced outside of the riparian area reducing the chance of spilling toxic fuels and lubricants. Spill response materials will be on site during project activities. Heavy equipment will be inspected and ensured that it is free of leaks prior to project activities.

• To minimize disturbance and release of fine sediments into the stream, any soil disturbance activities will be limited to low flow periods and relatively dry weather.

• If necessary to alleviate impacts, sites will be ripped to remove compaction in riparian areas and native debris will be placed on areas of exposed soil to reduce erosion.

• Extra care will be taken while removing and excavating the dam in order to avoid damage to the large noble fir tree growing on the north bank.

• The dam shall be removed in the largest chunks possible from the stream to avoid the crushing and input of small pieces and particles of concrete into the stream channel.

• If project access road is open during inclement weather, proper water drainage control structures (e.g., water bars) need to be in place during project operation.

• Site operations will be halted during storm events and days following storm events with higher soil moisture content.

• Decompacting of the access road mineral soil will be conducted upon completion of the project and local vegetation debris/slash will be placed over exposed soil.

• Stabilize potential erosion areas and control sedimentation. Minimize sedimentation potential by implementing appropriate measures to meet Oregon DEQ turbidity standards. Where necessary, install suitable erosion control devices (e.g., silt fences).

• Efforts should be made to remove dam structure largest portions possible as to minimize the availability of fine sediments entering the stream channel.

AG-04R4-S-10-0033

Mary's Peak Water System Siuslaw National Forest