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Project 2—Gravel Drive & East Slope Management During our site reconnaissance,it appeared that a significant amount of runoff came down the existing gravel drive located to the east of the drainageway. Digging shallow (2" to 4" deep) trenches diagonally across this drive so that runoff from the drive is intercepted intermittently and routed off to the west side of the drive will reduce erosion potential along the drive and downslope. Runoff from these trenches should dissipate and infiltrate,and possibly some will sheet flow into the drainageway. These diagonal trenches should be installed from near the top of the gravel drive all the way to the log pavilion,with extreme care given to the already eroded/unstable areas near the log pavilion. It may be advantageous to also install a narrow rain garden or infiltration area between the westernmost cabin and the log pavilion to manage runoff from the slope located just uphill. This could be designed similar to the Project 1 basin, but soil amendments would be important given the limited size, and the overflow would need to be designed such that overflow did not flood or compromise the log pavilion foundation or cause additional erosion. Important Notes: Regular inspections should be made after the diagonal trenches and/or narrow rain garden are installed to ensure that no new erosion/sedimentation problems are occurring. Project 3—Restore Eroded Gravel Drive The eroded gravel drive (extending from the log pavilion to the boat dock) was created as a result of: 1. concentrated runoff from the upper gravel drive and associated areas, 2. concentrated runoff from the drainageway leaving the original channel, 3. steep slopes, 4. lack of stabilizing vegetation, and 5. saturated/unstable soils resulting from groundwater seepage in the area. Before restoring the eroded gravel drive,all sources of concentrated runoff(including runoff from the upslope portion of the drainageway) must first be re-routed into the original drainageway alignment (currently a limestone swale with dense vegetation,located just west of the eroded gravel drive). Any areas expected to receive significant runoff should be graded to create a well-defined swale (as broad and flat-bottomed as space allows),lined with filter fabric, and overlaid with moderate-sized rip rap (>_6" diameter). Once all re-routing of concentrated runoff is accomplished, the eroded drive section should be lined with filter fabric and backfilled with gravel and/or sand,as long as the material drains freely and provides sufficient structural support for future uses in the area. The area should be compacted in lifts (layer by layer) to minimize future settling,which could result in a future runoff/erosion problem. Backfill should be slightly mounded (i.e.,higher than adjacent land) to prevent preferential flow of runoff across this area,which could cause erosion. Any areas not required for driving should be topdressed with 0.5 of topsoil,immediately seeded with cover crop and shade-tolerant, deep-rooted native plants,and overlain with erosion control blanket. Important Notes: The success of Project 3 is highly dependent on implementation of Projects 1 and 2; therefore,Project 3 should not be done first or by itself. Regular inspections should be made after the eroded gravel drive is restored to ensure that no new erosion/sedimentation problems are 080529:070908 3 of 4 Camp Teko Drainageway Retrofit—Conceptual Design