Work within stream (“In Stream Work,” see MaineDOT Standard Specifications 101.2 Definitions) requires special conditions to minimize impacts. The following special conditions shall apply to this project: A. In Stream Work applies to Large Culvert # 47394, located in Etna on Route 2, at GPS coordinates: N 44.816476, W -69.138409 B. In Stream Work shall be allowed between July 15 and September 30. In Stream Work shall not be allowed between the dates of October 1 and July 14. C. All in-water excavation, including excavation to place rip rap shall be conducted within a sealed cofferdam. D. The contractor shall notify the Resident Engineer and MaineDOT Environmental Office Biologist (Kelby Houtz (207) 441-1512, kelby.leary@maine.gov ) at least 2 weeks prior to cofferdam installation to coordinate fish evacuation. Cofferdams shall not be closed until fish evacuation is complete. E. The contractor shall fully remove all cofferdams from the stream immediately following completion of in-stream work using techniques to minimize turbidity releases. The contractor shall restore all areas of temporary stream bottom disturbance to their original contour and character upon completion of the project. F. All cofferdams will be removed using techniques to minimize turbidity releases. This includes allowing for the slow reintroduction of water into the work area and utilizing dirty water treatment systems for turbid water. G. Bypass pumps will be sized according to the expected flows during construction. See Section III(F)3 in the MaineDOT BMP Manual (MaineDOT 2008). H. When utilizing pumps to dewater cofferdams, in order to prevent ATS juvenile entrapment related to dewatering diversions, the Contractor will use a screen on each pump intake designed such that the approach velocity does not exceed 0.20 feet/second. Square or round screen face openings are not to exceed 3/32 inches (2.38 millimeters) measured on a diagonal. Criteria for slotted face openings shall not exceed 1/16 inches (approximately 1.75 millimeters) in the narrow direction. These screen criteria follow National Marine Fisheries Service (NMFS) guidance (NMFS 2008). Intake hoses shall be regularly monitored while pumping to minimize adverse effects to Atlantic salmon or other species. I. Sheet pile driving (if utilized) shall be completed using a vibratory hammer. J. Construction equipment shall not travel through flowing water unless substrate is non-erodible (e.g ledge, cobble) and is approved by the Resident. K. No work shall be allowed that completely blocks a river, stream, or brook without providing downstream flow. L. Permanent riprap placed in a stream below the bankfull elevation (Q1) shall be covered by streambed material.
