Scoping Comment of Delaware Riverkeeper Network under PF13-7.

and cumulative impacts. Each one of these four major impacts must be thoroughly addressed in the Environmental Assessment for the Project. Studies documenting the effects of stream crossing construction on aquatic ecosystems identify sediment as the primary stressor for construction on river and stream ecosystems. 1 During the pipeline stream crossings construction, discrete peaks of high suspended sediment concentration occur during activities such as blasting, trench excavation, and backfilling.2 The excavation of streambeds can generate persistent plumes of sediment concentration and turbidity.3 This sedimentation has serious consequences for the benthic invertebrates and fish species whose vitality is crucial for healthy aquatic ecosystems. There have been documented reductions in benthic invertebrate densities, changes to the structure of aquatic communities, changes in fish foraging behavior, reductions in the availability of food, and increases in fish egg mortality rates.4 In addition to the stream crossing construction activity itself, the associated new road construction increases the risk of erosion and sedimentation.5 Columbia should be required to accumulate baseline surveys of benthic invertebrates at all stream crossings to ensure that post-construction conditions are substantially similar to pre-construction conditions. Many of the sediment and erosion control best management practices are not designed to be protective during significant rain events. For example, heavy rains during two tropical storms in August and September of 2011 caused extensive failures to erosion and sediment controls on pipelines under construction in north central Pennsylvania resulting in environmental harm from 1 Scott Read, Effects of Sediment Released During Open-cut Pipeline Water Crossings, Canadian Water Resources Journal, 1999, 24: (3) 235-251. 2 Id. 3 Id. 4 James Norman, et al., Utility Stream Crossing Policy, ETOWAH Aquatic Habitat Conservation Plan, July 13, 2008, 9-10. 5 En Banc Hearing of the Pennsylvania Public Utility Commission on Jurisdictional Issues Related to Marcellus Shale Gas Development, Docket No. I20102163461. Page 2 of 14 sedimentation plumes in nearby water resources.6 Columbia should be required to provide design parameters and typicals for erosion control measures that can withstand significant rain events in vulnerable portions of the project area (for example, on steep slopes), or be required to submit detailed plans specifying how Columbia plans to address situations where erosion controls are overwhelmed, such plans should include response time requirements. Pipeline construction also results in the loss of riparian vegetation.7 For each pipeline construction technique, there is a resulting loss of foliage associated with clearing the stream banks. This reduction in foliage increases stream temperature and reduces its suitability for fish incubation, rearing, foraging ...