FEDERAL ENERGY REGULATORY COMMISSION Project No. 405 ...

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20100204-3055 FERC PDF (Unofficial) 02/04/2010 Project No. 405-087 5 Interior, The Nature Conservancy and SRBC all request modeling to assess the impacts of the project on water quality (including salinity) in the Susquehanna River and upper Chesapeake Bay. Interior also recommends collection of water quality data from the National Oceanic and Atmospheric Administration, Chesapeake Bay Interpretive Buoy System for the Susquehanna buoy at the mouth of the river for inclusion in the water quality model. Exelon is not proposing any changes in operation and the proposed water quality study with staff’s recommended modifications in conjunction with the other studies should be sufficient for an understanding of the effects of the project on water quality. If the data supplied in the water quality study report after the first year of study is insufficient to evaluate project impacts on water quality, modeling could be required for the second study season. 3.2 Downstream Fish Passage Effectiveness Study Exelon proposes to estimate entrainment, impingement, and related mortality of both resident and migratory fish at the project based on a literature review, on-site turbine mortality testing using balloon tagging methods, and project-specific physical characteristics such as hydraulic head and turbine specifications. Maryland DNR, SRBC, Fish & Boat Commission, and Pennsylvania DEP request several modifications to the turbine mortality part of Exelon’s proposed study as follows: 1) study of all five specific turbine models at the project not just the two general types (Kaplan and Francis) proposed by Exelon; 2) turbine testing during July and August to better simulate natural conditions during the most stressful downstream passage period; 3) testing during various operational scenarios, such as “aeration on” versus “aeration off,” over a range of wicket gate settings, etc.; 4) a better explanation of the statistical analyses to be used to determine turbine test sample size calculations; 5) mandatory American eel testing regardless of their seasonal availability; and 6) an increase in the sample sizes of fish and number of species to be tested. In addition to items (2) and (3) from the list above, Interior also recommends that Exelon be required to conduct turbine mortality tests on river herring. Given the amount of available literature on turbine mortality rates for rivers with similar species assemblages and dams of similar design to Conowingo, staff do not believe that on-site turbine mortality testing is necessary to make reasonable estimates of turbine mortality at the project. While Exelon is certainly free to conduct such studies, staff believe that a literature review, combined with a review of the compiled studies of migratory fish already conducted at the project during the current license term, will be adequate to evaluate proposed, recommended, or required measures. 3.3 Biological and Engineering Studies of American Eel at the Conowingo Project
20100204-3055 FERC PDF (Unofficial) 02/04/2010 Project No. 405-087 6 Exelon proposes both a literature review, as well as certain on-site field surveys to evaluate the biological and engineering feasibility aspects of American eel passage at the project. Maryland DNR, SRBC, Fish & Boat Commission, Pennsylvania DEP, and Interior request that Exelon be required to survey and sample the entire spillway, including the east shore area, as possible locations for an upstream eel fishway at the dam. Maryland DNR, SRBC, Fish & Boat Commission, and Pennsylvania DEP also recommend that Exelon conduct a literature review to identify and evaluate all known avoidance and exclusion techniques for American eel at hydropower plants. Staff agree that the entire spillway, including the far eastern end, should be studied because eels are known to congregate and attempt passage wherever a spillway surface is wetted and a suitable attraction flow is present. If reasonable safety precautions are taken, all areas of the dam could be safely studied. Staff also agree that the a review and evaluation of known avoidance and exclusion techniques should be included in the study report to assist in evaluating any proposed, recommended, or required measures. 3.4 American Shad Passage Study In order to summarize existing information on shad restoration progress and population trends, Exelon proposes to conduct a literature review and prepare a summary report of all fish passage studies and data available at the Conowingo Project. Exelon also proposes to develop a shad population model for the Susquehanna River. Maryland DNR, SRBC, Pennsylvania DEP, Fish & Boat Commission, and Interior question the necessity of this study and note that they did not request such a study, do not think it is necessary, and do not think it is a good use of the estimated $110,000 cost. The literature review and a summarization component of the study was specifically requested by Commission staff because staff believed it would be useful to have a single document on the extensive fish passage and behavior research that has occurred over the years in pursuit of agency migratory fish restoration goals. However, given that many of the other fish passage, fish protection, and fish behavior studies proposed in the revised study plan will include reports that contain summaries of existing literature, staff agree this study is no longer necessary. Staff also do not believe that the proposed shad population model is likely to contribute much to the analysis of potential restoration measures in any environmental document prepared by Commission staff. It appears that the reason for the rise and fall of the numbers of shad returning to Conowingo dam is not well understood at this time and it is unclear how a model could
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