Engineers also studied the combined potential effects of the two Samples valley fills.
"The fill drainage areas are adjacent to each other and form the headwaters of the same stream," said one draft of the study.
"The cumulative analysis indicates increase in the peak flow downstream of the valley fills at a point below where the two drainages converge," the draft said. "However, the peak flow increase (8 percent) represents influences of the individual valley fill drainage areas and any additional drainage area that flows to the cumulative analysis point.
"The influence of changes in the headwater areas will decrease as the point of analysis is moved further downstream," it said. "That is, the flooding effects would attenuate downstream from the mine site." In a summary document, federal officials said that "increases in peak flow did not cause a rise in water level overtopping the receiving stream channels. Flooding typically occurs only when water levels exceed channel capacities and spread across the flood plain where residential settlements may occur." But these statements were not contained in the actual flood study documents prepared by OSM and the Corps. It was not clear who added them to the summary document.
Also, the OSM and Corps documents cautioned that "Differences in stages are very site specific and may depend on conditions in receiving streams.
"Stage differences cannot be translated up or down stream away from the computed location and results should not be generalized." The summary document said that federal officials planned to recommend that "Site-specific hydrologic analysis of the impacts of steep slope mining and valley fills on peak flows should be routinely performed as part of the permitting process." When considering permit applications, the document said, the state Department of Environmental Protection "should include permit-specific and cumulative flooding assessments' reflective of local conditions." The summary said that DEP "currently requires these evaluations and other states should also include this type of analysis." But DEP officials only started to require flood studies late last year.
If there are no residences or private property in the potential flood path, DEP requires a Surface Water Runoff Analysis (SWROA). If a community could be affected, the agency requires a more sophisticated "flood routing analysis." "The impact on flooding had not been addressed before that," said Mike Reese, environmental resources program manager with the DEP Office of Mining and Reclamation. "It was something that did not have sufficient scientific validation." Over the last six or eight months, Reese has helped to review all new permit applications and permit revisions for their potential impact on flooding. In each case, Reese said, DEP found that mining would make flooding worse. The agency has started to require companies to change mining plans to minimize the threats, he said.
"We'll have problems with flooding if we don't put more controls on these operations," Reese said Tuesday.
But final guidelines for such studies are still not complete.
On Friday, a draft was given to DEP Secretary Michael Callaghan for his review.
And agency officials have no plans to review active or reclaimed permits for site-specific flooding potential. These reviews will be done only for new and revised permits, DEP officials said.
That means mines like those on Kayford Mountain will not be studied for flood potential, or made to reduce that potential, unless they apply for major permit changes.
"We have no approved permits at Samples with a SWROA," said Joe Parker, deputy assistant chief of the DEP mining office. "Some of those older permits would not have had one on them."