A study was conducted over a six-year period in East-Central Ohio to determine the effects of surface mining and reclamation on physical watershed conditions and on ground-water hydrology in three ground-water zones in three small experimental watersheds. Mining disturbances in watersheds adjacent to the experimental sites affected ground-water levels in the undisturbed experimental watersheds prior to actual mining in the experimental sites. New subsurface flow paths, with different characteristics, formed during mining and reclamation. At all three sites mining dewatered the saturated zone above the underclay of the mined coal seam. Mining and reclamation affected ground-water levels below the mined coal seam in the middle and lower zones within at least two sites. Ground-water level recovery in the mined upper saturated zone was slow and irregular both temporally and spatially after reclamation. Hydraulic conductivities of postmining (Phase 3) spoil were generally greater than those of Phase 1 bedrock, but wide spatial variability was observed. Modelers need to be aware of the complexities of new flow paths and physical characteristics of subsurface flow media that are introduced by mining and reclamation, including destruction of the upper-zone clay. (KEY TERMS: baseflow; water levels; water chemistry; spring flow; spoil; disturbed land; hydraulic conductivity; regulations.) 1Paper No. 91054 of the Water Resources Bulletin. Discussions are open until February 1, 1993. 2Respectively, Research Hydraulic Engineer, USDA-ARS,

The hydrogeology and ground-water quality in the vicinity of five landfills in southern Franklin County, Ohio, were investigated by use of data obtained from 46 existing wells, 1 seep, 1 surface-water site, and 1 leachate-collection site. Interpretation was based on data from the wells, a potentiometric-surface map, and chemical analyses. Four of the five landfills are in abandoned sand and gravel pits. Pumping of water from a quarry near the landfills has modified the local ground-water flow pattern, increased the hydraulic gradient, and lowered the water table.Ground water unaffected by the landfills is a hard, calcium bicarbonate type with concentrations of dissolved iron and dissolved sulfate as great as 3.0 milligrams per liter and 200 milligrams per liter, respectively.Water sampled from wells downgradient from two landfills shows an increase in sodium, chloride, and other constituents. The change in water quality cannot be traced directly to the landfills, however, because of well location and the presence of other potential sources of contamination. Chemical analysis of leachate from a collection unit at one landfill shows significant amounts of zinc, chromium, copper, and nickel, in addition to high total organic carbon, biochemical oxygen demand, and organic nitrogen. Concentrations of chloride, iron, lead, manganese and phenolic compounds exceed Ohio Environmental Protection Agency Water Quality Standards for drinking water.Water from unaffected wells within the study area have relatively small amounts of these constituents.

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Introduction Watershed C06 Summary of premining conditions Data collection during mining Groundwater hydrology during mining Groundwater quality during mining 13 Watershed M09 15 Summary of premining conditions Data collection during mining Groundwater hydrology during mining 15 Groundwater quality during mining

A 43‐acre watershed in Muskingum County, Ohio, was studied to determine the hydrologic consequences of strip mining for coal. A quantitative description of the effects on the ground‐water flow components of the hydrologic system has been obtained using digital models. The premining watershed was characterized by nearly flat‐lying sedimentary rocks of the Pennsylvanian System. Underclay beneath the two major coal beds formed bases for perched zones, creating three separate aquifers. Recharge to the ground‐water system occurred mainly by percolation of precipitation. Most of the discharge from the top and middle aquifers occurred by downward leakage to the underlying aquifers. A smaller amount of discharge occurred as springflow or streamflow near the intersections of the underclays and land surface. Mining has destroyed the top aquifer, and has replaced the bedrock by spoil material. Water levels in the spoils are at a much lower altitude than existed in the premining top aquifer because of a combination of (1) a larger hydraulic conductivity, (2) areal variations of the hydraulic characteristics of the confining bed, and (3) a slower rate of recharge from precipitation caused by removal of vegetation and soil compaction. Covering of previously exposed portions of the middle aquifer and a lower hydraulic head in the spoils has allowed less recharge to the middle aquifer. Additional flow is induced across the western boundary of the watershed and has reduced the outflow across the eastern boundary. Discharge from the middle aquifer as downward leakage and streamflow is less than before mining.