This report contains water-quality data for the Ohio River from river mile 51.1 (3.3 miles upstream from New Cumberland Dam) to river mile 84.0 (0.2 mile upstream from Pike Island Dam) that were collected during the summer and fall of 1993. The data were collected to establish the water quality of the Ohio River and to use in assessing the proposed effects of hydropower development on the water quality of the Ohio River. Water quality was determined by a combination of synoptic field measurements, laboratory analyses, and continuous-record monitoring. Water-quality characteristics were measured in the field along a longitudinal transect with 18 mid-channel sampling sites; cross-sectional transects of waterquality measurements were made at 5 of these sites. Water quality also was measured at two sites located on the back-channel (Ohio) side of Browns Island and at one site near the middle of the wingwall of New Cumberland Dam. At each longitudinal-transect and back-channel sampling site, measurements of specific conductance, pH, water temperature, and dissolved oxygen concentration were made at four depths (at the surface, about 3.0 ft below the surface, middle of the water column, and near the bottom of the river). An exception to this protocol was used to make the May and June measurements, which were made at three depths (about 3.3 ft below the surface, middle of the water column, and near the bottom). Cross-sectional transects and the site near the middle of the wingwall of New Cumberland Dam consisted of three to four detailed vertical profiles of the same characteristics. On most sampling dates, water samples were collected from four depths at the mid-channel vertical profile in each cross-sectional transect and were analyzed for concentrations of phytoplankton chlorophyll a and chlorophyll b. Estimates of the depth of light penetration (Secchi disk transparency) were made at all phytoplankton-pigment-sampling locations whenever light and river-surface conditions were appropriate. Synoptic sampling usually was completed in 12 hours or less and was repeated nine times between May and October 29, 1993.Continuous-record monitoring of water quality consisted of hourly measurements of specific conductance, pH, water temperature, and dissolved oxygen concentration that were recorded at a depth of 6.6 feet at sites upstream and downstream of New Cumberland Dam.The upstream monitor was suspended from a Coast Guard buoy located approximately in the middle of the navigation channel 0.2 mi upstream from the dam. The downstream monitor was located at the end of the downstream wingwall on the riverside, about 1,200 feet from the dam. Continuousrecording monitors were operated from May through October 1993.

This report contains water-quality data for the Ohio River from river mile 160.6 (1.1 mi upstream from Willow Island Dam) to river mile 203.6 (0.3 mi upstream from Belleville Dam) that were collected during the summer and fall of 1992. The data were collected to establish the water quality of the Ohio River and to use in assessing the proposed effects of hydropower development on the water quality of the Ohio River. Water quality was determined by a combination of synoptic field measurements, laboratory analyses, and continuous-record monitoring. Waterquality characteristics were measured in the field along a longitudinal transect with 24 mid-channel sampling sites; cross-sectional transects of water-quality measurements were made at 6 cf these sites. Water quality also was measured at six sites located on the back-channel (West Virginia) sides of Marietta, Muskingum, and Blennerhassett Islands. Water temperature, dissolved oxygen concentration, pH, and specific conductance were measured at three depths (about 3.3 feet below the surface of the water, middle of the water column, and near the bottom of the river) at each longitudinal-transect and back-channel sampling site. Cross-sectional transects consisted of three or four detailed vertical profiles of the same characteristics. Water samples were collected at three depths in the mid-channel vertical profile in each cross-sectional transect and were analyzed for concentrations of phytoplankton chlorophyll a and chlorophyll b. Estimates of the depth of light penetration (Secchi disk transparency) were made at phytoplankton-pigment-sampling locations whenever light and river-surface conditions were appropriate. Each synoptic sampling event was completed in 2 days or less.