Fluctuations and Relationships of Selected Physiochemical Parameters in Dardanelle Reservoir, Arkansas, 1975-1982

Annual and seasonal fluctuations and relationships are described for discharge, turbidity, chloride, total hardness, conductivity and suspended solids over an eight-year period in Dardanelle Reservoir. The parameters fluctuated rather widely primarily in response to seasonal patterns of rainfall. Chloride and conductivity were related and generally fluctuated together as did turbidity and suspended solids. Hardness appeared to vary independently of the others prior to 1979 then varied more closely with chloride after March 1979. Inherent differences between the Illinois Bayou arm and the main Arkansas River sections complicated the precise identification of any overall impact of power plant operation. No significant long term changes were seen, but chloride declined gradually whereas hardness and conductivity increased slightly. Suspended solids exhibited a significant rise in 1982

A Primary Ecological Survey of Dardanelle Reservoir Prior to Nuclear Facility Effluent Discharge

A preliminary ecological survey of Dardanelle Reservoir during the construction phase of Arkansas Power and Light Company\u27s nuclear generating facility was conducted from January 1970 through June 1974. The reservoir is characterized by relatively shallow depths and a high flow-thru rate. A number of features were associated with these characteristics. The reservoir carried a great deal of suspended material and exhibited high turbidities throughout most of the year. Typical thermal stratification and oxygen depletion were only rarely observed. Many of the physico-chemical parameters exhibited relatively high values in comparison to other Arkansas lakes and reservoirs, but due to absence of prolonged periods of stratification and stagnation, they did not undergo the extreme fluctuations sometimes observed in other reservoirs. Plankton and benthic samples were collected at least nine times per year from ten stations. These stations were selected to include both shallow and deep locations and to include points both within and outside the projected area of thermal influence when the plant became operational. There were a great variety of forms in the phytoplankton with the diatoms making up a considerable portion. The level of turbidity appeared to dampen somewhat the extreme fluctuations sometimes found in bloom periods. In the zooplankton the rotifers Brachionus, Keratella, and Polyarthra predominated followed by the microcrustaceans Cyclops and Bosmina. Both the plankton and the benthic fauna showed great seasonal variation. The benthic fauna consisted primarily of Chironomidae, Oligochaeta, and Hexagenia with the Chironomidae predominating in the shallower depths and the Oligochaeta exhibiting increased abundance and importance in the deeper stations

Phytoplankton Community Structure in Dardanelle Reservoir, Arkansas, 1975-1982

Phytoplankton data were collected with standard equipment and procedures over an eight-year period (1975-1982) in Dardanelle Reservoir, Arkansas. Community abundance and diversity at the genus level are described. Sixty-five genera representing 35 families and five divisions were identified. Total phytoplankton abundance and diversity were quite uniform among the stations but fluctuated considerably with time. These fluctuations did not correspond clearly with season. Dominant taxa were seasonal, though, with diatoms being usually dominant in January, April and October, and blue-greens dominant in July. The phytoplankton community structure has not been significantly altered by the operation of ANO Unit I

Phytoplankton Community Abundance and Diversity in Dardanelle Reservoir, Arkansas, 1981-1990

Phytoplankton samples were collected quarterly from 1981-1990 at five stations representing discharge water from Arkansas Nuclear One, a nuclear generating station, and four control or dispersal evaluation stations. Seventy-five taxa representing five divisions were identified and enumerated. Community structure was evaluated using abundances, number of taxa, and Margalef\u27s Richness, Shannon\u27s Heterogeneity and Pielou\u27s Evenness indices. No long-term trends were identified, but the beginning of cyclic variations, with a 7-year periodicity, in abundance, number of taxa, and Shannon\u27s and Pielou\u27s indices were apparent. Margalef\u27s index values were constant during most of the study period. For all samples, t-tests and Mann-Whitney U tests between station 5 (discharge) and each of four control stations, revealed no significant differences with any variable

Air Carrier Technique for Row Crop Spraying Applications

This study focuses on the problem of applying spray material to upper-plant, underside-leaf surfaces of corn and soybean plants. Aircraft and ground pressureatomizer applications of spray solution were quantified. Percent coverage values were generally less than 1 % on the sampling locations. Flat and hollow cone nozzle air carrier units were developed and evaluated for spray application to the upper-plant, bottom leaf surface. The air carrier method tested within a shroud improved spray deposition to the entire plant by 100% for corn and 234% for soybeans. Deposition to the upper-plant, bottom leaf surface was increased by 900% and 400% for corn and soybean plants, respectively. Deposition uniformity was also improved with the air carrier method

Long-Term Study of Benthos in Dardanelle Reservoir

Winter, spring, summer, and autumn samples were collected with a 15.24x15.24-cm Ekman grab from five stations on Dardanelle Reservoir, Pope County, Arkansas during the 24-year period from 1970-1993. Twenty-three taxa representing the eight phyla, Cnidaria, Nematoda, Nematomorpha, Entoprocta, Ectoprocta, Mollusca, Annelida, and Arthropoda, were collected. Numerically, oligochaetes comprised 36%, whereas chironomid larvae, Chaoborus larvae, and Hexagenia naiads mad up 29.7, 17, and 12%, respectively, of the samples. Asiatic clams, fingernail clams, amphipods, and Urnatella were collected frequently during the last 10 years but were not abundant. Other taxa were taken infrequently but consistently during the study period. Densities of all taxa fluctuated widely but generally not in close association with season, station, or year. A few significant differences (t-tests; cx=0.05) occurred between stations 5 (discharge) vs. 16 (intake) and 5 vs. 21 (upstream control), but most of them were due to natural differences in substrate composition. Margalef s Richness and Shannon\u27s Heterogeneity Indices did not identify any time-based trends and, with one exception, did not indicate any significant differences between stations

Zooplankton Community Structure in Dardanelle Reservoir, Arkansas, 1975-1982

Zooplankton was collected at 10 stations in Dardanelle Reservoir from 1975 to 1982. Current data were compared to a five-year preoperational study phase. Rotifer taxa strongly dominated the community. Overall abundance was higher, variety about the same and diversity lower than those of comparable studies. Thermal discharges caused a dominance shift between two rotifer taxa, slightly depressed abundance and variety, did not noticeably affect diversity and elevated the phytoplankton/zooplankton ratio. Heated effluent also stimulated stronger fluctuations in abundance and variety. Other studies indicate that in upper sections of the Arkansas River drainage, microcrustaceans dominate lake habitats whereas rotifers dominate river habitats. In similar northern and eastern habitats, microcrustaceans were generally dominant