WINTER HEAT BUDGET AND FRAZIL ICE PRODUCTION IN THE UPPER ST. LAWRENCE RIVER1

ABSTRACT: Winter heat budget and frazil ice production in the St. Lawrence River between the Ogdensburg-Prescott Boom and the Moses-Saunders Power Dam are analyzed. Contributions of each heat exchange component, and spatial distributions of heat exchange rates are calculated for three typical winters. Based on the calculated heat budget, the amount and distribution of frazil ice generated in the study reach is analyzed. The result of this study indicates that the thermal energy contained in the river water flowing into the study reach is a dominate factor in the heat budget analysis. The heat flux from the channel bottom accounts for an important portion of the total heat budget during the ice covered period.     

A HYDRAULIC TRANSIENT MODEL OF THE UPPER ST. LAWRENCE RIVER FOR WATER RESOURCES STUDIES1

ABSTRACT: A one-dimensional hydraulic transient model has been designed for water resource studies of Lake Ontario and the Upper St. Lawrence River. The model simulates water surface profiles and flows in the St. Lawrence River between Lake Ontario and the Moses-Saunders Power Dam under both open water and ice-covered conditions. Errors in water surface elevations were found to be less than 0.2 feet during quasi-steady conditions on the river. Comparable errors occurred during the ice-covered conditions. A sensitivity analysis found the model to be most sensitive to the roughness coefficients and the flow through the power dam.     

PRODUCTION PROCESSES UNDER THE ICE IN LAKE ST. CLAIR: 1. IRRADIATION AND TEMPERATURE1

ABSTRACT: Data from three ice-covered stations in Lake St. Clair were collected to evaluate the effect of ice and related variables on phytoplankton production. Primary production, phytoplankton standing crop, irradiation and temperature were measured from January to April, 1973. Mean production values ranged from 0.74 mgC/m³/h at station 1 near Mitchell Bay to 3.4 mgC/m³/h in waters at stations 2 and 3 below the Thames River mouth. A similar pattern was observed in chlorophyll a concentration, the mean values ranged from 0.63 μg/1 at station 1 to 2.1 and 1.3 μg/1 at stations 2 and 3. Temperature stratification occurred at the three stations. However, the temperatures at station 1 were consistently more than a degree warmer than at the other two stations. Irradiation was low, having a mean value at the sampling depth of .075 ly/min. The data is interpreted to indicate that the ice-bound phytoplankton were adapted to the low irradiation. It is suggested that the variation observed between stations is related to the formation of a plume by the Thames River and differences in nutrient loads carried by the St. Clair and Thames Rivers.     

PRODUCTION PROCESSES UNDER THE ICE IN LAKE ST. CLAIR II. NUTRIENTS (SILICATE) AS A LIMITING FACTOR1

ABSTRACT: During the winter of 1972 nutrient concentrations beneath the ice, and snow when present, were measured at three stations in Lake St. Clair. Nutrient patterns are compared and discussed in relation to primary production. Typically nutrient concentrations were high for a few weeks after ice formation and high again in the spring with mid-winter declines. At station 3 soluble reactive silica appeared to influence primary production and chlorophyll a. Nutrient limitation was not detected at the other two stations. The nutrient patterns, primary production and temperature provide evidence that a water mass or plume peculiar to the inflowing Thames River moves down the southeastern side of the lake beneath the ice.     

SURFACE WATER RESOURCES OF ST. JOHNS RIVER,FLORIDA1

ABSTRACT: The St. Johns River basin is the largest watershed entirely within the State of Florida, and is one of the few northward flowing rivers in the United States. The river basin contains 11,431 square miles, of which 9,430 square miles are drained by the river and its tributaries. The remainder drains into the Atlantic Ocean or the Intracoastal Waterway. Its largest sub-basin is the Oklawaha River basin, which has a drainage area of 2,870 square miles. Ground elevations range from sea level to 200 feet above mean sea level in the main river basin and as high as 300 feet above mean sea level in the Oklawaha River basin. This study was designed to investigate the surface water resources of the St. Johns River and the existing consumptive uses. The analysis revealed that the river is an extremely large and valuable resource which has been under-utilized and could play a much stronger role in serving the needs of the people in the basin.     

REGIONAL SCALE MODELING OF SURFACE AND GROUND WATER INTERACTION IN THE SNAKE RIVER BASIN1

ABSTRACT: Changes in irrigation and land use may impact discharge of the Snake River Plain aquifer, which is a major contributor to flow of the Snake River in southern Idaho. The Snake River Basin planning and management model (SRBM) has been expanded to include the spatial distribution and temporal attenuation that occurs as aquifer stresses propagate through the aquifer to the river. The SRBM is a network flow model in which aquifer characteristics have been introduced through a matrix of response functions. The response functions were determined by independently simulating the effect of a unit stress in each cell of a finite difference groundwater flow model on six reaches of the Snake River. Cells were aggregated into 20 aquifer zones and average response functions for each river reach were included in the SRBM. This approach links many of the capabilities of surface and ground water flow models. Evaluation of an artificial recharge scenario approximately reproduced estimates made by direct simulation in a ground water flow model. The example demonstrated that the method can produce reasonable results but interpretation of the results can be biased if the simulation period is not of adequate duration.     

EVALUATION OF WATER QUALITY AND MONITORING IN THE ST. LUCIE ESTUARY,FLORIDA1

ABSTRACT: The St. Lucie River and its tributaries form a major estuarine system on the southeast coast of Florida. This system is strongly affected by anthropogenic influences, including controlled releases of freshwater from Lake Okeechobee through the St. Lucie Canal and an extensive artificial drainage and irrigation system in the watershed. In the present study, three years of biweekly water quality monitoring data from the estuary were examined. The major stresses to the system stem from high variability of the salinity, frequent low dissolved oxygen (DO) events, and light limitation due to high levels of humic substances brought into the system with the fresh water. Nutrient levels also are high. Management goals for the system, including improvement of DO and water clarity, will require reduction in quantity and variability of freshwater releases.     

INTERACTIONS BETWEEN GROUND WATER AND SURFACE WATER IN THE SUWANNEE RIVER BASIN,FLORIDA1

ABSTRACT: Ground water and surface water constitute a single dynamic system in most parts of the Suwannee River basin due to the presence of karst features that facilitate the interaction between the surface and subsurface. Low radon-222 concentrations (below background levels) and enriched amounts of oxygen-18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where ground water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low-flow and high-flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River.     

REGIONALIZATION AND PREDICTION OF FLOODS IN THE FRASER RIVER CATCHMENT,B.C.1

Probability distributions that model the return periods of flood characteristics derived from partial duration series are proposed and tested in the Fraser River catchment of British Columbia. Theoretical distributions describing the magnitude, duration, frequency and timing of floods are found to provide a goof fit to the observed data. The five estimated parameters summarizing the flood characteristics of each basin are entered into a discriminant analysis procedure to establish flood regions. Three regions were identified, each displaying flood behavior closely related to the physical conditions of the catchment. Within each region, regression equations are obtained between parameter values and basin climatic and physiographic variables. These equations provide a satisfactory prediction of flood parameters and this allows the estimation of a comprehensive set of flood characteristics for areas with sparse hydrologic information.     

GROUND WATER SEEPAGE IN LAKE WASHINGTON AND THE UPPER ST. JOHNS RIVER BASIN,FLORIDA1

Direct ground water seepage measurements were made in Lake Washington, Florida, to determine the importance of seepage as a water and chloride source to the lake and upper St. Johns River. Over 200 seepage measurements were made in the lake and adjoining canals from July through December 1978. Results indicated that seepage into the shore areas of Lake Washington was an insignificant water source to the lake, representing 0.6 percent of the inputs, and was nearly balanced by ground water recharge in the midlake region. Drainage canals entering Lake Washington, however, exhibited high average seepage rates (17.7 L/m²-day), over eight times the lake average (2.01 L/M²-day). Discharge from the St. Johns River was the dominant factor in the water budget of Lake Washington and represented approximately 88 percent of the inputs during the study year. Although inputs from the drainage canals represented only 6.6 percent of the St. Johns River annual discharge, these canals represented 20.4 percent of the annual St. Johns River chloride loading and 62.1 percent of the river chloride loading during the five driest months of 1978. Evidence from this study indicates that rising levels of chloride in the river in recent years are largely attributable to ground water seepage in channelized areas, particularly in the headwaters. These chloride inputs assume greater importance during low water/low flow periods.     

EVAPOTRANSPIRATION MEASUREMENT AND ESTIMATION OF THREE WETLAND ENVIRONMENTS IN THE UPPER ST. JOHNS RIVER BASIN,FLORIDA1

ABSTRACT: Accurate estimates of evapotranspiration from areas dominated by wetland vegetation are needed in the water budget of the Upper St. Johns River Basin. However, local data on evapotranspiration rates, especially in wetland environments, were lacking in the project area. In response to this need, the St. Johns River Water Management District collected evapotranspiration field data in Fort Drum Marsh Conservation Area over the period 1996 through 1999. Three large lysimeters were installed to measure the evapotranspiration from different wetland environments: sawgrass (Cladium jamaicense), cattail (Typha domingensis), and open water. In addition, pan evaporation was measured with a standard class “A” pan. Concurrently, meteorological data including rainfall, solar radiation, wind speed, relative humidity, air temperature, and atmospheric pressure were collected. By comparing computed evapotranspiration rates with those measured in the lysimeters, parameters in the Penman‐Monteith, the Priestley‐Taylor, and Reference‐ET methods, and evaporation pan coefficients were estimated for monthly and seasonal cycles. The results from the data collected in this study show that mean monthly evapotranspiration rates, computed by the different methods, are relatively close. From a practical point of view, results indicate that the evaporation pan can be used equally well as the more complex and data‐intensive methods. This paper presents the measured evapotranspiration rates, evaporation pan coefficients, and the estimated parameter values for three different methods to compute evapotranspiration in the project area. Since local data on evaporation are often scarce or lacking, this information may be useful to watershed hydrologists for practical application in other project regions.