Dynamics of suspended sediment plumes in Lake Ontario

The author has identified the following significant results. Imagery obtained on 25 January 1974, shows a well-defined plume at the mouth of the Niagara River and a much smaller but intense plume emanating from Port Dalhousie Harbor, Ontario. Additionally, a plume can be seen trailing eastward from the outer end of the Welland Canal. This is the first time that a clear-cut winter view of these plumes was detected by the ERTS-1 satellite outside the navigation season. Since the Welland Canal was not in operation, it is likely that the plume, visible along the canal's outer jetty on frames 1551-15313-4-5, was the result of westward moving turbid water emanating from Port Dalhousie Harbor to the west

Hydrologic interpretations based on infrared imagery of Long Island, New York

Six remote-sensing flights over Long Island's north and south shores were made during the period July 13, 1967, to February 25, 1970. Infrared imagery in the 8- to 14-micrometer range was obtained; results varied from poor to excellent in quality. The ability of the RS 7 and Reconofax 4 imagers to discern thermal contrasts of as little as 1 to 2 C (Celsius) permitted identification of areas of heavy ground-water discharge. These areas were concentrated primarily along the eroded headlands of the north shore and in the lower reaches of watercourses draining into Great South Bay. Only a few highly localized examples of direct ground-water discharge into the embayments along Long Island's south shore were detected in the imagery. Thermal loading emanating from a powerplant near Oceanside is shown to be quickly dissipated in Middle Bay. Optimal time for the collection of infrared imagery for hydrologic studies on Long Island is in summer and in winter, when surface-water thermal differences are relatively large

Remote Sensing of Turbidity Plumes in Lake Ontario

ERTS-1 remote sensing of turbidity plumes generated in Lake Ontario by Welland Canal and Genesee and Oswego River

Dynamics of suspended sediment plumes in Lake Ontario

The absence of turbidity plumes during the winter was well documented in an ususually successful sequence of images obtained February 10 - 12, 1974. Useful imagery of the south shore of Lake Ontario was obtained on 3 successive days at a time when sky cover over the area normally approaches complete coverage. Imagery of the Oswego, Genesee, and Niagara rivers failed to detect any plumes, however faint. Despite strong northwest winds on February 11 there was no indication of shoreline erosion generated by wave action. Frozen ground, snow cover, shoreline icing and minimal construction and farm activity without doubt reduces the probability of sediment movement in winter. Thunderstorm activity over the study area is very rare during the cold season so that the erosive energy of rainfall is greatly reduced. Moreover, a fairly high percentage of the winter precipitation is in the form of snow or sleet further reducing the impact of rainfall energy on sediment transport

Dynamics of turbidity plumes in Lake Ontario

The author has identified the following significant results. Large turbidity features along the 275 km south shore of Lake Ontario were analyzed using LANDSAT-1 images. The Niagara River plume, ranging from 30 to 500 sq km in area is, by far, the largest turbidity feature in the lake. Based on image tonal comparisons, turbidity in the Welland Canal is usually higher than that in any other water course discharging into the lake during the shipping season. Less turbid water enters the lake from the Port Dalhousie diversion channel and the Genesee River. Relatively clear water resulting from the deposition of suspended matter in numerous upstream lakes is discharged by the Niagara and Oswego Rivers. Plume analysis corroborates the presence of a prevailing eastward flowing longshore current along the entire south shore. Plumes resulting from beach erosion were detected in the images. Extensive areas of the south shore are subject to erosion but the most severely affected beaches are situated between Fifty Mile Point, Ontario and Thirty Mile Point, New York along the Rochester embayment, and between Sodus Bay and Nine Mile Point

Dynamics of suspended sediment plumes in Lake Ontario

The author has identified the following significant results. An extensive clear-water plume emanating at the mouth of the Niagara River was detected on imagery obtained September 3, 1973 (frame no. 1407-15343). This plume (area over 500 sq. km.), which appears darker than the surrounding lake waters, extended 30 km offshore, or more than 60% across the width of the lake. The plume was 20 km across at its widest point. This plume is, by far, the largest generated by the Niagara River as viewed from the ERTS-1 satellite. A combination of high background lake turbidity relative to that of the Niagara River and gentle offshore (southerly) winds produced the well-defined turbidity feature

Application of remotely sensed land-use information to improve estimates of streamflow characteristics, volume 8

The author has identified the following significant results. Land use data derived from high altitude photography and satellite imagery were studied for 49 basins in Delaware, and eastern Maryland and Virginia. Applying multiple regression techniques to a network of gaging stations monitoring runoff from 39 of the basins, demonstrated that land use data from high altitude photography provided an effective means of significantly improving estimates of stream flow. Forty stream flow characteristic equations for incorporating remotely sensed land use information, were compared with a control set of equations using map derived land cover. Significant improvement was detected in six equations where level 1 data was added and in five equations where level 2 information was utilized. Only four equations were improved significantly using land use data derived from LANDSAT imagery. Significant losses in accuracy due to the use of remotely sensed land use information were detected only in estimates of flood peaks. Losses in accuracy for flood peaks were probably due to land cover changes associated with temporal differences among the primary land use data sources