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USGS2014

Radiotracer experiments in the Mohawk River, New York, to study sewage path and dilution

Sewage from the Knolls Atomic Power Laboratory near Schenectady, N. Y., was dosed with 4.53 curies of P prior to discharge into the Mohawk River. Its pattern of diffusion was measured in the river with immersible GM‐tubes and by sampling. The initial path of sewage was strongly influenced by differences in density between sewage and river due to temperature. During warm months relatively cold sewage moved on the river bottom perpendicularly to river current. For at least the first 800 ft of travel the maximum sewage concentration decreased logarithmically with distance from outfall. The term ‘half‐distance’ (here about 110 ft) is proposed to describe the concentration change. During cold months sewage rose to the river surface and at times was moved upstream by wind. However, when the river temperature was near freezing, the sewage first rose and then sank as the temperature of the sewage‐river mixture approached 39° F.

New York↗

USGS2008

Field determination of the three-dimensional hydraulic conductivity tensor of anisotropic media: 2. Methodology and application to fractured rocks

The analytical solutions developed in the first paper can be used to interpret the results of cross-hole tests conducted in anisotropic porous or fractured media. In the particular case where the injection and monitoring intervals are short relative to the distance between them, the test results can be analyzed graphically. From the transient variation of hydraulic head in a given monitoring interval, one can determine the directional hydraulic diffusivity, K d ( e )/ S s , and the quantity D / S s , by curve matching. (Here K d ( e ) is directional hydraulic conductivity parallel to the unit vector, e , pointing from the injection to the monitoring interval, S s is specific storage, and D is the determinant of the hydraulic conductivity tensor, K .) The principal values and directions of K , together with S s , can then be evaluated by fitting an ellipsoid to the square roots of the directional diffusivities. Ideally, six directional measurements are required. In practice, a larger number of measurements is often necessary to enable fitting an ellipsoid to the data by least squares. If the computed [ K d ( e )/ s s ] ½ values fluctuate so severely that a meaningful least squares fit is not possible, one has a direct indication that the subsurface does not behave as a uniform anisotropic medium on the scale of the test. Test results from a granitic rock near Oracle in southern Arizona are presented to illustrate how the method works for fractured rocks. At the site, the Oracle granite is shown to respond as a near-uniform, anisotropic medium, the hydraulic conductivity of which is strongly controlled by the orientations of major fracture sets. The cross-hole test results are shown to be consistent with the results of more than 100 single-hole packer tests conducted at the site.

Water Resources Research↗

USGS1949

Buried preglacial ground water channels in the Albany-Schenectady area in New York

A map is presented showing contours of the buried preglacial channel of the Mohawk River from Schenectady, New York, to its confluence with the Hudson River about 12 miles south of Albany and of associated buried preglacial channels. The Pleistocene history of a portion of the Mohawk and Hudson Rivers is discussed, and the relation of buried valleys to ground-water supplies is indicated.

New York↗