Measurement of streambed hydraulic conductivity and its anisotropy

A method is described for the measurement of streambed hydraulic conductivity. Unlike permeameter methods, this method applies straight and L-shaped standpipes directly to streambeds for measurements of in-situ hydraulic conductivity in the vertical (K-v) and horizontal (K-h) directions, as well as in other oblique directions (K-s). This method has advantages in determination of K-v values over grain-size analysis, permeameter tests, or slug test methods. Also unique to this method is that it provides K-s values of a streambed. The measured results can be used to construct a hydraulic conductivity ellipse and to evaluate the anisotropy of streambed sediments. Field examples from the Republican River, Nebraska, demonstrated the usefulness of this method in the determination of streambed hydraulic conductivity and anisotropy along or across a river channel. Results indicate that the K-h is about three to four times larger than K-v, whereas K-s values are larger than K-v but smaller than K-h.