Biological Systems Engineering


Date of this Version

Winter 1973


Illinois Research, University of Illinois Agricultural Experiment Station, Winter, 1973. Vol. 15, No. 1, pp. 18-19.


Nitrate levels in farm ponds are determined with the aid of a water sampler that can be operated from the shore

The quality of pond water in southern and western Illinois is being determined with the aid of a new type of water sampler developed in the Department of Agricultural Engineering.

Work on the sampler began as part of a study of water supplies in Washington County. This study, which is being conducted through the College of Agriculture Council on Environmental Quality, was initiated in the winter of 1970, after high nitrate levels were found in the county's water supplies. Both ponds and wells are being sampled to determine their acceptability as sources of water.

For accurate tests of pond water, samples must be obtained at various depths and distances from the shore. A boat, however, is bulky and difficult for one person to handle. The new sampler was therefore devised so that an investigator can sample pond water at any depth without ever leaving the shore.

How the sampler is made

The sampler consists of a telescoping rod manufactured for window- washing units; a float, a sampler head, and a bottle at one end of the rod (Fig. 1); and a T-handle and two operating reels at the other end (Fig. 2). One reel contains the cord to the float; the other, the cord that operates the sampler head. Cord guides are attached to the rod sections.

The sampler head (Fig. 1) is made up of three components: the sampler head base, the bottle plate, and the stopper plate. The sampler head base is attached to the sampling rod and contains the water port through which water enters the sample bottle. An extension to the water port, which extends into the sample bottle, is attached to the sampler head base. In addition, the base contains an air e cape port.

The bottle plate is attached to the sampler head base and is fabricated with threads for the sample bottle. The bottle plate may be easily removed from the sampler head base so that other bottle plates fitting different sample bottles may be used with the same sampler head. The stopper plate with stopper is spring-loaded to seal the water port while it is being positioned for sampling and after the sample has been taken.

How the sampler works

To obtain a sample, the rod is extended to the desired length and the bottle is attached to the sampler head on the pond shore (Fig. 3a). The bottle and sampler head are floated to the desired position on the pond surface with the float held tightly to the sampler end of the rod (Fig. 3b). The cord to the float is then released to allow the sampler head and bottle to sink to the desired sampling depth (Fig. 3c).