Clearwater Streams Research Articles

THE RELATIONSHIP OF LIGHT, TEMPERATURE, AND CURRENT TO THE SEASONAL DISTRIBUTION OF BATRACHOSERMUM (RHODOPHYTA)12

SUMMARYObservations of the 2 growth sites and the laboratory experiments performed on B. vagum and B. moniliforme indicate that B. moniliforme is better suited to higher intensity illumination than is B. vagutn. B. vagnm was found growing year‐round in a dark‐water stream protected from high intensity light by the filtering effect of the bog‐dark water. B. moniliforme was found growing in a clear water stream. Without the protection of dark water, the B. moniliforme disintegrated under the high light intensities of summer. In the laboratory, B. moniliforme retained a healthy macroscopic condition over a full range of light‐intensity treatments; above 250 ft‐c B. vagum was increasingly distintegrated.Light intensity, however, was not the only factor regulating the growth, of Batrachospermum in the 2 growth sites. The pattern of growth of B. vagum in Sinking Creek varied with the depth of the water and, therefore, with the light intensity it received. However, it was found that where all Conditions were the same, the greatest percent cover of the algae was in the center of the stream where the current was the greatest. Thus it was found that within the limitations caused by water depth, current velocity can become limiting to the growth of B. vagum. Although the evidence for environmental factors affecting the growth of B. moniliforme in Smay's Run is less extensive, light intensity and current velocity in this site also appear to interact to control the growth pattern of the algae.

Hydraulic Transport of Solids In A Sloped Pipe

The effects of heterogeneously suspended solids in a pressure flow of liquid on head losses or energy gradients for various pipe slopes, solid concentrations, and flow rates were investigated. Wooden balls, having an average specific gravity slightly larger than unity, were mixed with water in a heterogeneous suspension and transported through a lucite pipe in the experiments. Through proper choice of dimensionless parameters, the data were analyzed and presented in as general a form as possible. The results show that an increase of pipe slope, which does not affect the energy gradient of a clear water stream, evidently causes a rise of head loss from that in a horizontal pipe at a given solid concentration and flow rate. Also, the increase of solid concentration and flow rate raise the energy gradient in the pipe flow of solid-liquid mixtures.

DDT and Heptachlor as Black-fly Larvicides in Clear and Turbid Water

Field tests of several formulations of DDT and heptachlor as black-fly larvicides were made in 1953 and 1954 in irrigation canals in Alberta. The objectives of these tests were 1: to investigate further the relationship between larvicide effectiveness and the suspended solids content of the water, and 2: to investigate the use of formulations containing either emulsifiers or finely-divided inorganic particles which might improve larvicide effectiveness in clear-water streams.

Recreational Development on the Lower Colorado River

unique, scenically and recreationally, as the only large clear-water stream in the entire southwest desert area of the United States. The addition of large lakes to the combination of desert, mountains, and sun has made the area a source of pleasure and relaxation. Within easy driving distance of large and growing populations in both Arizona and California, the lower Colorado is attracting increasing numbers of vacationers from these areas, as well as from many of the more distant states.

Wider Application of the Electrical Method of Collecting Fish

Limitations of the electrical-shock method of collecting fish, as commonly used, are reviewed. Among these are the facts that the equipment considered necessary is cumbersome and costly; that the method is effective only on quite narrow, clear-water streams; that effectiveness varies greatly with chemical content of soil and water; and that it is dangerous. Equipment and techniques that overcome these limitations to a greater or lesser extent are described. It has been found that less and more simple gear can be used effectively and safely. Methods of handling equipment which eliminate many time-consuming delays have been developed. Equipment and procedures which are fully satisfactory on wider streams and in turbid waters are described. An electric “seine,” effective in streams 90 to 100 feet wide, has been developed. By employing special techniques, it can be used quite effectively in wider streams. In turbid water the method is less efficient but quite satisfactory sampling of the fish population can be made. Preliminary experiments have been made on the amount of electric current needed to stun fish without killing them. Apparently, most species of fish will be stunned but will recover in a few minutes from shock caused by 5 to 6 amperes of alternating current at 110 volts. Larger fish seem to be stunned more readily than those of fingerling size. Experiments on the efficiency of the method have been started. Factors influencing efficiency are believed to be chiefly those related to the recovery of stunned fish. Turbid water, swift current, and rough bottom all seem to decrease efficiency. Experimental evidence to confirm these beliefs is incomplete and inconclusive but it is evident that the method is highly effective in sampling qualitatively areas which otherwise could not be worked.