PLASTIC STANDPIPE FOR SAMPLING STREAMBED ENVIRONMENT 

 OF SALMON SPAWN 



INTRODUCTION 



The existence of adverse conditions of 

 the streambed as a limitation to the produc- 

 tion of salmon has received less attention 

 than have other phases of salmon biology. 

 The streambed, as a habitat for the eggs of 

 salraonoids, is subject to constant change. 

 The problem is to obtain continuous informa- 

 tion about the changes that Eiffect the 

 Survival of eggs, which the fishery manager 

 has previously gone to great effort to pro- 

 tect. Guaranteeing escapement of adult 

 spawners by measures of enforcement or con- 

 struction of costly fishways, for example, 

 can be wasted effort if the streambed has 

 become an unsuitable habitat for incubation 

 of eggs. Conditions that sometimes render 

 a drainage area unfit for fish include road 

 construction, mining and logging operations, 

 cind certain land cultivation practices. 



The prerequisite for the survival of 

 spawn is cin adequate flow of oxygen-bearing 

 water through the gravel containing the 

 eggs. Thus, in the management of a stream, 

 it is desirable to know (1) the concentra- 

 tion of oxygen present in the water of the 

 spawning bed and (2) the rate of seepage of 

 this oxygen-bearing water through the gravel. 

 Obtaining a water sample from the streambed 

 for determining the dissolved oxygen present 

 at the spawn level is relatively simple, 

 but the determination of the rate of seepage 

 is Somewhat involved. 



In the past, several methods have been 

 used for measuring seepage rate in the 

 gravel. Generally, these methods involve 

 pouring a saline solution or fluorescein 

 dye into a pipe that has been driven into 

 the streambed. The rate of flow then is 

 determined at a measured distsuice downstream 

 by inserting electrodes into the streambed 

 to detect the arrival of the salt solution 

 or by observing the arrival of the dye. One 

 weakness of this method stems from the com- 

 plexity of the pattern of flow in the stream- 

 bed. The dye, for example, may appear at 

 the test spot within 30 minutes and continue 

 to flow for the next 20 minutes. The same 

 pattern of flow is observed if a salt solu- 

 tion is used instead of dye. Thus, these 



methods still leave unsolved the question 

 how fast the water is moving past a parti- 

 cular point where incubating eggs may be 

 located. 



A new procedure being used in the 

 freshwater-survival studies of king salmon 

 in California has proved superior to other 

 methods. It involves the standpipe prin- 

 ciple that was pioneered in fishery work of 

 the Biological Station at Nanaimo, B. C. , 

 and reported by Wicket (1954), Pollard 

 (1955), and Terhune (1957). 



Essentially, the standpipe is a short 

 length of pipe that is lodged in the stream- 

 bed and extends upward above the surface 

 of the stream. In this position, it serves 

 as an access tube through which the quantity 

 of oxygen in the groundwater and the rate 

 of flow of water in the gravel may be tested. 



The standpipe may be used in either 

 one of two ways: (1) It may be inserted in 

 the streambed aind removed after one use, or 

 (2) it may be kept imbedded for a systematic 

 and progressive recording of conditions in 

 the gravel. 



In the first example, the standpipe is 

 driven into the streambed by means of a 

 sledge. This system has the advantage in 

 that the same standpipe can be used over 

 and over again to cover a number of streams. 

 In the second, the standpipe remains in the 

 gravel and becomes a component of the 

 streambed. It therefore may be inserted 

 by digging a hole, placing the pipe in it, 

 and then refilling the hole with gravel. 

 The placed standpipe has several advantages 

 over the temporary installation: 



1. Data obtained are continuous; thus, 

 observed fluctuations in the amount of dis- 

 solved oxygen or the rate of seepage of 

 water through the gravel then are known to 

 have occurred since the previous examina- 

 tion and not to be a result of local vari- 

 ability. 



2. The data are obtained more readily 

 than are data from a temporary standpipe, 

 which usually requires a period of waiting 



