easily occur, changing the nature of the che micals in a way that is not only unpre dictable but
beyond control. It is , of cours e, not only the groundwaters that are becoming conta minated,
but s urface-moving waters as well— streams, rivers, irrigation waters. A disturbing example of
the latter seems to be building up on the national wildlife refuges at Tule Lake and Lower
Klamath, both in California. These refuges are part of a chain including also the refuge on Upper
Klamath Lake just over the border in Oregon. All are linked, perhaps fatefully, by a shared water
s upply, and all are affected by the fact that they lie like small islands in a great sea of
s urrounding farmlands—land reclaimed by drainage and stream diversion from an original
waterfowl paradise of marshland and open water.
Thes e farmlands around the ref uges are now irrigated by water from Uppe r Klamath Lake. The
irrigation waters, recollected from the fields they have s erved, are then pumped into Tule Lake
and from there to Lower Klamath. All of the waters of the wildlife refuges es tablis hed on thes e
two bodies of water therefore represent the drainage of agricultural lands. It is important to
reme mbe r this in connection with recent happe nings. In the s ummer of 1960 the ref uge s taff
picked up hundreds of dead and dying birds at Tule Lake and Lower Klamath. Mos t of them
were fish-eating species—herons , pelicans , gulls. Upon analys is , they were found to contain
insecticide res idues identified as toxaphene, DDD, and DDE. Fis h from the lakes were als o found
to contain insecticides; so did s amples of plankton. The refuge manager believes that pes ticide
res idues are now building up in the waters of thes e refuges , being conveyed the re by return
irrigation flow from heavily sprayed agricultural lands.
Such pois oning of waters s et as ide for cons ervation purpos es could have cons equences felt by
every western duck hunte r and by eve ryone to whom the s ight and s ound of drifting ribbons of
waterfowl across an evening sky are precious. Thes e particular refuges occupy critical pos itions
in the cons ervation of wes tern waterfowl. They lie at a point corres ponding to the narrow neck
of a funnel, into which all the migratory paths composing what is known as the Pacific Flyway
converge. During the fall migration they receive many millions of ducks and geese from nesting
grounds extending from the s hores of Bering Sea eas t to Huds on Bay—fully three fourths of all
the wate rfowl that move s outh into the Pacific Coas t s tates in autumn. In s umme r the y provide
nesting areas for waterfowl, especially for two endangered s pecies , the redhead and the ruddy
duck. If the lakes and pools of thes e refuges become s erious ly contaminated the da mage to the
waterfowl populations of the Far West could be irreparable. Water mus t als o be thought of in
terms of the chains of life it s upports—f ro m the small-as -dus t green cells of the drifting plant
plankton, through the minute water fleas to the fis hes that s train plankton from the wate r and
are in turn eaten by other fis hes or by birds , mink, raccoons—in an endless cyclic transfer of
materials from life to life. We know that the necessary minerals in the water are so passed from
link to link of the food chains. Can we s uppos e that pois ons we introduce into water will not
als o enter into thes e cycles of nature?
The ans wer is to be found in the a mazing history of Clear Lake, California. Clear Lake lies in
mountainous country s ome 90 miles north of San Francis co and has long been popular with
anglers. The name is inappropriate, for actually it is a rather turbid lake becaus e of the s oft
black ooze that covers its s hallow bottom. Unf ortunately for the fis hermen and the res ort
dwellers on its shores, its waters have provided an ideal habitat for a small gnat, Chaoborus
astictopus. Although clos ely related to mos quitoes , the gnat is not a bloods ucker and probably
does not feed at all as an adult. However, human beings who s hared its habitat found it
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