n, to
the dismay of many conservationists. Often too they flood out large
areas of riverbottom farmland and other private property, arousing the
ire of some rural folk and small townsmen who feel that their interests
have been sacrificed to the water or flood-protection demands of
downstream city dwellers. Opponents of major dams sometimes assert that
many of them have been built not to meet real hydrological needs but to
foster economic development which may or may not materialize and may or
may not be worth the loss of natural or scenic or agricultural resources
disrupted by the reservoirs. Other thinkers, not necessarily against
reservoirs in general, express a doubt that the potential effects of
specific structures are always thought out sufficiently beforehand.
Among these are the authors of a recent publication of the National
Academy of Sciences--National Research Council, _Alternatives in Water
Management_:

"_We create great reservoirs that stop the migration of fish and then
provide costly fishways, hatcheries, and other devices to maintain the
fishery, and with no certainty of success. We impound water without
knowing the effects of that impoundment on its quality. We build an
irrigation project and then find salinity increasing dangerously in the
river downstream. We eliminate high-flood peaks by reservoir storage,
but downstream from some reservoirs we see unpredicted erosion,
sedimentation, bank-cutting, and other effects, even unto, as in
California, the loss of beaches along the seacoast, starved of their
supply of sand._"

The list of objections could be extended--and often is by objectors--to
a point of pettiness. Nevertheless, the main doubts are gaining much
acceptance and are imperatively having to be taken into account more and
more these days, as new elements of water technology and
philosophy--some of them mentioned earlier in this chapter, others to
emerge in subsequent discussions--come closer to full feasibility and
become a part of general human knowledge. Delay in building reservoirs
until it is certain they are needed is on the verge of becoming a
respectable element in planning, and in the future dams may well become
merely one of many ways to guarantee water and handle it. At least some
water authorities, though certainly not all, have voiced the opinion
that most present reservoirs will some day serve primarily for
recreation, if emerging new principles of water supply, water quality