This next abstract may seem daunting to anyone logged on here
who lacks a science background.  In a nutshell, what it says is
this:

Declining coastal and estuarine fisheries are simply a matter of
the laws of physics and systems science, according to
distinguished oceanographer, M.A. Rozengurt -> the coasts need
runoff input for coastal-estuarine-deltaic ecosystems and their
fisheries to function normally.


7th International Biennial Conf. on Physics of Estuaries &
Coastal Seas:  Buoyancy Effects on Coastal Dynamics.

Woods Hole Oceanographic Institution,
Redfield Laboratory & MBL Swope Centre,
28-30 November 1994;  Woods Hole, MAINE USA

RUNNING ON EMPTY: THE DISTORTION OF COASTAL ECOSYSTEMS
by Michael A. Rozengurt*

Abstract

     Among numerous coastal embayments, estuaries occupy special
places whose immense influence on the adjacent marine environment
and fishries has been recognized by humankind since time
immemorial.  By definition, *estuaries are intermediate, dynamic,
and cumulative links within the river-delta (estuary)-sea
ecosystems where continual variable confluence, interaction, and
mixing betwen river and sea takes place*.  These processes result
in development of 4 specific zones of mixed water m,asses.  In
accordance with the Venice International classification of 1958,
they are typified bya  strictly defined range of salinity, and
other chemicals and biological characteristics.  As is known, the
average salinity concentration of 5 g/L is a natural barrier for
strictly estuarine species at early stages of their development
withing the avant-delta zone, the latter confined by 0.1 to 0.5
g/L salinity from the deltaic side.

These and other natural combinations of regime characteristics,
developed under an umbrella of unimpaired runoff, have provided
for the unique diversity and highest biological productivity of
organisms directly or indirectly through food webs related to
estuarine systems.  But when the impoundment of watersheds has
become fully operational, the river-coastal continuum has been
mortally wound, and fisheries have started to fade away since
that time (Rozengurt, 1971, 1974, Rozengurt et al 1985).

For over the past two decades, the public perception has been
that discharges of treated wastewater into estuarine-marine
environments was the major cause of their progressive
impoverishment.

Although some pollutants might have had measurable progressive
effects on the health and reproduction of living resources, the
lack of sound scientific information on the more serious effect
of river impoundment on coastal systems has led many to
mistakenly believe taht more treatment or even "distilled" or
"zero" discharges will testore the fishery.  As a result, $200
billion out of $541 billion [US dollars] were expended over the
last two to three decades on pollution control to supposedly
remedy the obvious depletion of fish and shellfish stocks. 
despite this enormous cost and drastic improvement of treatment
processes and the implementation of stringent water quality and
foishery regulations (Clean Water and Magnuson Acts - in the US),
the despoilation of coastal resources and economic losses has
continued to persist.

It appears that the systematic depletion of river runoff over teh
same decades by numerous dams, water storage and networks of
water conveyance facillities have had many times higher direct
impacts on the aggravation of the regime and biota of the
ecosystems in question than effluents   (Rozengurt and Haydock
1981, 1993, 1994).  Ironically, in the Southern Californian
Bight, the submerged ocean outfalls discharging at a distance of
three to seven miles from the shore, at a depth of 60 metres are
the closest to being a fresh water source, as the 150 rivers and
streams of the Bight's watershed have ceased to exist due to
impoundment.  As a result of the latter, the sport fishery has
been remndered insignificant, the kelp beds have declined, and
more than hundreds of miles of beaches have experienced
ionexorable erosion.  This, combined with other examples of
ecological depreivation of the natioan's coastal embayments
(Columbia River Estuary, San Francisco Bay, Colorado River
Estuary, the Gulf of Mexico, Chesapeake Bay, etc.) provide strong
support to the statement that river runoff was, is, and will
continue to be the ultimate, intrinsic guarantee of the estuary-
coastal systems survival.  The pragmatic manifestation of this
statement is based on the universality of the Laws of
Thermodynamics, which govern the paths and control the runoff
energy distribution and dissipation along the river course
(Fig.1) Note that the basic principals of river hydraulics and
estuarine hydrodynamics are derivitaives of the laws of
conservation of mass and energy.  The 3 major equations 

1) the motion of water 
2) continuity of volumes of water exchanged between an estuary
and sea 
&
3) continuity of salt balance 

describe how these principals control the estuarine regime. 
their solutions ttogether with the results of a statistical
analysis of satochastic, seasonal and perrenial behaviour of
unimpaired runoff characteristics provides ample evidence that
the lesser the runoff, the greater is the salt intrusion, and the
higher the salinization of an estuary (Fig. 2).

Simultaneously, the diminishing runoff adversely effects
circulation, mixing and entrainment phenomenon of runoff energy
to repulse salt intrusion to maintain quasi-equilibrium dynamics
of estuarine ecosystems.  The failure to recognize these and
other universal regime features of the coastal embayments by
watershed developers have contributed to:

1) alarming depletion of runoff to 60% to 90% of normal spring or
annual values (note that the author had found that unimpaired
intra-annual and perrenial runoff fluctuations rarely exceed more
than +/- 25% to 30% of their norms (Rozengurt, 1971, 1974, 1985).

2) the deprivation of the Central, South Atlantic and Western
Pacific coastal zones of thousands of million of acre-feet of
freshwater.

3) the current remnants of "regulated" flow, [especially spring
flow] correspond to atypical chronic drought conditions regardles
of wetness of the year ( aseldom measured phenomenon for an
unimpaired regime), their volumes no longer capable of absorbing
even natural pollutants, nor maintaining an adequate environment
for migration and spawning, and 

4) the loss of millions of tons of oxygen, organic and inorganic
matter, and sediments, all so vital to coastal ecosystem
survival.

Concurrently, delta and coastal erosion, subsidence of levees,
oxygen deficit, hypoxia, eutrophication and agricultural
discharges laden with chemicals have further agravated the
precipitous declin of habitat.  The curtailment of 90% of
migration routes and spawning grounds by thousands of dams,
together with the conversion of deltas into little more than 
plumbing conduits, have inflicted the final mortal blow to the
[USA] Nation's and wiorld fishery.  Accordingly, an escalating
entropy has become a new, highly negative property of formally
healthy and rich ecosystems.  Subsequently, the new surrogate
riverine-coastal-delta ecosystems have only one thing in common
with their natural, lustrous past - the same geographic locations
and names on the maps.  The reason why many prognostic
contemporary models have provided erroneous results can be
attributed to their inability to integrate the cumulative role of
environmental losses (discussed earlier) on coastal systems,  
thereby rendering their results nothing more thaan whistes in the
dark.  Arguably, the Nation's estuary is in peril.


*Invitational presentation