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OVERVIEW AND CONCLUSIONS
Humankind Is in a continuous struggle with a vast
range of natural hazards. Many of these hazards (e.g.,
floods, earthquakes, tornadoes, and hurricanes) are
encountered as short-duration, high-intensity, and
relatively localized events. In this country, most
research and formal emergency planning procedures are
directed toward damage mitigation and rehabilitation
needs associated with such events. Drought is different
in that it seldom has a spectacular or sudden
onslaught. Damage inflicted by drought usually occurs
rather subtly over a span of months to years instead of
minutes to days. Truly serious drought is usually a
regionalized--as contrasted to localized--trauma, with
the attendant need to broaden preplanning and mitigation
efforts.
A precise definition of drought is difficult, because
the meaningful threshold of significant moisture
deficiency is a function of the water use being
impacted. For the purpose of the colloquium, drought
was considered to represent a period of time when
streamflows, reservoir storage, and shallow ground-water
levels are abnormally low as a result of climatically-
induced moisture deficiency. Drought severity as it
relates to public water systems is necessarily a
function of human actions and/or inactions as well as
the magnitude and duration of the individual hydrologic
event.
There is need to direct both research and pragmatic
mitigation efforts toward the neglected problems of
water management during drought episodes. This
colloquium was limited to the subject of drought as it
affects the management of public water systems. The
observations and recommendations summarized herein
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reflect that constraint. No attempt has been made to
capture individual views. Instead, emphasis has been
placed on those points for which a general consensus was
identified in the floor discussion.
Research Concerns
There are numerous areas of inquiry where research can
be expected to be productive. Categories of primary
interest include cause and effect aspects of the drought
mechanism, the probability distribution of drought
events, measurement of the consequences of system
failure, and the legal aspects of drought management.
Our lack of ability to provide a firm rationale and
explanation of the drought mechanism impedes efforts to
develop reliable alert systems. The development of such
systems would represent a crucial step toward
implementation of effective and efficient drought
contingency plans. Our present capability to predict
drought appears to be confined to empirical equations
relating such factors as sunspot numbers to streamflow
and various physical anomalies, such as sea surface
temperature and the positioning of land-based
high-pressure centers, and to projected precipitation
patterns. Though such correlations have been well
documented, why or when these relations trigger the
occurrence of significant drought is not understood.
Analysis of drought frequency relationships has lagged
appreciably behind the companion efforts related to
flood discharge. There are several reasons for this,
not the least of which relates to difficulties
associated with the definition of drought. Annual peak
discharges are a meaningful measure of flood size and
are easily identified for purposes of flood frequency
analysis. Neither minimum instantaneous flows nor
lowest daily Round-water levels provide a meaningful
measure of
and the magnitude ot flow oet~c~ency anti/or moisture
availability must be known in order to characterize a
drought. Clearly, design of water supply system
components based on drought of record begs the issue.
Tree ring analyses have suggested the possible
occurrence of historic droughts more severe than those
readily documented by available flow records in this
country. Nonetheless, we need to develop our knowledge
of drought occurrence, for such knowledge is a
, ~ , ~
of the magnitude of drought. Both the duration
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prerequisite for effective analysis of drought
management alternatives.
Equally key to the analysis of drought management
alternatives are valid assessments of the costs
associated with different types and durations of system
failure. Several difficulties are encountered in
attempting to develop generalized and transferable
relationships. First, certain costs can be very site
specific. Second, acquisition of firm data is difficult
until a drought is encountered. Third, the average time
span between significant droughts for a given system may
be so long that the local economic and social patterns,
and thereby the potential consequences of different
types of system failure, may have changed appreciably.
These obstacles should not be allowed to deter continued
inquiry. Though they may work against the
quantification of well-defined cost benchmarks, they do
not lessen the need to develop methodological concepts
to allow for an orderly process of analysis of
alternative management strategies.
Proper institutional arrangements can facilitate
effective management of water supplies during drought
periods. Conversely, inadequate or unwieldy
institutional frameworks can effectively destroy the
most industrious of management efforts. Since the
management of public water systems is primarily a local
responsibility, research is needed on the powers local
authorities require to implement effective drought
management programs. In addition, legislation at other
than the local level can either expedite or constrain
effective management choices. Little research has been
directed at the effectiveness or influence exerted by
different state laws and/or subregional, state, and
interstate organizational structures during droughts.
Management Concerns
A wide range of decision issues was touched upon
during the formal presentations and subsequent floor
discussion. They generally can be categorized as
follows: appraisal of risk, choosing between relying on
supplemental supplies or relying on the management of
demand, social aspects of demand management, water
transfers from other uses, and other regional solutions.
There was consensus that a uniform level of hydrologic
risk should not be advocated as a design or decision
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parameter for a variety of reasons. The use of this
approach in floodplain management has discouraged
rational evaluation of floodplain productivity. In
addition, the risk of system failure could be as
sensitive to the quality of system maintenance as to
variations in hydrologic events. Consideration of scale
also influences this decision. That is, a small system
can, from solely a logistic consideration, accept a
higher risk of having to resort to emergency supplies
than can a large system. Finally, site-specific
considerations must be taken into account. A system
with little access to alternative or emergency supplies
must seek a more risk-free environment than one not so
constrained. Despite lack of unanimity as to what
constitutes an acceptable risk, there was general
support for the need to integrate risk analysis into
system planning as opposed to basing evaluations solely
on the drought of record.
Without risk appraisal, quantitative comparison of
trade-offs between investments in supplemental emergency
sources and demand management techniques could be
meaningless. Application of demand management
techniques should increase as the relative risk of
system failure, especially the hydrologic portions
thereof, decreases. This concept is supported by the
recent trend in legal liability decisions that suggest
the designer or planner could well be required to keep
the risk of ~ ~ -
general agreement
management should capitalize on the decades of evolution
in trade-off analysis that has taken place in the
overall field of water resources planning. A primary
prerequisite is development of an orderly and systematic
matrix for analysis, and a current constraint is the
lack of reliable data for quantifying the consequences
of system failure.
Several major considerations surfaced in the comments
related to implementation of demand management
techniques. First, there is little evidence these
techniques will produce a continued reduction in water
demand in postemergency conditions. The public
obviously feels that such reductions do, indeed,
adversely affect the quality of life and finds them
unacceptable in the long term. Second, public
cooperation in implementing demand management techniques
has been shown to be excellent provided there is clear
evidence of need. Third, the successful implementation
r
hydra ~ og~c system failure low. There was
that system planning for drought
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of demand management techniques requires an adequate
legal foundation. These factors must be understood by
managers developing drought contingency plans.
Appreciable attention was directed toward the possible
diversion of water from other uses, primarily
agriculture, as a means of mitigating public system
drought issues. The legal concept is well established
via the route of condemnation, but implementation can
lead to much acrimony and is often costly and time
consuming. Two alternative approaches, responsive to
different physical situations, were examined and found
attractive.
In the case of large, rapidly growing urbanized
regions, the projected transfers may be so large as to
have an impact on the associated agribusiness industry.
In this case, urban investment in conservation
facilities for agriculture in return for the water saved
has been found attractive to all three parties (i.e.,
the public system, the irrigator, and the related
agribusiness interests). For many systems, the problem
is quite different: existing sources are adequate for
most years. The agricultural transfer is not needed on
a permanent basis. In such cases, negotiated lease
transfers wherein the irrigator is provided an initial
signing bonus and then compensated for each subsequent
year his water is used have proven successful.
Legal Concerns
Several legal concerns surfaced during the
presentations, some of which have already been noted.
Matters of primary concern to public systems confronted
with drought management issues relate to questions of
authority, water transfer, and constraints imposed by
state or federal actions.
Several participants in the colloquium emphasized the
need for public systems to have their legal house in
order before the onset of drought. The point was made
that, in some instances, this might require a regional
approach. Of main concern is the system's ability to
initiate demand management techniques involving
voluntary or mandatory conservation, revised rate
schedules, or imposition of penalties. For publicly
operated systems, this can be handled by the
pre-enactment of a drought contingency ordinance that
spells out the authority granted and the actions
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permitted. Privately operated systems, in the absence
of supporting ordinances from local government, can
establish the necessary authority via contractual
arrangements with individual customers.
The need for system managers to be aware of the status
of their water rights, and the related state
administrative and judicial procedures, was stressed.
In this light, system managers should explore ways of
increasing system yield within the confines of existing
rights and seek administrative or legislative relief if
unnecessary and ill-advised constraints are
encountered. For example, conjunctive use of ground and
surface waters is not widely practiced, although the
practical advantage of conjunctive management is quite
clear. Often its successful implementation would
require a higher maximum rate of withdrawal from the
ground water during the drought, although the overall
demand on the ground water through the combined wet and
dry cycle would be reduced. In such cases, existing
administrative and legislative policies may prohibit
implementation of a conjunctive use pattern. Public
system managers need to move to lessen such constraints.
There is every reason to believe that an increasing
number of water supply problems will be resolved via
water transfers. Again, the point was made that these
solutions may need to be appraised in a regional
context. This phrase "water transfer" may relate to
change of use or to change of location or both. Public
system managers need to know about the legal controls
relating to such transfers. Where the need for transfer
is of limited duration, the use of leases as described
above deserves exploration. The competition for water
has prompted the enactment of various state statutes
concerning both intrastate and interstate transfer of
waters. Judicial interpretation of these statutes is
undergoing rather rapid evolution. Similarly, recent
decisions citing the public trust doctrine may have an
impact on water allocation issues. These several
matters deserve continued examination.
Conclusions
1. There is substantial need for continued research
on drought and its impact on the management of public
water systems. Key research topics include (a) cause of
drought, (b) development of effective drought alert
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mechanisms, (c) probability analysis of drought, (d)
quantification of the consequences of system failure
during drought, and (e) identification of the
institutional environment necessary for successful
implementation of drought management plans. Federal
agencies, universities, the water supply industry, and
private foundations should all support research in these
areas.
2. Sizing of the physical facilities of a system
should not be based solely on full-service requirements
during the drought of record, nor should such facilities
be sized by the arbitrary specification of hydrologic
risk. The reasons are many and range from the
inadequacy of existing records to individual system
characteristics. Instead, the measure of facility
adequacy should be established by orderly comparison of
incremental facility requirements versus the use of
demand management techniques over the range of
probability conditions. As the risk of system
inadequacy decreases, the relative advantage of demand
management techniques can be expected to increase.
3. The key to adequate drought management of public
water systems lies in predrought preparation. This
consists of a variety of actions best typified as
drought contingency planning, including (a) a good
system maintenance program, (b) periodic assessment of
system capacity and the relative balance among all
system components (source, transmission, treatment, and
distribution), (c) identification and appraisal of the
reliability of emergency or supplemental sources of
supply, (d) analysis of the probable effectiveness of
demand management techniques and determination of
criteria for implementation, (e) development of the
framework of public information programs needed to
implement drought management measures, and (f)
establishment of the legal foundation necessary to
implement emergency source plans and projected demand
management techniques.
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Representative terms from entire chapter:
management techniques
