POLICY DROUGIT: THE CASE OF SOUTH FLORIDA1

ABSTRACT: In this paper, we review recent experience with drought in south Florida, and report some results of a study of the likely agricultural economic impacts of drought. Our conclusions can be summarized as follows. (1) Whether a period of low rainfall becomes a “drought” in south Florida is determined largely by institutional factors. (2) The impacts of a drought event are dependent on the rules the Water Management District uses to manage the event. If the rules involve effective reductions in irrigation supply, the financial impacts may be large, but are sensitive to the way in which cutbacks are imposed. (3) Current drought management regulations do not appear to minimize the short-run cost of drought. (4) Current policies which seek to minimize the short-run cost of drought are inconsistent with dynamically-optimal policies.     

DOWNSTREAM CHANNEL GEOMETRY FOR USE IN PLANNING-LEVEL MODELS1

ABSTRACT: There is considerable potential for use of channel dimension data in planning-level models for resource and impact assessment. The channel dimension data is used to route flows and sediment through the basin. The cost of obtaining actual surveyed data for large watersheds is typically prohibitive. Predictive equations have been developed based on 674 stations from watersheds across the United States which encompass a wide variety of channel types and sizes. These equations were tested against an independent data set and found to be adequate for use in planning-level models. Future research is advocated which would include data from regions and stream types not included in this study.     

Earthquake risk reduction: An examination of local regulatory efforts

We develop an understanding of local governmental efforts to address earthquake risks. Our data for a sample of California and Washington cities' risk-reduction efforts sort into two different clusters of leading jurisdictions as contrasted with a cluster of lagging jurisdictions. We explain differences among the three categories of cities in terms of different political-economic factors. Local governmental willingness and ability to undertake risk-reduction programs have more to do with local political demands and community resources than with objective risk or previous earthquake experience. State mandates have a selective impact on local risk-reduction efforts. The principal policy lessons concern the need to address gaps in local risk-reduction efforts through more careful targeting of federal and state earthquake programs and by including stronger teeth within state mandates.     

Ecologically derived guidelines for managing two New Zealand lakes

Lakes Manapouri and Te Anau, in Fiordland National Park, became the center of a major controversy after the New Zealand government offered their water resource to an overseas aluminum smelting consortium for electricity generation. Although the scheme proceeded, the lake levels were not raised as originally proposed. Rather, government sought guidelines to optimize hydroelectric potential while maintaining ecological stability of the vulnerable, largely forested, glaciated lakeshores. Guidelines were derived by relating the vegetation zonation to the natural lake-level fluctuations recorded daily for 37 years. Ahigh operating range in the upper third of the lakes' natural ranges, based on flood tolerances of the woody shoreline species, restricts both duration and frequency. Alow operating range (ca. lower third) safeguards stability of shoreline sediments by limiting drawn-down rates, duration, and frequency. Themain operating range (ca. middle third) has few limitations. These guidelines, which allow utilization of ca. 93% of the water resource, have now been verified by instances of flooding and draw-down rates that exceeded the natural rates recorded earlier. The guidelines were officially accepted by the government in 1977 as a basis for managing the valuable multiple resources of these two lakes and their environs, and they were formalized in legislation in 1981. The details and merits of the guideline approach are discussed.     

Construction of guilds for habitat assessment

This article outlines a procedure for developing guilds for use in habitat assessment studies. It is based on a matrix constructed around layers of vegetation and other physical features of the environment used by vertebrate species for feeding and breeding. Modifications to permit inclusion of other life requirements such as cover are discussed. Examples are used to illustrate how species are assigned to guild cells based on their use of habitat, and how the association between a species and its environment does not have to be direct to influence the species' placement within the matrix.     

UK interpretation and implementation of the EEC Shellfish directive

The EEC Shellfish Directive is a policy designed to protect and, where necessary, improve the quality of designated shellfish waters. Its implementation within the UK, however, has had no effect upon water quality for two reasons. First, the policy has important defects, having ambiguities concerning public health provisions and lacking designation criteria. Second, UK government has sought to achieve formal compliance, while at the same time ensuring that its full financial impact on public expenditure has been contained. Consequently, only those fisheries which already comply with water quality standards have been designated. Within Wales, one fishery has been designated, while other, commercially more important, but grossly contaminated shellfisheries have not.     

SENSITIVITY OF HIGH-ELEVATION STREAMS IN THE SOUTHERN BLUE RIDGE PROVINCE TO ACIDIC DEPOSITION1

ABSTRACT: The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of total alkalinity and describes the chemical characteristics of 30 headwater streams of this area. Water chemistry was measured five times between April 1983 and June 1984 at first and third order reaches of each stream during baseflow conditions. Sensitivity based on total alkalinity and the Calcite Saturation Index indicates that the headwater streams of the Province are vulnerable to acidification. Total alkalinity and p11 were generally higher in third order reaches (mean, 72 μeq/θ and 6.7) than in first order reaches (64 μeq/θ and 6.4). Ionic concentrations were low, averaging 310 and 340 μeq/θ in first and third order reaches, respectively. A single sampling appears adequate for evaluating sensitivity based on total alkalinity, but large temporal variability requires multiple sampling for the detection of changes in pH and alkalinity over time. Monitoring of stream water should continue in order to detect any subtle effects of acidic deposition on these unique resource systems.