CONTROLLING NONPOINT EXTERNALITIES WITH INPUT RESTRICTIONS IN AN IRRIGATED RIVER BASIN1

ABSTRACT: Irrigated agriculture is a major nonpoint source of surface water quality degradation. Nonpoint source discharges can be controlled by either output taxes or restrictions, or input taxes or restrictions. The economic theory of externality control with taxes or restrictions on input use is developed. The effectiveness of alternative input control policies in improving surface water quality is demonstrated with a mathematical model of the agriculture and water quality in Washington State's Yakima River Basin. Water quality parameters considered were river nitrogen concentration, water temperature, and cropland soil losses. Producer and social abatement costs were the most important measures of policy effectiveness.     

MONTANA'S EXPERIENCE IN RESERVING YELLOWSTONE RIVER WATER FOR INSTREAM BENEFICIAL USES - THE RESERVATION DECISION1

ABSTRACT: The Yellowstone River in Montana produces an abundant supply of high quality water, but in the early 1970's, the specter of mushrooming energy development in the drainage with its attendant demands for large volumes of water prompted this state to initiate steps to protect existing users and to control future water uses. A Water Use Act was passed in 1973, and a moratorium was subsequently placed on the granting of new permits for major diversion. During this moratorium, various governmental entities were given the opportunity to request the reservation of water for future beneficial uses, including instream purposes. An earlier paper described the reservation applications that were received by the state, and it also summarized the legal framework of the reservation process in Montana. Since that time, the responsible state agency has had the opportunity to review the reservation requests, and its final decision in this regard was announced in December of 1978. This paper describes the details of this decision. Basically, an attempt was made to preserve the integrity of the stream while also strengthening its agricultural uses. In addition, a portion of the flow was not earmarked which will provide some flexibility in reacting to future demands.     

FLUSHING CHARACTERISTICS OF A MISSISSIPPI DEAD-END CANAL SYSTEM1

ABSTRACT: A study of residential canal system on the Mississippi Gulf Coast and adjacent natural water bodies was conducted to determine the relationship in flushing characteristics between man-made and natural systems. The comparison was based on measurements of temperature, salinity, conductivity, coliform, pH, transparency, biological oxidation demand, dissolved oxygen, bathymetry, tides, water velocity, and Rhodamine dye concentrations. The results indicate that coliform bacteria increase with increasing distance of stations from St. Louis Bay and dissolved oxygen decreases in a similar manner. Biological oxidation demand was low at all stations; showing no differences between natural and man-made systems. The canal system Studied was shallower than adjacent water bodies and water velocities in the canal system are a function of tidal amplitude while velocities in the river are affected by both tides and runoff. The other parameters measured show little or no differences between natural and man-made systems, but reflect overall seasonal changes. Flushing rates between the residential canal systems and an adjacent natural system are equivalent on the basis of decline in dye concentrations measured over a five-day period.     

Allocation of River Flows for Restoration of Floodplain Forest Ecosystems: A Review of Approaches and Their Applicability in Europe

Floodplain forests are flood-dependent ecosystems. They rely on well-timed, periodic floods for the provision of regeneration sites and on tapered flood recession curves for the successful establishment of seedlings. These overbank flood events are described as regeneration flows. Once floodplain forest trees are established, in order to grow they also require adequate, although variable, river stage levels or maintenance flows throughout the year. Regeneration flows are often synonymous with flood flows and only occur periodically. There is a disparity between this need for varied interannual flows over the decadal time frame and the usual annual cycle of flow management currently used by most river management agencies. Maintenance flows are often closer to established minimum flows and much easier to provide by current operational practices.A number of environmental flow methodologies, developed in North America, Australia, and South Africa are described in this review. They include the needs of the floodplain environment in the management and allocation of river flows. In North America, these methodologies have been put into practice in a number of river basins specifically to restore floodplain forest ecosystems. In Australia and South Africa, a series of related holistic approaches have been developed that include the needs of floodplain ecosystems as well as in-channel ecosystems. In most European countries, restoration of floodplain forests takes place at a few localized restoration sites, more often as part of a flood-defense scheme and usually not coordinated with flow allocation decisions throughout the river basin. The potential to apply existing environmental flow methodologies to the management of European floodplain forests is discussed.     

RELATIONSHIPS BETWEEN FLOOD FREQUENCIES AND RIPARIAN PLANT COMMUNITIES IN THE UPPER KLAMATH BASIN,OREGON1

ABSTRACT: This study was conducted in the Klamath Basin of southwestern Oregon to evaluate the dependency of riparian plant communities upon infrequent flooding. Plant communities were sampled with 1 m² quadrats along established cross‐sections. Data collected for purposes of hydraulic modeling included channel and floodplain elevations (i.e., cross‐sectional profiles) and water surface elevations associated with specific discharges. The elevational distribution of hydrophytic plant communities relative to modeled return periods provided the basis for establishing relationships between these variables for nine sites. Results indicate that, on average, a peak flow frequency of 4.6 years (range of 3.1 to 7.6 years) was needed to sustain riparian plant communities at seven of nine sites. At two sites, results indicated return periods of more than 25 years were needed; these results possibly were influenced by local geomorphic conditions (a narrow steep channel in one case and an incised channel in the other). Overall, these results tend to confirm a strong dependency of riparian plant communities on overbank flows.     

STREAMFLOW CHARACTERISTICS OF SMALL WATERSHEDS IN THE BLUE MOUNTAINS OF OREGON1

ABSTRACT: Streamflow data for water years 1978–84 were evaluated to identify streamflow characteristics for 13 small watersheds (0.46–7.00 mi²) in the Blue Mountains of eastern Oregon and to determine differences among grazing intensities and vegetation types. The ranges for mean annual water yields, peak flows, and 7-day low flows for the 13 watersheds were 5.5–28.1 inches, 2.0–34.7 cfsm, and 0.006–0.165 cfsm, respectively. Two classes of vegetation were evaluated: (1) western larch-Douglas-fir (nine watersheds) and (2) other (four watersheds representing fir-spruce, lodgepole pine, ponderosa pine, and mountain meadow). The means for annual peak flows and the slopes of the flow.duration curve were significantly different (p=0.05) for the two vegetation classes; differences in mean annual water yield were marginallysignificant(0.05< p <0.10). After they were adjusted for precipitation, the means for annual water yield, peak flows, and slopes of the flow-duration curve were significantly different for the two vegetation classes; differences in the means for annual 7-day low flows were marginally significant. The western larch-Douglas-fir group had somewhat lower water yields but, overall, tended to have more favorable streamfiow characteristics including lower peak flows, higher low flows, and more evenly distributed flow regimes (flatter flow-duration curves) than the “other” class. Four levels of grazing intensity had no effect on streamilow characteristics.     

AN ADDITIONAL ANALYSIS OF PEAK-VOLUME RELATIONS AND STANDARDIZATION PROCEDURES1

ABSTRACT: Much has been written about the linear relationship in log space between the runoff volume of a hydrograph and the peak discharge. Three versions of this relation (an original and two standardizations) have been presented and recommended by various authors. In this paper, the standardized equations are compared to the original relationship and the behavior of the coefficient of determination (r²) in each case is discussed. It is shown that the r² of the standardized equations is increased or decreased relative to that of the original relation based upon the magnitude of the original slope. Further implications of these relationships are discussed and demonstrated using a data base of 90 watersheds and over 1,200 separate flood hydrographs.     

FLOOD FORECASTING FOR TUCURUI HYDROELECTRICAL PLANT,BRAZIL1

ABSTRACT: The construction of the Tucurui Hydroelectric Plant on the Tocantins River basin in Brazil requires flood forecasting for ensuring the safety of the cofferdam. The latter has been initially designed for a flood with a return frequency of one in 25 years. Lack of adequate forecasting facilities during the earlier stages of construction has resulted in significant damages and construction delays. Statistical forecasting models were developed by Projeto de Hidrologiay Climatologie da Amazonia (PHCA) for the purpose of preventing further damages at the site. These models are currently in use and are the subject of this paper. The application of these models during the 1980 flood season, when the highest flood on record occurred at the Tucurui site, proved of great assistance in preventing the flooding of the cofferdam. In conjunction with the development of these models a number of data collection platforms using data transmission through the GOES system were installed to provide automatically the data required for forecasting.     

TECHNICAL CLARITY IN INTER-AGENCY NEGOTIATIONS: LESSONS FROM FOUR HYDROPOWER PROJECTS1

ABSTRACT: We investigated the effect of technical clarity on success in multi-party negotiations in the Federal Energy Regulatory Commission (FERC) licensing process. Technical clarity is the shared understanding of dimensions such as the geographic extent of the project, range of flows to be considered, important species and life stages, and variety of water uses considered. The results of four hydropower licensing consultations are reported. Key participants were interviewed to ascertain the level of technical clarity present during the consultations and the degree to which the consultations were successful. Technical clarity appears to be a prerequisite for successful outcomes. Factors that enhance technical clarity include simple project design, new rather than existing projects, precise definition of issues, a sense of urgency to reach agreement, a sense of fairness among participants, and consistency in participation. Negotiators should not neglect the critical pre-negotiation steps of defining technical issues and determining appropriate studies, deciding how to interpret studies, and agreeing on responses to study results.     

ESTIMATING LOW-FLOW QUANTILES FROM DRAINAGE-BASIN CHARACTERISTICS IN NEW HAMPSHIRE AND VERMONT1

ABSTRACT: This study systematically develops, validates, and compares alternative approaches for estimating quantiles of the distribution of annual minimum seven-day-average flows (7Q) for ungaged, unregulated drainage basins in New Hampshire and Vermont via regression on map-measurable drainage-basin characteristics. At 47 gaging stations in the region, the hypotheses that 7Q is log normally distributed and serially independent are not rejected, and the regional average spatial correlation is R= 0.35. Step-forward examination of a suite of potential predictor variables revealed that logarithm of drainage area, mean elevation, and fraction of basin covered with sand and gravel deposits are significant predictors of quantiles of 7Q. The regression equations were incorporated into four approaches to estimate the 7Q value with a nonexceedence probability of 0.1, 7Q10. Comparison of observed values and values predicted via a delete-one jackknife resampling validation indicates that one of the approaches gives estimates with acceptable bias and precision, with median relative error of 33 percent and prediction error of 64 percent. This is equivalent to the precision obtainable with only one to two years of gaging records. In spite of this limited precision, the approaches developed herein are useful for predicting 7Q quantiles at ungaged sites. Further improvement in precision will likely be possible only by exploiting the spatial correlation of annual 7Q.