摘要:

ABSTRACT:The approximate streamflow partitioning method which uses daily rainfall and streamfiow data was applied in Coastal Plain, Coastal Flatwoods, and Southern Piedmont physiographic regions for estimation of the surface and subsurface flow components of total streainflow. Sizes of the watersheds ranged from 9.6 km2to 1,030 km. Although the streamflow partitioning method was developed and tested on the Coastal Plain physiographic region, results indicate that the procedure can be applied to other physiographic regions where available data are limited to daily values. The effect of channelization on the partitioned flow components in the Coastal Plain and Coastal Flatwoods physiographic areas was also examined. While channelization was found to decrease the storm‐time base, it had no significant effect on the relative percentages of the partitioned flow component

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00788.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:Since the majority of road drainage points in western Washington and Oregon enter small, often ephemeral streams rather than large, fish‐bearing waters, impact of road‐surface sediment on biota in permanent streams depends, to a large extent, on transport through these small watercourses. A series of experimental additions of road‐surface sediment was made to two ephemeral streams to examine the downstream transport of this material as a function of discharge and channel characteristics. These small streams were found to store large amounts of sediment washed from road surface. In no instance did either stream transport more than 45 percent of the added material to their mouths, distances of 95 and 125 m. Larger‐sized sediment particles were delivered at a lower rate than finer material. Added sediment<0.063 mm in size was transported efficiently through the systems at all but the lowest flows tested. Material between 0.5 and 0.063 mm and from 2.0 to 0.5 mm in size were retained at progressively higher rates, with sediment in the coarser size category never exceeding a delivery of 10 percent of the added material. There were significant differences in the transport of sediment in the two larger size categories between the two streams. These differences were due to a much greater amount of woody debris in the stream with the lower delivery rates, which acted to trap and hold sediment, as well as a slightly longer and less steep

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00789.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:The water resources of Nicaragua are largely undeveloped and distributed unequally throughout the nation. In addition, there is a significant geographical imbalance between the abundant water supply in the Atlantic Basin and the less abundant supply in the Pacific Basin which accounts for most of the water demand. The Lakes Basin, comprising Lakes Managua and Nicaragua, could be manipulated to solve the imbalance. Specifically, this paper presents a scheme to transfer water from Lake Nicaragua to Lake Managua and, subsequently, direct water from each lake for irrigation and hydroelectric generation. The scheme has been designed to maximize economic benefits and requires environmental impact analysis.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00790.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:A model was developed to evaluate the cost‐effectiveness of alternative “best management practice” (BMP) implementation schemes on two agricultural basins in Florida. The model selectively applies BMPs throughout the basin on a field by field basis, estimates the associated costs, and predicts the relative water quality improvement (reductions in nitrogen and phosphorus). The water quality model links field scale simulation (for detailed BMP evaluation) with basin delivery and attenuation functions to predict the basin‐wide effects of any combination of BMPs. Fifteen BMP scenarios were evaluated to aid in prioritizing BMPs for implementation in these basins. Applying the maximum level of BMPs is estimated to cost around $1.2 million (annually), while the four most cost‐effective BMPs would cost only one quarter as much, yet are projected to provide approximately 90 percent of the water quality im

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00791.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:In the absence of detailed outlines such as those characteristic of the National Pollution Discharge Elimination System permit program, Nonpoint source pollution control is being initiated in a variety of ways in different states. In California, Regional Water Quality Control Boards play a strong enforcement role in point source control, but agricultural Nonpoint source needs are still being evaluated. Tentative approval of State Board of Forestry Forest Practice Rules by the State Water Resources Control Board has the potential of bringing Nonpoint control to all State and private forestry operations in the state. Wisconsin had developed an agricultural Nonpoint control program which emphasizes a state‐wide policy of selecting priority watersheds under the administration of the state Department of Natural Resources, and developing implementation programs under the guidance of local county Land Conservation Committees. The Priority Watershed program institutes BMP's with cost‐share funds authorized by the legislature. Wisconsin had not seen a problem in silvicultural activities, and has developed no statewide control program in that area. Common to effective land use control in both states is a state‐level policy implemented by agencies within the state. This pattern may be the model for successful programs as development of areawide management strategies con

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00792.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:Flood potential data can be effectively interpreted if simple frequency analysis concepts are used to explain the significance of flood potential. Instead of simply presenting data as a quantitative amount or as a percentage of the average condition, predictions can be discussed in terms of their probabilities of exceedance, or return periods. Criteria are presented for evaluating the significance of various return periods. Frequency interpretations are applied to snow course data, peak flow forecasts, and streamflow volume forecasts in northern Utah to illustrate these concepts. In addition, access to realtime data allows tracking of snowmelt progression and identification of any deviations from the forecast flood potential situation. Several data elements, including snowpack, streamfiow volume and peak, and realtime data are jointly evaluated to assess potential hazard and probable risk.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00793.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:The increasing use of irrigation for urban landscapes is causing new demands for efficient watering systems. Conservation techniques for irrigated agricultural fields cannot be applied to urban landscapes without amendment. This paper attempts to review methods of urban landscape water conservation in the context of the diversity and complexity of urban landscapes and the demands upon them for quality of the urban environment. A development's initial site layout and planting design fundamentally determine how much irrigation water will be required; the complexity and creativity inherent in urban design open a number of specific possibilities for reducing water demand. Irrigation hardware is then designed to deliver the required volume of water to the specified landscape efficiently by implementing a number of physical and operational principles. Maintenance of the finished development involves monitoring results and making adjustments as the plantings grow and develop. The potential for conserving urban irrigation water is large. Effective conservation need not compromise other qualities of the urban environment such as aesthetics, screening, or shade. Urban design can address both the kinds of landscapes people need, and minimal consumption of irrigation water.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00794.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY