摘要:

ABSTRACT:A scheme is outlined to classify watersheds as ecosystems, based on their natural attributes. Two physical factors of the environment, climate and geology, are selected as state factors. Climate is the master factor that supplies energy and water to all ecosystems; geologic structure supplies the materal from which the forces of climate carve landforms to establish ecosystems. At the next lower level, soil and vegetation interact in a succession of transactions to produce a mosaic of tesseras within each watershed. It is these interacting tesseras that moderate climate and store energy within the ecosystem that influences the embedded stream. At the bottom of the scale is the stream with its passive role and inability to interact with the higher factors of the ecosystem. Thus, we have a controlling force consisting of two elements (climate and geology), a reacting force (soil and vegetation) that responds by circular conditioning to controlling forces, and at the lowest level, the stream which responds to all factors of the living system within its watershed.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02434.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:The HEC‐4 monthly stream flow simulation model, developed by the Hydrologic Engineering Center, Davis, California, is used to extend the available historical stream flow records in the Central Ohio area. The principal objective of this paper is to examine the effectiveness of the HEC‐4 model in generating synthetic monthly flows. Important statistical parameters are evaluated in order to relate the statistical properties of the historical and generated flows. In doing so, it is observed that the mean, standard deviation, and skewness of the generated flows are consistently larger than the corresponding estimates based on historical flows. However, results show that these statistics, as well as the lag‐1 serial correlation, are generally well maintained by the generated sequences. The degree to which any statistical dissimilarities would be critical, from an engineering design point of view, is demonstrated by utilizing their low flow characteristics. Estimates of reservoir safe‐yields, based on a nonsequential mass‐curve analysis of the historical and generated low flows, indicate a nominal difference in this particu

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02435.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:Indices of annual diameter growth of trees were used to reconstruct drought in southern California back to A.D. 1700. A regional Palmer Drought Index served as predictand and tree‐ring indices from eight sites as predictors in multiple linear regression analyses that yielded the prediction (reconstruction) equations. The regression explained 69 percent of the variance in Palmer Index in the period of calibration. The long‐term reconstruction indicated that drought was rare in the first half of the current century relative to other discrete 50‐year periods, and that based on evidence to date the last half of the 20th century may well turn out to be the most drought prone since A.D. 1700 in southern Calif

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02436.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:A dynamic programming model is presented for planning the optimal capacity expansion sequence of waste water treatment plants servicing sewerage systems with infiltration/inflow. The model employs a nonlinear deterministic demand function for waste water treatment plant capacity. Model output provides the optimal timing, size, and sequence for treatment plant capacity expansion projects and infiltration/inflow removal projects. An example problem is presented and solved.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02437.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:Feasibility of disposing treated sewage in wells sunk into a partially confined coastal limestone aquifer at Waimanalo in the island of Oahu was investigated using an electric analog model. Electric analog modeling was preferred over digital modeling because of ease with which tides could be generated at the ocean boundary in the form of sinusoidal waves. The results of model operation showed that high permeability, low storativity, and the presence of ocean render the Waimanalo aquifer highly suitable for the disposal of waste water in deep wells. Since the quality of water in the aquifer is already unsuitable for municipal, industrial, or agricultural use, waste water injection will not result in any loss of fresh water supply source to the island. It is also believed that the cost of waste water disposal through the aquifer will be considerably less than that through an ocean outfall. During model development it was discovered that electric analog models can help prepare certain graphs which can be useful for aquifer analysis without any further use of the model.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02438.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:Intensive temporal sampling of rainfall, surface runoff and subsurface drainage, and stream flow upstream and downstream of a suburban mall parking lot yielded expected patterns in time and space. Variations in temperature and conductivity showed strong dilution effects, while patterns of nine elemental concentrations in surface runoff showed a flushing effect early in the storm, following by dilution. Heavy nitrate loads in surface runoff were apparently from rainfall, not surficial sources. For the magnitude of storm studied and the existing study site, local impact on stream flow and water quality, like the run‐off itself, is rather ephemeral, and dissipates after about five hour

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02439.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:The Ontario Ministry of the Environment has based its water quality management approach on a set of guidelines published in 1970. In light of the changing societal and economic background, advancement in technology and scientific knowledge, and philosophical attitudes towards water management, the water management program was recently revised. Factors influencing the revised approach, including federal‐provincial interrelationships and international commitments under the Canada‐U.S. Agreement, are summarized.The revised program consists of a goal statement, policies to implement this goal, revised water quality objectives, and detailed implementation procedures for field staff use. Rather than promulgating regulations to impose arbitrary effluent or receiving water standards on a province‐wide basis, the revised approach involves the imposition of legally enforceable effluent requirements on a case‐by‐case basis. Although the paper emphasizes the surface water quality program, it also outlines the Ministry's goals, policies, and procedures for the management of surface‐water quantity, as well as ground water quality a

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02440.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:Runoff was measured from a 564‐ha catchment located on the Entiat Experimental Forest for nine years before a severe wild‐fire in 1970 destroyed the mixed conifer vegetation. Runoff records from the Chelan River (2 393 km2) were used as control data for determining changes in water yield during the seven years following the fire. The first post‐fire year was a period of transition in which the soil profile retained more water than in previous years and measured runoff was 8.9 cm greater than the predicted value based on pre‐fire conditions. Runoff from the burned catchment during subsequent years was much greater than measured values before the fire. Measured minus predicted runoff, based on the pre‐fire calibration equation, varied from 10.7 cm during the dry year of 1977 to 47.2 cm during the abnormally wet year of 1972. Flow duration curves indicated that runoff at each percent value after the fire was at least double the comparable pre‐fire value. Sediment production increased dramatically after the fire because of increased flow rates, increased overland flow caused by reduced infiltration capacity, and mass soil movement. Sediment yield is beginning to decrease as stream channels become stabilized and vegetation on upper slopes improves infiltrati

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02441.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:Direct measurements indicate that subsurface seepage in the littoral zone contributed 17.5 and 2.0 percent of the total hydraulic inputs, respectively, to Lakes Conway and Apopka, Florida. Two variations of seepage measuring devices were evaluated and gave relative standard deviations of 7 and 24 percent. Measurement inaccuracies were minimized by using large diameter (0.9 cm ID) plastic tubing. For a given transect perpendicular to shore, flow patterns were reproducible over time. Seepage flows ranged from 0 to 112 1/m2‐day and most were between 4 and 30 1/m2‐day. The detection limit was about 0.2 1/m2‐day for a one‐hour collection period. Seepage occured primarily within 30 m of shore and generally decreased exponentially with distance from shore. The shape of the bottom profile influenced flow patterns; lake bottoms with steeper slopes had higher flows that were compressed within a narrower zone. After a short‐term rain event at Lake Conway, seepage flows increased rapidly to 2.4 times the prerain flow for 1 h and decreased to near background within

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02442.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT:During the drought year of 1977, unusually low river flows during the summer caused the City of Fort Collins, Colorado, to institute lawn watering restrictions for six weeks as a conservation measure. Water use during the restriction period decreased 41 percent below the previous year. The effectiveness of the restrictions, however, has been unclear because abnormally wet weather also appeared to reduce evapotranspiration rates during the period the restrictions were in effect. The statistical analysis indicates that the reduction in water use due to lawn watering restrictions was 603 acre‐feet and that abnormal weather reduced use by an additional 659 acre‐feet during the same period. During a period of normal evapotranspiration rates, such restrictions would be expected to reduce Fort Collins municipal water usage by 19.7 perc

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1980.tb02443.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY