摘要:

ABSTRACTThree fundamental concepts linking drainage basin characteristics, stream behavior, and management of watersheds are deduced from field data and observations. An electrical analogy of a watershed clarifies definitions and broadens understanding of this complex natural resource. The three basic principles deal with (1) the interrelationships of watershed morphology, constitution, and appearance; (2) the nature of the control man can exert over runoff‐influencing forces, and (3) the efficiency of watershed management efforts. Recognition of these principles can assist educators, managers, planners and researchers to more fully inform students and to more effectively guide and evaluate management decision

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00458.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTA stream is set apart from all other aquatic ecosystems in that the water is continually entering and leaving the stream and is in almost constant motion. Thus, there is essentially a unidirectional flow, a constant mixing of the watery medium, a continuous erosion of the substrate with concomitant changes in the characteristics of the stream bed, and little or no opportunity for the accumulation and retention of the dissolved nutrients.The physical and chemical characteristics of the stream are largely reflections of the physical and chemical makeup of the watershed. Because of the constant replacement of the water as it flows away, new nutrients must be brought into the stream continually in order to support the biotic communities. The kinds and amounts of nutrients that enter the stream determine, to a large extent, the numbers and kinds of organisms in the different communities.The organisms that comprise those communities may be categorized as representative species indigenous to springs, riffles, and pools. Most plants in streams are sessile whereas most of the animals are vagile, at least during some phase of their life cycle. All sessile organisms must depend on the current bringing their foodstuffs to them, but the vagile forms may seek out their foods in different parts of the stream and may even move from one community to another. Each community is adapted to its particular environment.Spring communities, because of the constancy of the physical and chemical environment, may reach what is essentially a “climax” situation and remain stable over long periods of time. Communities that occupy riffle and pool habitats may change from season to season and from year to year depending on changes in temperature, volume of flow, and the character of the substrate. Between each of these kinds of communities there are transitional areas that may be occupied by wider varieties of organisms than any of the three principal kinds of communities. In any event, the continuity of these communities in time and space is determined by the speed of the current which in turn depends upon the volume of flow. On this basis it becomes evident that the characteristics of the biotic communities are different at the source of a stream than at any other location. Similarly, riffle communities are different than those living in pools.The most difficult evaluation to be made in studying a stream ecosystem is that of the interlocking relationships among the many kinds of organisms. The plants, whatever kind they may be, fix carbon and other elements into organic compounds that can be utilized as food by the animals. The multitude of organisms that make up the bottom fauna of any stream are largely supported by the food formed directly by the plants. Such animals as small crustaceans, insect larvae, worms, turbellarians, mollusks, and the like serve as food for the carnivorous species. To determine the role of each organism in maintaining such a complex structure is a tremendous challenge. Many tools and methods are at the disposal of the biologist who dares to undertake such a project. Still, the greatest of all these is the dedication to spending long hours of tedious and, frequently, very hard w

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00459.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00460.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTAny scheme for developing our water resources must eventually focus on the hydrologic theme for answers to pressing questions about anticipated availability of water. These answers will only be as realistic as the data is reliable, inferring accuracy as well as sufficiency. To that effect, more hydrologic and meteorologic data collection stations must be added to the existing network throughout the country, and the basic instrumentation presently in use should be made more versatile, but without an accompanying near‐astronomical increase in cost and in complexity. The ubiquitous so‐called current meters are a case in point.Current meters have almost certainly received more man‐hours of use in the field of Water Resources than any other instrument ever devised to measure stream velocity. In spite of more esoteric equipment appearing on the specialized market each year, the time‐honored method of stream gaging by the velocity‐area method is still widely practiced, and the basic instrument remains the current meter. The same persistent use is essentially true for the anemometer, or “wind current meter.” Over the past 30 years, a great many studies have been made to define operational parameters, particularly with respect to the statistics of data reliability. Today's needs are different from those acceptable a few years back, yet in many instances yesterday's instrument can be metamorphosed to satisfy present practice.Besides a discussion of some of the fundamental problems of data collection which must be accounted for in all areas of water resources where water and air currents must be known in space and in time, the authors present a brief critique of several new hybrid types of current meters. Two of these meters were designed especially to fill the gap between sophisticated and specialized equipment of high cost, and relatively inexpensive simpler devices lacking however the advantages of automation and self‐recording features.Since the mechanical performance of current meters has been the subject of many past studies fully reported in various professional journals, it appeared advantageous to develop electronic refinements on such a type of widely used instrument. A period of research, first at Washington State University and presently at Clarkson College of Technology, produced two electronic packages applicable to current meters. The rationale of these studies was to increase the usefulness of current meters by providing velocity readout, either instantaneous or time‐averaged; to include data recording on tape if and when such would be desired, together with the necessary playback facility; and to keep the electronic system independent of the current meter size.The paper describes in some detail the photo‐electronic tachometer which seems to offer more reliability and flexibility of operation than induction‐type transducers. One of the features most worthy of consideration is the adaptability of such device to any size of current meter frame and vanes. The rotation of an impeller one‐half inch in diameter is recorded by the instrument as faithfully as that of one six inches in diameter. Where velocity transients are to be observed, the advantages of a greatly reduced inertia are evident. The inherent ruggedness of low current drain transistors and integrated circuits should make this light‐actuated meter readout device well‐sui

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00461.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTHouston, the Nation's sixth largest city, is taking appropriate steps to assure an adequate water supply for its industrial and population needs for the year 2000.Houston's situation is unusual in that it now relies on groundwater sources for 80 percent of its domestic water supply but must convert this system to depend on surface water for 60 percent of its total supply source.Problems concerning the conversion are not only varied but complex. Surface water is more costly. Reservoirs that meet the plans and standards of state and federal water authorities as well as conveyance and treatment facilities must be developed. In the case of Houston, the total groundwater withdrawal rate must be increased but at the same time shifted from one area to another because of subsidence problems. Solutions to these problems require careful engineering study as well as economic and sociological planning.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00462.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTOnly very recently has a limited amount of attention been focused directly on electrophoresis as a method for improving water quality. This approach has been proposed primarily as a method for removal of suspended colloidal material, although solutes can also be removed by this method. Very simply electrophoresis is defined as the movement of charged suspended particles in a dc electric field.Several electrophoretic clarification systems and techniques have been developed and evaluated primarily for removing colloidal clay from suspension. The methods should apply equally well to any negatively charged particulate matter. Design for optimal clay removal efficiency and operating cost efficiency has been based upon previous theoretical results and upon modification of the combination filter‐el ectrophores is model of Bier. These systems and techniques along with the theoretical developments leading to their design are discussed. Results and conclusions are given for tests that have been concluded concerning the feasibility or practicality of these electrophoretic clarification systems for commercial use. These are viewed in light of various limiting factors such as electrical conductivity of the medium, quality of water desired, colloid concentrations and electrophoretic mobility of the suspended material

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00463.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTStep‐IB in the first phase of an “Operational Watershed Model” recently initiated by the Central and Southern Florida Flood Control District for managing its water resources is to compute water surface elevation, spatially and temporally, in the Kissimmee River Basin system of reservoirs, channels and spillways. An approach is based upon the principles of gradually varied flow. Mathematical relationships to compute lake stage as a function of storage, and to compute discharge through the control structures as a function of gate opening and differential head across the structures are developed. Their feasibility for application is clearly demonstrated by the simulated mean daily water surface elevation for a period of two years on the tail side of one typical gated spillway and on the head side of another gated spi

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00464.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThe determination of the total flow of an alluvial stream by rating a gaging station with a current meter may not be sufficiently accurate for a water yield study. If a large part of the total water yield consists of low flow, a means for accurate measurement must be employed. A technique for the design of a low flow control is described in this paper. Eight low flow controls have been designed on streams of the Southern Plains Watershed Research Center, Chickasha, Oklahoma. Field calibration measurements from these installations have been used to verify the design technique.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00465.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTTraditional conservation measures may not be, and usually are not, all that is needed to assure a quality environment. They are, however, fundamental. A national course of action involving land and water management is determined (1) at the market place, (2) at the ballot box, and (3) in the hearts and minds of individuals. To inform people about environmental management and conservation and appropriate uses of land, water and related resources is an exceedingly difficult problem. Research, action and educational programs dealing with environmental problems must have greater attention and support.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00466.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1970.tb00467.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY