Category: Research

Principal Investigator: James R. Wallace (Georgia Institute of Technology)
Principal Investigator: Unal A. Sorman (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1971-07-01; Completion Date: 1972-08-01;
Keywords:
Description:

The purpose of this study was to obtain a better understanding of the temporal and spatial variability of thunderstorm rainfall and to develop a digital model for the stochastic simulation of thunderstorm rainfall for the Southeast Coastal Plain areas.

In the present study rainfall cells were thoroughly analyzed from rainfall data made available by the Agricultural Research Service, U.S. Department of Agriculture. The data source was a dense network of raingages located over the Little River Experimental watershed near Tifton, Georgia. The study area is monitored by a network of 55 digital type raingages covering a 250 square mile area. Statistical properties and frequency distributions of cell characteristics, such as cell duration, size, spatial and temporal distribution of rainfall intensity, cell movement, and number and orientation of cells, were analyzed. A conceptual model of thunderstorm rainfall was formulated from the observed storm cell characteristics and the parameters of the model were evaluated from isolated thunderstorms which occurred in the summer of 1967. The model was coded for a digital computer and a number of rainfall events were generated by the dynamic model, which is based on the stochastic generation of rainfall patterns from thunderstorm cells.

These simulated precipitation sequences preserved certain of the fundamental statistics of the historical thunderstorm rainfall records. The model was validated by comparing synthetic precipitation events with events observed on Little River watershed during the summers of 1968, 1969, and 1970. Rainfall characteristics which are considered to be representative of the most important features of thunderstorm rainfall were analyzed during the model validation. For the validation of the model a number of statistical rainfall parameters determined from simulated rainfall, such as frequency distribution of the maximum amount of rainfall, maximum accumulated rainfall versus duration of rainfall at the maximum rainfall raingage, and maximum ten-minute rainfall intensity, were compared with the 1968, 1969, and 1970 historical data. In addition, relation ships between correlation coefficients and spacing between the first and the second maximum rainfall gages, as well as time lag of rainfall between them, were derived graphically and a comparison was made between the simulated and observed results. The performance of the model was considered to be successful on the basis of comparisons made between the observed and simulated rainfall characteristics.

This study has lead to the development of a body of knowledge on the characteristics of summer thunderstorm rainfall in the Coastal Plain of Georgia. The size, movement, and intensity of rainfall thunderstorm cells has been measured, and a stochastic model has been developed which will generate precipitation patterns like those observed by the raingage network. The dependence of the characteristics of individual cells on the location, movement, and size of other cells already existing in the same general area needs additional study. Such a study will require a network of gages covering an area larger than that available for the current study or a study using radar measurements in combination with a raingage network.

It is suggested that the simulation model can be used in conjunction with watershed models for generation of synthetic streamflows and that the knowledge gained through this study will aid in the efficient use of water resources throughout the Coastal Plain areas.

Principal Investigator: Gene E. Willeke (Georgia Institute of Technology)
Principal Investigator: F. William Kroeck (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1970-04-15; Completion Date: 1972-07-31;
Keywords:

Description:

The objectives of this study were 1) to describe the nature and scope of metropolitan water resources management programs; 2) to determine the strengths and weaknesses of existing institutional arrangements; 3) to specify and evaluate a feasible and equitable means of financing metropolitan water management programs; and 4) to suggest ways in which management of water resources in metropolitan areas can be improved.

The study included a literature search, a mail questionnaire of state officials to aid in the selection of study areas, and field interviews with 190 respondents in five Standard Metropolitan Statistical Areas: Macon, Georgia; Lansing, Michigan; Charleston, Columbia, and Greenville, South Carolina. Field interviews were conducted according to a plan of questioning rather than according to a fixed interview schedule.

Water management, and the physical, economic, social, and political context within which it takes place, was described for each of the five study areas. Both the similarities and differences among the areas were considered, with special emphasis placed on the difference. Water management, in this study, included the specific functions of water supply for domestic, commercial, and industrial use; storm drainage; collection, treatment, and disposal of sanitary wastes; flood hazard reduction; and recreation.

Water management is treated primarily as a social process. The roles of various participants, the nature of decisions and non-decisions, actions and inactions, functional priorities, intergovernmental relations, management style, and public participation are discussed. The multiplicity of functions and jurisdictional units is discussed in the context of developmental specialization rather than fragmentation.

Conclusions and recommendations are numerous. Many of them center on the issues of accountability, measures of performance, and on revision of the social process of water management rather than on functional and territorial structuring per se. Financing is considered from both efficiency and equity viewpoints, and the importance of viewing water management financing in the context of the financing of other public programs, especially taxation programs, is emphasized.

Specific recommendations are made that apply to the Federal Government, State Governments, local governments and local water managers, local and regional planning agencies, and COGs, consultants, universities, associations and societies, citizens, and citizen organizations. Of special interest to local water managers are recommendations for an expanded program of technical assistance, a floating labor pool, more effective use of consultants, and for more participation in the political process.

Technical Report

Principal Investigator: Albert A. Liabastre (Georgia Institute of Technology)
Principal Investigator: Robert A. Pierotti (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1968-07-01; Completion Date: 1972-06-30;
Keywords:

Description:
The solubility of benzene, toluene, n-pentane, cyclohexane, cyclopentane, cyclopentene, cyclohexene, 1, 4-cyclohexadiene and cycloheptatriene in H2O and D20 have been measured using gas-liquid chromatographic techniques over the temperature range of 278°K to 3l8°K. The solubility data has been used to compute Henry Law constants and from the temperature dependence of the Henry Law constants, the thermodynamic changes associated with the solution process such as âˆ

Principal Investigator: Gerald J. Thuesen (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1970-07-01; Completion Date: 1971-06-30;
Keywords:
Description:

When decisions are made to allocate resources for the development and construction of water related projects, it is critical that the implications of water quality be specifically understood. Because the meaning of water quality is rather subjective it has been difficult for water planners to objectively translate the public’s attitudes and conceptions about water quality into objective criteria that would be useful for the evaluation of various alternative courses of action. The primary purpose of this study is to investigate methods that would provide the decision-maker more useful and objective information about water quality. The primary objective is accomplished by investigating the following three questions.

1. How should one develop an assessment structure for quantatively considering the impact of water quality?

2. What is the value of the information provided by the assessment structure and how might this value be quantified?

3. Once an assessment structure is developed and measures of performance are established, how should the information be displayed and what decision rules are appropriate for assessing preferences between alternatives?

A systematic procedure for developing a multiple objective assessment structure is presented so that water quality can be incorporated into the planning process as a multivariate consideration. Although the economic effects of water quality are significant the primary emphasis of this study is to identify and quantify the non-monetary factors of water quality which have an impact on the public.

Principal Investigator: Albert McSweeney (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1970-07-01; Completion Date: 1971-06-30;
Keywords:
Description:

Use of optical transformation techniques for measuring sediment particle size distributions has been investigated. An optical Fourier transformation system was set up in conjunction with a bundle of fiberoptic light-pipes connected to an array of photodetectors for analyzing the transforms of samples.

A simple analysis of two of the seven information channels of the fiber-optic bundle was performed as a test. The measurements of intensity due to two known monodisperse samples were used to generate a 2 x 2 matrix of weight functions. This matrix was small enough to be easily calculated and provided an example for calculating the larger transformation matrix required for using all seven channels. The matrix of weight functions was then used to transform the measured intensity from a mixture where one of the two particle sizes present was significantly different from either of the sizes used to determine the matrix. Quantitative results show that while the system could not distinguish between 160 ~m and 187 ~m diameter particles, it did discriminate well between 267 ~m and 321 ~m diameter particles. The implied size resolution and accuracy are encouraging and both characteristics are expected to improve as more fiber-optic channels are used.

Principal Investigator: James R. Wallace (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1969-10-01; Completion Date: 1971-09-30;
Keywords:

Description:
A complete analysis of the relative potential utility of alternative flood plain management techniques must include an examination of many interrelated aspects of urban flooding. For example, the hydrologic aspects of the flood problem are influenced by the land-use pattern that develops with urbanization, and the land-use patterns are a reflection of the social values and economic needs of the community.

In order to examine the relationship between the pattern of land use and storm runoff, the development of the Peachtree Creek watershed in metropolitan Atlanta, Georgia, was traced for a period of ten years and the influence of the development on streamflow was analyzed. During the period of analysis (1949-1968), the percentage of the watershed surface covered by impervious area increased from 17.13 to 31.21, an increase of about 12,000 acres. During the period 1949-1955 dense development occurred primarily along the rail lines and principal city thoroughfares. The rail lines and thoroughfares are predominantly located on ridge lines, and the earlier development was concentrated at the extremities of the watershed. During the period 1955-1968 the most significant changes were located in the vicinity of the newly constructed interstate highway system which paralleled the entire length of one of the major forks of the creek. Hence, the most recent development has been located very near the creek, and in some cases within the flood plain.

The affect of this development on the hydrology of Peachtree Creek was determined by comparing runoff from Peachtree Creek with that of an adjacent control watershed and by analysis of storm hydrographs. It was found that the average storm runoff per square mile from the major storms during the months of August and September for the period of 1963-1969 was approximately three times that which occurred during the same months for the period 1959-1963. On the other hand, the wet season base flow from the non-urbanized control watershed has been about 1.46 times as great as the base flow from Peachtree Creek. Thus, it seems clear that urbanization has affected the seasonal
distribution runoff. However, the hydrograph analysis showed no systematic trend in unit hydrographs derived from winter (wet season) storms during the period of record. This is consistant with the fact that no significant increase in the volume of direct runoff, as compared to the control watershed, occurred during the period of record. The overall implication of the study is that the development of the watershed has increased storm runoff in the dry months, decreased base flow in the wet months, and significantly increased the peak runoff from summer storms. Such a trend, if continued, could result in an extended “flood season” in which large flood peaks could become as common in the summer months as they have historically been in the winter and spring.

Principal Investigator: Eugene A. Laurent (Georgia Institute of Technology)
Principal Investigator: George Roy Elmore, Jr. (Georgia Institute of Technology)
Principal Investigator: L. Douglas James (Georgia Institute of Technology)
Principal Investigator: Guy J. Kelnhofer (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1969-10-01; Completion Date: 1971-09-30;
Keywords:

Description:
Successful implementation of a program to alleviate the consequences of flooding by restricting urban development in flood plains requires a good understanding of the pressures causing urban development to locate in hazard areas. Some of the needed insight must come from analysis of the history of flood plain settlement. The Peachtree Creek flood plain in metropolitan Atlanta, Georgia, occupies a very small portion of a large surrounding and rapidly expanding metropolitan area. Still, many homes and businesses have located in areas subject to flooding every few years. This report is a case study of how this development pattern came to be.

The case study is contained in three sections. The first presents the historical sequences and causes and the role of government officials in influencing development in the watershed from the time of earliest settlement and stresses flood plain development. The second presents an analysis of the relative values of undeveloped lots on and off the flood plain and discusses the extent to which observed differences are caused by expected flood damage as opposed to differences in other residential choice factors. The third presents the changes in stream water quality associated with urbanization as an example of the magnitude of the problem created by storm water washing of urban areas even if no sanitary sewer effluent is directly discharged into the creek. A concluding section presents the implications of the findings for planned flood plain management. Management programs deal with people, and multiple management approaches are needed so that at least one approach will communicate with each kind of individual involved.

Principal Investigator: L. Douglas James (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1969-10-01; Completion Date: 1971-09-30;
Keywords:
Description:

Because of the necessity of working with many interactive linkages between hydrology, engineering design, economics, esthetics, perception and communication mechanisms, and many other factors, the involvement of an interdisciplinary team was seen as essential to research on developing an approach for prescribing an effective combination of remedial and preventive flood plain management to alleviate the consequences of flooding along small urban waterways. A team organized through the Environmental Resources Center (an entity having a role of research coordination) at the Georgia Institute of Technology was comprised of eleven people in six disciplines plus two or three times as many others in supporting roles. Each had a strong commitment to function in an interdisciplinary manner and not through a group of loosely coordinated multidisciplinary efforts. In addition to attacking the flood management problem, the interdisciplinary team represented a deliberate effort to probe the constraints on interdisciplinary research at the university level and propose institutional and organizational adjustments for making such groups more effective.
While the team did make some significant contributions in terms of gathering data pertaining to the research problem, none of its members were really satisfied with their accomplishments. The working team was asked to use its experience as a basis for making recommendations which it believed would help subsequent teams to be more successful and through an iterative process of individuals forwarding propositions and group discussion produced a set of 27 specific recommendations. The report, written by a member who joined the team about a year afterwards, contains material describing the objectives of interdisciplinary organization, a history of how the team was organized and functioned, a discussion of organizational problems encountered, and an assessment of team morale and team effectiveness. Each point is discussed in the context of the 27 recommendations made by the team.

Key recommendations were that team members be recruited who are problem oriented but have sufficient discipline focus to function successfully, that the administration of the project not be tied to any specific discipline, that a core staff within the administrative unit be organized to keep the team moving, that viable research assignments be given each team member early in the total effort, that the role and responsibility of each team member be clearly defined, and that informal support from the university hierarchy and community be cultivated. If universities are to address successfully the social issues of our times, they must seek such mechanisms for extending their competences beyond issues neatly fitting within traditional disciplinary molds.

Principal Investigator: Kevin C. Beck (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1968-07-01; Completion Date: 1971-09-30;
Keywords:

Description:
Georgia lower Coastal Plain streams are characterized by low suspended load, low ionic strength, low pH, high PC02, dominance of Na-Cl over the more usual ca-Hco3-S04, relatively high proportions of Si02, AI, and Fe and high dissolved organic content. These characteristics become less pronounced in streams heading in the Piedmont and Fall Line. The chemistry of the streams is controlled by atmospheric input, weathering of the already strongly leached soils, and by the organic compounds produced on decay of vegetation in the low gradient, swampy terrain. Hydrologic conditions, largely flushing of swamp waters into the streams after rains, control the relative importance of these factors.

The relatively high Cl content and constant ratios of Na, K, Mg, Ca, and S04 to Cl at values not far removed from sea water suggest that these species are derived from rain (concentrated by evaporation-transpiration) and atmospheric aerosols, and that mineral weathering contribution is minor. The relatively abundant AI, Fe, and Mn are significantly complexed by organic matter, and complexation is an important factor in solubilization and concentration in the streams. Their free ion activities can be related to equilibration with their hydroxides and oxyhydroxides through pH and Eh measurements, although Eh measurements are of doubtful validity. The dark brown color of the clear waters is due to dissolved organic matter; darker color is associated with higher contents of organic carbon, lower pH, and higher PCO2. The organic matter spontaneously settles in collection bottles and in the lower reaches of the streams. Additional flocculation occurs in the estuaries. Low levels of oxygen saturation are related to organic reaction. Silica decreases systematically downstream, as does pH. The correlation is due to addition of Si02-poor, organic-rich swamp waters. The stream waters lie in the stability field of kaolinite, and exchange sites in associated soils and sediments are occupied dominantly by H+ and hydroxy -Al. Unlike Piedmont and Fall Line streams, lower Coastal Plain streams have an inorganic anion deficiency; charge balance is attained by organic anions.

The stream chemistry departs markedly from that of the world average river and from almost all rivers previously described. However, many large tributaries of the Amazon and other low gradient tropical rivers, none of which have been studied extensively, are expected to show similar characteristics.

Estuaries of Coastal Plain streams normally exhibit simple river water-sea water mixing of major dissolved constituents, but with the introduction of low pH, low SiO2 waters by flushing of swamps during heavy rains silicate minerals in the estuary interact to modify water chemistry. The exact mechanism is unclear. Montmorillonite, with Mg++ as the dominant exchange cation, appears to be involved, either absorbing H+ and releasing Mg++ and Si02 to form kaolinite or dissolving incongruently. Estuarine levels of Al and Fe appear to be controlled by pH-dependent precipitation reactions in addition to mixing.

Principal Investigator: Alva R. Lines (Georgia Institute of Technology)
Principal Investigator: W. Andrew Thompson (Georgia Institute of Technology)
Principal Investigator: John E. Humphrey, Jr. (Georgia Institute of Technology)
Principal Investigator: Louis F. Jourdan, Jr. (Georgia Institute of Technology)
Principal Investigator: Michael W. Harris (Georgia Institute of Technology)
Principal Investigator: Glen D. Baskett (Georgia Institute of Technology)
Principal Investigator: C. Michael York (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1969-07-01; Completion Date: 1971-06-30;
Keywords:

Description:
The focus of this research project has been instrument development and field tryouts relating to the broad question of citizen-conceived Environmental Quality and, more specifically, the public’s relative importance attributed to water-resource issues. A major urban area in the Southeast served as the initial data source both in the construction of the measures and in collection of preliminary problem-oriented information from the people. Sampling design and implementation was a fundamental task, and is immediately available for use in Atlanta, on a range of topics. One substudy empirically tested the telephone interview as a viable method for gathering qualitative data about the environment and other citizen-perceived urban problems. These resident-generated suggestions provided the content for construction of an Environmenta1 Quality measure. The resulting one-page rating scale, the established Citizen Panel in Atlanta, and the survey research capability at the Georgia Institute of Technology are now available to the technical specialists and the managers of urban Environmental Quality. Use of the scales in studies elsewhere will also enable comparative data analyses.

Another substudy, having theoretical and methodological significance, provided citizen data relating to perceived source credibility. The trustworthiness of officials and agencies by the public has been demonstrated to be a major variable in the communication process. A brief rating card was field tested in the Atlanta area, using Governor and Mayor as stimulus-figures.
Preliminary substantive information bearing on public perception of environmental priorities is given in this project completion report. Ratings from student and resident samples on 51 issues (obtained in the telephone interviews) were submitted to factor analysis in search of the underlying dimensionality of their environmental concern. The specific item clusters are tabled in the report, but in general, the salient issues were water and air pollution control, crime control, and drug control. These data from the Atlanta residents constitute a base line for continuing research relating to urban priorities in Atlanta and elsewhere. This kind of research contributes to the understanding of citizen concern for national and environmental issues, including empirical support for the preservation of natural resources.