Category: Research Sponsored by GWRI

Principal Investigator: Joseph P. Gould (Georgia Institute of Technology)
Principal Investigator: Byung R. Kim (Georgia Institute of Technology)
Principal Investigator: Michael A. Rollor (Georgia Institute of Technology)
Principal Investigator: Wendall H. Cross (Georgia Institute of Technology)
Principal Investigator: Makram T. Suidan (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1978-11-01; Completion Date: 1982-09-01;
Keywords: carbon, granular activated carbon, regeneration, solvent regeneration, adsorption
Description:
he in situ solvent regeneration of activated carbon by means of organic solvent extraction has been suggested as an economically attractive alternative to thermal regeneration. Therefore, an experimental investigation was performed in order to identify, characterize, and evaluate the important physical-chemical aspects of the solvent regeneration process. Four adsorbates of varying molecular weights and size were employed along with five commercially available activated carbons in a series of continuous flow column studies in order to evaluate the effects of molecular size, regeneration temperature, solvent type and activated carbon characteristics on regeneration efficiency. In addition, the reuse of non-recovered (contaminated) solvent and the corresponding effect upon the economic feasibility of the regeneration process were examined. From the extensive experimental investigations, it was concluded that the important aspects of the solvent regeneration process include:

1) the physical and chemical characteristics of the adsorbent, particularly the pore size distribution and energy of adsorption associated with the activated carbon

2) the degree of solubility of the adsorbate in the organic solvent

3) the miscibility of the organic solvent in water

4) the temperature at which the regeneration is performed.

In addition, the economic feasibility of the process was determined to be directly related to costs incurred for energy requirements and to the recoverability of valuable adsorbates for subsequent reuse in the industrial process.

Principal Investigator: George Roy Elmore, Jr. (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1972-05-01; Completion Date: 1972-05-01;
Keywords:

Description:
Responsibilities of the states for management of their water resources have been increasing rapidly in the view of the public and under the requirements of Federal programs. The State of Georgia has been among those governments in states with abundant water resources which have given minimum attention to water resources management. As a result the organization of the State’s executive branch has been inadequate to meet many current demands for management. The issue by issue response of the State has proven unsatisfactory to those who desire more comprehensive and coordinated water resources management. The organizational structure of resources management agencies in Georgia has appeared to impede progress toward better coordination and more comprehensive management. Therefore many concerned citizens have viewed reorganization as a necessary step toward improved State programs. However there has been disagreement over the appropriate form of organizational structure and over the significance of organizational structure in achieving better water resources management. The objectives of this research are to identify effects of organizational structure of the executive branch of Georgia state government on its functional programs of water resources management so that a more objective assessment of the importance of organizational structure can be made.

The natural resources organization structure of Georgia has been compared to that of five other states with the aid of a research model developed from classical public administration theory. An outline of an ideal state water resources program was developed and applied to Georgia’s state and Federal water resources programs. This information was used to test hypotheses about the effect of organizational structure on water resources programs.

It was found that, although the power of the available techniques of analysis and the available data were not sufficient to define organizational structure as cause and program as effect, the structural forms recommended by classical public administration theory were regularly associated with more highly developed programs. Existing and potential shortcomings of Georgia’s water resources programs which appear to be related to organization are interagency conflict, ineffective leadership from the governor, difficulty in adapting to change, and the omission of programs for water resources planning, flood protection, dam safety, and water rights. Possibilities for improvement of Georgia’s organization suggested by the organization of other states are discussed.

Principal Investigator: William C. Little (Georgia Institute of Technology)
Principal Investigator: Paul G. Mayer (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1972-05-01; Completion Date: 1972-05-01;
Keywords:
Description:

The objective of this study was to systematically investigate the effects of sediment gradation on channel armoring. The primary variable was gradation of the sediment material. A geometric mean diameter of 1.00 millimeter was used for all sediments with geometric standard deviations, ago, of 1.12, 1.50, 2.00, 2.50, and 3.00. These mixtures of crushed quartz were placed in a recirculating flume with a sediment bed 1.97 feet wide, 40.0 feet long, and approximately 0.15 foot deep.
Arbitrarily selected flows, to purposely induce armoring, were kept constant throughout each experiment. Bed slope was initially set at 0.002. Depth of flow was held constant throughout each experimental run by a sluice gate. The armoring process was considered to be stable when the final
sediment transport rate was not more than one percent of the initial transport rate. The surface layer of particles was then removed by the wax method and the distribution of the armored particles determined. An empirical equation was developed through dimensional analysis relating the sediment properties of the original and armored distributions to the flow properties, when the sediment bed had become stable because of the armoring process.
The equation is

[3 -I 0.353u*c = 0.908 v(s-l)g dgo ° go (1)

where dga and dgo are geometric mean diameters of the armored and original sediment mixtures, respectively, σgo is the geometric standard deviation of the original sediment mixture, u* is the bed shear velocity defined by u* = gRS where g is the acceleration of gravity, R is the hydraulic radius and S is the slope of the energy grade line, ν is the kinematic viscosity of the water, and s is the specific gravity of the sediment (2.65). From the equation, for the given flow conditions and original sediment properties in a channel, the geometric mean diameter of the armored material, dga, can be calculated. The armored diameter calculated from this equation is applicable only if the channel would armor.

Another criterion was developed to determine, for the given sediment and flow properties, if the sediment bed could armor. If the calculated geometric mean diameter of the armored surface material was between the d05 and d95 (that size for which 5 and 95 percent, respectively, by weight is finer) size of the original material, the original bed material would armor for those flow conditions.

With the broadly graded materials, σgo >= 2.00, where channel armoring occurred, the bed degraded uniformly in depth along the length of the bed. However, for uniform materials, σgo < 1.50, little or no armoring could be induced, and the bed did not degrade uniformly in depth but degraded more at the beginning of the reach and less at the outlet end resulting in a reduced bed slope.

Dunes formed initially and as they moved off, armoring was immediately observable. Armoring of the surface had no significant change on the average bed shear stress throughout the armoring process.
After an armor coat had developed, a very low sediment transport rate continued for long periods of time. This transport was by local scour of fine material around larger particles. Fine material could be observed hiding in the wake or zone of separation of the large partides. Turbulence caused shifting of the zone of separation and sporadic movement of fine material. The results of this study were compared with the calculated armored distributions by a method developed by Gessler. The geometric mean diameters calculated by Gessler’s method were consistently lower than the measured values of this study and differed from 3.5 to 29.0 percent with an average difference of approximately 20 percent.

Principal Investigator: Alfred W. Hoadley (Georgia Institute of Technology)
Principal Investigator: Mark A. McClanahan (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1970-12-01; Completion Date: 1972-06-30;
Keywords:

Description:
Seasonal limnological changes in the vicinity of a major (1200 acres) recreational facility on Lake Sidney Lanier, Georgia were studied from November, 1970 to November 1971. During the study period only the beginning phases of construction occurred (clearing and grading land, road construction and utility installation). Parameters measured included: temperature, dissolved oxygen, pH, Secchi disk transparency and iron and nitrate concentrations. A positive heterograde oxygen profile with the maximum in the metalimnion developed during summer stratification. This type oxygen profile was found both around the construction site and in the open lake. Occurrence of this type of profile at both 10 cations indicates that the lake water contained the nutrients necessary for the production of oxygen rather than their being washed into the lake from the construction site. The only detectable influence of the construction activity at the site on lake water quality was siltation of some of the bays near where large areas of land had been cleared and the soil disturbed. Analysis of the available data indicates that the part of Lake Lanier studied could be classified as mesotrophic. However, it could be caused to become eutrophic in a rather short period of time if the influent waters are allowed to be degraded by man-made wastes.

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.