Category: Research Sponsored by GWRI

Principal Investigator: Augustine O. Esogbue (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1979-10-01; Completion Date: 1982-12-31;
Keywords: Nonpoint source water pollution, best management practices, public

Description:
Agencies designated to implement the Clean Water Act of Public Law. PS 72-500, Section 208 often encounter difficulties associated with the management of systems consisting of complex interactions of soft and imprecisely stated phenomena. Two such major areas in this implementation process concern the use of the publics in water resources plan formulation and the use of the so called best management strategies in the control of nonpoint source water pollution. The quantitative analysis of these systems as well as the development of quantitatively based models for measuring their effectiveness is the subject of the inquiry whose results are reported here.

The central thesis of our work is that because of the presence of soft imprecise variables, any quantification efforts should invoke the tools of fuzzy set theory. To prove this point, the goals of State Planning Industries particularly relative to Erosion and Sedimentation Control were reviewed and the problems inhibiting compliance highlighted. The essentially fuzzy variabIes and phrases were syphoned out and a plan to minimize the fuzziness developed.

The use of the publics in water resources planning was next considered leading to the development of a working definition of their effectiveness. A fuzzy multi-level hierarchical model which provides a pessimistic as well as an optimistic measure of this effectiveness was then developed and validated using the Water Resources Advisory Group of the Atlanta Regional Commission as the leitmotif. Various fuzzy clustering algorithms were developed to group the field data. This model was also used to analyze the contributions of various hypothesized variables (factors) on the total system effectiveness of public participants and planners.

A comprehensive list of BMPs in use in the State of Georgia as well as in the nation was developed and a statistical analysis of their effectiveness performed. Effectiveness was approached both from the system and cost effectiveness perspectives. The total effectiveness of BMPs as a control approach for nonpoint source pollution was assessed using a modification of the fuzzy multilevel model. As in the public participation effectiveness measurement, the contributions of each design principle to total system and cost effectiveness were determined. A statistical analysis of the importance and effectiveness of each BMP was also performed leading to a ranking of these BMPs, structural and nonstructural, in terms of their effectiveness. Their policy implications are obvious.

Principal Investigator: David L. Cochran (The University of Georgia)
Principal Investigator: Jerry L. Chesness (The University of Georgia)

Sponsor: GWRI
Start Date: 1981-04-01; Completion Date: 1982-06-30;
Keywords: Irrigation, crop water requirements, simulation modeling

Description:

A number of techniques are available for predicting irrigation water demands. However, many are applicable only to arid and semiarid climates where the probability of rainfall during the growing season is low. The rapid increase in irrigated acreage in the southeastern region of the U.S. dictates the need to develop methodologies suitable for humid climates.

A continuous simulation model was developed for predicting seasonal irrigation water requirements of crops. The model was derived by writing water balance equations for successive soil zones in an irrigated soil profile. The quantity of water infiltrating the uppermost zone was the difference between daily precipitation and runoff (according to the SCS equation for runoff volume). Zonal water volumes exceeding field capacity were passed into the next lower zone. Irrigation was called for whenever calculated soil water removal increased soil water tension to a preset level in the profile.

Input data to drive the model are: (1) historical or synthetic daily precipitation and pan evaporation values, (2) crop canopy growth factors; (3) soil water tension-content relationships, (4) irrigation water management depth and level (tension) and (5) SCS runoff curve number.

Daily measured values of soil water tension and irrigation amounts for nine crop (corn and soybeans) seasons were obtained from Dr. James Hook, Assistant Professor, Agronomy Department, Coastal Plains Experiment Station, Tifton, Georgia. Predicted seasonal irrigation water requirements averaged within 11.2% of measured values for eight of the crop seasons.

Principal Investigator: Ronald M. North (University of Georgia)
Principal Investigator: Jackie Sellers (University of Georgia)

Sponsor: GWRI
Start Date: 1978-10-01; Completion Date: 1982-08-01;
Keywords: financing, cost sharing, revenue sharing, *benefit pricing

Description:
Historical aspects of Federal/non-federal sharing of water resources costs were reviewed for projects and programs. The theoretical basis for these sharing arrangements were explored and the authors suggest that the only theoretically sustainable purpose for cost sharing is that of effecting changes in economic distribution or equity — not efficiency. The alternative cost sharing policies proposed in 1975, 1976, 1977 and 1978 were described and evaluated with respect to anticipated changes in shares of cost burdens should certain options be adopted. These evaluations were done in detail for flood damage reduction in the south Atlantic Gulf region. General estimates of cost sharing in Georgia were developed from available State budget data. All cost sharing and financing proposals emanating from Federal and state sources, in common, support or accede to a decreasing Federal financial and cost burden offset by increasing state assumption of both financing and cost burdens – some of which would be recovered from beneficiaries through user charges.

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