A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, Texas Based on Chlorophyll A (open access)

A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, Texas Based on Chlorophyll A

Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted means and were at the mesotrophic-eutrophic boundary of the OECD model. Six years after impoundment, observed MSE chlorophyll a for Main Body, was closer to its predicted mean and in the eutrophic category of the OECD model. Six years after impoundment, Elm Fork arm was the most productive area of Lake Ray Roberts. Observed means of chlorophyll a, total phosphates, suspended solids and turbidity were often highest in the Elm Fork arm. Wastewater effluent from Gainesville and Valley View, TX, had an impact on productivity in Elm Fork arm.
Date: May 1999
Creator: Lytle, Lili Lisa
System: The UNT Digital Library
Pre-Impoundment Estimations of Nutrient Loading to Ray Roberts Lake and Prediction of Post-Inundation Trophic Status (open access)

Pre-Impoundment Estimations of Nutrient Loading to Ray Roberts Lake and Prediction of Post-Inundation Trophic Status

Excessive nutrient loading of natural and artificial lakes has led, in some systems, to plethoric algal and aquatic macrophyte growth which can result in aesthetic degradation and undesirable tastes and odors. It would be advantageous to have some indication of the potential trophic status of a reservoir before it is filled. An objective of this study was to assess the water quality and nutrient loading potential of the tributaries entering Ray Roberts Lake, a large reservoir located in north central Texas. Samples from a maximum of thirteen sites were collected on the Elm Fork, Trinity River, Isle duBois Creek, and five additional tributaries. Data were also collected during six storms, from atmospheric deposition collectors, and from soil-water microcosms. The relationship between watershed landuse and mean water nutrient concentrations was evaluated. Significant differences will exist between the two major arms of Ray Roberts Lake: Elm Fork, Trinity River and Isle duBois Creek. While the majority of the annual phosphorus and nitrogen load entering both tributaries is coming from overland flow, the proportion is higher in Isle duBois Creek. Point sources in the Elm Fork contribute a larger percentage of the bioavailable phosphorus, which is significantly greater than in Isle duBois Creek. …
Date: May 1988
Creator: Pillard, David Alan, 1958-
System: The UNT Digital Library
A Survey of Landowner Attitudes Toward the Construction of Lake Ray Roberts (open access)

A Survey of Landowner Attitudes Toward the Construction of Lake Ray Roberts

Documentation of social impacts resulting from the construction of Lake Ray Roberts is to be incorporated into a two year post-impoundment study. Research objectives are to: 1) locate current residences of landowners and previous landowners who were displaced; 2) determine social impacts resulting from construction of Lake Ray Roberts; 3) document degree of satisfaction with current living conditions; 4) document landowners' degree of satisfaction associated with COE negotiations; 5) document landowners' observations. Landowners were identified by telephone and sent a mail-back questionnaire. Respondents were generally happy with current residences and communities. While courtesy and sufficient information were provided by the COE, respondents would have preferred for property settlements to be more consistent and timely.
Date: August 1991
Creator: Norris, Paula Sue
System: The UNT Digital Library
Habitat Evaluation Procedures at Ray Roberts Lake: an Analysis of the Relationship with Ecological Indicators and a Study of Observer and Temporal Variability (open access)

Habitat Evaluation Procedures at Ray Roberts Lake: an Analysis of the Relationship with Ecological Indicators and a Study of Observer and Temporal Variability

Habitat Evaluation Procedure data gathered at Ray Roberts Lake in 1989 and 1990 were analysed for temporal variability, observer variability and relationships between Habitat Units (HUs) and species density/diversity. observer variability within a group was analysed by cluster analysis and bootstrapping. Five out of 36 sites showed significant differences in Habitat Suitability Index (HSI) values within the group. A nonparametric Mann-Whitney test was used to analyze temporal variability. One of 6 sites showed a significant difference in HSI values between years. Using Spearman's Rank Correlation Coefficient, a correlation was found between indicator species density and HUs. No significant correlation was indicated between species diversity and HUs.
Date: December 1993
Creator: Wattrus, Jane M. (Jane Marie)
System: The UNT Digital Library
Responsibility of the Secondary School for the Social Development of its Students (open access)

Responsibility of the Secondary School for the Social Development of its Students

The problem in this study is twofold. First, there will be an attempt to determine the values that organizations in the secondary school have for the development of its students. Second, a survey will be made of the four-year accredited high schools in District Five of Texas to determine how and to what extent they are realizing their responsibilities in this respect.
Date: 1947
Creator: Baxter, Billie Otella
System: The UNT Digital Library
The Role of the Administrator in the High School Guidance Program (open access)

The Role of the Administrator in the High School Guidance Program

This study was proposed to determine to what extent guidance is actually being practiced in the schools selected and to determine a plan for more comprehensive use of guidance. This plan will emphasize the role the administrator should play in the guidance program.
Date: 1948
Creator: Wilson, W. Andrew
System: The UNT Digital Library
Methods of County Financing in Relation to County Government in Texas (open access)

Methods of County Financing in Relation to County Government in Texas

This study aims to show the relation of the methods of county financing in Texas to the present form of county government. It argues that the present form of county government in Texas is antiquated and inadequate to meet the requirements of efficient administration of county financing.
Date: 1939
Creator: Yoakum, Gladys A.
System: The UNT Digital Library
Electricity in Rural Areas of North Texas (open access)

Electricity in Rural Areas of North Texas

"This study shows three things: (1) a precedent for the expenditure of public funds to teach electricity in our public high schools has already been established by the school system in the larger school systems of Texas, (2) the rural families living on electrified farms in the North Texas area want instruction of this type given to the boys and girls in their communities, and (3) both the rural people and the professional people of the North Texas area believe that instruction dealing with the use of electricity and electrical equipment had spread until by 1935 more than twenty-one million homes, about eighty percent of the total in America at that time, were electrified, only eleven American farms out of every 100 had central-station electricity. More than five million American farms lacked electric service. "--leaf 50.
Date: January 1949
Creator: Greathouse, Charles Simmons
System: The UNT Digital Library
A Study of the Shopping Goods Trade Flow from Lewisville, Lake Dallas, Sanger, and Valley View, Texas (open access)

A Study of the Shopping Goods Trade Flow from Lewisville, Lake Dallas, Sanger, and Valley View, Texas

"The purpose of the study is to determine the trading centers that receive significant amounts of shopping goods trade flow from the communities surveyed. The position that the Denton trading center holds as a source of shopping goods for households in these communities is compared with the postions held by some competing trading centers. This study is made in cooperation with the Denton Chamber of Commerce for the benefit of the merchants of Denton. It is based on a survey made in December 1953, by the Business Administration 470 (Marketing Research) class of North Texas State College."-- leaves 1, 58.
Date: August 1955
Creator: Robinson, David Charles
System: The UNT Digital Library