Abstract: Lajas Valley is plagued with problems of salinity and waterlogging the soils. Use of brackish (500 milligrams per liter) irrigation compounded ground water for the problem until an irrigation-drainage system was constructed in 1955. Lajas is an alluvium-filled limestone highlands. The alluvium, mostly clay and as much 300 feet (90 meters) thick, contains brackish ground water except in the recharge areas located along the foothills...Results from a digital model show that a network of discharge wells could alleviate waterlogging of the soils in the artesian area.

From introduction: A post-drought analysis of the sources of water supply for the metropolitan area indicated a need for better knowledge of the ground-water resources. A study was implemented through the cooperative water-resources investigation program between Commonwealth agencies of Puerto Rico and the U.S. Geological Survey.

From introduction: The scope of work of the study was to compile and analyze information on the resources and requirements of the southwestern, southeastern, and north-central coastal regions of the Commonwealth, and assess industrial and agricultural activities which in conjunction with the power and desalting plants, might comprise the energy center complex. The study was also to identify the need for any experimental, pilot or demonstration projects which benefit the practical application of the Energy Center concept in Puerto Rico.

From introduction: The PRWRA has contracted with the AEC to study the application of an Energy Center in Puerto Rico. The authority in turn has retained Burns and Roe, Inc. as a subcontractor and the Dow Chemical Company as a major sub-subcontractor to carry out this study.

From introduction: The scope of work of the study was to compile and analyze information on the resources and requirements of the southwestern, southeastern, and north-central coastal regions of the Commonwealth, and assess industrial and agricultural activities which in conjunction with the power and desalting plants, might comprise the energy center complex. The study was also to identify the need for any experimental, pilot or demonstration projects which benefit the practical application of the Energy Center concept in Puerto Rico.

From introduction: This report concerns nuclear power plant deployment in Puerto Rico.

From background: The study is an outgrowth of investigations by the Atomic Energy Commission and the Office of Saline Water into the use of nuclear energy to supply heat for desalting seawater and for generating electricity, and of work on the energy center concept conducted at the AEC's Oak Ridge National Laboratory. The bases for the study were set forth in a Memorandum of Understanding signed by Commissioner James T. Ramey of the United States Atomic Energy Commission, Under Secretary David S. Black of the United States Department of the Interior, Acting Executive Director Fernando Torrent of the Puerto Rico Water Resources Authority, and Executive Director Orlando Gonzalez of the Puerto Rico Aqueduct and Sewer Authority.

From introduction: The purpose of this report is to summarize available information concerning iron-ore resources in the United States in order to provide a general background for understanding and appraising the present status of this basic commodity.

Abstract: Laguna La Torrecilla, Laguna de Pinones, Laguna San Jose, and Laguna del Condado, in the San Juan, Puerto Rico area, are located within a metropolitan area of more than 1 million people. Bathymetric maps made during the study, in 1973, showed that Lagunas La Torrecilla, San Jose, and del Condado have been modified by dredging and filling; whereas, Laguna de Pinones has remained in a near natural state. Laguna La Torrecilla has been dredged to a depth, in places, of about 18 metres, and Lagunas San Jose and del Condado, in places to about 11 meters. Dredging in the San Juan lagoons has been harmful, beneficial, and in a few instances has had little or no noticeable effect on the water quality. Usually, dredging in the connecting canals has been beneficial if the water entering the lagoons through the canals was of better quality than the water in the lagoon. Dredging in the mouths of lagoons has been beneficial; whereas, filling or blocking the mouths has been harmful.

From introduction: This report presents observed data on the interlagoon and ocean exchange of the flows of water, sediment, and selected chemicals for a tidal cycle in January 1974.

From introduction: The North Coast Limestone area is one of the two most important ground-water provinces of Puerto Rico--the other being the South Coast Alluvial aquifer. The investigation of the water resources of the South Coast has progressed to the point that at this time (mid-1971) an electric-analog model of the area is being prepared. The hydrology of the North Coast Limestones, however, was never investigated as a whole before this investigation, and, therefore, this study was designed to assess the most important hydrolic features of the area.

From introduction: This report summarizes the results of the study in the Manati-Barceloneta area. The study includes an analysis of the availability of water from both surface and ground-water sources, and water quality. The major focus of the study was the alluvial valley of Rio Grande de Manati north of Highway 2. Areas outside of the valley were included as necessary only to the degree in which these influence the local hydrology.

Report discussing earthquake activity in the United States during 1928. The report is broken down by regions and has sections for specific earthquakes.

Report discussing earthquake activity in the United States during 1929. The report is broken down by regions and has sections for specific earthquakes.

This report presents an analysis of "three limestone aquifers on the north coast of Puerto Rico west of the RÍo de la Plata" using "analog modeling techniques."

This report used "annual peak-discharge records at fifty sites with five or more years of record" to determine individual site frequency curves. It includes several maps.

Report containing an aeroradioactivity survey of Puerto Rico made on behalf of the Division of Biology and Medicine, United States Atomic Energy Commission. Topics include the types of bedrock noted in the area as well as their levels of radioactivity.

Map with graded color shading to show levels of naturally-occurring gamma aeroradioactivity within Puerto Rico. Details about the survey and map creation are printed at right. Scale 1:250,000.

From Introduction: "This publication includes the laws of the States, the District of Columbia, Puerto Rico, and the Virgin Island through 1964. Only those portions of the workmen's compensation laws which apply to or are related to and deletions from the basic law have been incorporated into the text of the law, thus making it unnecessary to search out the various amendments made each year."

Report discussing earthquake activity in the United States during 1931. The report is broken down by regions and has sections for specific earthquakes.

Report discussing earthquake activity in the United States during 1930. The report is broken down by regions and has sections for specific earthquakes.

From purpose and study: The principal objectives of this study were as follows: (1) to determine the existing water-quality conditions in Lago Loiza as reflected by the principal chemical, physical, biological and bacteriological characteristics in the lake and its tributaries. (2) To estimate the reservoir's water budget during the study period, including the contributions from the tributaries and other sources. (3) Estimation of the reservoir's overall nitrogen and phosphorus budget, including the principal sources and sinks of these nutrients. (4) Definition of the sedimentation rate in the reservoir.

Abstract: The principal chemical, physical and biological characteristics, as well as the hydrology of Laguna Tortuguero, Puerto Rico, were studied from 1974-75. The lagoon, with and area of 2.24 square kilometers and a volume of about 2.68 million cubic meters, contains about 5 percent of seawater. Drainage through a canal on the north side averages 0.64 cubic meters per second per day, flushing the lagoon about 7.5 times per year. Chloride and sodium are the principal ions in the water, ranging from 300 to 700 mg/L and 150 to 400 mg/L, respectively. Among the nutrients, nitrogen averages about 1.7 milligrams per liter, exceeding phosphorus in a weight ratio of 170:1. About 10 percent of the nitrogen and 40 percent of the phosphorus entering the lagoon is retained. The bottom sediments, with a volume of about 4.5 million cubic meters, average 0.8 and 0.014 percent nitrogen and phosphorus, respectively.

From abstract: A statistical summary of the available continuous and once-daily discharge, specific-conductance, dissolved oxygen, temperature, and pH data collected at NASQAN stations during the 1973-81 water years and documentation of the period of record on which the statistical calculations were based are presented.