Environmental Water Resources Engineering

El cumplimiento de las profecías bíblicas a la luz de nuestros
ojos y al cada vez más cerca eminente regreso de nuestro Señor y Salvador, Jesucristo, nos ha llevado a escudriñar y estudiar el tema de las "Vestiduras Blancas" mencionadas en las Sagradas Escrituras. Hacemos un esfuerzo para que los creyentes puedan comprender la importancia de las "Vestiduras Blancas" y la necesidad de las mismas para participar en el rapto de la iglesia de Jesucristo, cuando suene la trompeta. Este tema es de gran importancia en estos tiempos finales donde la apostasía está entrando a la iglesia en un gran número de formas. El propósito de este escrito es el de inquietar la conciencia de los creyentes para que evalúen su condición espiritual y se preparen para que les sea concedido el vestirse de blanco para el evento de las bodas del cordero. Para beneficio del lector, el autor esclarece y enfatiza que el escrito está hecho desde un punto de vista bíblico
y con una interpretación escatológica premileniar.

Como en toda ocupación o profesión el obrero cristiano
necesita ciertas herramientas que resultan básicas para
ejecutar sus funciones y que le harán capáz de desarrollar
otras destrezas y, en el caso del obrero cristiano, facilitar el
fluir del don de Dios en su vida. Este primer volumen de la
serie: “Obreros Para la Mies” intenta presentar dichas
herramientas y hacer concientes a los participantes del
Campamento Evangelístico Misionero Antioquía u otro
instituto o escuela de capacitación de obreros de la
importancia de las herramientas aquí presentadas para su
vida y desarrollo ministerial. Como nos enseña la Palabra “el
amor es el vinculo perfecto” (Colosenses 3:14) el cual no
permitirá que nos separemos del vencedor, Jesucristo
(Romanos 8:35).

Introduction 2 Background 2 Purpose of excursion and field guide 3 Physical setting 3 Land use 5 Climate 5 Drainage 7 Flood alert system 10 Irrigation works 13 Portugues-Bucana flood control and water-supply project 13 Geology and hydrogeology of the South Coastal Plain 14 Groundwater hydrology 17 Groundwater quality trends 17 Groundwater quality conditions 18 Road log 20 References cited 24

The feasibility of injecting, storing, and recovering excess streamflow in a saline aquifer was investigated for a well site in the lower Rio Grande deArecibo valley, at Arecibo, Puerto Rico. Six injection-recovery tests were made, which included various injected volumes and storage periods. Injected volumes ranged from 0.6 to 6.6 million gallons. Ttie storage period ranged from 6 minutes to nearly 31 days. Chloride-load accounting was used to indirectly measure the volumes of injected water recovered. Injected water recovered during the tests ranged from 0.12 to 2.1 million gallons (21 and 32 percent, respectively, of total volumes injected). Graphical projections were used to predict the maximum recovery efficiency for various combinations of injected volumes and storage periods. Predicted maximum recovery efficiency generally was less than 60 percent. TJie specific capacity of the test well was decreased about 25 percent as a consequence of injecting water that had a relatively large concentration of suspended sediment (about 100 milligrams per liter). Calculations of chemical equilibrium were made to determine if chemical reactions would occur between the injection water and minerals commonly found in limestones. TJiese calculations indicate that the injected water was supersaturated with calcite, and the aquifer water may be supersaturated with calcite, dolomite, aragonite, and magnesite; this presents a possibility for mineral precipitation.

Seepage from Rio Grande de Arecibo to the groundwater system at the east side of the valley is probably the key to the development of groundwater resources in the Arecibo area. San Pedro spring, with an average discharge of 8.6 million gallons per day (9,600 acre-feet per year), is undeveloped and represents a potential alternate source of water.

A preliminary assessment of subsurface injection, storage and recovery of fresh canal water was made in the naturally brackish lower Hawthorn aquifer in Cape Coral, southwestern Florida. A digital modeling approach was used for this preliminary assessment, incorporating available data on hydrologic conditions, aquifer properties, and water quality to simulate density-dependent groundwater flow and advective-dispersive transport of a conservative groundwater solute (chloride ion). A baseline simulation was used as reference to compare the effects of changing various operational factors on the recovery efficiency. A recovery efficiency of 64 percent was estimated for the baseline simulation. Based on the model, the recovery efficiency increases if the injection rate and recovery rates are increased and if the ratio of recovery rate to injection rate is increased. Recovery efficiency decreases if the amount of water injected is increased; slightly decreases if the storage time is increased; is not changed significantly if the water is injected to a specific flow zone; increases with successive cycles of injection, storage, and recovery; and decreases if the chloride concentrations in either the injection water or native aquifer water are increased. In everal hypothetical tests, the recovery efficiency fluctuated between 22 and about 100 percent. Two successive cycles could bring the recovery efficiency from 60 to about 80 percent. Interlayer solute mass movement across the upper and lower boundaries seems to be the most important factor affecting the recovery efficiency. A sensitivity analysis was performed applying a technique in which the change in the various factors and the corresponding model responses are normalized so that meaningful comparisons among the responses could be made. The general results from the sensitivity analysis indicated that the permeabilities of the upper and lower flow zones were the most important factors that produced the greatest changes in the relative sensitivity of the recovery efficiency. Almost equally significant changes occurred in the relative sensitivity of the recovery efficiency when all porosity values of the upper and lower flow zones and the leaky confining units and the vertical anisotropy ratio were changed. The advective factors are the most important in the Cape Coral area according to the sensitivity analysis. However, the dispersivity values used in the model were extrapolated from studies conducted at the nearby Lee County Water Treatment Plant, and these values might not be representative of the actual dispersive characteristics of the lower Hawthorn aquifer in the Cape Coral area.