El estudio obedece a la necesidad de las comunidades Tolontag y El Marco de la parroquia de Pintag, provincia de Pichincha, de disponer de infraestructura basica para el uso integral del agua, tanto para regadio como para uso domestico y animal. En un plano topografico escala 1:5000 se ubico los perfiles y se tomo muestras de los horizontes para los analisis fisico-quimicos y de fertilidad. Los datos de laboratorio permitieron elaborar el mapa de suelos, el mismo que tenia 11 unidades de suelo. Con los datos meteorologicos y utilizando el metodo mixto Thornthwaitw y Blaney-cuddle se calculo la dotacion (numero de litros/ha) que hay que entregar al suelo, la misma que se estimo en 0,6 l/seg regando 16 horas diarias y 0,41 l/seg regando las 24. Posteriormente se diseno el sistema de riego con sus respectivos calculos hidraulicos como son: calculo de secciones, pendientes, tomas cajas de distribucion, acueductos y caidas. Este sistema consta de 2 tomas principales, 2 canales principales y 13 canales secundarios, permitiendo regar durante todo el ano 377 ha. En relacion al proyecto de agua potable los trabajos se iniciaron con la cuantificacion de la poblacion actual, mediante encuesta, permitiendo conocer que existian 1965 personas en Tolontag y El Marco. En datos del censo de 1974 y 1984 se obtuvo la tasa de crecimiento poblacional 2,8 por ciento, que permitio proyectar la poblacion futura para 15 anos, tiempo de vida util del agua potable. Una vertiente natural ubicada a 4100 msnm proporciona agua constantemente, el analisis del laboratorio determino que esta no requiere tratamiento, unicamente se aconseja una cloracion como tratamiento preventivo. Los datos de poblacion y necesidades diarias permitieron conocer el consumo maximo y el caudal constante que se debe captar en la vertiente. Con el plano base y los datos de consumo es posible calcular el sistema de distribucion de agua potable; sus tuberias principales y secundarias, tanto de almacenamiento y los respectivos accesorios como valvulas y llaves de paso. Existen memorias tecnicas y planos de la obra.

El ensayo se realizo en el Campo Docente "La Tola" de la Fac. de Ciencias Agricolas de la Universidad Central ubicado en la parroquia de Tumbaco, provincia de Pichincha, con las siguientes coordenadas geograficas, 0 grados 13' S, 78 grados 22' W, altitud 2465 msnm, temperatura media anual 15,5 C, humedad relativa media anual 75 por ciento y precipitacion anual 950 mm. En un suelo Typic Ustropepts, Franco-Arenoso, con irrigacion de acuerdo a las necesidades del cultivo, se estudiaron 4 laminas de riego hasta obtener un 35 por ciento de volumen de humedad en el suelo, cuando esta llegara a la3=30 por ciento; la2=25 por ciento; la1=20 por ciento; y la0=15 por ciento. Mediante riego por surcos se aplicaron en la lamina la3: 220 mm de agua en dos riegos (80 y 140 mm), en la lamina la2: 100 mm y en la lamina la1: 120 mm. En la lamina la0 no se efectuo ninguna dotacion de agua, ya que las precipitaciones ocurridas en el ciclo del cultivo cubrieron las necesidades de este tratamiento. Las parcelas experimentales de 150 m2 fueron distribuidas en un diseno de bloques completos al azar, con 4 repeticiones (area total del ensayo 2400 m2). Cada lamina de riego estuvo separada por caminos de 4m a fin de evitar la infiltracion lateral al momento del riego. El almacenamiento de agua y las necesidades de irrigacion fueron detectadas mediante lecturas periodicas de la humedad volumetrica del suelo con la sonda de neutrones, hasta la profundidad de 80 cm. La evapotranspiracion real se calculo mediante la ecuacion del balance de masas; la evapotranspiracion potencial mediante los metodos de Peuman y Tanque clase "A", y la eficiencia de aplicacion fue determinada mediante la relacion: agua almacenada/agua aplicada. El rendimiento de las laminas la3 con 29700 kg/ha, la2 con 24300 kg/ha y con tuberculos de peso mayor a los 150 g fueron superiores a los rendimientos proporcionados por las laminas la1 con 18400 y la0 con 24300 kg/ha; concluyendose por tanto, que la aplicacion oportuna de agua al cultivo de papa es de vital importancia para alcanzar buenos rendimientos.

Water availability and management issues related to the supply of drinking water in northern communities are problematic in Canada. While rivers and lakes are abundant, they are vulnerable to contamination and may become dry in winter due to freezing. Groundwater can often provide a more secure and sustainable water source, however its availability is limited in northern Canada due to the presence of permafrost. Moreover, the exploitation of northern aquifers poses a dual challenge of identifying not only permafrost-free areas, but also permeable areas which will allow groundwater recharge and exploitation. Suitable aquifers are not as common in northern Canada since the shallow subsurface is mostly composed of low-permeability crystalline rocks or unconsolidated sediments of glacial origin that are highly heterogeneous. In order to investigate groundwater occurrence and associated geological contexts in Nunavik (northern Quebec, Canada), along with exploring how these resources will evolve in response to climate change, field and compilation work were conducted in the surroundings of the four villages of Salluit, Kuujjuaq, Umiujaq and Whapmagoostui-Kuujjuarapik. These villages are located in different permafrost zones, ranging from continuous to discontinuous, as well as in different geological environments. It was found that despite the ubiquitous presence of permafrost, unfrozen aquifers could be identified, which suggests that groundwater may be available as a source of drinking water for small communities. Expected climate change, with predicted permafrost thawing and increases in temperature and precipitation, should enhance groundwater availability and may contribute to a more secure source of drinking water for northern communities.

Groundwater recharge and evolution in the Shule River basin, Northwest China, was investigated by a combination of hydrogeochemical tracers, stable isotopes, and radiocarbon methods. Results showed the general chemistry of the groundwater is of SO₄ ²⁻ type. Water–rock reactions of halite, Glauber’s salt, gypsum and celestite, and reverse ionic exchange dictated the groundwater chemistry evolution, increasing concentrations of Cl⁻, Na⁺, SO₄ ²⁻, Ca²⁺, Mg²⁺ and Sr²⁺ in the groundwater. The δ¹⁸O and δ²H values of groundwater ranged from −10.8 to −7.7 and −74.4 to −53.1 ‰, respectively. Modern groundwater was identified in the proluvial fan and the shallow aquifer of the fine soil plain, likely as a result of direct infiltration of rivers and irrigation returns. Deep groundwater was depleted in heavy isotopes with ¹⁴C ages ranging from 3,000 to 26,000 years, suggesting palaeowater that was recharged during the late Pleistocene and middle Holocene epochs under a cold climate. These results have important implications for groundwater management in the Shule River basin, since large amounts of groundwater are effectively being mined and a water-use strategy is urgently needed.

Road salt is pervasively used throughout Canada and in other cold regions during winter. For cities relying exclusively on groundwater, it is important to plan and minimize the application of salt accordingly to mitigate the adverse effects of high chloride concentrations in water supply aquifers. The use of geospatial data (road network, land use, Quaternary and bedrock geology, average annual recharge, water-table depth, soil distribution, topography) in the DRASTIC methodology provides an efficient way of distinguishing salt-vulnerable areas associated with groundwater supply wells, to aid in the implementation of appropriate management practices for road salt application in urban areas. This research presents a GIS-based methodology to accomplish a vulnerability analysis for 12 municipal water supply wells within the City of Guelph, Ontario, Canada. The chloride application density (CAD) value at each supply well is calculated and related to the measured groundwater chloride concentrations and further combined with soil media and aquifer vadose- and saturated-zone properties used in DRASTIC. This combined approach, CAD-DRASTIC, is more accurate than existing groundwater vulnerability mapping methods and can be used by municipalities and other water managers to further improve groundwater protection related to road salt application.

In cold regions, hydrologic systems possess seasonal and perennial ice-free zones (taliks) within areas of permafrost that control and are enhanced by groundwater flow. Simulation of talik development that follows lake formation in watersheds modeled after those in the Yukon Flats of interior Alaska (USA) provides insight on the coupled interaction between groundwater flow and ice distribution. The SUTRA groundwater simulator with freeze–thaw physics is used to examine the effect of climate, lake size, and lake–groundwater relations on talik formation. Considering a range of these factors, simulated times for a through-going sub-lake talik to form through 90 m of permafrost range from ∼200 to > 1,000 years (vertical thaw rates < 0.1–0.5 m yr⁻¹). Seasonal temperature cycles along lake margins impact supra-permafrost flow and late-stage cryologic processes. Warmer climate accelerates complete permafrost thaw and enhances seasonal flow within the supra-permafrost layer. Prior to open talik formation, sub-lake permafrost thaw is dominated by heat conduction. When hydraulic conditions induce upward or downward flow between the lake and sub-permafrost aquifer, thaw rates are greatly increased. The complexity of ground-ice and water-flow interplay, together with anticipated warming in the arctic, underscores the utility of coupled groundwater-energy transport models in evaluating hydrologic systems impacted by permafrost.