examen hidrology

Freshwater (agua dulce): represents 2.5% of all water on Earth. usable by humans is 0.3% of all water on Earth. can be renewed. usable by humans is mainly stored in glaciers and permanent snow cover. usable by humans is 0.39% of all water on Earth. represents 3.5% of all water on Earth.

Water in rivers (agua en los rios). is salty. is not accessible. is renewed in 16 days. is renewed in 17 days.

The hydrologic cycle (El ciclo hidrológico). keeps water in motion. is stimulated by the Sun. is stimulated by the Moon. is intermittent. has no effect on water properties.

evaporation (evaporación). changes a liquid into a gas. occurs when the boiling point is reached. brings the water vapour liberated from the land and oceans into the atmosphere. changes saltwater into freshwater.

Precipitation. changes the water vapour into a liquid. falls from clouds. is intermittent.

Infiltration (Infiltración). describes the interception of water by plants. represents the flow of water through the soil. is the groundwater storage. is the groundwater flow.

Runoff (escorrentía). occurs when the soil cannot retain water. appears as stream flow. is the groundwater storage. is the groundwater flow.

A hydrologic region can be (Una región hidrológica puede ser). a country. a continent. topographically defined (e.g. a river basin). a lake.

The water budget (El presupuesto del agua). is an inventory of water. uses the basic equation of hydrology. does not require a limit of time. is reliable when the hydrologic terms are properly measured or estimated.

The hydrologic cycle is accurately explained by. Marcus Vitruvius (1st century B.C.). Leonardo da Vinci (15th century A.D.). Bernard Palissy (15th century A.D.). Bernard Plaissy (15th century A.D.).

Watershed orientation influences (Influencias de la orientación de las cuencas hidrográficas). the runoff. the infiltration. the melting speed.

Watershed geology influences (Influencias de la geología de las cuencas hidrográficas). surface flow. sub-surface flow. groundwater flow. runoff.

The agro-pedo-geological factors are (Los factores agropedogeológicos son). the geology. the soil type. the vegetal covering.

The time of concentration characterizes (El tiempo de concentración caracteriza). the speed of a watershed reaction to a stress. the flow of water through the soil. the intensity of a watershed reaction to a stress.

The shape of a watershed can be (La forma de una cuenca hidrográfica puede ser). long shape. fan-shape. various shapes. perfect circular shape. rectangular shape.

The hypsographical curve (La curva hipsográfica). establishes the average amount of water from the soil. establishes the average amount of precipitation. shows the watershed behaviour.

Methods for watershed average slope estimation were developed by (Los métodos para la estimación de la pendiente promedio de las cuencas hidrográficas fueron desarrollados por). Marcus Vitruvius. Carlier and Leclerc. Gravelius.

The big slope of a watercourse (La gran pendiente de un curso de agua). favors the infiltration. favors the runoff. accelerates the runoff.

The degree of development of a hydrographic network. was introduced by Schumm. was introduced by Horton.

Watershed geology. influences the surface flow. influences the runoff. influences the groundwater flow. has no participation at the water hydrological cycle.

Transformation of water vapour into liquid state through a process called: evaporation. condensation. sublimation.

What is the nature of the rainfall created by an ascendent current of warm air, which lifts at high altitudes being lighter than the surrounding air: convective. orographic. cyclonic.

What kind of precipitation is a mixture of rain and snow: dew. rain. ice. snow. sleet. hail. fog.

In which sphere are precipitation lighter than evaporations: hydrospheric sphere. lithospheric sphere.

In measuring rainfall, through which device is allowed the localization of the clouds: rain gauge. graphic rain gauge. tele-rain gauge with tilting baskets. meteorological radar.

The frequency distribution of the precipitate layer occurs on the y-axis of: the rain gauge diagram. the histogram.

For the calculation of the average rainfall for a basin, in which method the following relationship is used: the arithmetic method. the Thiessen polygons method. the isohyets method. the squared grid.

evaporation. is influenced by the wind. is influenced by the heat flow. is influenced by the atmospheric pressure. is influenced by the Sun. is influenced by the Moon.

evaporation amounts are high. in Polar Regions. in Tropical Regions. in the summer in temperate climates. in the winter in temperate climates.

The evaporation amount is reduced. by strong winds. when there is a deep-water surface. when there is a shallow water surface. when water is salty.

Transpiration. takes place at the roots level. takes place at the leaves level.

Evapotranspiration is not conditioned by. the soil type. the vegetation type. relief. climatic conditions.

evaporation flux-resistance. is the water quantity existent in the superior layers. is the aerodynamics resistance. is the diffusion resistance.

The potential evaporation. represents the sum of water quantity evaporated from soils and vegetation. indicates the water loss in the atmosphere superior limit. represents the maximum water quantity capable to be transformed in vapour. represents the minimum water quantity capable to be transformed in vapour.

For quantitative estimation of evaporation can be used. Turc Formula. Primault Formula. Rohwer Formula. Penman Formula.

To estimate the evapotranspiration can be used. empirical relations. semi-empirical relations. direct determination. formula.

The transpiration process. depends on meteorological factors. doesn't depend on meteorological factors. maintain a thermical balance of the leaves. has no participation at the water hydrological cycle.

The infiltration capacity is: the quantity of water that can be absorbed by soil. the total quantity of water that goes into the soil. the maximum rate at which water can be absorbed by a given soil per unit area under given condition.

The infiltration regime depends on: water supply regime. climatically conditions. soil properties. temperature.

The percolation process. follows the infiltration process. is characterized by atmospheric conditions. is the vertical water flow in the soil. is the horizontal water flow on soil surface.

The factor that does not influence the infiltration process is: the soil coverage. the initial humidity of the soil. the wind intensity. soil compaction state.

The cumulative infiltration is: the total amount of water that passes through an 1 m soil layer. the total amount of water infiltrated during a given period. the total amount of water that passes the soil layer and goes into the nearest stream.

Horton's formula is: an empirical one. a physical one.

Infiltration functions were expressed by: Dooge. Holton. Horton. Newton.

In the Green & Ampt model the main hypotheses are: the suction forces of the humidity front are constant. the temperature is constant during the process. the humidity front is perfectly defined. the atmospherically conditions are constant.

Which model introduced the notion of "sorption". Green & Ampt Model. Philip Model.

During a shower the infiltration rate: increases till the end of the shower. decreases continuously. decreases to a limit value.

The simple hydrological regime is characterize. by a maximum and generally only a water supply. by two maximums and two minimums per year. by many ways of water supply.

Flow types are. superficial flow. surface flow. subsurface flow. groundwater flow.

The submersion time. depends on soil type. depends on rain intensity. depends on initial soil humidity.

On saturated surfaces, the flow is produced because. there is an impermeable shallow layer. the soil capacity to retain water is overtaken. the capacity to transmit laterally the water flux is overtaken.

Subsurface flow. has a drainage capacity smaller than the superficial flow. has a drainage capacity bigger than the superficial flow. has a drainage capacity smaller than groundwater flow. has a drainage capacity bigger than groundwater flow.

The amount of water depends. on geology. on soil type. on the water volume which comes from a rainfall. on soil saturation.

Groundwater flow. maintains a rapid water discharge. maintains a low water discharge. assures stream discharge in the absence of rainfalls.

Suspended load are composed. of gross matter. of silts. of clays. of colloidal substances.

Factors that influence the quantity of dragged particles are. streambed characteristics. aggregate grading. aggregate shape. water speed.

Downstream of a dam take place. streambed erosion. solid matter sedimentation.

The lakes. favorize evaporation. have no interference in the hydrological balance. increase the river flow. slow down the river flow.

Subsurface water level is influenced. by groundwater. by irrigation water. by rain percolation regime.

Soil humidity can be expressed through. infiltration rate. volumic humidity. saturation index.

In case of a saturated environment. water effective pressure is positive. water effective pressure is negative. it depends on submersion depth.

The aquifer. is a surface water reservoir. is a groundwater reservoir. has impermeable geological patterns. has permeable geological patterns.

The storage coefficient. conditions the storage of the groundwater in reservoir voids. characterizes the volume of exploited water. is a parameter determined in laboratory.

Snow melting depends on. heat transfer. solar radiation. latent heat transfer. water quantity capable to be transformed into vapour.

Glaciers water represents. 1% of the Earth water. 2% of the Earth water. 5% of the Earth water. 10% of the Earth water.

Water from glaciers is. salty. potable. renewed in 16 days. renewed in 20 years.

Ice width in rivers and reservoirs is measured. with a sonde. with a rule. using infrared from satelites. with a scale.

The hydrological response cant be. total. partial. fast. delayed. light.

The fast hydrological response is important. only in case of surface flow. only in case of subsurface flow. in both cases: surface flow and subsurface flow. in case of groundwater flow.

The production function. allows determination of the net rain hyetogram. allows determination of the hydrograph.

The response time of a catchmentare not/is not. are time intervals that separate the net rain gravity centre from the peak flow. are time intervals that separate the net rain gravity centre from the flow hydrograph. is the time interval where rainwater arrives from the farthest point of the catchment to the measuring point.

When rainfall begins the river level. is low. is increased. begins to rise. rises after a period of time.

Effective rainfall. is the proportion of rainfall which is lost through evaporation. is the proportion of rainfall which is retained in soil. is the proportion of rainfall which is retained at the soil surface. is the proportion of rainfall which arrive in the stream.

Rising limb. is the descendent curve of discharge. is the ascendent curve of discharge. represents the time between the beginning of the rain and the peak of the hydrograph.

The annual distribution of rainfall within a storm may be uniform. when the catchment is large (>500km2). when the catchment is small or medium (<500km2). when the catchment is homogeneous in composition.

Among the research workers who studied the extension of the unit hydrograph can be named: Dooge. Holtan. Diskin. Singh.

Dooge. used a linear theory. used a nonlinear theory. combined the storage effect with translation effect.

To measure evaporation are used. float recorders. autographic recorders. atmometers.

Atmometers are. current meters. percolation gauges. lysimeters. evaporimeters.

Rain gauges can be read. daily. twice a week. monthly. annually.

The sampling orifice of gauges is made of. glass. brass. coper. steel.

Atmometers. are simple and easy to operate. are cheap. are expensive. are complex and difficult to operate.

Infiltration measurement can be made with. the Mûntz infltrometer. the Guelph infiltrometer. an infiltrometer with a cilinder. an infiltrometer with sprinkling-irrigations.

The water stage is read with an accuracy of. ± 2mm. ± 3mm. ± 5mm. ± 7mm.

The crest gauge is. reset after several readings. reset after each reading. benchmark on the bank. leveled into a normal staff gauge.

The electromagnetic flow measurement methods are. ultrasonic methods. current meters.

Dilution gauging. measures stream discharge by adding a chemical solution. measures stream level. measures stream discharge by adding a tracer.

Data archive. is available to the public. is available for water authorities.

The hydrometric data gathering agencies are. local government authorities. national authorities. private agencies.

Hydrological Data. shows the climatic changes. shows past extreme rainfalls. allow the use of information from a catchment to a neighboring ungauged catchment. do not allow the use of information from a catchment to a neighboring ungaged catchment.

Data are disseminated to users. on magnetic tapes. through internet. through computer programs. through yearbooks. through news.

The hypotheses for statistic analysis used in practice are. the data series is nonstationary. the consistency of data. the measurements reflect the real values. the data is aleatory and simple.

A data series is considered homogeneous when. reflecting two similar events. reflecting two different events. reflecting many different events. the event is stationary.

Categories of statistic tests are. tests subsequent to their physical properties. tests subsequent to their mathematical properties. tests subsequent to their object. tests subsequent to the nature of information.

The test subsequent to their object is. non-homogeneity test. conformity test. adjustment test. autocorrelation test.

Depending on the nature of the information, for local and regional flow it is necessary to control. one type of data. different types of data. selected data.

A quality control computer routine is specially designed to deal with. known conditions. unknown conditions. known events. unknown events.

The undesired changes in the environment that are provoked by reservoir-type works in urban areas and their surroundings are: A high humidity state in the area. A low level of the water table. A disruption of the sanitary state of the area. The salinization of the soil.

The effects of the levees are: An interruption of biological liaisons between the flood plain and the river bed. They do not guarantee the full protection of the flooding areas. A decrease of the flooding effects while the dikes are overtopped or broken.

The holistic approach of the water management implies planning actions that have to be. Only profitable (maximum of economic profit). Ecologically (taking into account that knowledge and perspective). Anticipatory (preventing outcomes that would be detrimental). Ethically (showing respect for other natural systems).

The sources of flood formation and circulation within the urban area are: Stormwater formed over the rural and suburban areas that flow towards the urban area. Stormwater (snowmelt originating water, inclusively) formed exclusively over the urban area. Flooding water originating from the rivers which flow at the limit or inside the urban area. Flooding water originating from the wind-causing seiche of the sea or shallow-depth lakes found at the limits of urban area.

The influence of the urban areas on the runoff formation and circulation is derived from: The area of the cities. The low rainfall intensity over the city area. The prevalent impervious land cover. The high velocities of the water flow at the surface and in the sewer system. The high intensity of water infiltration.

In urban areas rainfall is gauged with: Raingauges once in 24 hours. Rain automatic self-recorders once in 1-2 minutes. Meteorological radars.

The water level/discharge stations are installed: At 100 m one from another or even less. At significant points of confluence of sewer canals so that to allow for complete knowledge of the water balance. At the points of large streets intersection. At the points that allow for determining the water discharge under different hydraulic conditions.

The potential maximum discharge in an urban basin is achieved when: Rainfall has at least an intensity of 1.2 mm/minute. The impervious coverage of the urban area represents at least 75 % of the total city area. The duration of rainfall is at least equal or greater than the lag time of the urban catchment. Rainfall is evenly distributed over the urban basin.

The best solution for the water release during an urban rainstorm is: To directly derive all the quantity of stormwater to the receiving river in order not to produce the treatment plant silting. The derive a part of water to a ponding storage and to release it afterward in the treatment plant. To bypass a part of water to the receiving river and to send an acceptable discharge magnitude to the treatment plant.

In case that the urban area is large or very large the rainstorm-runoff model should be applied to: Partial areas that have an impervious land cover. The entire area of the urban catchment. Subbasins of the urban catchment before adding the maximum flow computed for each of them. Subbasins of the urban catchment according to the topologic model before successively integrating the flood hydrographs from upstream to downstream.

Which are the components of water disperse system?. dissolved substances, dissolved gases, radioactive components. dissolved and not dissolved substances, gases, microorganisms. dissolved and not dissolved substances, gases, microorganisms, radioactive components.

Which anions and cations form the ionic composition of river waters?. HCO3-, SO42-, Fe, Cl, Na. HCO3-, SO42-, Cl-, Ca2+, Mg2+, Na+ (K+). Ca2+, Mg2+, SO42-, Cl, Na, HCO3-.

Which of the following answers contains all the factors that form the quality of waters?. climate, vegetation, rockstructure, soils, aquatic organism. precipitation and temperature, forest vegetation, rocks and soil. precipitation and temperature of the air, soil and plant cover, rocks, vital activity of water organisms.

Which of the following processes describe the interaction between rocks and sheet flow?. dissolving, hydrolysis. diffusion and convective transportation. bioaccumulation, settling.

In which of the following cases waters in rivers have the lowest mineralization?. if rainfalls and subsurface waters predominate. if snow and glacial feeders predominate. if snowfalls and rainfalls predominates and a great amount of subsurface waters.

Which of the chemical processes is decisive for the pH of river waters and respectively for their quality?. hydrolysis. sorption. oxidation-reduction processes.

What is the role of the phytoplancton for the formation of quality of waters?. source of not organic substance and CO2. source of organic matter and O2. source of the basic anions and cations.