Hydrology Pointers PDF

1. The fundamental tools in hydrology, depicting the rate of flow over time at a specific point in a river, channel, or conduit carrying stormwater or wastewater. Hydrograph/s 2-4. As a graphical representation of the relationship between flow rate and time, its graph illustrates how the flow of wat...

1. The fundamental tools in hydrology, depicting the rate of flow over time at a specific point in a river, channel, or conduit carrying stormwater or wastewater. Hydrograph/s 2-4. As a graphical representation of the relationship between flow rate and time, its graph illustrates how the flow of water changes over time in response to, what various factors? (can be interchange) Rainfall, Snowmelt, Human Activities 5-8. What are the components of a Hydrograph? (can be interchange) Rising Limb, Peak Flow, Base Flow, Recession Lim 9. It is the initial upward slope representing the increasing flow rate as precipitation or runoff enters the system. Rising Limb 10. It is the highest point on the hydrograph, indicating the maximum flow rate during the event. Peak Flow 11. It represents the slow, steady contribution of water from groundwater sources. Base Flow 12. It is the downward slope as flow rates decrease following the peak, reflecting the drainage of excess water. Recession Limb 13. It is a crucial technique used in hydrology to discern the contributions of different flow sources within a watershed. Hydrograph Separation 14. Comprises the rapid response to precipitation events, often flowing overland and through surface channels. Stormflow 15-17. What are the methods used for separating the various components of hydrograph (such as baseflow and stormflow)? (can be interchange) Graphical Methods, Chemical and Isotopic Tracers, Mathematical Models 18. It is a graphical representation of the runoff response of a watershed to a unit amount of rainfall over a specific duration. Unit Hydrograph (UH) 19-20. Among the applications of Unit Hydrograph (UH), give at least 2 of those. Flood Prediction, Floodplain Mapping, Stormwater Management, Watershed Modeling, River and Reservoir Operations, Bridge and Culvert Design, Environmental Impact Assessment 1. It is water that exists in the pore spaces and fractures and sediments beneath the unsaturated zone of soil which can flow freely into a well, tunnel, spring, etc. GROUNDWATER 2. It is a ground-water reservoir composed of geologic units that are saturated with water and sufficiently permeable to yield water in a usable quantity to well and springs ACQUIFER. 3-4. What are the two types of Aquifer? CONFINED AQUIFER and UNCONFINED AQUIFER 5-9. What are the 5properties of aquifer? - POROSITY, SPECIFIC YIELD, DARCY'S LAW, HYDRAULIC CONDUCTIVITY, TRANSMISSIBILITY, T 10. It is a groundwater reservoir composed of geologic units that are saturated with water and sufficiently permeable to yield water in a usable quantity to well and springs. UNCONFINED AQUIFER 11-13. State the 3 applications used in Travel Time. DESIGNING EXPLOITATION MONITORING SYSTEM IDENTIFYING AREAS AFFECTED BY CONTAMINANT MIGRATION ASSESSING THE POTENTIAL FOR NATURAL ATTENUATION POLLUTANTS 14-16. What is the formula used in calculating the Travel Time? 17-20. What are the Darcy’s Law Formula? critical components of the hydrological cycle. Aquifers 1. also known as water table aquifers, are groundwater reservoirs where the water table is at atmospheric pressure. Unconfined Aquifers 2-4. Key Characteristics of Unconfined Aquifer. storage properties, dynamic water table behavior, variations in permeability that influence water movement and availability 5. involves dewatering processes to access groundwater for various purposes such as irrigation, industrial use, and domestic supply. Pumping in unconfined aquifers 6-9. The equation is derived from the is equation, which describes the transient flow of groundwater in a confined aquifer. 2. These are sandwiched between impermeable layers of rock or clay, restricting the movement of groundwater. Confined Aquifers 3. It is the lack of confining layers that allows groundwater to flow more freely. Unconfined Aquifers 4. Give at least one application of the Law of Darcy. Groundwater modeling employs Darcy's law to predict flow patterns, contaminant transport, and water availability. Well design relies on Darcy's law to determine optimal locations and depths for wells to efficiently extract groundwater. 5. What is the formula for solving Law of Darcy. 6-10. Solve this problem using Law of Darcy formula. 10. 𝑄 - flow rate 11. K - hydraulic conductivity 12. b - aquifer thickness 13.h - initial water level 14.r - distance from the well 15. 𝑟𝑤 -radius of the well 10. Also known as an artesian aquifer, it is an underground layer of permeable rock or sediment that is bounded above and below by impermeable layers. Confined Aquifer 11. It can cause the water level in wells to rise above the top of the aquifer. Artesian Pressure 1. The underground reservoirs of water stored within permeable rock or sediment layers, are 12. It occurs through natural processes such as rainfall, snowmelt, and surface water infiltration. Recharge of confined aquifers. Recharge of confined aquifers 13.-17. Give the 5 examples of aquifer. Ogallala Aquifer Edwards Aquifer Floridan Aquifer System Floridan Aquifer System Nubian Sandstone Aquifer System 18. It prevents water from freely moving in or out of the aquifer, resulting in the confinement of water. Impermeable Layers 19. It is one of the largest confined aquifers in the world, located beneath the Great Plains of the United States. Ogallala Aquifer 20. It is a vast, confined aquifer located in the Sahara Desert, spanning across Chad, Egypt, Libya, and Sudan.. Nubian Sandstone Aquifer System 1. It is the simplest, most reliable and standard device to measure the evaporation. a. Empirical Equations b. Energy Budget c. Class A Pan evaporation d. none of the above 2. It is the process of conversion of water from liquid into vapor. a. Evaporation b. Condensation c. Precipitation Rain d. b. Energy d. Pan 4. are simply the ration of the water body evaporation to pan evaporation. a. Pan ratio b. Pan Coefficients c. Rate of Evaporation &b a. Lysimeters b. Empirical Budget c. Energy Budget d. Evaporation II. Enumeration 1 point each 1-6 Factors affecting the Evaporation. ✓ Degree of Wetness of the surface ✓ Temperature of the Air ✓ Temperature of the Soil ✓ Atmospheric Humidity ✓ Wind Velocity ✓ Vegetative Cover 7-8 Give at least two measurements of estimating the factors for Evaporation. Pan Evaporation Energy Budget Lysimeters Empirical Budget 9-10 Evaporation is usually measured in two stations using a pan evaporator. Meteorological Agrometeorological 1.Who is Horton's equation named after? Answer: Robert E. Horton. 2.It is an empirical formula that says that infiltration starts at a constant rate (t) , and is decreasing exponentially with time (Jo). Answer: Horton’s Equation 3. A weather measurement system that integrates several climatic conditions including rainfall, humidity, solar radiation, wind temperature and drought dispersion. a. Rain gauge Budget c. Lysimeters Evaporation 5. A measuring device which can be used to measure the amount of actual evapotranspiration which is released by plants (usually crops or trees). d. a 3. What happens to the rate of infiltration according to Horton's equation as time progresses? Answer: decreases exponentially with time 4.Who pioneered the analytical solutions for infiltration and presented the first analytical solution to Richard's Equation for vertical and horizontal infiltration? Answer: John Robert Philip 5-6.What are the two key factors besides time that determine cumulative infiltration in Phillip's proposed equation? Answer: Sorptivity and hydraulic conductivity 7-8. Who are the two scientists associated with the Green-Ampt Model? Answer: Gustav Adolph Ampt and William Heber Green 9. What type of flow does the Green-Ampt model simulate? Answer: Unsaturated flow 10. Which of the following is NOT an assumption of the g-a model for soil infiltration? a. The soil is heterogeneous and unstable. b. The supply of ponded water at the surface is not limited. c. A distinct and precisely definable wetting front exists. d. The soil is uniformly saturated above the wetting front. e. The capillary suction below the wetting front is uniform throughout the profile Answer: A 11. What happens to rainfall when its intensity is lower than the maximum downward hydraulic conductivity? Answer:All rainfall will infiltrate into the ground and runoff will never occur. 12. Which case describes a situation where rainfall intensity is greater than the infiltration rate, leading to possible runoff? Answer: Case 3, where 𝑖>𝑓 13-15.What are the three parameters involved in the Green-Ampt derivation, and what does each parameter represent? Answer: Ks - This parameter depends on pore size and grain size properties. ψ - This parameter represents the difference between atmospheric and hydrostatic pressures. Ma - This parameter is a function of effective porosity and initial saturation. 16-20. Given the following parameters: 𝑓𝑜=10 mm/hr (initial infiltration capacity) 𝑓𝑐=5 mm/hr (final constant infiltration capacity) 𝑡=2 hours (time from the beginning of rainfall) 𝑘=0.5 (exponential decay constant) Calculate the infiltration capacity (𝑓𝑝) after 2 hours from the beginning of rainfall using the equation: 𝑓𝑝=𝑓𝑐+(𝑓𝑜−𝑓𝑐)⋅𝑒 −𝑘𝑡 Answer: Plugging the given values into the formula, we get: 𝑓𝑝=5+(10−5)⋅𝑒−0.5×2fp=5+(10−5)⋅𝑒 −0.5(2) fp=5+(5×0.3679) =5+1.8395 ≈6.84mm/hr Thus, the infiltration capacity after 2 hours is approximately 6.84 mm/hr. 1. It is the elapsed time between the time rainfall begins and the time water begins to pond on the soil surface. Answer: Ponding Time 2. During a rainfall event, water will pond on the surface only if? Answer: if the rainfall intensity is greater than the infiltration capacity of the soil. 3. When does ponding occurs? Answer: When the rain is falling at a higher rate than the infiltration rate. 4. It is the process in which water enters into soil and the rate at which water entering into soil. Answer: Infiltration Rate 5. What does "p" stands for? Answer: Effective Porosity 6. What does "K" stands for? Answer: Hydraulic Conductivity 7. What formula should be used in calculating the depth of infiltration at time t? Answer: 8-12. Infiltration rates are input for deduction of abstractions in hydrograph analysis which in turn, is utilized in _________, ________, ________, _________ and ________. Answer: Design of Hydraulic Structures, Design of Urban Drainages, Estimation of Design Flood, Development of Flood Forecasting and Flood Warning Systems. 7. Thiessen Polygon Method where: the region is divided into polygons based on the locations of rain gauges. Divide Area 8. Thiessen Polygon Method where: the rainfall value at each gauge is assigned to its corresponding polygon. Assign Values 9.Thiessen Polygon Method where: the areal rainfall is calculated as the weighted average of the polygon values. Calculate Areal Avg. 10. Isohyetal Method where: Lines of equal rainfall (isohyets) are plotted on a map based on gauge data. Draw Isohyets 11. Isohyetal Method where: The areas between isohyets are measured using planimeters or GIS tools. Measure Areas 12. Isohyetal Method where: The areal rainfall is computed as the weighted average of the isohyetal areas. Calculate Areal Avg. 1. Areal rainfall data is crucial for accurate flood risk assessment and mitigation strategies. Flood Planning 2. 2Areal rainfall estimates improve the management of water supplies and irrigation systems. Water Resource Management 3. Areal rainfall inputs enhance the reliability of hydrological models and simulations. Hydrological Modelling 4. 5The uneven distribution of rainfall across a region can impact the conversion process. Spatial Variability 5. Terrain features like mountains and valleys can influence the spatial patterns of rainfall. Topography 6. The size, intensity, and movement of rainfall events affect the conversion to areal data. Storm Characteristics 13. It is used to estimate the average precipitation across an area by drawing lines of equal precipitation. Isohyets are contours of equal precipitation analogous to contour lines on a topographic map. Isohyetal Method 14. It is a graphical technique used to identify potential trends, changes, or anomalies in two related data sets over time. By plotting the cumulative values of one data set against the other, it helps detect potential shifts or divergences between the two. Double mass analysis 15. Data requirement for Double Mass Analysis where the data sets must have consistent and continuous measurements over time, without gaps or missing values. Continuous Data 16. Data requirement for Double Mass Analysis where the two data sets should have a proportional relationship, where changes in one variable correspond to changes in the other. Proportional Relationship 17.Data requirement for Double Mass Analysis where the data sets should have a sufficient number of observations to identify trends and patterns reliably. Adequate Length 18-20. State the Step-by-Step Procedure of Double Mass Analysis. Cumulative Data, Plot Curve, and Analyze Curve 1. It is the transformation of a liquid into a vapor phase due to the escape of molecules from the liquid's surface. EVAPORATION 2. Evaporation depends on factors such as temperature, surface area, humidity, and the nature of the liquid. RATE OF EVAPORATION 3. TRUE or FALSE: Higher temperatures increase the average kinetic energy of the liquid molecules, leading to faster evaporation rates. TRUE 4. The pressure exerted by the vapor when it is in equilibrium with the liquid phase. VAPOR PRESSURE 5. TRUE or FALSE: Higher vapor pressure implies a greater tendency for molecules to escape into the gas phase. TRUE 6.This process is influenced by the concentration gradient of the molecules and their diffusion coefficients. DIFFUSION 7. TRUE or FALSE: Diffusion: Evaporation involves the diffusion of molecules from the bulk liquid to the surface. TRUE 8. TRUE or FALSE: Higher temperatures increase the kinetic energy of molecules, leading to faster evaporation rates. TRUE 9.MODIFIED TRUE or FALSE (WRITE THE CORRECT TERM): A smaller surface area allows more molecules to escape simultaneously, accelerating evaporation. FALSE – LARGER 10. Reduces the rate of evaporation since the air already contains a high concentration of water vapor, slowing down the diffusion of water molecules from the liquid to the gas phase. HUMIDITY 11. Evaporation depends on the ____ as well. When the wind is light, a thin layer of air just above the surface gets nearly saturated. WIND SPEED 12. -20. Write a brief explanation about Evaporation. 1. This is the most common type of rain gauge used for measuring rainfall. It consists of a funnel with a known area that collects rainwater and directs it to a measuring cylinder. Standard rain gauge 2. This type of rain gauge uses sound waves to measure the size and frequency of raindrops. An acoustic sensor sends a signal to a computer, which calculates the amount of rainfall based on the data received. Acoustic rain gauge 3. This type of rain gauge measures rainfall by weighing the amount of water collected. The gauge consists of a container with a known weight that is placed on a scale. Weighing rain gauge 4. This type of rain gauge uses an optical sensor to detect the size and frequency of raindrops. The sensor sends a signal to a computer, which calculates the amount of rainfall based on the data received. Optical rain gauge: 5. This type of rain gauge uses a bucket that tips over when a certain amount of rainwater is collected. The number of times the bucket tips over is counted electronically, and this is used to calculate the amount of rainfall. Tipping bucket rain gauge: 6. They provide accurate measurements of rainfall when placed in an open area away from obstructions. Standard rain gauges 7. What type of rain gauges that is suitable for heavy rain fall? Weighing rain gauge 8. It is essential instruments for measuring precipitation. Rain gauge 9. This type of rain gauge can withstand harsh weather conditions and are less prone to damage. Tipping bucket rain gauge 10. Provide a continuous record of rainfall intensity. Provide a continuous record of rainfall intensity 11. Precise rainfall data informs decisions on water storage, distribution, and conservation efforts, ensuring sustainable water supplies. Water Management 12. Farmers rely on accurate rainfall forecasts to time planting, irrigation, and harvest activities, maximizing crop yields. Agricultural Planning 13. Continuous rainfall records allow scientists to study long-term climate trends and the impact of environmental changes. Climate Analysis 14-16. Give at least 3 factors Affecting Rainfall Patterns. Geographic Location Climate Change Seasonal Variations Anthropogenic Factors 17. Physical rain gauges placed across a region provide direct measurements of precipitation levels. Gauge Stations 18. Weather radar systems detect rainfall intensity and patterns over large geographic areas. Radar Observations 19. Satellite-based remote sensing collects data on cloud cover, moisture, and other precipitation indicators. Satellite Imagery 20. Mathematical models use historical data to estimate rainfall based on factors like temperature and humidity. Statistical Modeling 1.It is a plot of the cumulative depth of rainfall against time, plotted in chronological order. MASS CURVE OF RAINFALL 2. It represents a plot of the intensity of rainfall against the time interval. It can be prepared either from the mass curve of rainfall, or directly from the data obtained from rain gauges. The area under a hyetograph represents the total rainfall received in that period. HYETOGRAPH METHOD 3. It is defined as the ratio of the total amount of rain (rainfall depth) falling during a given period to the duration of the period. It is expressed in depth units per unit time, usually as mm per hour (mm/h). INTENSITY 4.It gives only total rainfall occurred during particular time period. Recording type rain gauge gives hourly rainfall. Under nonrecording type rain-gauges, one most commonly used in Symon’s rain-gauge. NONRECORDING GAUGES 5.____________ is the amount of precipitation, in the form of rain (water from clouds), that descends onto the surface of Earth, whether it is on land or water. It develops when air masses travel over warm water bodies or over wet land surfaces. RAINFALL 6. Point rainfall data is also known as____________. The rainfall data of a particular station is known as point rainfall. The rainfall data can be presented as daily, weekly, monthly, seasonal or annual values for various periods. It is graphically presented as plots of magnitude vs chronological time in the form of bar diagram. STATION RAINFALL 7. It refers to the length of time rainfall occurs. DURATION 8. _______________ intensity produces larger size raindrops which have more impact energy, and thus higher intensity storms can damage delicate vegetation and bare soil. HIGHER RAINFALL INTENSITY 9. The gauge is installed on a concrete or masonry platform ______ square in the observatory enclosure by the side of the ordinary rain gauge at a distance of 2-3 m from it. 45 cm. 10. An instrument used in measuring rainfall. RAIN GAUGES 1. What are the common rainfall amounts associated with hurricanes within a 24 hour period? 350 to 500 mm or 14 to 20 inch 2. Typical wind speeds associated with welldeveloped hurricanes. 120 km/h 75 mi per hour 3. A storms results of a warm moist air rises from lower elevations into cooler overlying air. Convective storms 4. What atmospheric phenomenon results in the formation of precipitation? Condensation of moisture in the atmosphere due to the cooling of air. 5. A term of precipitation where formed when air rises over mountains. Orographic storm 6. This is a type of precipitation formed when melted snow mixes with rain. Sleet 7. The term for the lifting of air as it converges on areas of low pressure, contributing to cyclonic precipitation. Convergence 8. Storms generally move from west to east and have both cold and warm air associated with them. Cyclonic storm 9. A tropical storms that develop over oceans with surface temperatures exceeding 29°C ~~~ 84°F. Hurricanes and typhoons 10. It is a common type of precipitation associated with dynamic or adiabatic lifting of air. Rain