CEE 1030 1nd Edition Lecture 17: GroundwaterOutline of Last Lecture I. Hydrolic cycleII. Running waterIII. Divides and drainage networksIV. Vocab termsV. Stream erosion, transport, and depositionOutline of Current Lecture I. GroundwaterII. Infiltration of waterIII. Permeability featuresIV. Groundwater movement and storageV. ReviewVI. Hydraulic gradientVII. Groundwater systemsCurrent LectureI. Groundwatera. Source of drinking water, source of irrigationb. Most of Earth’s freshwater is contained in groundwater and glaciersc. Groundwater is found in pore spaces of soil and sediment and fractures in bedrockd. Groundwater: water that has infiltrated the land’s surfaceII. Infiltration of watera. Soil moisture zone: uppermost layer of the regolith from which plant roots extract waterb. Some water retained as surface film on soil particlesc. Saturation zone: layer of regolith in which all voids in sediment and rock are completely filled with waterd. Groundwater: water in the saturation zonee. Upper limit of saturation zone: water tablef. Aeration zone: all ground above saturation zonei. Some groundwater drawn upward from saturation zone by capillary actionii. Lowermost layer of aeration zone: capillary fringeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.g. Water table depth is irregulari. Water table depth usually a subdued replica of ground’s surface topographyii. Also associated with variations in rainfall and permeabilityh. Groundwater moves slowly, tends to “pile up” between high areas (beneath valleys)III. Permeability featuresa. Aquitard: impermeable layer of rock or sediment that hinders or prevents water movementb. Aquifer: permeable rock or sediment that allows groundwater to move freelyIV. Groundwater movement and storagea. Rate of groundwater movement and storage potential depends on the composition and nature of the regolith and bedrockb. Key factorsi. Porosity: the percentage of total volume of rock or sediment that consistsof pore spacesii. Permeability: the ability of sediment or rock to transmit fluidc. Effects of porosity and permeabilityi. Specific yield: portion of groundwater that drainsii. Specific retention: portion of groundwater retainedd. Groundwater dissolves rocki. Rainwater dissolves CO2 from the air and decaying plants, forming carbonic acidii. Carbonic acid reacts with limestone to form calcium carbonateiii. Acidic groundwater flows through joints in rock, forms cavernsiv. Cavern features1. Speleothem: general term for dripstonea. Stalactites: hanging from ceilingb. Stalagmites: form on floorc. Dripstone: calcite deposited as dripping water evaporates2. Karst topography: landscape shaped by groundwater that dissolves the bedrocka. Sinkholes: surface depression produced in a region where soluble rock has been dissolved and removed by groundwaterV. Reviewa. Most of Earth’s freshwater is contained in: glaciers and groundwaterb. Most of Earth’s water is contained in: oceansc. Rocks with lots of pore spaces between particles have high: porosityd. In order to have reliable access to groundwater, a well must be drilled below the: water tableVI. Hydraulic gradienta. How steep the slope is related to the movement of waterb. Steeper the slope, faster the water flowc. Hydraulic conductivity: how fast groundwater flows through the ground, determined by sediment permeability, fluid viscosityd. Darcy’s Law: discharge rate varies with hydraulic gradient, hydraulic conductivity, and cross-sectional area of aquiferVII. Groundwater systemsa. Water may flow for meters to hundreds of km from recharge to dischargeb. Localized near-surface flow may move in a different direction than deep regional flowc. Spring: a natural outflow of groundwater that occurs where water table intersects land surfacei. Hot springs: water heated by cooling of igneous rockii. Geysers: intermittent hot springs that erupt from the ground with great forced. Wells: most common way to access groundwater, drill hole into the saturation zonei. When water is drawn up through the well, the water table around the well is lowerede. Artesian systemsi. Where groundwater is under pressure, well or spring that pierces aquitard will flow outii. Water towers are artificial artesian