Hydrologic
Cycle
Cycle
Define "percolation" and explain its role in converting surface water to groundwater
Percolation: the downward movement of water through soil/rock to become groundwater; it moves surface water into aquifers.
What property of water is responsible for capillary movement in xylem and the movement from roots to leaves? Name the property and give one sentence explaining the mechanism.
High surface tension (cohesion/adhesion): allows capillary action up xylem.
Define the difference between lotic and lentic systems in one sentence each.
Lotic = flowing water (rivers/streams); Lentic = standing water (lakes/ponds).
Name the littoral, limnetic, profundal, and benthic zones and give the primary ecological characteristic of each.
Littoral: shoreline with rooted plants; Limnetic: open, sunlit surface water; Profundal: deep, low-light colder zone; Benthic: bottom sediments and organisms.
Predict the effect of filling a wetland for a parking lot on local runoff and briefly explain why
Increased runoff — impervious surfaces reduce infiltration, increasing volume and rate of runoff and downstream flooding.
Calculate the percent of Earth's water that is freshwater and then the percent of that freshwater stored in glaciers and ice packs (use the values given in the review).
Earth's water freshwater = 3%; freshwater in glaciers/ice packs = 75%
Explain why ice floats and why this property protects aquatic ecosystems in winter.
Ice is less dense than liquid water due to hydrogen-bonded crystal lattice; it insulates liquid below and prevents whole-waterbody freezing.
Distinguish perennial, intermittent, and ephemeral streams with definitions and typical flow-duration examples.
Perennial: flows year-round; Intermittent: dries for weeks/months; Ephemeral: flows only after rainfall.
Define oligotrophic, mesotrophic, eutrophic, and hypereutrophic lakes and describe one ecological consequence of eutrophication.
Oligotrophic: clear, low nutrients; Mesotrophic: moderate nutrients; Eutrophic: high nutrients, algal growth; Hypereutrophic: extreme nutrient enrichment → frequent harmful algal blooms, low DO.
State the only large naturally formed lake in Texas and explain why most large Texas lakes are manmade.
Caddo Lake; others formed by dams (manmade reservoirs).
Describe how transpiration links the biosphere and atmosphere and give one example of its ecological significance
Transpiration: plants release water vapor through stomata; links biosphere to atmosphere, contributes to local humidity and precipitation recycling.
Compare and contrast infiltration and percolation — include where each occurs and how soil texture affects both
Infiltration: water entering soil surface; percolation: deeper movement through soil into groundwater; sandy soils increase both, clay reduces them.
Explain what "stream order" means and identify how a 3rd-order stream is formed from lower-order tributaries.
Stream order: first-order = headwater with no tributaries; when two first-order join → second-order; two second-order → third-order.
Explain lake succession (how a lake becomes a marsh/swamp) and identify at least two processes that accelerate succession.
Succession: sediment accumulation and plant colonization convert open water to marsh then terrestrial habitat; accelerated by sediment influx, nutrient enrichment.
Analyze how urban development changes flood frequency and severity; include at least two hydrologic mechanisms.
Urbanization increases impervious area, reduces infiltration, increases peak discharge and faster hydrograph rising limb; stormwater systems concentrate flows.
Explain the processes and energy transfers involved when water evaporates from a lake surface and later precipitates as rain
Evaporation: solar energy breaks hydrogen bonds, vapor rises; condensation releases latent heat and forms clouds; precipitation returns water to surface
Define surface tension and describe two ecological consequences of high surface tension at the air–water interface.
Surface tension arises from hydrogen bonding; affects insect locomotion on water, formation of droplets, gas exchange across surface film.
Describe four physical and chemical characteristics typical of lotic systems and explain how they influence aquatic organisms' adaptations.
Flowing water, more oxygen (turbulence), stable temperature in some reaches, variable substrate; organisms adapted for attachment, streamlined bodies, or high aerobic capacity.
Differentiate between swamps, marshes, bogs, and fens in terms of vegetation, hydrology, and nutrient status.
Swamps: tree-dominated, mineral-rich or organic soils; Marshes: herbaceous plants, often nutrient-rich; Bogs: acidic, peat-accumulating, low nutrients, carnivorous plants; Fens: peatlands fed by groundwater, less acidic, more nutrient-rich than bogs.
Evaluate ecological consequences of converting a riparian buffer to developed land for stream health and biodiversity
Loss of riparian buffer increases erosion, raises water temperature, increases sediment and pollutant loads, and reduces habitat complexity for riparian and aquatic species.
Construct a brief, evidence-based explanation of how changes in precipitation patterns (e.g., increased heavy rainfall events) could alter groundwater recharge rates and surface-water availability.
More intense storms can increase surface runoff (less recharge) but between-storm droughts may reduce continuous recharge; infiltration/percolation depend on soil saturation and land cover.
Given rising temperatures, analyze how increased evaporation rates would affect lake stratification and dissolved oxygen profiles over a season.
Increased evaporation strengthens thermal stratification, can lower hypolimnetic oxygen, leading to longer anoxic periods.
Using the concept of a drainage basin, analyze how land-use change upstream (e.g., increased impervious surface) can change downstream sediment load and flood frequency.
Impervious surfaces increase runoff velocity and volume, carry more sediment and pollutants, reduce infiltration and groundwater recharge, increasing downstream sedimentation and flashier floods.
Propose a management strategy to restore a eutrophic lake and justify how it would reduce nutrient loading and improve ecosystem health.
Examples: reduce external nutrient inputs (agricultural runoff controls), aeration or hypolimnetic oxygenation, restore riparian buffers and wetlands to trap nutrients; monitor and adaptive management.
Design a short mitigation plan (3–4 actions) a city could implement to reduce flood risk and protect aquatic ecosystems while accommodating new development; justify each action with expected hydrologic benefits.
Example actions: preserve/restore riparian buffers and wetlands (increase infiltration, trap sediment), implement green infrastructure (bioswales, permeable pavements to reduce runoff), limit development in floodplains (reduce exposure), and retrofit stormwater retention basins (attenuate peak flows). Each reduces runoff peaks, promotes recharge, and filters pollutants.