Question 1: What is the meaning of river systems being hierarchical?
Smaller units are repeating elements nested in larger units—larger units, and any impacts on them, can strongly affect the smaller units, but not so much the other way around. The systems, from largest to smallest are:
Question 2: What is Lane's law?
Stream Channels are in equilibrium when sediment loading equals (or is close to) stream power:
sediment loading = sediment discharge (Qs) * average (50th percentile) sediment particle size (d50)
stream power = stream discharge (Q) * stream slope (S)
Question 3: What is "re-meandering" of streams and what is the effect on slope?
A straightened-out stream may naturally meander again on its own, or else it may be artificially restored to its former meanders. Either way, it lowers the slope and thus decreases the stream power, which in turn causes sediment deposition, or aggradation.
Question 4: Give a broad overview of the food webs and energy sources in streams.
Stream energy sources:
Autocthonous-originates within the stream channel, i.e. algae, plankton, water plants, decomposed stream biota
Allocthonous-enters the stream from outside; for instance, leaves, invertebrates, and other things falling into streams
Primary producers: algae (diatoms, green or blue-green), and phytoplankton, periphyton
Microbes settle on leaf litter and other sources, and some invertebrates shred it into coarse particulate organic matter, which is later converted into fine particulate organic matter. In the meantime, dissolved organic matter may leach out of sources.
Invertebrates: grazers/scrapers-feed on periphyton from stones and other surfaces; shredders-feed on leaves and other coarse particulate organic matter; collectors/gatherers-feed on fine and dissolved organic matter from water column and stream bed; predators-feed on other macroinvertebrates
Fish will also be included as a trophic level, feeding on zooplankton and invertebrates
a) Where do Rivers get their power?
A: Discharge amount and slope
b) What is meant by a "Sediment Hungry River"?
A: When a river receives more water supply into its stream, it increases the power of the flow, causing it to dig into the sediment and pick it up.