Bio 346 - Freshwater Eco. (Chpt 29) --> Reservoirs Flashcards
What are 3 things reservoirs are primarily used for?
- Irrigation
- Water supply
- Fish farming
How are reservoirs typically constructed?
Constructed by damming rivers in regions where evaporation approaches or exceeds precipitation with the water typically derived from local rivers during rainy periods
What are large volumed reservoirs primarily used for?
Hydroelectric power generation
- Constructed where precipitation can be low or high to have river discharge
What has major ramifications on reservoirs for river discharge and its timing for sediment and nutrient retention behind dams?
Water retention
What are 3 things that happens to reservoirs at lower latitudes?
- Longer growing season
- Longer stratification period
- Higher water temp
- Lack of ice cover
- Receives a much greater put of inorganic matter from their well-vegetated catchments than dimicdic lakes
Epilimnion
The upper layer of water in a stratified lake
Thermocline
A steep temp gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temps
Hypolimnion
The lower layer of water in a stratified lake
- Typically cooler than the water above
Lacustrine (define)
In the deepest region downstream from the transition zone and where strictly limnteic processes dominate
Riverine Zone (define)
An island or coastal area comprising both land and water, characterized by limited land lines of communication with extensive water surface and/or inland waterways that provide natural routes for surface transportation and communications
Transition zone (define)
Area between 2 states (land and water)
What does increase in erosion lead to? (5 things)
- Degradation of the original river channel
- Effects sediment characteristics
- Lowers the groundwater table
- Impacts the feeding and spawning habitats of fishes
- Impacts the biota of the rivers in general
Whats happens when you trap sediment and their absorbed nutrients behind dams?
It removes the rivers role as a fertilizing agent to previously undisturbed and seasonally flooded wetlands, crop-growing areas downstream and the receiving estuaries
- Dams act as barriers
What kind of sediment is in high flowing waters?
Course sediment
What kind of sediment is in low flowing waters?
Fine sediment
What do flood control dams do?
Reduce seasonal variations in discharge
What are 6 factors both artificial and natural lakes lie along?
- Gradients of climate
- Geology
- Morphometry
- Flushing
- Chemistry
- Biology
What are the 3 types of reservoirs?
- Mainstream reservoirs
- Tributary storage reservoirs
- Mainstream storage reservoirs
Mainstream reservoirs (4 things)
- Most river like (WRT = days–>weeks)
- Constructed to generate electricity
- Experience no temp stratification
- Experience no seasonal lowering of the water
Tributary storage reservoirs (4 things)
- Longest WRT (month–> years)
- Greatest possibility of temp stratification
- Built on small rivers
- Usually built for flood control and irrigation
Mainstream storage reservoirs (2 things)
- Intermediate WRT (usually a few months)
- Its more lotic during high runoff periods and switches to more lentic at other times
When does washout of phytoplankton commence?
At lower WRT in turbid, deeply mixed or cold reservoirs where conditions for photosynthesis are much less favourable than in shallow systems of low turbidity at summer temps
Larger organisms have what kind of growing rate and doubling time?
- Slower
- Longer
Riverine Zone (7 things)
- Narrow
- High flow and rapid water flushing
- High turbidity - High suspended spoils
- Low light
- limits planktonic pp, but high benthic pp - Relatively high nutrients
- Growth rate is less than flushing rate
- Coarse sediment
