Exam 2 Flashcards
What is riparian
- of a belonging to the bank of a river
- riparian areas are the lands adjacent to rivers and streams
Some attributes of Riparian zones
- variable environments in space and time
- collection points for resources
- High species diversity
- Biotic communities adapted to disturbance
Dynamic hydrology creates_____
complex vegetation
4 dimensions of riparian zones
- longitudinal: links upstream to downstream
- lateral: links upslope areas with the channel corridor
- vertical: integrates the critical zone (atm, soil, groundwater)
- temporal: tracks ecosystem dynamics overtime
5 primary vascular plant zones on floodplains
- permanent water with submerged vegetation
- permanent flooded areas with rooted or floating emergent vegetation
- seasonally flooded areas with emergent vegetation
- areas that are occasionally flooded
- areas that are not flooded, but whose water table is influenced by the flood regime
Riparian zones have high spatial variation in
- texture
- organic matter
- nutrient content
- moisture capacity
- redox potential
- micro-fauna
Abandoned channels support:
riparian forests
Adaptions of riparian plants
- ability to grow on unstable substrates
- establish on floodplain mineral soils
- grow in saturated or flooded soils
- develop seeds or pant fragments well suited for dispersal/survival in riverine areas
Intermediate disterbance hypothesis
-predicts that biotic diversity will be greatest in communities subjected to intermediate levels of disturbance
vegetative diversity
- plant diversity increases downstream in longitudinal patterns (greater topography and habitat diversity)
- -peaks at intermediate levels of disturbance and moisture availability
River continuum concept
- invertebrate diversity is greatest in middle-order reaches
- most productivity is derived from upstream
- downstream reaches depend on the leakiness of upstream
Flood pulse concept
- within reaches with extensive floodplains, ecosystem productivity is controlled by lateral interactions of river and floodplain
- different from RCC which predicts productivity is determined by longitudinal linkages
Ecosystem engineers
- beaver
- conversion of forest to wetland
- increase in landscape diversity
- creates a beneficial habitat for waterfowl, amphibians, and weland plants
Riparian forest management
- old growth riparian forests are more structurally complex than young ones
- riparian buffers should target old growth riparian corridors
- by protecting large trees, this will promote stand development to old growth
why are riparian buffers prescribed
-to stabilize banks, filter pollutants, and provide favorable micro-habitats
Main functions of dams
- STORAGE OF WATER for water supply, power generation, to capture flood peaks
- TO RAISE THE WATER LEVEL BEHIND THE DAM: to increase hydraulic head/water pressure, and to divert into irrigation canals and water supply intakes
Earliest remnants of dams or water diversions
- ancient mesopotamia
- 8000 BP
Earthfill dams
- made of rock and soil
- oldest, cheapest build
- accounts for 63% of dams
- worlds largest dam in Pakistan is one of these
Gravity dams
- mostly concrete
- built across narrow valleys with firm bedrock
- accounts for 4% of large dams
Arch dams
- arches point upstream and distribute the hydrostatic pressure
- economical use of building material
Modern purposes of dams
- HYDROPOWER: provides almost 20% of worlds electricity
- WATER SUPPLY: for agriculture, irrigation, households
- FLOOD CONTROL
- NAVIGATION
- LEISURE ACTIVITES
When were the glory years of dam construction in the US
-1930s-1960s
FERC
- Federal Emergency Regulatory Commission
- licenses and inspects private, municipal, and state hydroelectric powers
- Established by the Federal Water Power Act of 1920
Dam facts
- 90,580 damas in the US
- Average age is 56 years
- > $45 billion required to repair high hazard potential dams
Large dams
> 15 m high
>57,000 large dams in the world
Top dam building countries
-china, US, India, Japan
Giant dams
-over 300 in the world
>150m tall
-> 15 million cubic meters of volume
-Reservoir storage > 25 cubic km
Negative impacts of dams
- forces people to move from homes and farms
- harms livelihoods of communities who rely on natural fisheries
- habitat destruction, disrupts fish and wildlife migration
- expensive
- sediment can build up, decreasing effectivness
hydrologic response to dams
- fewer high magnitude floods
- less seasonal variability with flow stabilization
- decreased discharge due to irrigation diversions
geomorphic response to dams
- less bed mobilization
- reduced sediment supply
- riparian vegetation loss which leads to more bank erosion
- decreased floodplain inundation
Serial Discontinuity Concept
-dams result in upstream-downstream shifts in biotic and abiotic patterns
Alluvial river response to dam construction (trinity river)
- eliminated snowmelt peak and recession
- lack of scouring floods allows trees to establish in the channel
- floodplains were isolated and abandoned
- reduces habitat quantity and quality for salmonids, vegetation, etc
Potential effects of dam removal
- unbalancing fine and coarse sediments
- filling of downstream impoundments
- decreased streambed particle size
- will be substantial short term changes in many ecological variables bc this is a disturbance
Systems of water rights in the US
- riparian rights
- Appropriative rights
- regulated riparian rights
What is the most common water right system in the US and what is NY
- US: Appropriation doctrine (west)
- NY: regulated riparian
Riparian rights
- eastern states
- based on proximity to water
- use must be reasonable and must not interfere with resonable use by others
- right granted is to use, not to own, water
Representative riparian rights
-landowners with land that lie within the water source have access/rights to the water
Appropriative rights
- based on seniority, (first come first serve)
- water appropriated for beneficial use and absolute measurement
water as a public resource
-instream uses support ecosystem health and env quality
Water as a market commodity
- home uses
- industry, agriculture
What is the purpose of water policy
-to restore and maintain the chemical, physical, and biological integrity of the nations waters
What is water pollution
-man made, or man induced alteration of the chemical, physical, biological, and radiological integrity of the water
Point source
- any discernible, confined and discrete conveyance
- pipe, ditch, channel, tunnel, conduit….
Nonpoint source
- pollution induced by natural processes (rain, runoff, seepage)
- pollution not traceable to any discreet or identifiable facility
Jurisdictional wetland
- 14 continuous days of saturated conditions at or near the surface in the growing season
- hydric soils on the NRCS list, must have characteristics of hydrology in the soil
Waters of the US
- waters which are currently/past used in interstate/foreign commerce
- all interstate waters and wetlands
- territorial seas
- impoundments of waters in 1 and 3
What are not waters of the US
- waste treatment systems
- prior converted cropland
- ditches with ephemeral/intermittent flow that are not a relocated tributary
What is vegetation management
- human caused changes in vegetation cover
- often implemented as cuttiing trees and maintaining a desired physical forest structure
Issues with vegetation manipulation
- deforestation effects on water quality
- effects of urbanization on water yield and quality
Changes in catchment runoff from timber cutting
- increased storm runoff in harvested catchment
- changes in peak flow timing
Changes in runoff from forest cutting
- increased runoff
- flashier system, flood peaks arrive sooner
- increased hillside erosion
Why do forests function as natural flood protection
- trap water during heavy rainfall
- release water slowly into streams
- maintains stream flows during dry periods
Removing 10% of raining native forest would
- increase the frequency of floods by 4-28%
- lengthen flood duration by 4-8%
What should be used for reforestation
-native species
Ecosystem value of floodplains
sediment and nutrient reduction
- groundwater recharge
- flood risk reduction
- provide about 25% of all non-marine ecosystem service benefits
