Exam 2 Flashcards
API
aniticipated precipitation index
Runoff ratio
- tells us how much of the water that came from precipitation was converted into runoff
- specific discharge divided by precipitation
- can only have a high RR after a storm (greater that 1)
- typical RR is 20-30%
Antecedent moisture
- relationship between precip and stream flow
- is not measured by moisture
How is antecedent moisture measured
- measured by stream flow in the US (antecedent flow conditions)
- measured by precipitation–antecedent precip–
What is SRP
- soluble reactive phosphate
- the stuff that goes through the filiter
What is PP
- particulate phosphate
- the stuff that doesn’t go through the filter and has organic matter
Zone 3 buffer
- runoff control zone
- typically grasses
- intersects any type of overland flow entering the buffer
Zone 2 buffer
- managed forest
- 10 to 20 meters wide
Zone 1 Buffer
- undisturbed forest
- 5 to 10 meters wide
- grows good root systems to stabilize banks
- can provide organic matter and habitat to streams by falling in
Denitrification
- needs OM and nitrate, anoxic
- minneralization (occurs best in anerobic env but can work in anoxic ones)
- as OM is being oxidized (e donor), NH4+ is being created
Nitrification
- strictly aerobic (NH4+—>nitrate)
- Anoxic wetlands have high NH4+
Methylmercury in wetlands (NeHg)
- need to be in a place with atm deposition of Hg
- Hg prefers OM, wet, anoxic env
- makes wetlands a perfect spot for Hg deposition
- anoxic wetland creates sulfate reducers and produces NeHg with Hg
- NeHg is produced in high amounts in NE US
PRB
- permeable reactive barriers (bioreactors)
- remove nitrate
- needs sand/gravel, OM, water (anerobic env)
- OM helps with denitrification
- sand/gravel allows water to flow through system and OM, allowing denitrification to occur
- woods chips commonly used for N removal
what happens when ag is not tilled over time
- natural porosity comes back and allows soil to not be overly compact
- roots and worms provide OM when they die
- there is less overland flow and PP when natural porosity comes back
- reconnects the soil profile to water
- allows P to move through the soil profile, giving more SRP in subsurface flow (can lead to algal blooms)
Conventional tillage
-break down of the top layer of soil profile to maintain soil porosity
Systematic pesticide
- water that is absorbed by plants
- pesticide resides in plant tissue
Non-systematic pesticide
-on outside of plant`
TP
-total phosphorous
=SRP + PP
-SRP is generally less than 50% of TP
When are P exports the greatest
-during high flow periods and in the spring due to snowmelt
Reduction potential
-a measure of the tendency of a chemical species to acquire electrons and be reduced
Oxidation vs reduction
- oxidation is loss of electron
- reduction is gain of electron
most favorable conditions for minneralization and nitrification
-70% RH, 27 C, aerobic conditions
TN
- total nitrogen
- TON+DIN
LID
-low impact development structures
Examples of LIDs
- Green roofs
- Bioretention cells
- permeable pavement
Types of treatment wetlands
- free surface water (small amount of substrate, most versitile and has best benefit)
- Horizontal subsurface flow (enhances contact time bt water and substrate)
- vertical subsurface flow (pesticides degrade very well, and maintains aerobic conditions)
Riparian zones
- designed to trap sediment, pesticides, and P in overland flow
- up to 90% reduction in sediment load to the stream
- designed to trap nitrate in subsurface flow
2 variables for riparian zone placement
- contributing area to the point (amount of water)
- slope of area (steep slope has a lot of water accumulation vs a flat slope)
What can riparian zones provide
- timber
- water quality benefits
- habitat for wildlife
- minimize bank erosion
Principles of watershed management
- 1st principle: Source control (limit the amount of contaminants put into the landscape)
- 2nd principle: Contaminant removal/interception
Questions to ask to find a solution
- What is the issue?
- what are the tools at your disposal?
- what are the expectations and how much money do you have?
- where to place EEPs and BMPs in the landscape and how to combine them to achieve multiple goals
three variables looked at with respect to water quantity when investigating the impact of land use or cover on streams
- peak flow
- base flow
- erosion
3 hydrological variables looked at with respect to water quality when investigating the impact of land use or cover on streams
-sediment
-organic carbon
-
compared to row crops, cow-calf operations impact water qualit in the following ways
-cow-calf operations lead to higher TP concentrations and NH4+ concentrations
