Research Scale
The general rule for research is to keep the scale large enough with respect to what?
Big enough so + or - 1 controlling element does not have much effect
What sorts of contaminants appear with the first flush
Nitrogen diffused, sediment, nitrate in interflow/baseflow
in which of the lake/reservoir ecosystem zones are we most likely to find sediment-borne contaminants?
Benthic zone
What is the primary difference between a scientific model and a management model
They have different purposes
Scientific-looks at system as whole
Management- look at any specific inputs
Why are soil health and biotic integrity indices considered “interpretive measures”?
The indices are up to interpretation by experts for what factors are considered important
5 advantages of lab scale studies
More replication , Can be done indoors, More precise measurements, control variables
Continuous sample, settles sediment so can measure, pretty good accuracy, provide runoff volume
Describe what causes overturn of lakes/reservoirs, and when it can normally occur.
Overturn is caused by cool water sitting on top of warm water. Can most commonly occur in spring when ice melts quickly and contributes a cold water layer to the top of the lake, and the other is fall when the air starts to get colder. Overturn happens very quickly, in a matter of minutes or even seconds.
scientific model is defined on what basis
management model is defined on what basis
How well it defines the systems and interactions
You get better answers than without
3 things healthy soil does for us in terms of the hydrologic cycle
Controls infiltration, good water holding capacity, biochemical filter
6 weaknesses of lab-scale studies
size => cost
Weight => cost
sunlight
lack of soil variability
"edge effects"
when sampling a stream for the impact of a factory’s discharge, why would we not want to measure the concentration immediately downstream of the discharge point?
Not representative, not mixed up yet
Describe why flow patterns through lakes/reservoirs can be very hard to predict.
Inlet vs. outlet. Combination of circulation pattern “short circuiting” (straight from inlet to outlet). It can take time for basin to circulate inputs before flowing out
Describe how modeling data collection is an iterative process
Collect large amounts to look at a range of conditions
start with initial data - develop a conceptual model, look at results, do you need to change your model
In the study that looked at a multitude of factors affecting soil health, what 2 specific indicators of soil health were shown to be most important?
Erosion
Soil Organic carbon
Example of problems caused by edge effects
Side sliciking, cracking/fracturing, raindrop impact/displacement outside of plot (not getting measured) , soil bins (Creates gullies along side of plot because cant flow past)
Based on data, how does sediment transport during a storm event relate to the hydrograph?
Some first flush & throughout the whole thing (bc of delay)
Why do reservoirs riparian zones tend to have very poor productivity?
Their soils tend to be poor due to flooding and draining of the reservoir as well as the steepness of the sides along the reservoir. These soils tend to be formed from upland soils and very shallow.
In developing a management model, data are generally used for what
In developing a scientific model, data are generally used for what
Aid in making decisions
Describe a system
We discussed 5 things that should be similar between the current and reference stream in order for a comparison to be meaningful. List 3 of those.
Climate Hydrology Geology (soils)
Describe the two techniques used to collect runoff at bottom of a plot
Collection slot
Collection Triangle - must be kept at 2% slope to prevent sedimentation from settling out and needs to account for rainfall
What is isokinetic sampling?
Velocity in inlet= water velocity
Describe the temperature zones in a typical lake/reservoir.
The epilimnion is the top layer in a vertical water column. It is the warmest of the layers. The surface water tends to mix by wind in the epilimnion and the temperature is relatively even throughout.
The thermocline (or the metalimnion) is the middle layer. There is a temperature gradient as you move through the the layers, usually -1C per layer.
The hypolimnion is the bottom and coldest layer, with very low dissolved oxygen and very little mixing.
how to use a model included 7 steps.
Describe each step
step 1 model selection - Must answer your question, Often designed for another question, does it answer my question
step 2 familiarization with model - Terminology, assumptions, data used to build, does their conceptual model match yours
Step 3 Collect data - Follow instructions (model depends on technique, collect data in the form that it was used, can use calibration) Collect input (drive model) and output (answers)
Step 4 model calibration - require in order to fit to situation, collect some inputs, collect some outputs, Calibrate coefficients
Step 5 Model validation- qualitative -> does it look right? matching the conceptual model. Use independent data for validation
Step 6 Use of results - answer question
Step 7 Humility in results - know that your model does not represent everything everywhere
We mentioned 7 specific measures that tend to change as ecosystem integrity deteriorates. List 4 of those
1) Biomass, 2) abundance, 3) richness, 4) diversity, 5) sensitive species, 6) opportunists and tolerant species