Major topics discussed during this second part of the course include the following:

Lecture 12:

Groundwater

geologic context (glacial-interglacial cycles) for recently-deposited aquifers

Groundwater flow: Hydraulic head, pressure head, elevation head

What is the origin and structural nature of the Franciscan Complex (i.e. the “bedrock”) found beneath the thin mantle of sediments and sedimentary rock? Is the Franciscan Complex a predictable aquifer?

Water table

Influences on the shape of the water table surface

Potentiometric surface

distinction between water table and potentiometric surface

Aquifers

Unconfined and confined aquifers- what are the advantages and disadvantages to each with respect to water quantity, quality?

Lecture 13

Canceled.

Lecture 14

Copeland Creek field trip

Know how to select a site for accurate flow measurement

Know how to create a cross-sectional profile of the stream channel and to select a reasonable interval that will enable you to estimate accurately the streamflow.

Lecture 15

Soil components

What are the four main components of a soil

How does soil differ from sediment?

Physical weathering

Just know that abrasion in all its forms leads to greater surface area of rock, which then can be attacked by chemical weathering agents. Physical weathering will preferentially remove those rock components that have inherent weaknesses. The main component that is not affected significantly by physical weathering is quartz.

Chemical Weathering

We discussed the different chemical weathering processes that decompose original rock materials and replace them with materials that are more stable in the surface environment.

Physical factors affecting soil development

Note the environmental controls on soil development and soil loss, including temperature, water availability, slope, vegetation, time and original rock composition.

Soil Profiles

What are the main soil horizons (O,A,E,B,C) and why does each form?

Please review the 12 soils orders and have a sense of how each one forms (i.e. which of the physical factors listed directly above are key to a particular soil order).

Lecture 16

Soil texture

Know the importance of grain size on soil moisture and field capacity

Soil structure (peds)

What are peds and how does their structure affect water movement through the zone of soil moisture?

Soil moisture terms

(the equations)- know that you can use these terms to calculate specific parts of the soil moisture equation, and you can use your results to approximate those parts of the soil moisture balance that are difficult measure (similar to the inflow-outflow +/- changes in storage approach)

Field Capacity

Review this term.

Measurements (tensiometer)

How one goes about measuring moisture that is available to plants.

Lecture 18

Hydrologic cycle through paleoclimate

Note that the recent geologic past had much hydrology that was dissimilar to what we find today. These differences included more storage of freshwater in ice form, less seawater, more sea ice, and temperature changes that led to different climate and weather paths, which ultimately led to different availabilities of water than there are today. In short, the hydrology of today cannot be truly appreciated (and understood) until it is placed into historical context on a geologic time scale. The hydrologic cycle is not in balance. It is a dynamic system that is responding to changes in environment. What we have today is not what we had yesterday, and what we have tomorrow should be anticipated to be different than what we have today.

Thermohaline circulation

Note that the equatorial oceans are stratified, whereas the polar oceans are not stratified.

Note that there are several pools of cold deep water that are fed from different surface sources (e.g. North Atlantic Deep Water, Antarctic Bottom Water, Antarctic intermediate water)

Next to atmospheric transport this is the primary way that heat is moved from equator to poles. Since water vapor is controlled largely by heat, changes in the thermohaline circulation patterns will lead to changes in hydrology.

Sea ice

Note that sea ice is the main driver of thermohaline circulation. Know how sea ice formation drives thermohaline circulation. Consider what will happen if the northern Atlantic sea ice doesn’t form. How might that disrupt the northern hemisphere’s hydrology?

Stable isotope systems (in water)

Recall that there are stable (non-radioactive) isotopes of oxygen and hydrogen that can be used to interpret the transport history of water. The general way that this is done is by recognizing that it takes less energy to move water molecules that contain lighter isotopes of oxygen or hydrogen. Another way of saying this is that those water molecules have a higher vapor pressure than do heaver molecules, and so they will move into and stay in the vapor phase more readily than will the heavy ones. This means that you can measure the isotopic abundances of hydrogen or oxygen in water to determine how much of the original water vapor survived to the point where is precipitated into the water that you are measuring. (as an aside it turns out that biology does the same thing with carbon, oxygen, nitrogen and hydrogen; all the lighter isotopes of these elements are found preferentially in biology).

Lecture 19

Mulholland’s Dream: Part 1 of the Cadillac Desert series, which is available from the media library

This video provides very good context for water issues that affect California. Watch this video and consider the ramifications of the actions taken by Mulholland, and what it will mean to untangle those water rights issues in order to restore California’s habitat.

Lecture 20

Drilling a water well

Site selection

Consider how you’d go about choosing a site to drill a water well. Consider geology, contamination, water rights restrictions, finding the best well driller, assessing how much water you’ll need from the well, the location of the well relative to where the water will be used, the effects of drawdown by neighbors.

Drilling methods

We talked about different types of drilling apparatus and the potential benefits and liabilities of each

Components to a water well. We talked about casing, well screens, gravel pack, formation sealer, concrete cap.

Well development

We talked about the methods of well development and why it is necessary to develop a well before permitting it to be used as a water source.

Lecture 21

Saltwater intrusion- Displacement of freshwater by saline water

Complexity caused by the nature of the young coastal aquifers (recall that the continuity of aquifers are disrupted by glacial-interglacial cycles.)

hydraulic head for groundwater and ocean are in competition- the stronger force moves the zone of dispersion away.

Passive vs. active saltwater encroachment

Ghyben-Herzberg principle