# Groundwater

## General Concepts

In no particular order ...

- Porosity vs permeability of sediments and other geologic materials.
- Confined vs. unconfined aquifers.
- Groundwater table.
- Saturated vs unsaturated zone.
- Compaction.
- Springs
- And more of course!

## Handouts and Case Studies

### Principal Aquifers of the United States
From the US Geological Survey.
- [Principal Aquifers of the United States](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/Ebncd70AuZZLrW8ObMsWZIABgnHMjF75S449PzDDyHfTLw?e=YFji5s)
- How does the aquifer composition change in different parts of the country? i.e. for example carbonate vs sedimentary vs fractured rock?

### The Los Osos Coastal Aquifer
A local coastal aquifer that has/is dealing with seawater intrusion and other contaminants from the srface.
- Los Osos [aquifer structure and sedimentary formations](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/EQ4OScmiGWdFthNs5SacFdEBXNTnf4qm_QFP0od6DJvbUQ?e=ufd9oK) and the Los Osos seawater intrusion issue.
- What is the composition of the main aquifer formations? What does the clay do to vertical water motion?

### Darcy's Law and Well Production Rate
- [Darcy's Law and Well Production Rate](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/ETWKNBtz_85BoKwe6vtALeoBigvltse1XdMJ5Gjf4mxJ6g?e=JqoS2v)
- How does the subsurface geology affect a well production rate?

### Additional Resources
- Here are some [Groundwater Thought Questions](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/Ee5PeFUZUstPmvUGKH6h430BwapvQTk4PoyYahAP6k41ZQ?e=BBk90z)
- Aquifer terminology labeling activity: [Example 1](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/Efhjbxid5GdMtuAqOgobGb4B0C1Ap0MB4czF49lz9w_9EA?e=Ym1TbH).
- Interesting reading from the US Geological Survey: [Southwest Principal Aquifers Regional Ground-Water Quality Assessment](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/EcmMt8jbBLVJs5Uko5FBtzQBiKg2bLiM7BJA0VqJMcOXPA?e=FO4S6c)
- Article about [nitrate contamination in the Ogallala Aquifer](http://u.pc.cd/fnRctalK) in the United States midwest.
- [Aquifer terminology labeling activity](https://cpslo-my.sharepoint.com/:b:/g/personal/jjasbins_calpoly_edu/Efhjbxid5GdMtuAqOgobGb4B0C1Ap0MB4czF49lz9w_9EA?e=O66D4k)
- [Porosity and permeability demo](https://cpslo-my.sharepoint.com/:v:/g/personal/jjasbins_calpoly_edu/EbX6aecnophPotRLqooIK94BWgTEKFdFPC0XE_bBJYXeJw?e=QcMfP6) - video. The low permeability clay layer prevents water from moving through it.

## Geology and Hydrogeology
Hydrogeology is the interplay between the relatively shallow subsurface (< 1,000 meters, but often much much less) geologic structure and composition, and the movement and storage of groundwater resources.

It is a critical area of investigation to (1) identify new groundwater resources, and (2) understand how to manage existing resources.

Hydrogeology consulting companies (or similar in governmental agencies) is probably the primary area that our geology students obtain jobs with the bachelor's degree (the other most prominent area is with geotechnical consulting companies).

"Exploration" for groundwater is based on fundamental geological observations at the surface, but also increasingly by using *geophysical* methods to interrogate the subsurface.