Week 5 Crux Questions Feedback

General comments:

Attempt to use the accounting approach - observe, report, decide - on issues of water resource use. It is not necessary to get a right answer to the issue.

Water resources can be categorized by the processes that renew them: reservoirs from streams and rivers, ground water from recharge, snowpack from snowfall, etc. These all have characteristic strengths and weaknesses.

Apply this approach to the freshwater sources in your local area.

How would this information help make a decision about water sources in your region?

Expected points to address:

• list of water resources identified by the source and recharge
• what decision you might make based on this information
• collect information for making a decision (using the observe/report/decide approach)
• use to decide about storage needed
• examples:
  • using Bull Run vs. the pumps
  • covering the reservoirs in Portland
  • desalinzation as a choice for water in other areas

My comments to students:

+ snowfall has different outcomes than rain

-You need to address how accounting helps makes decisions

I would have liked you to be more explicit about the decisions that could be made under low rain years, and how this accounting approach would help. For example, when there is low rain, need to switch to well water.

Example of a really good answer:

Environmental accounting is the process of creating an organized system that simplifies a complex set of information in order to help make decisions. Categorizing water resources by the process that renews them helps locations understand if they can rely mostly on natural sources of water or if a recycling process would be required in order to maintain an adequate supply of water.

Portland has two major sources of fresh drinking water, which are renewed by natural processes. The Bull Run Watershed and Groundwater Aquifers. A watershed is a large body of water that is made of rain and snow run off. The Bull Run Watershed is Portland's largest source of fresh drinking water. The Groundwater Aquifers extract water from underground sources and are used as a backup source. The Aquifers are renewed by groundwater recharge.

The Watershed relies on snow, rain and runoff sources, while the Aquifers rely on groundwater recharge, understanding the different processes that replenish each source, helps predict how much each source needed to be relied on. If there were little snow and precipitation during a certain year, it might be necessary to use more water from the Aquifers because there would be less available from the Bull Run.

Understanding the natural sources that replenish a water supply would help in preparing and making future decisions. Luckily, in Portland we have an abundance of water and don't need to rely on recycling it. Instead, we use the Aquifers as a natural backup source of water in the case that the Bull Run can't supply the needed amount.

Q2. The concept of "embedded" water accounts for all of the water it takes to make a product including irrigation and processing. However, the amount of water to grow crops varies depending on the crop and climate. Discuss this in terms of using this type of accounting to save water in agriculture.

Expected points to address:

• low water efficiency of some crops leads to high embedded water
• water accounting, such as LCA, would identify all the water needed

My comments to students:

What information do you need to identify the choices or make decisions?

that's the guts of the answer, but what is the accouning approach that supports this decision?

that's the key question that this approaches illuminates - Do those other areas allow for more renewable water so that the overall embedded water is lessened?