For Volunteers

Thank you for volunteering! This project is only possible because of the time, effort, and contribution of people like you.

This page contains information—including instructions and helpful answers to common questions—that will hopefully assist you throughout the duration of the sampling season. If you think of something to include that would be helpful, but isn't here, please let us know and we'll add it: beachproject@stanford.edu

Thanks again!

Sampling Protocol Information

  • Coastal rivers/creeks are often sources of pollution to the surf zone, so we're interested in understanding how these fresh water flows mix and move in the surf zone.
  • When you receive your sampling kit, it will contain detailed instructions about when, where, and how to sample.
  • Each week, volunteers will:
    1. Measure water salinity and color at 5 locations on the beach near the river/creek mouth and record data on a data sheet.
    2. Collect one water sample and deposit it at a nearby drop-off location (where we will pick it up for additional measurements in the lab).
    3. Sampling will take about 30-60min per week, but will get faster as you become more familiar with the process.
  • See below for Frequently Asked Questions... and answers!

Water Sampling Demonstration Video

6 Simple Steps!

Frequently Asked Questions

If your question (or answer!) isn't here, email us beachproject@stanford.edu!

FAQs about Water Sampling

1. Conditions were too rough to sample

"What should I do if the weather or surf were too rough and I decided not to collect samples?"

If you have to miss a day of sampling due to bad weather (or other conditions at the beach), that's okay—safety first! Please still submit a data sheet for that day (include it with your next set of samples) so that we know that you skipped and why. If you are able to sample on two different days in the following week to make up for it, that's great, but not required."

2. Sand in your water samples:

"I cannot get a sand-free water sample under the current conditions at the beach. What should I do?"

Do your best avoid sand in your sample. The reason to try to avoid sand is so that you are seeing the color of the water against the white bottom of the bottle, not the brown color of the sand. With strong waves or turbulence, however, it can be very difficult to avoid sand, so just do your best to determine the color.

Sometimes, it may be impossible to get a “clear” water sample. If the water has a lot of fine particles in it, it may appear brown and fairly opaque, even if there is no sand in your sample. That is OK. Just match it to the closest color on your color comparator.

3. Salinity measurements and the white dropper bottle:

"How and why are we measuring the salinity of the water in the white dropper bottle (that is, the 'calibration solution')?"

HOW: Each week, place three DROPS of calibration solution on the lens of your refractometer, and measure the salinity in the same way you do for all of your samples. If you use 3 drops per week, there should be more than enough calibration solution to last 13 weeks. But if you run out, please let me know.

WHY: We are measuring the calibration solution each week because the refractometer's accuracy can change from week to week. The true salinity of the calibration solution is 34. However, you may measure it to be 34 some weeks, and 31 or 28 or 38 etc. other weeks -- depending on temperature and the alignment of the refractometer's prism, which can get jostled.

In this way, we can adjust all your salinity measurements relative to that reference level. This is analogous to making sure the weight scale at the grocery store reads "0" before you try to weigh your produce.

4. Recording your height:

"Why do you want to know my height?"

We are measuring the distances between sample locations by asking you to take X number of normal walking steps. Each person's step length is different, and it turns out that you can estimate your step length if you know your height. Step lengths are in general approximately equal to 0.4 times a person's height.

5. What to do if a mistake happens:

"I realize I made a mistake in my measurements, especially my first time sampling. What should I do?"

That's OK! Just do your best, and let us know if you think you made a mistake, or have questions about why or how to do something.

6. There's a sandbar now and the beach looks totally different.

"A sandbar has formed at the mouth of San Lorenzo River. Should I walk out onto the sandbar and sample from there?"

No, there is no need to walk out to the sandbar. Please just sample from the shoreline as usual. If you have time to take a picture of the conditions, however, we would love to have those so that we can document the changing morphology of the river mouth.

FAQs about Participation

  1. "I can't make it every week, should I still participate?" Yes, you should still participate! The more weeks you can make it, the better, but we totally understand if something comes up.
  2. "I have to miss a week: should I ask a friend to collect the samples for me?" We'd prefer that all the samples are collected by the same person (the person that signed up). In other words, it's better to miss a week than to have someone else collect the samples.
  3. "My partner/spouse/friend/buddy/etc and I want to sign up to do the sampling together: is this okay?" Ideally, you would both sign up and each collect your own independent samples: that would mean more data and scientists love data! But if that seems excessive to you, no worries, we just ask that for consistency's sake, one of you is designated as the "primary sampler" who will be responsible for the data sheets and other project-related communication.