MEFW Session 13

Introduction

On February 29 2008 we drove down to South Boulder Creek and did some field investigation. We also got really wet.

What To Bring

• Scientists
• Rubber boots and warm clothing plus a change of socks
• Phone, wallet, watch, snack, water bottles with drinking water
• Garmin GPS receiver
• Meter stick
• Measuring tape (30 feet is good)
• Camera in camera bag
• Ziplock baggies
• OneWire iButton thermochron temperature data loggers (pre-programmed, pre-waterproofed)
• Soil tins, tape, sharpie
• Empty water bottles for samples
• Trash bags
• Rubber ducky
• VO-meter with temperature probe

Goals

• Clean up any trash we find
• Take many many photographs (can assemble using Photosynth)
• Acquire GPS coordinates of key sites (with photos)
• Measurements at multiple points
  • Total stream width
  • Active channel width
  • Channel depth
  • Flow speed
  • Temperature / location table using temp probe
• Obtain soil and water samples
• Write down local biota
• Emplace temperature sensors in air
• Emplace more temperature sensors in water
• Make observations including questions in notebook

What we accomplished

• We noticed that there were some small fish swimming in the pool by the culvert under S.Boulder Road.
• Acquired: One water sample from the main part of the Creek. We'll measure the electrical conductivity of this water later.
• Acquired: One flow estimate: 30 feet travel in 85 seconds with depth 6 inches and width about 18 feet estimate for the active channel. At that point the creek was about 24 feet wide where the extra width was not noticeably moving. We'll use these numbers to calculate a flow or discharge rate.
• Temperature measurements using a digital thermometer:
  • Mid-stream: 34.3 degrees
  • Side-stream: 37.5 degrees (quite a difference!)
  • Side-stream, rocky: 36.7 degrees
  • waterfall: 38.2 degrees (quite warm!)
  • We'll compare these to what the thermochron data looks like.
• We left three water-proofed pairs of thermochron sensors in the creek, to be recovered in two weeks. They will take temperature readings every 10 minutes. One pair is upstream from a little waterfall, two are downstream.
• We left three individual thermochrons above the creek bank, i.e. exposed to air (the parents did this) to get air temp records.
• We noticed trash and cleaned some of it up.
• We noticed that there is a lot of greenish-brown algae in the creek, mostly stuck to rocks.
• We noticed that the water is pretty darn cold especially when you sit down in it.
• We took a lot of photographs (and they make a very nice Photosynth collection, whatever that is...)
• Location stream center by our gear drop: 39 deg 59.059 min N 105 deg 13.269 min W, {.060, .268} was 2nd measurement
• Location at waterfall 39 deg 59.081 min 105 deg 13.259 min W

What has happened since

We noticed that Saturday March 1 was very warm spring weather, up in the 60s (Fahrenheit) during the day. The next morning the wind started up very strong, the temperature dropped, and about three inches of snow fell in the Boulder area. March 2 the temperature was around freezing during the day.

On Sunday March 9 RF went down to the study site and verified that 5 of the 9 thermochrons were ok. The other four: We'll see on the morning of March 14 when it's time to collect.

Downstream of our original measurement we found a faster flow and measured: 6" depth, 7 feet wide, 27 feet in reach, the floating probe (rubber ducky) required 28 seconds to traverse this distance.