Railroad Creek was cold at the touch of a fingertip. It was very clear and clean. There was no litter in it and you could see the bottom as good as you could see the
trees. At 10:00 AM on the 11th of October, 2000, the air temperature was 11 degrees Celsius. The water temperature was 8 degrees Celsius at 4 inches under
water.

Railroad Creek Water

The surrounding was beautiful and relaxing. There were plenty of trees in Holden and around Railroad Creek. Some trees were young and some were small. Most of
them were green and healthy. Railroad Creek was a spectacular sight. If you ever go up to Holden Village, be sure to visit Railroad Creek. It was a habitat to many
animals and meant much to the people. Remember, please don’t pollute our creeks, rivers, and lakes.

Railroad Creek surroundings

This is how we got our water insects. First we marked off our space, then we set a big net at the end of our spot with two people holding it up so any bug that fell
would be caught. After all this we then put a little water in a bucket and got out the brushes. Finally Mrs. Page (our teacher) stepped into the water, with rubber
boots on, and started to hand us rocks to scrape off over the bucket, so any thing on the rock would fall into the bucket. We needed to make sure that we scraped
the bottom of the rock because insects live on the bottom of rocks. We didn’t scrape all the rocks in the area because there would be a big hole and we would be
there for a long time. When we were done we shook all the bugs on the net into the bucket and walked back to our camp at Holden.

Collecting macroinvertebrates

A couple of people from the sixth grade class and a biologist helped count the insects. At first we tried to just pick them out of the bucket which was not easy. When
we had picked out as many as we could, we took out some of the debris. When most of the debris was picked out, we poured the remaining debris, insects, and
water into two butter dishes.

After we had done that, we picked out more debris and started looking for the insects. When we were positive we had all the insects out of the butter dishes, we
looked on the nets to see if any bugs were still clinging on the net. If we found any, we put them in the butter dish too. Once we were sure we had all the insects in
ice trays, we counted them all.

Our count showed: 36 mayflies (Class—Insecta, Order—Ephemeroptera, Genus—Epeorus)

6 stoneflies (Class--Insecta, Order—Plecoptera, Genus—Hesperoperla)

3 caddisflies (Stone house caddis—Limnephilidae Dicosmoecoes and Stick house caddis—Limnephilidae Onocosmoecus)

1 unidentified fly larvae

Mayfly

Stonefly

These water tests were done in Railroad Creek above the mine by 2 high school counselors. Since we do not know how to convert the drops to ppm, the Dissolved
Oxygen that we submitted, 11.6, was a figure from a data sheet prepared by scientists involved in an environmental study of the area.

Dissolved Oxygen Test: 10 drops of Sodium Thiosulfate Titrant (we just found out we do not know how to change that to ppm) PH: 7 Another test was done in the
water seeping out of the old Holden Copper Mine. Dissolved Oxygen Test: 15 drops of Sodium Thiosulfate. PH: 7

An environmental specialist who was at Holden Village to supervise the reopening of Holden Copper Mine told us that the location we collected insects might still
have seepage from the mine. We were upstream from the mine tailings, but we were straight down the mountain from the mine settling ponds. The water seeping out
of the mine is very high in minerals. Iron precipitates in the creek and collects on the rocks. Many rocks become cemented together with iron precipitates. This
interferes with insects, especially the burrowing and scraping insects. He recommended we look further upstream and likely find more insects. The next collection we
took from ¾ mile upstream.

Mine tailings above Railroad Creek

At the new location, we found a 3 foot square area to sample. After scraping only 3 rocks we counted 24 mayflies. We then continued to scrape at least 30 more
rocks. We knew we had a lot of insects to count. We found a healthy sized stonefly and several caddisfly cases with larva. We took the collection back to the
Creekside room for counting.

We were in for a surprise when we gathered to count our sample. We left a lot of mayflies and one stonefly in a bucket for about two hours, not knowing that the
stonefly was a carnivore. When we came back there were only 14 mayflies, and we didn’t know what had happened to the poor mayflies. Then we got a thought.
We made an experiment that involved a mayfly and a stonefly. We put one stonefly and one mayfly in a small ice tray. In a few minutes we began to realize what
happened to all our mayflies as the stonefly slowly devoured the mayfly.

Carnivorous Stonefly

We are sure we would have counted more insects if the stonefly had not eaten them. A report from the environmental group that studied Railroad Creek confirmed
this hypothesis.

Railroad Creek far upstream from mine: 1065 total organisms, 43 species

Railroad Creek immediately upstream from mine (this is where we sampled but our net was not fine enough): 330 organisms, 37 species

Railroad Creek just below mine tailings: 52 organisms, 9 species (This is where the rocks are cemented with iron precipitates)

This is how we measured how fast the water moved in Railroad Creek. First we put down ten rulers in a straight line. Then we grabbed more than one stick. We
grabbed five sticks to test the water and then test it again to make sure it was right. We threw a stick about six feet upstream of the first ruler so it would speed up
before timing. When it got there, they’d say go. When it got to 10 feet then we would say stop! The water was moving 10 feet every 3 or 4 seconds. We got that
about four times. So we thought that we had it right.