[Rockhounds] US rivers are changing from blue to yellow and green, satellite images show - one perspective

[Tim Fisher]

I guess I'm one of the exceptions when it comes to drinking water. Our river
(Clackamas R. in OR) is almost all in the National Forest, so all I have to
do on my end is filter out the chlorine that the EPA forces them to add.
Next door to us, Portland has what (used to be anyway) called the purest
drinking water in the country. Their source is the Bull Run River, which is
100% a protected forest. They never treated the water until EPA came down on
them for a few barely positive cryptosporidium tests. Which is a shame, when
I worked in Portland I'd stop at the public fountains (the "Benson
bubblers") just for the taste. There is an old fountain just before the gate
on the access road up into the watershed, with a little pullout, that was
installed around 1895. When I did some field work for the water bureau we
always stopped there to fill up our water jugs. Almost nobody knows about
it. And yes zebra mussels are the #1 pest in Great Lakes area drinking water
intakes (and underwater structures in general), but they do a decent job of
cleaning up the nasty Lake Erie water :D

But, I wonder now what our water will be like with something like 60% of the
watershed totally burnt down during the Riverside Fire. The river was muddy
looking during the heavy rain 2 weekends ago, I don't think I've ever seen
it that chocolatey brown color before :(

Tim Fisher
Http://OreRockOn.com 
Email nospam at orerockon.com


-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at rockhounds.drizzle.com] On
Behalf Of Alan Goldstein
Sent: Wednesday, December 30, 2020 5:39 PM
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
Subject: Re: [Rockhounds] US rivers are changing from blue to yellow and
green, satellite images show - one perspective

>From my perspective looking over the Ohio River at the Falls of the Ohio 5
days / week for the last 35 years, I can't say I've seen much "long-term"
changes in water color. But I'm not a satellite. Of course, the Ohio is
second only to the lower Mississippi in terms of water volume, so it tends
to average things out compared to smaller rivers.

One change that predates me, is the deposition of clay on the limestone
fossil beds. I've seen photos taken in the 1950s where fossils and the
limestone are clean. With the construction of the high lift dam and lower
water velocities, clays from soil are clinging to the rocks. It's thin - a
fraction of a millimeter (more in backwater areas). No doubt more soil is in
the water, though there are significant efforts to mitigate field and
construction runoff into feeder streams. The fossil beds are clean when
gravel washes over. Also, the summer after the coal barge accident just
above the dam, the fossil beds were extraordinarily clear of clay.

When the river is running (dam gates are open), the water contains much
suspended sediment. The water is brown. I've never seen yellow river water
(snow, yes!). When the gates are closed (mostly or completely), the water is
pretty clear, albeit with a green tinge. These gates move water from the
bottom of the river where sediment should be maximized. This is a single
point perspective. Five miles down or up river may have a different
perspective.

Zebra mussels may have a role in removing microscopic algae from the water,
reducing the green color. Populations were large but reduced and seem to
have stabilized based on what I've seen. One summer (1999, a drought year?)
our water tasted funny because the river was so clear that the water company
couldn't get the algal 'flavor" out.

Regards,
Alan G.