Fresh water quality question.

[exfactor]

I live by Lake Cachuma in Santa barbara county. We had a major fire by our lake a couple of years back. The fire fighters dropped tons of fire retardant on the flames, and since that time, I've noticed that our lake hasn't really cleaned up in terms of water clarity in the winter. We had an algae bloom that lasted nine months last year, and I'm thinking that the phosphorus in the fire retardant act's like a fertilizer in the lake water, encouraging the algae growth. The fishing has been awful when the lake is dirty, and every time it rains, more phosphorus run's into the lake. Do any of you have any experience with water conditions in your lakes where something like this happened, and how many years it might be until the lake returns to a normal condition? I've got a buddy who works on the water testing crew here, and they are now studying the phorsphorus content on their own. However, they didn't start the study until AFTER THE FIRE! If any of you have any knowledge that would help me figure this out, please let me know. Mike

[TShooter]

Interesting question.

I live in Alpine, we have a little lake there that during one of the fires a few years back came right down to the edge. What I found was that fishing on that side of the pond was not as good as the other side. This went on for a few years after. Now it is fine. I didn't really notice a color issue, but when we fished on that side you could smell the ash for a while.

Didn't notice a die off either. My opinion is it will just take a couple years for things to settle down. See if you notice a difference fishing the side of the lake that was not directly affected by the fire (unless it encircled the whole lake)

T

[Supa711]

Could also be sodium hydroxide, or lye, from the burnt wood ash that is washing into that side of the lake and causing aquatic life to stay away or die off. Just a thought.

[exfactor]

Thanks for the responses guys. I don't know how long it takes for fire retartant to break down in the environment, but given California's stance regarding pollution, it seems to me that ultimately, property value's take precitant over everything else, no matter what the long term effects are. Funny how anything involving fishing gets dumped on here.

[Supa711]

I'm by no means a chemist, but if you were inclined to do so you could take a pH testing kit (any fish store, pool supply) and take samples from a non-burn part of the lake as well as a burn part of the lake and compare the two if you feel that Phosphorus/phosphate is a culprit. It would give you a limited but general idea of the levels in the area. Although pH will only tell you the potentiality of hydrogen atoms in the area, this will tell you further whether it is habitable for for Large Mouth Bass (assuming this is your sought after game fish) which 'prefer' PH levels in the 6 -9.5 area. If the results are within this area then you know there is another issue affecting the game in the area. As you stated before, large amounts of algae could be potentiated by phosphorus/phosphate and could affect phytoplankton and zooplankton, the basis of the food chain.
I would be interested to hear what you or your friends find in their study if any results come to light.

[exfactor]

it will be a while before anything conclusive will be determined by my water buddy. The fire burned all the mountainous areas surrounding the lake. Therefore, every time that it rains, more sediment comes running down the hills into the water. I've only got my fishing experience to base any conclusions with, but generally the lake is clear by spring, and it didn't clear up until end of July last year, then w got some rain in October, and it went back to dirty. My bass buddies are crying the blues about how bad the bite was this last year, and most are still struggling to get even a bite. The trout haven't taken off either yet.

[benitosan]

i wonder if there is a similiar situation happening at poway lake? i don't know about fire retardent but there is a lot of soot and ash being washed into the lake from the rain. anybody notice a difference there?

[MeCrankMate]

It's probably less about the fire retardant and more about the various acids (hydrochloric acid for one) washing into the lake as a result of the ash and carbon deposits. Not that there are acid concentrations in the lake per say, but it does contribute to the PH change overall.

[CrimsonRider]

Did they plant scrubs and ground cover after the fire? They did that up in Tahoe; they're really worried about water clarity and took measures to control run-off in the lake.