Saucon Creek Algae Bloom

[mcneishm]

It seems to happen every year about this time on the Saucon Creek: Large quantities of green algae line the bottom of the stream. I had not been on the stream for a couple of weeks when I fished there last Thursday. The water temp was around 65. When last I had been there, maybe the 3rd week in May, there was some algae but not near what I saw last week and then again yesterday. I was at the special reg area at the park in Hellertown at the cement wall yesterday, not fishing, just to have a look at the water and whether anything was rising. Just prior to that, I walked along the stream near the big pond and mill at Grist Mill Park. There was not nearly the amount of algae there. So, a couple of questions for those who know more about this than I:

What is the source/reason for the bloom? I would think it has to do with the golf courses upstream as well as the development both with large amounts of nitrogen fertilizer that washes into the stream. However, I would have thought the bloom would at least be as prolific in the stream at Grist Mill Park as it is at Saucon Park. I did not take the stream temperature at Grist Mill Park but there are a number of big springs the empty into the stream above there so perhaps that keeps the water temp below some threshhold value needed for the bloom.

Anyway, the bloom makes it difficult to fish anything other than dries and emergers or nymphs that are not dragging the bottom.

 

[krayfish2]

Low, clear water with slower currents usually promotes the blooms. Excess nitrogen getting to the system probably doesn't help either

 

[Mike]

Just for starters, most of the drainage from Hellertown's residents' lawns enters the stream farther downstream than Grist Mill Park. Also, I agree that there COULD be some threshold temp for formation of certain algae blooms as well as possibly some threshold daylight length.

 

[mcneishm]

What about the runoff from the two golf courses upstream from Grist Mill plus the Center Valley sewage treatment plant along 378? The golf courses at least must contribute fertilizer runoff. I would have thought that those three together would have created a bloom upstream from Grist Mill even with the springs and tribs that dump in there. (There's also the outflow from the pond which is now fully choked with algae.)

 

[troutbert]

Are the areas with big algae blooms open to the sun?

Stream stretches open to the sun tend to get more weed growth than shaded sections.

Maybe some tree planting would help.

 

[mcneishm]

Some are and some aren't. The Saucon Creek is generally tree lined and/or tree covered over the lower section where the primary trout water is. I'm not familiar enough with the sections above Hellertown to say whether those are or are not tree covered/lined.

 

[Chaz]

65 degrees is pretty warm and may be the main cause of the algae bloom, but there is plenty of sunlight that hits the stream also even though a lot of the stream is trees lined, the trees generally don't create a tunnel of vegetation. I have seen temps on Saucon Creek spike to 72 degrees, so I'm pretty sure temps are a factor.

 

[troutbert]

What type of plant is this? Do you have a photo or description?

Is it filamentous green algae?

Or maybe some other water plant, such as elodea?

Right now Spring Creek in Centre Cty has a heavy growth of elodea, heavier than in most years.

Some people think this is a bad thing. But is it?

Is elodea, or other aquatic plant growth in a stream actually abnormal or harmful?

I think the reason the elodea growth is particularly abundant this year is probably because we have not had any high flow events at all from spring to the present.

High flows probably scour away a lot of the attachments of the water plants to the rocks, knocking back the amounts of these plants.

But I'm not sure that the elodea is harmful. In low flow situations like now, the elodea occupies a lot of volume of the stream channel.

The water is flowing in channels between the elodea. The water may be flowing deeper and faster because of the influence of the elodea then it would be just flowing through the wide stream channel without the elodea.

 

[FrankTroutAngler]

Not that it matters, but I believe the weed currently exploding on Spring Creek is curly-leaf pondweed.

 

[mcneishm]

The Saucon Creek bloom is filamentous green algae. I will take some pictures the next time I'm down at the stream and post here. The last temp I took on the stream, last Thursday evening, June 30, was 64 degrees.

 

[gulfgreyhound]

Ban fertilizers after May 31. Problem solvedgGG

 

[mcneishm]

I happened to be at the Saucon Creek the other day, not fishing, but with my grandson at the playground near the cement wall pool. To my amazement, the algae bloom seems to be gone. Anyone have any thoughts on this?

 

[troutbert]

Have you had any high water events?

Bankful or higher flows will move gravel and cobble on the streambed and take a lot of that vegetation away.

On Spring Creek the streambed vegetation (not filamentous green algae, a leafy plant) is very prolific this year. I've heard numerous local anglers talk about this.

The reason, IMHO, is that we have not had high water, not even close to bankful, anytime this spring or summer.

And that is very unusual. Most years you get at least one or two high water events in the spring.

The vegetation is anchored to the bottom substrate (cobble and gravel). During high flows much of the cobble and gravel goes rolling down the creek, and any vegetation attached to it is removed.

 

[mcneishm]

In the last two weeks or so we have had several heavy thunderstorms that brought the water up significantly for a day or so. It is back to the normal level for this time of year.

 

[troutbert]

On Spring Creek we had some rains a while back that brought the water up.

You can see lots of the water plants that the high flows dislodged deposited on tree branches, and on stream improvement structures.

In the streambed the plants have been thinned out quite a bit. Not all gone by any means. I don't think the flow ever got up to bankfull or really even close.

But it got high enough that it increased flow velocities enough to scour away a lot of the weeds, in the faster current areas of the stream. While there are still plenty of weeds in the slower areas.

So, I think the explanation of why the amount of water weeds was higher this year than in most years is pretty clear. It was because we had not had any high scouring flow all through the season.

So the weeds just kept growing. Most seasons you get some high flows now and then that reset conditions by carrying away a lot of weeds.

Whether the water weeds in Spring Creek are harmful, beneficial, or neutral, I really don't know.

My guess is that they are beneficial. They provide some cover for trout in flat shallow sections. And in low flows the weeds take up some volume of the channel, so probably make the depth of the water slightly greater than if there were no weeds.

These plants are rooted, leaved, "macrophytes," which are quite a different thing than the filamentous green algae you saw on Saucon Creek.

I don't think anyone is a fan of that slimy stuff.