Interesting Water Quality Information
 

So Marty (and the dead fish I have been seeing) got me interested in looking at some of the water quality data that is available.

Couple of items - Marty correct me if I am wrong :)


> The 30 day average O2 level in the Patapsco has been about 10ppm, with a decline over the last week or so, culminating in some numbers below 5 during the period 5/28 to 5/30. The levels, of course, go up at night.

> The 30 day average O2 level at the Annapolis station was lower, about 8 ppm, with a dip near 4 on 5/30.

So looking at the graphs it does appear that the low levels are moving down the Bay, however, I was surprised that the Patapsco had a higher average O2 level for the past month.

The O2 levels although low were ok for Striped Bass, not for Menhaden though. They seem more sensitive to the lower levels.

Could be causing the rock to look for alternative foods like worms, clams, crabs, etc...and keeping them further down....

Salinity levels are still too low in the upper bay for blues and the rain will not help that...Cooler temps should help get the O2 levels back up and some of this algae out of the way...Maybe by this time next week we will be back into a better pattern....

Mike; I have a spread sheet of the O2 levels for Patapsco, Annapolis, Gooses, and Patuxant on my other computer. When I get time, I will post some numbers. I don't know about the 30 day average, but my single day results showed the O2 numbers being bad and moving south. Maybe the outgoing tides move the "mahogany tide" southwards toward the Annapolis buoy.

On TF there is a post about a fish kill off Podickery Point on the 30th. This would support the theory it's moving south.

Later
5th (Marty)

I was out today 31st near Hacketts. Very distinct tide line - one side brownish - other side much cleaner dark green color. The tide line was littered with bloated fish - one about every 4-5 feet for about a mile and a half.

Not much on meter below 20 feet down - even out in 35 to 40 feet. Likely that is the low O2 break line.

Water temp. at surface was 75*.

Curious about the various DO (dissolved oxygen) levels being reported:confused:. The depth for the reporting at Annap and Patapsco is at 3.3 feet; no DO or depth indications for Gooses. I assume this means that the water samples are being taken at 3.3 feet below the surface. But how does this compare with the DO levels down deeper, out in the channel during an incoming or around the pilings at the BB. By the way, the fish have been AWOL around the pilings lately:(.

Don,

Really good point about the depth...I have told many people I am seeing good amounts of bait, but much deeper than I usually see it. Also seems like the bite has moved deeper than my usual shallow water spots...

I have to agree with you though, before Memorial Day weekend I was tearing it up...Since then I have had a couple of my worst trips in a while...Not skunked yet, but have been close...

Spoke to some DNR cops recently and folks have still been catching in the Belvedere area, on ledges, and mostly deeper parts of the shoals...

Maybe the middle of the bay (east to west) with deep water on either side, helps increase the O2 levels and purify the water out there a little more...

The storm today/tomorrow should help the O2 levels (and get rid of some of the algae I keep seeing) but I have been rooting for the salinity levels to rise and this might put a little damper in that for a week or so...

Mike

Probably started before that. We've had dead fish washing up on our beach (not far from Podickery) for a few days now. Mostly small White Perch, with a few big Perch and a 22" +/- Rockfish here and there.

Some dead crabs too, but most were really small....hartd to attribute their death to any specific cause.

Can we call it a fish kill yet?

I'll post the pics later, but tonight I had hundreds of dead White Perch and a few big shad washed up on the beach. Didn't see any Rockfish this time.

The Perch ranged from about 3" up to 11 or 12" on a few of them.:mad:

Mike; Finally got some time to myself and I'm sitting here watching the wreck; I mean race, at Dover.
I just pick a couple of dates at random to look at the water quality on the CB Interactive Buoy System. Whenever I think about it, I plug in the numbers to my spreadsheet, hoping to see a pattern. Here are some numbers:

Beginning of the yr; cold water; no snow melt or sewage problem. I would assume these are as good as the numbers get:D.

Pat=Patapsco A=Annapolis G=Gooses Pot=Potomac

Date Buoy Dissolved O2 Turbidity
1/23/12 A 12.08 5.24
G 12.35 1.9
Pot 11.93 1.75

2/10/12 Pat 12.16 7.94
A 14.5 2.52
G offline offline
Pot 12.7 1.29

Just before and during Trophy season

4/2/12 Pat 10.41 5.04
A 12.24 6.98
G 10.28 5
Pot 9.79 2.71

4/29/12 Pat 15.43 5.6
A 11.72 3.08
G 9.78 4.3
Pot 8.49 2.11

After the poop spill?

5/27/12 Pat 6.82 3.42
A 6.99 5.24
G 9.8 2.1
Pot 6.82 3.42

6/3/12 Pat 7.29 5.64
A 6.05 7.72
G 8.21 3
Pot 6.92 3.42

So; you want the O2 number to be HIGH and the Turbidity number to be LOW.

By looking at the numbers; I'm going to GUESS that I want the O2 number to be greater than 8.

And, I want the turbidity number to be less than 5.

We can clearly see the impact of warmer water and poop plant discharge. Now let's see how the numbers react to the latest rainfall. It usually takes days after the rain to change the turbidity and maybe weeks to affect the O2 levels. Look at it this way, after the rain, the influx of debris and sediment may take a few days to come down from Pa. or the susky. All the nutrients come down with the debris. We then have an algae bloom (maybe 7-10 days later), but it's when the algae bloom falls to the bottom of the bay and begins to decay that the O2 levels are affected.
At least that's my understanding. If this is incorrect, please feel free to inform me and others of the process.

I don't know if this helps you any, but it's all I've got:D.

5th (Marty)

OK; so I had the numbers situated like a spreadsheet, but the post bunched them all together.

So to read it, you see the date, then the Buoy and the two numbers that follow. The first number is the O2 number and the second number is the turbidity number. Sorry it looks the way it does. Take a pencil and paper and and make a chart as follows and fill in the numbers to make it easier to read.

Date: Buoy: O2: Turbidity

5th

Very good point on the turdibity...Also did not think about the algae falling through the water column and the effects...Nice job !

Have to say this though, upper bay last night, slow at first, but once it turned on, it was one of the best days of the year....