[David BresslerParticipant]

Purpose:  General sensor station management, sensor fouling, battery issues, troubleshooting problems

[Carol ArmstrongParticipant]

Turbidity values above 5 NTU recorded on online sensor stations may not be valid in many streams due to fouling of the sensors, though each stream has its own baseline turbidity. The major rain event of 4/16 caused the greatest increase in depth for the year in many locations. Flooding made it difficult to locate the sensors. Four days later, rocks had moved under the sensors, leaf masses were attached underneath, and all of this was not visible by looking through the clear water above the sensors. Turbidity values were >200NTU – see pictures, but this was a false reading as after cleaning, turbidity returned to <2 NTU.

Eight days after this, on 4/28, turbidity was 26 NTU, and the increase was caused by algae on the sensors and on the benthic structures – see pictures. Again, cleaning returned turbidity to a valid value of 2 NTU.

[Paul WilsonParticipant]

Folks I just wanted to reinforce what you already know. It’s really important to have good relations with the people that live near your stations. On the evening the flood took out my station I got a text from the caretaker of the property telling me a tree had hit the station. Without that text I may not have known about the problem until my next cleaning visit. Bertie really saved my bacon on that one 🙂

[Carol ArmstrongParticipant]

Attached are pictures of the sensors at SL138 – Phoenixville YMCA, which are blackened by reactions with water minerals.  They appear to show that the turbidity sensor’s optical window is blocked by the mineral reaction, but the Stroud EnviroDIY Troubleshooting site states that it might not require a fix.  Could a blocked window underestimate turbidity?  How to tell?  The turbidity at SL138 was reading low, except for differences betw hi and lo turbidity, but the sensors were covered by sticks and leaves, though not necessarily by sediment

The CTD pressure transducer window looks black and is it normal or a problem?

Attachments:

1. 

   IMG_2207.jpg
   

2. 

   IMG_2209.jpg
   

3. 

   IMG_2210.jpg
   

[David BresslerParticipant]

It’s a good idea to have an extra charged battery on hand in case adequate solar charging does not happen.   The newer Mayfly boards are programmed to stop transmitting to Monitor My Watershed when battery goes below 3.5v.  To ensure transmission of data to it is good to have a spare battery (and associated charging equipment).

Here are the four items that you need: Recommended battery (https://www.sparkfun.com/products/13856), charger (https://www.sparkfun.com/products/15217), adaptor (https://www.sparkfun.com/products/15092), and wall charger (https://www.sparkfun.com/products/11456). See Figure 3.8 in manual

The battery will arrive about 40% charged so let it charge for about 4 hours. When you bring the old battery in charge it immediately for about 4 hours – don’t let it sit dead.

[David BresslerParticipant]

There have been some recent issues with logger boxes being left unlatched after station visits.  This is a critical issue because if boxes are not latched moisture and insects can get in and damage the Mayfly board, wiring, etc.  Anyone doing station maintenance needs to make sure the box is fully latched before walking away from a station. 

In her DRWI  EnviroDIY technical support role, @hicks has found four or five instances this year time in which logger boxes had been left unlatched, so station owners/managers should make sure this issue is addressed with those who are maintaining the stations.

[David BresslerParticipant]

If you haven’t been out to check on your station(s) and reviewed the data after the hurricane it is highly recommended you do both these things.  Even if your station appears to be functioning fine there have been a number of stations that have been damaged and some have remained functioning but have data that indicate sensor damage (e.g., data readings like -9999 which indicates sensor damage.  Also if your depth and water temp are directly correlated then that could indicate damage as well.

[Author]

Posts