ADVM Installation Tips and Maintenance

1. ADVM Installation Tips and Maintenance Streamflow Record Computation using ADVMs and Index Velocity Methods Office of Surface Water

2. Overview • Cables and connectors • Grounding • Periodic Maintenance • Biofouling and Sediment • O-rings • Electronics

3. Communication Cables • Protect cables • Flexible conduit • Pool hose • Use armored cable when needed • Steel-jacketed well logging cable • Secure cables to mounts (no big loops or loose cable)

4. Cables/Connectors • Inspect cable when you service instrument • Look for wear, nicks, breaks, or dry rot in the cable • Inspect connector and pins periodically • Lightly grease plugs and pins with silicone

5. Splicing Cables • Common ADVM cables are easily spliced • Color coded – match wire to wire • Use a waterproof splice kit for underwater, occasionally flooded locations, excessively damp areas • Resin splice kits • Shrink wrap

6. Cable Junction Box

7. Cables, Special Communications • Spec – 250 ft maximum cable length • SDI-12 radios for long runs • Line-of-site • Master & slave radios • Slave requires shelter, power source

8. Ground Rods in Series 6 ft min Grounding Better location Ground-rod here could cause a ground loop • Ground rod should not be exposed more than 3-4 inches • Ground rods can be run in “series” but should be at least 6 feet apart – for better dissipation • Grounding could be a major source of electrical problems

9. Maintenance • Check bolts, fittings, and connectors for excessive corrosion or wear • Minimize dissimilar metals in mounts • Remove growth from mount during periodic maintenance • Mussels/barnacles • Algae • Sediment • Clean with a non-metallic brush • Check transducers for deep gouges, bubbles • May or may not affect data quality – look for change in beam • Talk to manufacturer if unsure

10. Biofouling • Microfouling • Biofilm, algae • Bacteria adhesion • Macrofouling • Barnacles • Mussels • Seaweed Ugh! Marine deployment, USGS Woods Hole Science Center

11. Biofouling Where’s my ADVM?

12. More Zebra Mussels….

13. Biofouling’s Effect on Data Velocity data went bad – sudden drop in magnitude

14. Biofouling Prevention • Anti-fouling paint • Pepper extracts/Vaseline • Cuprous Thiocyanate • Interlux - TriLuxII www.yachtpaint.com/usa/ • Petit – Vivid • Urethane transducers: MDR www.mdramazon.com • Follow mfgrs recommendations for each instrument!! • Do not use cuprous oxide paints • Thick layers may decrease measurement range Photo source: http://www.naturesrepellent.com/

15. Sediment Deposition • SonTek SW Up-looker • Periodic burial of 1 beam by sediment • Sudden drops in beam SNR • Requires periodic cleaning, will raise mount

16. O-Rings • Check manufacturer recommendations • O-rings should be free of cuts, scratches, or foreign matter • Replace flattened O-rings • Lubricate lightly with silicone grease. Don’t overdo it! • Check O-ring grooves in head and end-cap and make sure they free of foreign and that they are not damaged Something you really don’t want to see!

17. Electronics • When opening the instrument for maintenance: • Work in as clean and dust-free environment as possible • Follow the step-by-step instructions in the manual for your instrument • Check for a desiccant bag. Replace the bag unless you are sure it is completely dry

18. Mounting Tips • If at all possible – mount so that you can retrieve instrument! • Allow adjustment for pitch/roll • Mount as level as possible • Prevent 1 beam from striking surface/bottom before the other • Acoustic stage not approved by OSW as primary stage sensor but useful as backup • 2 degrees off level can cause significant differences from base gage • SonTek IQ/IQ+ provides angle-compensated water level

19. ADVM Stage Transducers If ADVM were 5o off level….. Acoustic stage = 3.00 ft; True stage = 2.99 ft Acoustic stage = 30.00 ft; True stage = 29.88 ft ADVM Stage Sensor Primary stage = 32.88 ft Primary stage = 5.8 ft Offset between primary and acoustic stage (e.g. 3 ft) Primary Stage Sensor (e.g. bubbler) Difference = (Acoustic + Offset) - Primary = (30.00 + 3.00 ft) – 32.88 ft = +0.12 ft Difference = (Acoustic + Offset) - Primary = (3.00 + 3.00 ft) – 5.99 ft = +0.01 ft

20. ADVM Stage Transducers

21. TRDI Mounting in WinHADCP

22. SonTek Mounting • If ADVM has a compass/tilt sensor, in SonUtils, type “compass cont” to view real-time pitch, roll, and heading Front View Side View UP ROLL PITCH Note: Pitch and roll for SonTek instruments opposite to what you might expect.

23. Questions?