b'C H A P T E R N I N EOn Troubled Waters7:30 on a Tuesday morning in summer.Weather: partly cloudy. Wind force: Beaufort 2. Direction: southwest.Water condition: cloudy. The four of us get into realtor Johns outboard. Russ, a retiree, Barbara, who runs a greenhouse and is our captain, and I load $1,300 worth of testing equipment. We head south to the middle of Chathams Oyster Pond and an orange buoy. Anchoring close by, we begin our water-testing. The four of us are among 140 volunteers out this morning to use science to check on how much our waterways have deteriorated, over-loaded with nitrogen. Soon our data will underpin the Waste Water Management study. It will tell citizens the sobering cost of extending sewers and other waste water treatment systems through this ever-growing town.Barbara feeds overboard the black-and-white Secchi disk. How deep is it when it disappears? Whats the depth when it reappears, as she reels it ini Russ squints through an optical instrument to measure salinity.John pays out the heaiy Niskin cylinder to collect water samples at different depths; the lab will assess them later.Using a hand-held meter, Barbara takes readings on the ponds dissolved oxygen, along with surface and bottom temperatures. As scribe, I jot down the measurements. Then our job is done, and by 8:15, the water samples and my notes are on the road to the lab.This effort by volunteers will save the community $200,000 a year in wages alone. Andf ar rom being make-work, the information is essential4.f*****The seven summer-season outings of the 140 Chatham Water Watchers are what gives voluntarism a good name in this seaside town. The savings inBarbara Streibert, a team captain for Chatham Water Watchers.With her are Russ Barclay, in front, and John Lynch.Each crew member does a different task of measuring certain properties of water at a designated site.The results from the various sites25 in allare then turned over to the Towns lab for shipment to New Bedford.158'