Quote:
Originally Posted by ApS
A hatchery that has been in business for decades shouldn't begin to have a magnified effect on the rest of Lake Winnipesaukee. I suspect the water entering from upstream is already loaded with Phosphorus runoff from emerald-green lawns.
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Unless of course the hatchery has been spewing phosphorous for decades, and now the issue is more important because, as you point out, it's not just the hatchery that's a problem.
Also, as I noted above, you guys should read the links before you criticize with conjecture. Here's an excerpt from Lake Winnipesaukee Association (linked by the OP) which quantifies the inflow and outflow of the hatchery--water before hatchery is 3.5 ppb, water going is is 5, water going out is 43!:
Merrymeeting Lake provides the Powder Mill State Fish Hatchery with 7 million gallons of fresh water per day. The water leaving Merrymeeting Lake has an average phosphorus concentration of 5 µg/L (micrograms per liter or parts per billion-ppb). The PMSFH withdraws and discharges a near-constant water load containing phosphorus levels approximately 12 times higher than the outflow concentration from Merrymeeting Lake. The discharge from the facility in summer during low baseflow conditions increases the concentration of phosphorus in the river and downstream waterbodies (leading to algae and cyanobacteria blooms and excessive plant growth)(Ref: Merrymeeting River & Lake Lake Loading Response Model Report, March 2019. FB Environmental & Associates and DK Water Resource Consulting.) Total phosphorus concentrations start at 3.5 ppb in Merrymeeting Lake, and increase to 43 ppb in Marsh Pond, the first waterbody downstream of the fish hatchery.