Good work Dr Luke!
How much time have you been putting in to reduce your nutrient load? Have you been doing other things to improve your water as well?
Would you say you are doing a lot of work, or are you just doing some work?
The reason I ask is to gauge your efforts for others. Often times there are people new to ponds who want to fix their problems overnight at little to no cost and without a lot of effort. Your efforts would be another good data point for them. Knowing how much effort you put in to your 2.5 acre pond and are seeing your kind of results would be a good data point.
Thanks for the report.
Brian, very good question. Summer 2015 was our first 'pond season'. We had almost 90% FA coverage at times throughout that summer, and didn't like it. I found PB forum and began my education as to the 'why' we were having FA (or what FA even was). The nutrient overload in my 2.5 acre pond seems to stem from inflow issues and eutrophycation over it's 40 year lifespan. We spent hours raking out FA mats and hauling them away that summer. I understood it to help haul away nutrients in the FA mats themselves, plus it is direct 'battle' as you are literally removing the unwanted stuff. BUT, after 5-6 hr sessions of raking and loading and hauling, the wind could shift and easily push FA mats into where you were working to where you couldn't tell you'd done a thing. A bummer to say the least. I learned about cutrine liquid and granules in 2015, but refrained from applying any in fear of a DO crash with FA decay. I began saving up for our aeration system.
We attacked the first of the two inlet dams that year too. I hired a local dirt company to come in and rebuild one of them with clay and a new 8 inch pipe with seep collars. It had been partially breached, with direct flow through during rain events. This inlet was fed by almost 100 yards of heavily grassed draw, which we think really helps abate and absorb nitrates from the Ag fields across the road that feed it. But restoring the silt pond impoundment function seemed like a good idea too.
We had aeration installed in April 2016. Aquamaster rotator vane with 4 bottom diffusers. I had learned this was no cure all, but part of the big picture. I was also hopeful to activate our native bacteria in the sludge, to see what they could do over the next 4-5 years. I also applied pond dye shortly after ice out (early April) and then sprayed early mats with cutrine liquid, and spread cutrine granules as well. We spot raked as well. And initially, the pond looked great. But I took a week off of raking and spot spraying for a trip to Canada (fishing, of course!) and the FA flaired out of control. We had 60-80% coverage again, and didn't really get a handle on it again that season. The raking continued (say about 2-3 times per month) and I still sprayed cutrine selectively.
The other inlet dam was also not functioning properly, with water running around the two 6 inch pipes (one on each end). My pond budget didn't allow for repairing it till this May 2017, and we had the dam widened slightly and a single 10 inch pipe with seep collars installed. This sediment pond gets direct Ag run off from the field (and tile) across the road, with no grassy draw to filter through. I have looked for any research (or posts) regarding nitrate mitigation, but found none. My hope is that by partially impounding this run off before it gets to my pond, some of the nitrate content will be reduced. I also did apply pond dye again in April this year. We have continued to rake out FA, but focusing on the dock areas. We've also been raking the bottom muck in the same locations, hoping to give access to sludge eating bacteria. Our dogs seem to be the best barometer of sludge; when they waded in 2015, they had black nasty sludge socks past their elbows (on a lab). Now, they either have clean feet or 'footies' that wash off quickly. The bottom is noticeably firmer when I wade the edges in boots, and went from 12-16 inches thick to 2-4 inches thick and firm this season.
Results: Our FA matting at worst this year has been 20-30%. Our water clarity runs 12-18 inches typically. Our fish have been noticeably thicker this year, the crappie in particular. My scale blew in the pond (again!) but I just got a new one for father's day so more WRs will be done. But from the picture, it's plain to see much thicker fish. They were half that thick in 2015. Improved forage (BG fry) survivorship (from better bottom)?
That is a long post, sorry. My next step is coming in this week. I plan to plant water celery in both inlet fingers of the pond. My hope is to tie up more nutrient, and rob the FA of real estate.
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