Pondology
news from the waterfront by Tim Matson

SUMMER OF '14 REVIEW

I saw plenty of evidence that low budget pond contractors may look like a good deal, but if they are inexperienced and screw up, you will be back at it, throwing good money after bad trying to square a circle or vice versa. That old saying, If you're in a hole quit digging probably originated with ponds! I saw one job where the muddy clay made it impossible for the novice builder to finish the job (he almost sunk the excavator); however, all it would have taken was a constructed stone road into the pond to create a platform to work from.

When water quality goes south, a quick fix is probably out of the question. There are many factors that can contribute to turbid water and/or algae problems and it may take a combination of long term water testing and multiple attempts at a remedy to clear the water. But one common flaw in ponds with troubled waters is often just plain water shortage. That is, not enough supply of good cool clean water creating a continuous exchange. In other words, you want your pond overflowing as much of the time as possible. But a good inflow won't help much if it enters near the spillway! That good water doesn't get enough time to spend in the pond adding oxygen and cooling temperatures and destratifying temperature layers and flushing floating debris before it's down and out the discharge. Adding to water quality problems is often a lack of depth, so that a pond's shallowness encourages overly warm temperatures, and allows too much light to reach plants that then thrive on photosynthesis. Yes, it's possible to knock out algae with chemicals, but some folks are tempermentally opposed to their use. And state laws often prohibit their use. And if used, the dead vegetation often comes back to feed the next cycle of problem growth, so you find yourself with a chemical dependency. I suggest doing a lot of research, experiment with possible solutions, and accept that it will probably take time. But chin up, there are many possible solutions for water quality problems, including bacteria blends, dye, aeration, supplementary water, cleanouts, and more.  And keep repeating, it's a pond, not a swimming pool!

This aluminum pier is light enough for installation by two people. Adjustable legs and options for extensions give you a chance to change location and adapt to a fluctuating waterlevel. Your choice of wood or plastic boards to lay in the pier frame.

An item that impressed me with its simplicity was an aluminum dock. They're ubiquitous from pond suppliers on the internet, and often available from local hardware suppliers. The aluminum makes them relatively light to assemble and install, with legs that can be adjusted to make the pier level. The dock itself is a frame that holds the planking you choose, wood or long lasting synthetic recycled plastic. I happen to prefer the look and feel of cedar boards, which are pretty long lasting themselves. The dock I saw was light enough for two people to take apart in late summer and put away until next season. The piers can be lengthened with an extension, which came in handy at one pond where the waterlevel dropped. By adding six feet the owner was able to get the pier out far enough to reestablish a safe diving platform.

 

 

 

This '60s era spillway consists of a concrete box that receives water from pond bottom pipe, which fills first chamber, and then overflows boards into second chamber with a discharge pipe through the dam. The boards are adjustable, and depending on their height, you set pond waterlevel. Here the water is not overflowing the boards because they have leaks. New boards will restore spillway to working order. The slot in front appears to be an emergency spillway.

It was also interesting to come across a '60s era  spillway design I'd never seen before. It involved a concrete box built in the dam, with an intake pipe from the pond bottom into the bottom of the box. The box was divided into two chambers. Water filled the first chamber until it overflowed a dam of adjustable boards, and then discharged through a pipe at the bottom of the second chamber. By adding or removing boards from the slot between chambers, you adjust the waterlevel. (This is similar to the Agri Drain In Line spillway available nowadays.) At a time when concrete spillway systems are pretty rare in these parts, the ones you see are usually the more simple drop box with discharge leaving the pond at waterlevel. The adjustable boards (if any) are at the front of a simple one chamber drop box. The two chamber design allows for water to be taken off the bottom of the pond, not the top. This may have the advantage of discharging low oxygen water, and helping destratify temperature layers. Hence, better water circulation throughout the pond. It also moves out silty bottom water, while preserving the cleaner top layer. I've also heard that beavers are less inclined to try to plug a submerged discharge pipe than a noisier  waterlevel spillway. Beavers are apparently
attracted to plugging water outlets they can hear.
This type of spillway is rarely built now in the private ponds I see, due to expense and complexity of design and installation. But if you're looking for a pre fab system to discharge from the pond bottom check out Agri Drain.

One of the new ponds I watched go in filled fast to the deight of the owner and builder. Exacavated material sequestered to the side was allowed to sit and drain prior to use for shoreline construction. Driving by the pond occasionally I kept watching for
the machines to return for final grading. After I while I noticed that the dirt pile was gradually getting smaller. Drying out and settling, I figured. But then I saw a small tractor driving away with a bucket of dirt. Turns out that the owner had decided to use the surplus material to build new gardens. The pond was functioning perfectly as the farm irrigation source it was intended for, and now the dirt too was all about work not scenery. I really dig thinking of this new pond as part of the vibrant small farm renaissance in Vermont.

September 5, 2014

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