news from the waterfront by Tim Matson
FLOODS, POND RESCUES & TRENDS -- REFLECTIONS ON THE 2009 POND SEASON
With the pond season winding down, it’s our traditional time to look back, take stock of the season, and suss out trends in pond construction and use.
Here in the northeast it was a sopping wet spring and summer, with colder than normal temperatures. Swimming activities on my farm were way down, as I gather they were all around the region. Nevertheless, despite the weather and the economy (it was bad, right? – or good, if you had stocks or gold? Go figure…) new pond building and fix-ups
of older ponds were quite active.
Judging by the ponds and pond sites I visited, there are several solid continuing trends, as well as a few new
directions in pond use.
First, the majority of work focused on existing ponds that needed cleanouts or repairs, often both.
These were usually ponds that had been in the family for many years (sometimes decades), or part of a new purchase of country property.
In the case of old family ponds, they’d often been neglected until the invasive vegetation or water quality got so bad something had to be done – or lose the pond. Often these ponds are on vacation places that the owners may visit only occasionally, and they can be easy to ignore.
On the other hand, an aging pond might be part of a recently purchased property, and one of the first things the new owners want to do is restore the pond to its former glory. Which is why I always want to find out as much prior history as possible. If there was any old glory, great,
the pond should be able to be restored. If the pond was always a problem, well, there may be more involved.
Rejuvenation work often involves drawdowns, dredging, disposal of material, and perhaps improvements of design features and water supply. If the pond has a water retention problem or water supply deficit, consideration of a liner may be involved.
In addition to invasive aquatic plants getting out of control, I saw quite a few ponds where trees had been allowed to grow on the dam. This can turn into a problem if tree roots compromise the integrity of the embankment. And after a certain point, cutting down the trees may not be much of a solution because of the leak potential of rotting roots.
I also saw several native spillways that had been allowed to clog up with aquatic vegetation and debris. With the heavy rains, these jammed up spillways raised pond waterlevels to heights near flood level. The dams and shore areas were saturated. In one case water was pouring through a leak started in an animal burrow.
After some spillway maintenance, the waterlevels were dropped, and these ponds restored to safe levels. Moral of the story: mind your spillways, especially in monsoon weather.
Seeing a lot of these aging ponds got me to thinking about the big wave of pond building in northern New England in the late 60s and 70s. These ponds are now over thirty years old, and it’s natural that they need work, especially if they’ve been ignored.
I also like to remind their owners that many of these ponds were built in the pre-wetland law days, and building them today might not be permitted. That makes them even more valuable and worthy of care.
So we’ve got a bunch of vintage ponds that need maintenance and repair, and if it’s not done the ponds will be swallowed up by invasive plants and sediment, or the dams will fail, etc. True, there’s nothing radically new about that. Work used to be done by bulldozers and draglines, today you’re more likely to see excavators and backhoes. What is new is an increasing interest in follow-up water maintenance. In other words, if you’re going to go to all the bother and expense of cleaning out your pond, how about taking care of it afterwards so you don’t have the same problem a few years down the road.
That’s where aeration comes in. Lots of folks are recognizing the potential of aeration to help decompose nutrients and circulate the water and generally improve water quality. It might be with an electric powered diffuser system or a windmill compressor. Owners might even combine aeration with crawfish or grass carp (where permitted) to graze down unwanted aquatic vegetation. Sometimes a new supply of water might be added to a rejuvenated pond to improve fresh water exchange.
It might come from a well or springs, field drainage, or even water catchments from a roof or foundation drain.
Sediment and erosion control is also important.
OK, those are the older ponds getting a recharge. What about new ponds?
Wetland laws can throw up some expensive and time consuming permitting hurdles, putting a land owner or possible land buyer in pond limboland. So here’s some good news: in one northern New England town several pond projects were able to detour around wetland permitting because the builder agreed to install a fire hydrant. Simple as that. So if permitting’s got you down, check with your fire department
to see if they’re interested in a hydrant connected to your pond. Along with fire hydrants, ponds used for agricultural purposes can sometimes overcome wetland permitting hurdles.
Another permitting solution: plastic liners. Move the pond out of the wetland (and, alas, your natural water source) and use a liner to hold runoff or well water or spring water. This is a growing trend that I will discuss in a later Pondology, but for now just keep in mind that with liners it’s possible to build reliable ponds just about anywhere.
Alas, I saw a few new ponds this season that just didn’t work: they needed rebuilding or major repairs. This brings up a few points, but the main one is, hire an experienced contractor and be clear about following all best practice construction steps. It might cost more at the outset, but it could save a lot in the long run. Remember too that there’s always a gambling factor, a luck factor, in bringing in a successful earthen pond. The more you do your homework and make clear your contractor’s obligation to Make It Right, the better your chances.
Here’s to better swimming in 2010!
November 16, 2009