Ask the WWM Crew
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"Now that's a pond!" At four surface acres (43,560 square feet per acre) and 22 feet deep, what couldn't you do with such a body of water? Actually, in the Far East I've seen aquaculture "ponds" of several thousand hectares (each 10,000 square meters, 2.471 acres), so I guess calling Lake Helix a pond or even a puddle is okay.
This ornamental basin does double duty in providing beautiful sights and sounds for its inhabitants, as well as a reservoir for irrigating common landscape grounds. Herein are my observations and suggestions for what this freshwater body is and what it might be through some cost-effective changes.
I was there back in 1973 with Orville P. Ball & Associates (that's me, doing the labor), Lake Consultants, and KTA (Kawasaki, Theilacker and Associates, Landscape Architects, for M.H. Golden, developers (perhaps their first and last residential project) taking a long, hard look at an approximately ten acre "swamp" that was to be turned into a lake and 27 pads for new custom residences. The existing land/water was about a foot deep, completely covered in cattails and other amphibious weeds... and stinky. Where to get the soil to build up the surrounding home sites? Why not at the bottom of the proposed lake? So, this is what was done; big caterpillar tractors gouging out soil and rock, building up the perimeter twenty or so feet.
The lake basin was made by digging out the center of the previous swamp down to 22 feet. The remaining soil was tested for it's water-retention properties and found to not percolate. The berm perimeter was shot out in shotcrete to prevent erosion, and planter area walls were cast in concrete using forms such as is done for street curbs.
Filtration: is "natural" with a low density of intended fish life and substantial aquatic plantings to shade out light and use of nutrients in the shallows. Just the same, this body of water has it's share of pest plant and algae problems. Some of these are unpredictable, one is definitely human-caused. Ducks bring in plenty of starter stock from other bodies of water, add their own fertilizer, and yet are not the major source of "food". Unfortunately a number of septic systems feed into this lake and they are the principal cause for having to periodically remove "fixed carbon" from the system.
The iatrogenic problem alluded to comes from a lack of cooperation between the landscape and lake maintenance personnel; namely purposeful fertilization that makes its way into the lake. Liquid fertilizers, not granular, should only be utilized near the waters edge and then only conservatively. A pound of solid fertilizer can make a thousand or more pounds of vascular and algae weed material.
Plumbing is of four separate plans. The northern waterfall has its own intake and discharge. The stream and irrigation lines are tied together with two in-series 35 HP pumps equipped with intake strainers, clean-outs and butterfly-valves . There are overflow pipes to the storm-drain system. There is an automated make-up system that has been secured to save money; and instead a deep (500') well can supply sufficient volume to keep the lake topped off and adequate water for irrigation. Quite a savings.
Livestock: Forage is supplied by incidental insect and amphibian life, and two species of Sunfishes (Blue-Gills and Red-Ear Sunfish). The top predators are Florida LMB (Large Mouth Bass, Micropterus salmoides), and Channel Catfish. Some ornamental Carp, aka Koi, have escaped their stream pond confines to the larger lake below.
Aquatic and bog plants are planted in the soil in and around the designated planters, and physical efforts are made to keep them from jumping their barriers. The plants are fertilized once a year via concentrated slow-release tablets, and thinned and replanted throughout the warm season.
Involves testing, trash removal, chemical treatment, and reporting. Testing mainly involves developing a profile of depth versus temperature and dissolved oxygen weekly. Through this "window" the turnover/stratification of the lake can be monitored, and very importantly, the number of hours to run the pumps kept to a minimum. You see, pumping the water is done for more than human appreciation and irrigation. It is the principal means of keeping the water oxygenated and preventing an obnoxious anaerobic zone from "rising" too far from the lakes bottom. The main intake is a "Tee" bar that comes off the bottom in about the lakes middle some four feet or so up. Without mixing the water by way of pumping, the stinky cooler water on the bottom accumulates and gets sucked into the holes drilled into the upper pipe of the intake. The resultant discharge in the stream is, to put it mildly, an undesirable rotten egg smell. See below for my suggestions on how to improve on all this.
Trash removal is done with sturdy "swimming pool" leaf rakes and going hand-to-hand with floating tubs removing plant litter manually. All waste is hauled to a dumpster topside.
Chemical treatments are minimal during the wintry colder months. In the summer, algae is periodically sprayed with liquid (for submersed filamentous) and granular (for mats and Chara infestations) copper compounds. For aphid problems, evidenced by many tiny black dots on chlorotic lily pads, Volck oil is mixed with water and sprayed via a hand or back-pack pumper.
Are not many, but substantial in their effects in money savings and improved appearance.
1) Aeration: The money spent currently on aerating the water by pumping it around could be reduced by about nine-tenths by it's reverse; pumping the air into the water. A compressed air/destratifier would easily pay for itself within a year, reduce the oxidizable nutrient load to noxious weeds, and their proliferation. Such a compressor, storage tank, and its controllers should be mounted in the existing pump vault and a protected, pressurized line brought out parallel to the main pumps' intake line. A "bubbler" either set on the bottom, or within and above a pipe reaching down to the bottom, will lift the low/no oxygen water to the surface for warming and aeration.
3) Pumped up Water: Needs to be left on longer to raise the lakes depth, and dilute the ever-incoming nutrients. This is cheap insurance and wise management practice, though, yes "it may rain" and a good part of the water wash away.
Wouldn't you like to live in such a setting? Me too! I remember the shock of being told that the homes around this private lake were going for one hundred some-thousand dollars in the early seventies; I couldn't believe it! "Wow, who has that sort of money?" Now, they're several hundred thousand... in large part because of the attractiveness of their central feature. In fact the community is called... Lake Helix!
With some stepped up plant management and the addition of an aerator/destratifier the recirculating pumps operation could be cut back and the lakes appearance and function enhanced appreciably. The Home Owner's Association has heard my pitches for this set-up over the years and I've no doubt such will be adopted within the next few years.
Fenner, Bob & Rick Aspray 1983. Ornamental fish ponds. Filters: design, construction and maintenance. FAMA 6/83.
Fenner, Bob 1988. Water Effects: size and shape. FAMA 5/88.
Fenner, Bob & Matt Tsunoda 1988. Waterfall construction. FAMA 11/88.
Fenner, Bob 1988. Aquatic Gardens: Plumbing. FAMA 12/88.
Fenner, Bob 1989. Pumps: An introduction. FAMA 1/89.
Fenner, Bob 1990. Upflow filters (for biological ponds and multi-tank systems). FAMA 2/90.
Fenner, Bob 1990. Pond construction: (Processes in) Building concrete and liner (production) ponds. FAMA 9/90.
Fenner, Bob 1991. Thorosealing cementatious water features. FAMA 5/91.
Fenner, Bob 1994. Pond construction methods. FAMA 5/94.
Fenner, Bob 1994. Concrete and block construction of ponds. FAMA 6/94.
Fenner, Bob 1994. Filter media for ponds: A discussion. FAMA 8/94.
Fenner, Bob 1993. Electricity and electrical use around water gardens. FAMA 12/93.
Fenner, Bob 1994. In-pond (versus outside) filtration. FAMA 9/94.
Fenner, Bob 1995. Selecting a site for your outdoor water feature. FAMA 5/95.
Fenner, Bob 1996. Plants and planting for water gardens. FAMA 6/96.
Fenner, Bob 1996. Surrounding landscape plants for your aquatic garden. FAMA 9/96.
Fenner, Robert M. 1997. Aquatic Gardens; Designing, building & stocking a backyard pond. Microcosm, VT.
1) An overview of the lake itself, approximately 2 by 1 football fields in size, deceiving over open water, eh?
2) Detail of the Island-Bridge on the northern edge of the lake.
3) Detail of the boat dock, paddle-boats... dock made of pressure treated wood, in-water section supported by air-filled fiberglass floats.
4) The lake perimeter showing the shotcrete (small aggregate, 3/8", concrete applied with pump and air pressure) berm... this is penetrated by shore drainage lines periodically to alleviate "swamping" of the surrounding walkway by run-in.
5) Waterfall detail; yes, these are real rocks, real heavy... water recirculated via a dedicated ten horsepower pump.
6) Stream detail (dry at this time), powered by one of the two 35 horsepower pumps when they're not working in tandem on the greenbelt irrigation. The stream and waterfall runways are formed with waterproof liner material covered by wire and shotcrete, with the rockwork added and mortared in at a later date to prevent leaking.
7) Shows one of the three foot overflows... to the storm-drain system; just in case of the proverbial flood.
8) Into the pump-vault: Six inch cast iron pipe, on its way to one of the 35 HP pumps, showing the strainer housing, clean out access and a butterfly valve to secure the water, preventing loss of prime.
9) The two 35 HP pumps shown in series; one runs alone for the stream recirculation, both to boost pressure for the irrigation. Note the timed heat lamps. These come on as the pump(s) cycle off to prevent water condensation on the motor windings.
10) The sump pump and flexible green discharge pipe... this is supposed to keep extraneous water out of the pump & controller vault?... not a good idea. Much better to have bored a large outlet or two down slope of the enclosure. I trust in gravity.
11) An outside shot showing the pump room door (the enclosure is cut into the hill below the residences), and the all important electric meter and shut off.
12) The 500' well and related plumbing and meter. The pumped up water is iron and other solid-laden, but cost effective to extract, even at 11 cents a kilowatt hour.
13) The controllers to the potable water and alternative lake water, showing the bold notices regarding which one is to be actuated during the seasons.
14) A planter area in need of augmentation, showing the cast concrete planter wall; invaluable for keeping what you want where you want it.
15) One of more less disagreeable waterfowl picks, a group of mallards that have become "resident" from bread feeding, etc. This is about the maximum number you want for a four surface acre water effect. The noxious weed floating is the reproductive phase of Potamogeton natans.
16) Iris in and out of water; always a tasteful improvement.
17) Tropical lilies (of extended above-water stems and cool colored flowers) are periodically mixed along with hardies along the lakes perimeter. This tropical day-bloomer is "King of the Blues"; very odoriferous as well as beautiful.
18) "Honey, what's that invading the lawn?" Yikes, it's the dreaded Hydrocotyle. Pennywort can be a gorgeous addition in or out of the water's edge, and aid in erosion control... but also a royal pain to eradicate. Keep it in check.
19) Like fleas on a domestic pet, that's how I feel about the lowly cattail; this species, Typha latifolia. To be used only in confined areas or tubs.
20) The California sycamore, Platanus racemosa, with it's large maplelike leaves, makes a striking water's edge addition to large features. Their deciduous leaves are easily raked up.
21) A view of some of the hardy lily beds. The lake has large stands of the large yellow Marliacea Chromatella, the changeable Comanche (apricot day one, to yellow or copper red...), and the best hardy white on the market, Virginalis.
22) A lily bed in need of thinning. Allowing the pads to stack up like this results in stagnant, stinky water and reduced blooming. Old tubers must be pulled out to promote the remaining plants health.