In recent years, pre-formed ponds and rubber liners have become so readily available that every Landscape Contractor resorts to their use without thinking twice. As a result, concrete water features have all but become a thing of the past. There is no substitute for the quality, crisp look that a custom-made concrete water feature affords. It is true, however, that with the exception of water, there are few similarities between concrete construction and other heavily used materials. Installation Installation of concrete water features presents many problems in central Virginia. First, the soil in Charlottesville is red clay. In dryer summer months, the clay becomes very hard and compacted. On the other hand, when water penetrates the soil during heavy periods of rain, the clay soil absorbs water, expands, and becomes very slick. The constant expansion and contraction of the soil can be devastating for foundations. Concrete will quickly crack if installed incorrectly. The first step in constructing this water feature was to excavate the soil from the pond area. The pond area was laid out using stakes and string lines. Then the outline was spray painted on the ground so that the strings could be removed for equipment access. Using a backhoe, the soil was then excavated to within a couple of inches of final grade. Approximately 150 yards of soil were removed from the site. Virginia clay will not compact very easily. So the last few inches of soil were removed by hand to avoid the need for backfill. Once the entire area was at the appropriate grade, three inches of gravel was installed and compacted. This is also the time to install all of the drains and make sure that they are sloped correctly. Next, the area was formed with 2- by 6-inch lumber and 6 inches of concrete was poured. This pond was a little unique in that it was actually a series of ponds that were about 18 inches lower than each other. When finished, the ponds would flow from one to another creating a series of five waterfalls. Each pond area was formed independently. Great care was taken to make sure that all of the concrete pads lined up perfectly. Once the foundation had dried, work on the walls started. The walls were erected by laying courses of 8-inch block on top of each other in a running bond pattern. Extra care was taken in the areas separating the pools. To add strength, the blocks were interconnected at every corner. At this stage, the pond begins to take shape, but it still will not do one important thing; hold water. The process of water-proofing the pond is known as "parging." A combination of mortar, sand, and water is mixed to the consistency of pancake batter. Then one shovel full of concrete is added to the mixture to provide strength, along with a black dye for coloring purposes. The mixture is then trowelled onto the entire wall and floor surface of the water feature. Though the mixture is considered water tight, it still is not waterproof. There is one more step that needs to be done before the ponds will hold water. Two coats of a waterproof coating is applied. Thoroughseal is a masonry product that looks similar to concrete mixture, but it contains silica as a waterproofing agent. To use the thoroughseal, water is added to the mixture along with black dye for color before the mixture is painted onto the entire wall and floor surface using a heavy brush. Finally, bluestone was cut and mortared onto the top of the walls to create a finished look, and the walls were backfilled with gravel. The area around the ponds is graded so runoff would drain away from the pond. This is a very important step. Any rain water that drains into the ponds will bring silt with it. It would be impossible to keep the ponds clear. With excitement building, the last step was to fill the pond. The process of filling the ponds took a total of 14 hours using two garden hoses. Once the two ponds were full the 9,600 gph pump was turned on and the creation came to life. Since the pond was not going to be used for swimming purposes, a filter system was not needed. However, the pump that was used is considered a sewage pump. It is actually capable of passing solids up to 1.5 inches in diameter. Any leaves or debris that enter the system will simply be shredded and passed through the pipes. Things to Remember There are a few things to consider when installing concrete water features, both in constructing and operating the ponds. 1) Measure, measure, measure... There is nothing worse than not having enough concrete to finish a job, or for that matter having too much left over. It is very expensive to have to order one yard of concrete to finish an area. In the same respect, if you begin to build a wall of the pond and realize that the concrete pad doesn?EUR??,,????'???t quite line up, everything may have to stop until you obtain additional concrete to extend the pad. Measure and mark very carefully to avoid mistakes. 2) Foundation perfection... As with any construction project, the job is only as good as its foundation. Make sure that the soil is solid and compacted correctly. Unlike a house foundation, any cracks that occur will be devastating. Water is the ultimate test. Any crack that develops, no matter how small, will turn a work of art into trash. Furthermore, if anything is out of level, the water will quickly point it out. 3) "Weather" or not to work... Know when to stop working. If the weather turns bad, you may be better off heading for shelter. Think about it. You are working in a hole in the ground, often on the side of a hill, and usually surrounded by disturbed soil. It doesn?EUR??,,????'???t take much rain to make a mess. Make sure that you take steps to divert runoff if necessary and be able to stop construction before you end up working underwater. On the same note, make sure that you give your concrete and mortar a chance to cure before temperatures drop below freezing. As stated before, you can?EUR??,,????'???t afford any cracks in the ponds. 4) Winter wonders Many people do not plan on running a concrete water feature through the winter. However, it is possible. First, make sure that the ponds are deep enough. Here in Virginia, ponds are made at least 30 inches deep. This is below the frost line, which helps prevent heaving. It also allows the earth to heat the water enough to keep it from freezing completely. Perhaps the most important thing is to use a large pump that is capable of circulating enough water in order to re-circulate the pond water once every two or three hours. The pump will actually draw warmer water from the bottom of the pond and push it through pipes that are also 30 inches below ground level. The heat in the ground will actually warm the water enough to prevent freezing. This part of Virginia normally sees temperatures as low as 5 degrees Fahrenheit, although it can occasionally dip to ?EUR??,,????'???5 or -10 degrees Fahrenheit. The arrangement may work differently depending on the project's geographic location. 5) Knowing is half the battle... Make sure your customer realizes that there is some maintenance required with concrete ponds. First, the ponds will need to be refilled on a regular basis, especially when using a large pump. Depending on the size of the pond, using a garden hose may become very tiring. It is also very important to inspect the pond once a year and take care of any cracks or problems before they get out of hand. This usually involves draining the entire pond and refilling it. If you do not want the customer to become upset, it is very important to tell them the maintenance requirements before you begin installing the pond. I strongly believe that concrete water features are under-utilized in the landscape. Contractors have steered away from concrete because of the costs and work involved. However, there are certain situations in which there is no substitute for concrete. If you are not currently utilizing concrete water features in your landscapes, I strongly encourage you to investigate their benefits. Patrick Crusse is a landscape designer for William & Mary's Flowers & Landscapes in Charlottesville, Va. He has a B.S. in Landscape Architecture from West Virginia University. William & Mary's is a family-owned Landscape Design and Installation company.