Entretien et conseils
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Waterfall and stream   Building a waterfall, a fountain or a stream is not only very important for the oxygenation of your aquatic garden but it also brings it that added touch !   Waterfall   We will discuss, in this chapter dedicated to a waterfall, a construction with a PVC liner :   For the difference in levels, you use the natural slope of your garden, or you build a little mound with earth; the extra soil left from digging the water garden for example. The earth used will be compacted and will be solidified by adding large natural stones up to the desired height. The size of the waterfall cannot be disproportionate to the size of the water garden.   In order to avoid a steep slope, several basins can be carved out in steps to progressively slow down the waterfall. We will see later that these bowls have an important role to play. Each basin can be consolidated with a mixture of Rhine sand and cement. After that we use the same technique as for the water garden; that is a place a protective layer of geotextile felt and cover it with a piece of PVC liner (may be leftover pieces from the big water garden liner).     The liner which covers the little basins can be held tight and camouflaged with a mixture of natural stones, flat stones and pebbles. In the bottom of the basins you can put little pebbles and lava rocks which have a filtering capability. And why not take advantage of one of those basins to grow oxygenating and filtering plants ! You must be really careful with the last step of the waterfall, where it meets with the water garden basin. Water flows wherever it can find a space. You must carefully check the folds of the liner in order that some of the water does not spill out on the sides of the cascade rather than go into the water garden. The big surprise would be several thousands litres of water missing after a few hours!! It is not very easy to do. You may need to give it a few tries, but it’s all worth it when you see the final result... Incompatible...   The final decoration may be some rock-garden plants that you can place between the stones on the edge of the waterfall. The water is supplied to the waterfall by a submerged pump in the pond, as close as possible to the bottom of the waterfall. The water is pushed up to the highest level of the waterfall through a water hose approximately 2.5 cm in diameter. The first criteria to know to chose the right pump is the maximum height the water must climb (the pumping height). How do you calculate this measurement? Here is a theoretical formula to help you :   A. Measure the distance between the surface of the water in the pond and the highest point of the cascade.   B. Calculate the extra height necessary in function of the length of the hose. For each 3 meters of hose you add 30 to 50 cm to your “height”. The difference in centimetres is related to the diameter of the hose (30 cm= small diameter, 50 cm = large diameter).   C. Calculate the minimum pumping height = A+B   D. Calculate the maximum pumping height = C + (C/2)   It is from that last basic value (D) that you can make the proper choice for your pump. Refer to the manufacturers charts.   Notice: Often, the pumps have a pre-filtering device that you need to clean out often if it is too small. Preferably chose a pump with a larger filter or without any. A bigger pump allows you more flexibility should you wish to add other items later (fountain(s), water jets…). Beware, these formulae are strictly theoretical and do not take into account each make, or type of materials used. We cannot be held responsible for a poor choice of pump.      Other projects :   The tilting bamboo waterfall It is placed beside the pond. The water is pushed with a pump, the tilting bamboo spout fills-up with water and then tilts and pours the water in the basin.     A Stream While a waterfall benefits from a mound or a steeper slope, a stream must be built on a slight slope. Just as for the waterfall, plants and stones will give it a wilder and natural look. - Dig the bed for the stream. - Put a layer of sand, then the geotextile felt, and then cover it with the liner (exactly the same as for the pond). - Camouflage the liner with pebbles, flat stones and plants.   Water foutain   A water fountain remains the easiest project to make. A water fountain pump is generally commercially available and sold with all the various accessories necessary. However, do not place a water fountain too close to nymphea (water lilies); their floating leaves and flowers cannot stand to be watered constantly.